Aces High Bulletin Board
General Forums => Aircraft and Vehicles => Topic started by: Simaril on January 27, 2006, 04:13:46 PM
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I've really enjoyed some serious file hunting lately, and I came across these 2 reports that might have some bearing on recent and continuing LW whines....I mean AH constructive criticism.
So here goes....
(http://furballunderground.com/gallery2/data/media/33/p47-fw190_post.jpg)
(http://furballunderground.com/gallery2/data/media/33/p47-fw190-2_underline.JPG)
And the second report, using different airframes at the UK's testing center:
(http://furballunderground.com/gallery2/data/media/33/p47c-fw190-3.jpg)
(http://furballunderground.com/gallery2/data/media/33/p47c-fw190-4_underline.JPG)
Now, these tests werent looking at exactly the same thing, but they are similar in pointing out that the Fw190 didnt do nearly as well down low -- and at slow speeds. As others have suggested, this situational factor may explain the major difference seen between the reported WW2 experience with Fw190s and the "AH2 experience." Most combat here is -- or quickly ends up -- low and slow, where the 190 wasnt designed to be and where it apparently became so unstable that it took lots of work to keep "in the game".
The 1944 report goes into more detail about handling charactereistics, but it also seems to be the less standardized of the 2 (as we'd expect in field testing rather than testing centers). The 190 engine is described as being very rough: while I dont pretend to know if that was usually the case for the bird, it may represent poor tuning by the US mechanics. On the other hand, if the engine required the hands of an artist to run right, it may have run rough indeed late in the war.
These reports (particularly the first one) suggest that the LW may not be discriminated against at all. I've elsewhere expressed my opinion that the "conventional wisdom" about HT preferring US rides for marketing reasons is nonsense (brief synopsis: other games with dominant non US equipment flourish), and these papers raise the possibility that HTC is spot on.
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how about the ailerons?
It is said that if Fw-190s ailerons are not properly adjusted the port or starboard wing will dip, causing hi speed stall that is currently WAY higher than any plane in this game.
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Originally posted by 1K3
how about the ailerons?
It is said that if Fw-190s ailerons are not properly adjusted the port or starboard wing will dip, causing hi speed stall that is currently WAY higher than any plane in this game.
Look at the second page with the red underlining. The stall instability was described as "extremely bad" in turns, and then separately the report says that even at high speed you can get "straight down spins" if "trimmed and pulled hard enough".
I'd take that to mean that trimmed right the stalls were a big problem, but even at the planes optimal speed you could still get the spins if you were heavy handed trimming or controlling.
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Frank Klibbe of the 56th FG described a dogfight in early 44 where we found himself in a tight lufberry circle in his P-47 at 8000ft with a 190 on his tail. The way he describes the fight, it sounds like the 190 is using a series of high yoyos to get in firing position. After a few minutes of failing to hit him, Frank had gained a little and the 190 rolled out and left.
In the Jugs vs. 190s snapshot this week, I found myself doing this same thing in a 190. I'd get on the 6 of a Jug, and if I didn't get it right away, it would start to outturn me a bit. I'd then use a high yo-yo to come diving back down on them to get another shot.
This makes sense to me, as the 190's wing loading is actually a bit worse the the P-47, but it's rate of climb is somewhat higher (meaning it has more excess power to use for manuevering).
In the game it seems to work out that the combo of pilot skill and energy situation is the deciding factor. And that seems to fit pretty well against the stories I've read - sometimes the 190s won, sometimes the 47s won.
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Thumbs up for HiTech.
Or HTC rather :aok :aok
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Problem is that the BMW801 did not run rough in Luftwaffe service. The FW-190A5 did have an altitude band were heavy vibration was experienced but this was solved. It was a consequence of overcooling the frontbank of cylinders. The band was narrow and at high altitude.
Aileron adjustment, not trim, is very important to the FW-190's turn ability. A Luftwaffe technical bulletin specifies the stall characterisitics of the Focke Wulf with properly adjusted ailerons.
Only the Focke Wulfs horizontal stabilizer was adjustable in flight for trim. All other surfaces had fixed trim tabs.
It specifically states that the stick will burble just before the stall. This is also confirmed by the Luftwaffe veterans who flew the Focke Wulf. Properly adjusted the aircraft gave warning.
The stall speed will change according to CG adjustment as well. Testing reports I have put the power on stall speed clean between 90-110mph depending on configuration.
I don't think this report of an P47D4 with water injection and High activity propeller vs an FW-190G series has the Focke Wulf Yo-Yoing. It is level turning below 250IAS.
meaning it has more excess power to use for manuevering
Wingloading has little effect on turn radius. Power loading is the key to angle of bank. A small reduction in radius adds up to a large improvement in turn rate.
(http://img11.potato.com/loc146/th_03566_PaequalsPr.jpg) (http://img11.potato.com/img.php?loc=loc146&image=03566_PaequalsPr.jpg)
Thrust also contributes a portion to lift and reduces stall speed:
(http://img9.potato.com/loc206/th_d06a4_lift_forces.jpg) (http://img9.potato.com/img.php?loc=loc206&image=d06a4_lift_forces.jpg)
So the "rough running engine" or loss of power experienced by the allies use of natural petroleum fuels in the BMW801 is very significant to the performance of the aircraft.
All the best,
Crumpp
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Crumpp,
I was hoping you'd reply, as your LW knowledge is far deeper than mine.
As to the rough runnning engine, I came across several references in British reports as well as the USAAF one I posted, that refer to the rough running 190 engine. The report I read followed up by interviewing captured pilots who apparently stated that the 190 engine ran rough normally and was a cause fro their concern. They apparently also told the Brits that they were very uncomforatble over water because of the engine's percieverd reliability.
These reports do not identify the version of the 190. The one I'm remembering did say that the test sample was "apparently downrated" because the settings at time of capture didnt match the placards.
Lastly, I'm not sure how decreased power woudl affect stall characteristics; wouldnt it more affect the stall threshold than the suddenness or controllability of the stall?
I can post these if desired. What are your thoughts?
Simaril
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Hey Simari,
Glad to be of help.
The report I read followed up by interviewing captured pilots who apparently stated that the 190 engine ran rough normally and was a cause fro their concern.
Of course they told the British the problems the RAE experienced were normal. You would not expect them to be disloyal to their country and jump in to help solve the issues would you?
I can just picture some German POW thinking:
"Why yes Mr interrogator, we hated the damn thing too. Always ran rough like that. In fact I was scared to death it was going to fall out of the sky on the flight over!"
The Luftwaffe personnel were trained to maintain the design not the allied personnel. A properly maintained BMW801 does not vibrate anymore than any other radial engine.
The synthetic fuel the Germans used requires a different engine set up. Hotter plugs, timing, and mixture changes etc... The allies simply did not have sufficient quantities of it to allow for flight testing of captured aircraft.
Lastly, I'm not sure how decreased power woudl affect stall characteristics; wouldnt it more affect the stall threshold than the suddenness or controllability of the stall?
No one has claimed differently.
What I said was:
Thrust also contributes a portion to lift and reduces stall speed:
Aileron adjustment does affect stall characteristics and causes the stall to occur early. It also causes the stall to be much more violent.
Notice that nowhere in the extensive trials of WNr 313 is the harsh stall mentioned. A high stall speed is noted of 110 mph and is most likely due to the poor performance of the motor the RAE experienced.
While I cannot say for a fact this particular aircraft had ailerons in need of adjustment, the harsh high speed stall is an indicator.
I am sure if WNr 313 exhibited these same stall characteristics the RAE would have duly noted them.
All the best,
Crumpp
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Well, it was a capture Japanese technician that apparently fixed the capured A6M2 so it didn't suffer negative G engine cutouts, so you never know. :p
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Wingloading has little effect on turn radius.
1. So a modern jet fighter could use its massive excess thrust to turn a smaller radius than a 50hp Piper Cub? No, I don't think so.
Wingloading(or more accurately, liftloading) is the primary factor in determining turn radius.
Power loading is the key to angle of bank.
True(For sustained, level turns).
BUT: From the graph you can see that an increase in bank angle also requires a higher speed. Bank angle has a fixed relationship with G-load, thus the G-load is also increased.
Since A=V^2/R you can see that an increase in bank angle will:
1. increase G-load(A), which requires:
a. an increase in speed(V).
b. and/or a decrease in radius(R).
Doing the math for various angles of bank(using data from graph):
30º bank = 1.15G @ 102mph. R = 183m (Turn time = 25s)
45º bank = 1.40G @ 113mph. R = 184m (Turn time = 23s)
60º bank = 2.00G @ 131mph. R = 175m (Turn time = 19s)
70º bank = 2.9G @ ~158mph. R = 174m (Turn time = 15.5s)
80º bank = 5.8G @ ~224mph. R = 177m (Turn time = 11s)
You can see that as bank angle is increased, the turn radius is not reduced by much, but speed and turn rate are increased by a large margin.
A small reduction in radius adds up to a large improvement in turn rate.
This can be seen easily on an EM diagram, or the examples above. The small reduction in radius is tied to a large increase in speed and G-load, to thus increase the turn rate.
Thrust also contributes a portion to lift and reduces stall speed
The added thrust will cause the aircraft to climb. WW2 fighters had enough excess thrust to climb even at stall speed, there is no way you can use this excess thrust to reduce speed, unless you can increase the AoA. But you cannot, because you are already at Clmax.
Prop planes have lower stalling speeds with some added thrust because the prop wash increases the local velocity of the air over part of the wing, increasing the lift generated by that part of the wing. It has rapidly diminishing returns though, as can be seen in the NACA trials with Spitfire V stalling speeds. Increasing power from 3.75lbs to 7lbs boost only lowered stall speed by 1mph.
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Hi Simaril,
>These reports (particularly the first one) suggest that the LW may not be discriminated against at all. I've elsewhere expressed my opinion that the "conventional wisdom" about HT preferring US rides for marketing reasons is nonsense (brief synopsis: other games with dominant non US equipment flourish), and these papers raise the possibility that HTC is spot on.
Thanks for the reports! :-)
When they first surfaced, I prepared a performance analysis based on absolute data for a captured Fw 190 tested in the US, and absolute data for a P-47D from a US report, and concluded that the tested Fw 190 was a bit lacking in performance as the report shows it falling behind in climb, indicating a lack of power in spite of reaching the proper boost pressure.
Of course, this lack of power would make the Fw 190 lose a bit of its edge in most points of the comparison.
Here is the original thread, but unfortunately, I only linked my analysis instead of re-posting it, and it seems it was lost when the AAW board where I actually posted it went down:
http://www.hitechcreations.com/forums/showthread.php?s=&threadid=74720&highlight=italy+captured
So though the details are lost and I'm working from memory, I'd suggest not to focus on stall too much as there was definitely a power issue.
Regards,
Henning (HoHun)
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HoHun:
Did you base yuor analysis of these reports, or on others like them?
AS I've thought about it, the British Air Fighting Development Unit report (which compared to a P-47C) didnt report the impressive stall characteristics that the more informal US field testing one did a year or so later. (The 1944 report was based on flight tests in Italy in 1943). With Crumpps suggetions, I'm wondering if its airelon trim was off, while the British example was trimmed at time of capture. Alternatively, the US pilot may jsut have not been as experienced.
It seems to me, though, that if the trim had to be set before takeoff, wouldnt that have already been done on a captured bird that had already been flown by the germans?
What caught my non-engineer's eye in these reports was the qualitative sense of stall difference highlighted in the US paper, since their description pretty well matches the AH experience of having to fight stall harder and earlier in the 190s compared with the US rides.
originally posted by HoHun
Notice that nowhere in the extensive trials of WNr 313 is the harsh stall mentioned. A high stall speed is noted of 110 mph and is most likely due to the poor performance of the motor the RAE experienced.
While I cannot say for a fact this particular aircraft had ailerons in need of adjustment, the harsh high speed stall is an indicator.
I am sure if WNr 313 exhibited these same stall characteristics the RAE would have duly noted them.
HoHun, I'm not familiar with the abbreviations...WNr 313, RAE?
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WNr 313 is the German serial number of the 190.
RAE = Royal Aircraft Establishement.
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Well, it was a capture Japanese technician that apparently fixed the capured A6M2 so it didn't suffer negative G engine cutouts, so you never know.
Hi,Karnak,
No you don't but I am sure it would have been noted had a prisoner been cooperative. Instead the reports simply notes it is understood from POW's has confirmed the engine runs rough.
Implying they were cooperating, while possible, is not the most likely explanation IMHO.
Additionally we do not know the experience of the POW. He could be very well speaking the truth from his point of view but referring to the time before his capture and experience in the BMW801C powered versions.
Facts are the BMW801D2 did not run rough in Luftwaffe service when properly set up or maintained.
What caught my non-engineer's eye in these reports was the qualitative sense of stall difference highlighted in the US paper, since their description pretty well matches the AH experience of having to fight stall harder and earlier in the 190s compared with the US rides.
That is because the FW-190's flying characteristics in AH are modeled from Allied reports.
WNr 313, RAE?
WerkNummer 313 = Serial Number of Oberstleutnant Arnim Faber, Gruppen-Adjutant III/JG2 FW-190A3.
RAE = Royal Aircraft Establishment = Organization responsible for the testing captured enemy aircraft.
With Crumpps suggetions, I'm wondering if its airelon trim was off, while the British example was trimmed at time of capture.
That is pretty much what I think. I have found no evidence or mention of the harsh stalling in the RAE reports on WNr. 313.
Aileron adjustment was off in some of the US aircraft. On several captured FW-190's flown I can prove the ailerons were out of adjustment.
The Luftwaffe had a difficult time keeping the ailerons adjusted. IMHO the design of the adjusting blocks was not one of Focke Wulf’s highpoints. Why they did not add teeth to the mated surfaces is unknown. Instead they left them smooth with the tension of two bolts to hold them at the adjusted point. The adjusting block bolt rides in a long oval groove with only the flanges of the bolt making contact with the block.
I am sure that just taxing around a bumpy field would cause the ailerons to come out a adjustment in a short period of time. This aspect of FW-190 maintenance and it's importance to the flight characteristics of the aircraft is very much emphasized in the maintenance instructions.
For the low speed stall:
The "no warning stall" in the FW-190 is not correct. The ailerons would vibrate just before the stall when properly adjusted. They would not reverse, however. Oscar Boesch has told me that you had to pay attention, however. If your mind was on anything other than flying the plane or you were not relaxed you could miss it. Once you got used to it though, it became second nature to him. So it was not a huge amount of warning. When you felt the bumping and your stick forces disappeared, relax the backpressure immediately.
Properly adjusted recovery was immediate with a relaxing of the stick. Left unchecked the wing would dip and develop into a spin. Which is pretty much most single engine fighters.
For the high speed stall:
It is a fact that the FW-190 can enter an aggravated stall at high speed. All aircraft with the ability to change AoA fast enough and at high enough speeds can do this. Many WWII fighters have too high a Stick Force Per G to do this or lack the elevator authority under G to change the AoA fast enough to create the stall conditions.
Oscar also has related you pretty much had to be crass to do this unintentionally. As the US pilot relates, it required trimming the nose down and a rather violent yank of the stick. Aero elasticity would remove the twist in the wing. The twist was put there to reduce the harsh stall of the NACA 230XX airfoils. This would shift the load outboard of the wing and bring the CL to nearly equal alone the span. If the wing was then stalled in this configuration it would stall alone most of the span at the same time causing the wing to rapidly drop. Left unchecked the aircraft would invert and spin. This characteristic was actually used by many Focke Wulf pilots as an escape manuver.
Wingloading(or more accurately, liftloading) is the primary factor in determining turn radius.
Good post Justin.
(http://img14.potato.com/loc129/th_8eb5a_turnperformance.jpg) (http://img14.potato.com/img.php?loc=loc129&image=8eb5a_turnperformance.jpg)
It takes a significant increase in liftloading. A moderate increase can easily be overcome with powerloading and thrust.
With increased thrust, the Spitfire Mk XIV was able to overcome a 1000lb weight increase and a 5lb sq ft wingloading increase. It simply was able to pull a larger angle of bank at the same speed than the Spitfire Mk IX. This reduced the turn radius, increased the turn rate, and allowed it to match the much lower wingloading of the Spitfire Mk IX.
The tactical differences are caused chiefly by the fact that the Spitfire XIV has an engine of greater capacity and is the heavier aircraft (weighing 8,400 lbs. against 7,480 lbs. of Spitfire IX).
The all-round performance of the Spitfire XIV is better than the Spitfire IX at all heights. In level flight it is 25-35 m.p.h. faster and has a correspondingly greater rate of climb. Its manoeuvrability is as good as a Spitfire IX. It is easy to fly but should be handled with care when taxying and taking off.
The turning circles of both aircraft are identical.
http://www.spitfireperformance.com/spit14afdu.html
All the best,
Crumpp
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Ehh,,,,,look a wee better into this:
"Wingloading has little effect on turn radius"
Same wing with more loading and same power: YES. It does have a negative effect on turn radius.
A superior wing will give better liftloading.
Then you have powerloading.
But with the same wing, just more loading, WINGLOADING HAS EVERYTHING TO DO WITH ITS EFFECT ON TURN RADIUS!
The difference in liftloading pr sqr in WW2 fighters is not so much, so while liftloading will give a better comparison, it's not all.
And if you have different wings to compare, - well, you have Wingloading, liftloading, spanloading, bank angle, and even chord to play with, as well as G's & wing shape/characteristics, plus induced drag, - and at what speed?
Turning aint just turning.....
Before you go further, powerloading, elevator authority, C.o.G. and departure characteristics..........
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Guess you don't get that whole "fundamental relationship of" portion underlined, Angus.
As the exerpt I posted states turning is much more of a general problem. There are many factors that go into it and many shortcuts to estimate turn performance.
However as this engineering text states, they are each in turn derived from fundamental relationship of thrust required and available or power required and available for various angles of bank.
http://img14.potato.com/img.php?loc=loc129&image=8eb5a_turnperformance.jpg
http://img11.potato.com/img.php?loc=loc146&image=03566_PaequalsPr.jpg
AFAIK there was not one single WWII fighter with the power to fly at CLmax in a sustained turn.
All the best,
Crumpp
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What I find interesting about those two aircraft reports is they seem to be contradictory. One says the P-47 pwns the 190, the other says the opposite.
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Crumpp: You either did not read my text properly, or it is you who does not understand the fundamental issues.
With the same airframe,wing, and same power, increased weight, and thereby wingloading will ABSOLUTELY affect turn ability, in a negative manner.
(As well as climb, top speed, acceleration, partially zoom, - basically everything except dive and terminal velocity)
RIGHT?
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AFAIK there was not one single WWII fighter with the power to fly at CLmax in a sustained turn.
Ehh? So no ww2 fighter could sustain a level turn at the edge of a stall? WW2 fighters had enough power to climb in a CLmax turn - eg: 109 spiral climb!
The turning circles of both aircraft are identical. The Spitfire XIV appears to turn slightly better to port than it does to starbord. The warning of an approaching high speed stall is less pronounced in the case of the Spitfire Mk XIV.
How can turning circles be "identical" when they admit that the XIV turns better to port. The IX would turn better to starboard, because the engine rotates in the opposite direction. Perhaps the XIV could match the IX in left turns - best XIV turn, worst IX turn. They mention this difference in other comparisons:
Spitfire XIV can easily turn inside the FW 190, though in the case of a right-hand turn, this difference is not so quite pronounced.
If we look at the Spitfire V vs IX trial, we see this:
The Spitfire IX was compared with a Spitfire VC for turning circles and dog-fighting at heights between 15,000 and 30,000 feet. At 15,000 feet there was little to choose between the two aircraft although the superior speed and climb of the Spitfire IX enabled it to break off its attack by climbing away and then attacking in a dive. This manoeuvre was assisted by the negative 'G' carburettor, as it was possible to change rapidly from climb to dive without the engine cutting. At 30,000 feet there is still little to choose between the two aircraft in manoeurvrability, but the superiority in speed and climb of the Spitfire IX becomes outstanding. The pilot of the Spitfire VC found it difficult to maintain a steep turn without losing height, whereas the pilot of the Spitfire IX found that he had a large reserve of power which enabled him to maintain height without trouble. The all-round performance of the Spitfire IX at 30,000 feet is most impressive.
Here we see the benefit of having greater excess power - at high alt the IX can maintain an angle of bank that the V cannot.
Also, note that the V and IX have "little to choose" in turning circles. V=IX, IX=XIV? So the (2,000lb/30% heavier XIV actually turned as good as a V!;)
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Also, note that the V and IX have "little to choose" in turning circles. V=IX, IX=XIV? So the (2,000lb/30% heavier XIV actually turned as good as a V!
I find it funny that the entire FW-190A series gained much less than that and just as much power yet is seen as become "piggish" in it's handling.
None of the Focke Wulf pilots who flew the FW-190A8 felt that way or related that to me. When asked they all loved it in comparison to other Antons.
Only the R7/R8's were seen as having poor handling.
What I find interesting about those two aircraft reports is they seem to be contradictory. One says the P-47 pwns the 190, the other says the opposite.
One is for a P47C the other is a P47D4 using water injection and mounting the paddle blade prop.
All the best,
Crumpp
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With the same airframe,wing, and same power, increased weight, and thereby wingloading will ABSOLUTELY affect turn ability, in a negative manner.
Sure unless a corresponding increase in power occurs. I don't think anyone has disputed that in this thread so I am confused as to why you posted it.
WINGLOADING HAS EVERYTHING TO DO WITH ITS EFFECT ON TURN RADIUS!
Actually what is important is not the wingloading increase but the reduction in excess power. Adding weight has the effect of increasing power required and reduces powerloading.
All the best,
Crumpp
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Stack up the best turners of WW2 fighters - you will find out it has almost a paralell list as their wingloading tables.
So it also does in AH.
Oh and this:
"--------------------------------------------------------------------------------
With the same airframe,wing, and same power, increased weight, and thereby wingloading will ABSOLUTELY affect turn ability, in a negative manner.
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Sure unless a corresponding increase in power occurs"
Did you read:
"same power" above??????
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In principle, Crump is right - In practice he is wrong.
Given enough power loadaing you can hang on the prop and rotate on the spot. It's called a helicopter. When you do not have enough power loading to hover, you need speed and fixed wing lift. You want the smallest speed but on the other hand to produce minimum drag. So you want a wing whose induced drag will not be too high at slow speeds, but still produce enough lift to keep you flying - meaning high aspect ratio + less AoA - meaning more area.
Try turning in a glider - it turns really tight and looses very little alt/speed. Just a small engine would give enough power to keep it level. It's wing efficiency, loading and power loading all mixed.
Bozon
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In principle, Crump is right - In practice he is wrong.
I hardly think Perkins & Hage is wrong.
It is an engineering test about fixedwing aircraft design.
Try turning in a glider - it turns really tight and looses very little alt/speed.
It still looses......
No way around it.
However improve the power available to power required and:
Just a small engine would give enough power to keep it level.
And you prove the point in practice.
Stack up the best turners of WW2 fighters - you will find out it has almost a paralell list as their wingloading tables.
It's obvious some people are reading into this and fearing for a game shape. As the text states, there are numerous methods of estimating turn performance. However turning is a fundamental function of power required to power available.
As demonstrated by flight testing, a moderate increase in wingloading can be overcome with a corresponding increase in thrust. Hence the improvement in the P47's turning ability with the High Activity Propeller. And of course the Spitfire flight testing mentioned above or the F18/F16 trials.
All the best,
Crumpp
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Actually what is important is not the wingloading increase but the reduction in excess power.
power required to power available.
I believe those are your own words that I copied and pasted. Bigger and more efficient wings means less power required, therefore more power available. You may claim it is weakly dependent on the wings, but it still is.
It is nothing short of a miracle (no kidding), but it is possible to fly with an engine that produce less thrust than your plane weights and manuver with it. The minimum requirement is wings. This means that wings are more efficient in keeping the plane in the air than pure thrust vectoring.
Also notice that on the page you posted (Airplane preformance p.202) it says:
"It is shown in figure 4-1d that minimum radius in level flight accures at the CLmax provided PA>PR".
First, figure 4-1d is not on this page. Second, while minimum radius is achieved at CLmax, it doesn't say anything about its value. Third, as you can see, at the slower side of the drag curve, what eats your power is the induced drag which is dominant over the viscous drag. Increasing wing size and efficiency (aspect ratio etc.) will reduce the induced drag at a given speed for a small cost in viscous drag. Of course you can't go too far with that since at some point viscous drag will be so high it will not be worth the tradeoff (not to mention the weight of the wings themselves).
Bozon
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Hehe, Crumpp:
"a moderate increase in wingloading can be overcome with a corresponding increase in thrust"
Moderate yes. The tendency was normally within WW2 fighters, to lose turning ability while getting better climb and top speed.
A Spit I outturns a XIV, a 109E outturns the K and so on.
There are exceptions, 109F turned equal to or better than the 109E and so on. Or maybe it isn't an exception, have to look at the wingloading, for the 109F has some lighter parts?!?!
A boosted Spit IX will outturn a none boosted one (since the boosting in that case doesn't come with a weight penalty) and so on.
But Generally, - to put it simple, - wing loading.
And then the little odds and ends.
On gliders, the span loading is also very favourable ;)
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Angus,
FACTS are the Spitfire was able to compensate for the 5lbs wingloading increase. You cannot get around the fact that in the air, the aircraft were seen as having identical turning ability by the RAE test pilots.
The FW-190 series only gained 3 lbs and just as much power as the Spitfire series.
Why is the FW-190A8 such a pig in AH? What is the scientific basis? While it is a common perception that the aircraft gained weight and no power. That is not the case at all.
bozon,
Third, as you can see, at the slower side of the drag curve, what eats your power is the induced drag which is dominant over the viscous drag.
You’re correct that induced drag is the dominant force at low speed. However do not confuse coefficients and force with power.
While the cooefficient of inducued drag will gradually increase the slower the aircraft, the power application is different.
http://www.av8n.com/how/htm/4forces.html#fig-coeff-ias
The force of induced drag also rises along with the coefficient.
http://www.av8n.com/how/htm/4forces.html#fig-force-ias
However the power of induced drag rises very little. It's power comes on very rapidly like a wall and not a gradual tug that increases. The wall occurs after CLmax on the backside of the polar at the stall.
In the mushing regime, most of the drag is induced drag. As you go slower and slower, induced drag increases dramatically and parasite drag becomes almost negligible.
http://www.av8n.com/how/htm/4forces.html#fig-power-ias
Additionally, designers have been well aware of the benefits of reducing induced drag and ways to manipulate wing efficiency since the 1930's. The differences in WWII fighter wing efficiency are imperceptible in the air.
A square-tipped rectangular wing is almost as efficient as the elliptic wing.
http://www.centennialofflight.gov/essay/Theories_of_Flight/Reducing_Induced_Drag/TH16.htm
The induced drag is a completely seperate subject and should not be the focus of this thread. I suggest a new thread to cover this subject or feel free to PM me. We can discuss it and summerize the results.
It is nothing short of a miracle (no kidding), but it is possible to fly with an engine that produce less thrust than your plane weights and manuver with it.
Yes it is and engines have produced less thrust than the weight of the plane for the vast majority of the time man has been using heavier than air flight.
Second, while minimum radius is achieved at CLmax, it doesn't say anything about its value.
It's not talking about a specific plane, it is referring to all aircraft. CLmax will change too with conditions.
You may claim it is weakly dependent on the wings, but it still is.
Nowhere do I claim it is weakly dependant upon wings. I claim the fundamental relationship is not derived from wings. It is derived from power available to power required.
Even a Glider uses this relationship. It must be towed to altitude where it converts the potential energy it stored during the tow to kinetic energy for flight.
To focus solely on wing loading is incorrect. Wing loading is nothing more than one of many shortcuts of estimating this relationship.
Just as Perkins & Hage state.
It is a fact that a wing loading increase can be overcome with thrust.
All the best,
Crumpp
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Gentlemen you will have better luck in this discusion if you seperate the two concepts.
Turn Radius.
Turn Rate.
HiTech
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But one most certainly effects the other.
Rate is a function of velocity and the angle of bank at Pr = Pa.
Although angle and velocity for minimum time will not be the same as for minimum radius,of course.
It still remains a fundamental relationship of Power required to Power available. It does not change the fact a thrust increase can overcome a wingloading increase.
All the best,
Crumpp
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CC HiTech, see what you mean. All a matter of velocity in the turn so a wider turn may still be faster around the dial. (More G then).
Anyway as a sidenote was fighting 190A5's with a Spit V yesterday.
Must say that a correctly flown 190 will give the Spitty a hard bird to catch.
Did not seem to be too off for my taste the only way to catch a 190 was with superior alt or if they could be forced into slow maneuvers.
I clobbered one in a Hurricane though :D
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Is that a plea to please don't make them correct?
The Flight Model of the FW-190's was never changed and is based on faulty data for service for model fighter variant.
It is what the allies got off a recovered crash of a Bomber version, converted with little knowledge of actual differences to a fighter variant, and serviced by allied personnel untrained in the type.
The performance of EB-104 looks very good in the climb only because the USAAF did it at USAAF combat weight as opposed to the Luftwaffe data which is generally converted to take off weight.
All the best,
Crumpp
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lol..funny thing is..that the VVS and the RAF had worser turntimes on the 109E than on any later model.
109E i know 24-25secs..
later ones between 21 and 23 for an turn.
but...the radius of the E could be lower...but the E was the worst turning 109 when looking to and 360 and turntime
wastel
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Crumpp
is your idea of CLmax include the area of the wing or is it unitless?
Bozon
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is your idea of CLmax include the area of the wing or is it unitless?
It's 3D.
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The equations you need for this discusion.
(http://www.hitechcreations.com/hitech/TurnEqu.JPG)
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but...the radius of the E could be lower...but the E was the worst turning 109 when looking to and 360 and turntime
I am not an expert on the 109 so how much weight did the 109F gain over the 109E vs Power gains.
I am willing to bet that each weight gain accompanied a power gain with the probably exception of the early Bf-109G6.
Don't discount props either. Look at the Spitfire Mk I's increase in performance from prop alone.
I can post the VDM Ersatzteilliste for the 109 if you need it. It had fewer props than the 190 but did change them several times.
And whether you are talking about radius or rate, the fundamental relationship or power available to power required remains.
All the best,
Crumpp
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The equations you need for this discusion.
That is another method of estimation.
The problem with that method is your not determining the angle of bank the aircraft is actually able to achieve. Your simply picking an angle.
Therefore your bypassing the relationship. So while the formula is correct, the input data could be sheer fantasy.
All the best,
Crumpp
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Absolutly not crumpp. The equations I listed are not estimates, nore fantisies.
The bank angle is not guessed at or picked but is simple high school trig given by the total lift and speed which is known and what this discussion is about.
In fact if you know the max bank angle and speed of any aircraft you could use these equations (along with a little trig) to calc all the values about turn performance. You could determin how a change in the % of wieght would effect turning. You could determin how a change in the % of power effects the turn.
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Sorry for the following but an answer may help my limited understanding.
Whilst the angle of bank adjusts the turn force by vector ratio is not the "Weight" increased by the rudder down force?
So if an approximation of turn rate and radius (at various bank angles)was being derived from climb rate data (to discern lift and thrust characturistics)..........
how would the change in stabalising forces be modelled against bank angle.............?
Given this would such a "stabalising force vector" (against bank angle) be the same for all ac? or modified by such criteria as the stabalising "torque" (eg distance the rear stabalisers are from the C of G and the position of the C of G relative to the wing lift point )
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Originally posted by Tilt
[BGiven this would such a "stabalising force vector" (against bank angle) be the same for all ac? or modified by such criteria as the stabalising "torque" (eg distance the rear stabalisers are from the C of G and the position of the C of G relative to the wing lift point ) [/B]
The horizontal stab would not effect the equation, because it all shows up in the net lift caculation. But obviously a more nose heavy airplane will produce less net lift for any AOA.
Debating about rudder, but my gut feeling is, if you have the ball centered, the rudder effect will be almost none existant.
HiTech
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Originally posted by Crumpp
It's 3D.
This reminds me when Mr. Crumpp announced (http://www.hitechcreations.com/forums/showthread.php?s=&postid=1368542#post1368542) that English unit will give different Cl value than metric units...
gripen
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The bank angle is not guessed at or picked but is simple high school trig given by the total lift and speed which is known and what this discussion is about.
Sure they are unless your using:
In fact if you know the max bank angle and speed of any aircraft
Which is derived from the fundamental relationship of power available to power required just as Perkins & Hage state.
Which is a KEY piece of information left out of your posting of the formula.
This should come from the measured polars of the aircraft.
All the best,
Crumpp
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Sigh, these Luftwaffe threads make my head hurt. I am sure glad I went Mechanical Engineering rather than Aeronautical Engineering.:eek:
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And post them in English units NOT metric, as mine are in, which you think are wrong.
I meant your calculations Gripen. Not the answers. You cannot retrace the steps without them posted.
So please be sure and put quotes in context.
Turning is a function of the relationship of power required to power available:
(http://img15.potato.com/loc24/th_66d83_Turnperformanceindex.jpg) (http://img15.potato.com/img.php?loc=loc24&image=66d83_Turnperformanceindex.jpg)(http://img129.potato.com/loc24/th_3d56f_Turn1.jpg) (http://img129.potato.com/img.php?loc=loc24&image=3d56f_Turn1.jpg)(http://img130.potato.com/loc24/th_53502_Turn2.jpg) (http://img130.potato.com/img.php?loc=loc24&image=53502_Turn2.jpg)(http://img108.potato.com/loc24/th_81b2f_Turn3.jpg) (http://img108.potato.com/img.php?loc=loc24&image=81b2f_Turn3.jpg)
All the flight testing and the math confirms an increase in wingloading can be overcome with thrust.
All the best,
Crumpp
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Crumpp you are so far off on the discusion of power weight and lift as it applies to turn performance ill just throw out some basic numbers from spreed sheet I did.
Given a plane with a max turn of 2.3 g at 160 mph . (In the realm of a lot of war birds)
Would create a turn radius of 825 ft and a time around turn of 22.1 secs. I.E. Bank angle of 64.22.
Now lowering the weight of that plane. by 10 % would make a turn raidus of 727 with a circle time of 19.46, Bank Angle 66.96
Increasing power by 30% on the orignal weight would have the following effect.
Turn Radius 798 circle time rate 19.5 and a speed of 174. Bank Angle 68.59
Ill let you draw your own conclusions. They should be very entertaining.
HiTech
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is your idea of CLmax include the area of the wing or is it unitless?
Just to clarify,
These equations are 2D. 3D is even more accurate.
As you did not refer to these equations I thought you were asking my personal preference for data.
David Lednicer did a nice 3D analysis of the Spitfire, Mustang, and FW-190. If you need a copy of it let me know.
Here is a good idea of the variation:
http://www.risoe.dk/rispubl/VEA/veapdf/ris-r-1376.pdf
So it adds some interesting insight 2D calcs cannot give.
All the best,
Crumpp
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They should be very entertaining.
Let's here your explaination for the Spitfire Mk XIV and the VVS testing.
Also could you run the following through your spreadsheet.
Taking a base weight and angle of bank.
Increase weight by 3.11% adding no power.
Now increase weight by 6.8% from the original weight (not added too the 3.11% increase) and add 22.75 % power to check the results.
On last set of problems for the spread sheet.
Increase the weight by 11.9% and increase the power by 24%
Could you post the relative results.
All the best,
Crumpp
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Starting conditions:
Given a plane with a max turn of 2.3 g at 160 mph . (In the realm of a lot of war birds)
Would create a turn radius of 825 ft and a time around turn of 22.1 secs. I.E. Bank angle of 64.22.
No increase in weight, 30% increase in power.
Turn Radius 798 circle time rate 19.5 and a speed of 174. Bank Angle 68.59
They should be very entertaining.
Here is the first joke. P & H specifies constant Speed to see the results of added thrust.
All the best,
Crumpp
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Originally posted by Crumpp
I meant your calculations Gripen. Not the answers. You cannot retrace the steps without them posted.
Nonsense, anyone can follow the link and read your claims (and your errorneous calculation as well). Cl is a dimensionless factor it does not matter at all which unit system (metric, english or what ever) is used to calculate it.
Originally posted by Crumpp
These equations are 2D. 3D is even more accurate.
This is truly entertaining.
gripen
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Oh Crumpp:
"It is what the allies got off a recovered crash of a Bomber version"
The thread opens with what? Quotes from several airframes, yes?
Anyway, HiTech gave numbers, and there is a formula, you're about to say you know better in a moment or what?
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"The thread opens with what? Quotes from several airframes, yes?"
What do you mean? What quotes? I don't see them.
"Look at the second page with the red underlining. The stall instability was described as "extremely bad" in turns, and then separately the report says that even at high speed you can get "straight down spins" if "trimmed and pulled hard enough".
I'd take that to mean that trimmed right the stalls were a big problem, but even at the planes optimal speed you could still get the spins if you were heavy handed trimming or controlling."
Trimmed? Trimmed for turning or trimmed for straight flying? The Spitfire could enter an uncontrollable spin by simply a slight pull. Of course an aircraft with strong eleveator will enter a spin if "pulled hard enough".
What the heck is "fore and aft control" anyway?
To me it seems that that paragraph describes the characteristics of 190s wing pretty much as I see it too: It does stall in sudden heavy turns but should give ample warning if the turn is increased gradually. Isn't it strange that it is described as an abrupt stalled with no mention of blackouts in high speeds but in another paragraph the 190 pilot blacks out in it. How the hell he does that if the plane flips uncontrollably when pulled into a hard turn?
Also I would't draw any conclusions of the relative maneuvering performance of those aircraft in that document because the considerable differences in combat experience between the pilots. The other has 17 months of combat experience and the other has none. If the inexperienced pilot is able to beat the more experienced one then what does that tell about the a/cs?
Well, in the end you see what you wish to see in those documents...;)
-C+
PS.
"Thumbs up for HiTech.
Or HTC rather "
"Anyway, HiTech gave numbers, and there is a formula, you're about to say you know better in a moment or what?"
Thumbs up for Angus, you'll surely get a cookie soon. :rofl
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Some ideas, gathered from the text Crumpp has posted.
1. Radius can be calculated in relation to speed and angle of bank. "From equation (4-62)" on Pg 203. For minimum radius; it can be seen that it would be desirable to have a combination of high angle of bank, and low airspeed.
However:
2. The stalling speed at any given angle of bank, which can be calculated using equation (4-59) on Pg 201, increases at a rate "inversely proportional to the square root of the cosine of the angle of bank". IOW, speed and bank are tied together - you can't freely choose any combination you want.
This equation allows you to calculate the minimum speed for any given angle of bank.
So simply by knowing the stalling speed of the aircraft, it would appear that we can calculate the radius of turns at CLmax for any angle of bank & the corresponding airspeed.
Example: Aircraft with stalling speed of 100mph at sea level.
Angle = speed, radius, 360º time, G
15º = 102mph, 2578ft, 1.8m, 1.04G
30º = 107mph, 1334ft, 53s, 1.15G
45º = 119mph, 944ft, 34s, 1.41G
60º = 141mph, 770ft, 23s, 2.00G
65º = 154mph, 736ft, 21s, 2.37G
70º = 171mph, 710ft, 18s, 2.92G
75º = 197mph, 691ft, 15s, 3.86G
80º = 240mph, 678ft, 12s, 5.76G
85º = 339mph, 670ft, 8.5s, 11.5G
Graphically, this is the left boundary of an Energy-Maneuverability diagram.
Now as you can see, if you had an aircraft that had enough power to sustain at best a bank angle of 60º, corresponding stalling speed 141mph and a radius of 770ft - to reduce radius by about 10% to 691ft would require an increase in bank angle of 15º - which requires a speed increase of about 40% - the increase in power necessary to acheive this would probably be in the region of 100% !!! For a 10% improvement in turn radius...
Now if you could reduce the stalling speed by just 5mph, a 60º bank would only require a speed of 134mph, and have a radius of 695ft...
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Charge, I was refferring to Crumpp mentioning a single airframe, but the thread opens with documents of more. There seem to have been more 190's tested than we think.
See what you like from it, but is seems at least that the text in those old dock give ze LW crowd a wee of a chestburn.
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Basically, my point is:
Wingloading(more accurately liftloading, eg: high CLmax airfoil, flaps/slats etc) is the primary factor in determining turn RADIUS.
Powerloading(thrust:drag) is the primary factor in determining turn RATE.
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This is truly entertaining.
Read the paper Gripen. Or Read Lednicer's article.
Your implication that I don't understand the difference between a unitless CL and a finite span wing is what is entertaining.
All the best,
Crumpp
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See what you like from it, but is seems at least that the text in those old dock give ze LW crowd a wee of a chestburn.
I really don't understand why it would Angus?
At low speed the FW-190 easily outturned the P47. In dives the FW-190 outaccellerated the P47 by a wide margin. In level accelleration, the FW-190 left the P47 behind for a good while.
It pretty much is what you want to see. I see some very combat useful traits for the FW190.
This is the P47 using water injection and the paddle blade prop too. It's the best it gets for the P47. The FW-190 still has not added in a major power increase nor recieved a more efficient propeller.
Of course not considering it is G series captured in Sicily they are testing and not a fighter variant.
All the best,
Crumpp
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Originally posted by Crumpp
.....
At low speed the FW-190 easily outturned the P47. In dives the FW-190 outaccellerated the P47 by a wide margin. In level accelleration, the FW-190 left the P47 behind for a good while.
It pretty much is what you want to see. I see some very combat useful traits for the FW190.
This is the P47 using water injection and the paddle blade prop too. It's the best it gets for the P47. The FW-190 still has not added in a major power increase nor recieved a more efficient propeller.
Of course not considering it is G series captured in Sicily they are testing and not a fighter variant.
All the best,
Crumpp
Crumpp,
I gotta say you're losing a little credibilty here. Please read the documents including all the words....
The Fw-190 gained 200 yards during its acceleration advantage, limited to "up to" 275mph. So, during its advantage it had minimal separation and (at least in AH) would remain in guns range during its entire advantage.
When speed did pick up (thats the point of acceleration!) the P-47 gained 2000yards rapidly. I wouldnt consider this balance a combat advantage, and only bias could make it seem so.
As to diving, the FW held its advantage only for 3000 feet altitude change. In AH, this is an adjustment, not a dive. :lol After that, the p47 held great advantages in both dive speed and recovery angle -- either of which would likely mean a kill if the FW tried to get away by diving. ALso, not an advantage.
Charge,
High speed blackouts. Low speed turn advantage and stalling. Am I missing something? I dont see the contradiction.
All,
Just to throw another fish in the pirhanna pond, I found it interesting that the cockpit seemed cramped. Could we consider that HTC's modelling of the views for 190s might be a game equivalent of that limitation?
With Regards (and backing up rapidly to clear the combat zone),
Simaril
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As to diving, the FW held its advantage only for 3000 feet altitude change.
I think your reading that backwards. The P47 gained in the last 3000 feet.
The Dive was from 10,000 feet to 3000 feet. At 3000 feet the P47 passed the FW-190.
I found it interesting that the cockpit seemed cramped. Could we consider that HTC's modelling of the views for 190s might be a game equivalent of that limitation?
I wouldn't say so. We just mounted the armoured glass in Black 3. HTC's cockpit does not account for refraction. You cannot see the armoured glass frame from the inside from the sighting view.
All the best,
Crumpp
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When speed did pick up (thats the point of acceleration!) the P-47 gained 2000yards rapidly. I wouldnt consider this balance a combat advantage, and only bias could make it seem so.
In a dogfight it sure is an advantage. The FW-190 would want to force the low slow fight where the ability to turn and accellerate would make a decisive difference.
Of course these findings do not include a substantial power increase to the FW-190 nor the more efficient propellers.
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Originally posted by Crumpp
is your idea of CLmax include the area of the wing or is it unitless?
It's 3D.
Sorry, bad translation to english on my part. I meant 'dimentionless'.
I completly do not under stand what 3D has to do with it. The reason I saked is that we appear to be speaking in different terms and do not understand each other. CL is normaly taken to be a pure number (no units, therefore the same in every units system and do not depend on the scale of the wing). For the lift it should be multiplied by the wing area which adds the scale. CLmax alone tell you nothing about the value of the lift produced and this is why I asked.
Bozon
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Originally posted by Crumpp
I think your reading that backwards. The P47 gained in the last 3000 feet.
The Dive was from 10,000 feet to 3000 feet. At 3000 feet the P47 passed the FW-190.
Oops. You're right.
A 7000ft drop in alt would definitely count as an AH dive. :)
I willpoint out tho that my comments are correct with a 7000ft drop in alt.
Originally posted by Crumpp
I wouldn't say so. We just mounted the armoured glass in Black 3. HTC's cockpit does not account for refraction. You cannot see the armoured glass frame from the inside from the sighting view.
All the best,
Crumpp
I guess I dont follow you here. I'm asking if the cramped cockpit, whcih cant be experienced in front of a monitor, might be effectively modelled by limiting view variability -- ie hard to get around the canopy frames. Im not understanding where the armored glass comes in to refute the point.
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Originally posted by Crumpp
In a dogfight it sure is an advantage. The FW-190 would want to force the low slow fight where the ability to turn and accellerate would make a decisive difference.
Of course these findings do not include a substantial power increase to the FW-190 nor the more efficient propellers.
Now as to this point -- the FW advantage only holds if the p-47 agrees to go low and slow.
Two poinits:
One. Both the p-47 and the FW are best used in energy roles. The Fw isnt going to outturn a zeke, or an MA spit. So, when used as appropriate for wingloading etc, the goal woudl be to keep speed up and use energy techniques. IRL, US pilots were hammered with the mantra -- dont go low and slow! The planes were designed for power and speed, and if they were used that way the P47 should win. Over 275mph and all....
Two WE'RE TALKING ABOUT A FREAKIN P-47 HERE!!
You know, the "milk jug"? The beast that was hated when it first appeared -- until the pilots realized it shined at alt? The plane that only a VERY few MA pilots can use as a consistant killer? Crumpp, this is not the cream of the allied crop, and we're bragging that the Fw outmatches it at certain limited points of the flight envelope? Reality check....
Simaril
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For bozon:
The value of CL will be different depending on the equation used. You can consider a 2d wing which has infinite span, or a 3d wing which has a finite span. Search "Thin Airfoil Theory" for 2d, "Lifting line theory" for 3d.
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Originally posted by Crumpp
Read the paper Gripen. Or Read Lednicer's article.
Your implication that I don't understand the difference between a unitless CL and a finite span wing is what is entertaining.
The paper you linked and Lednicer's article has nothing to do with this.
Formula of the Cl (used for turning performance calculations) is simply (from NASA (http://www.grc.nasa.gov/WWW/K-12/airplane/liftco.html)):
Cl = L / (A * .5 * r * V^2)
The area of the wing is used for the calculation so the wing span is finite (3D). But calculated coefficient itself does not incluce wing area because Cl is dimensionless factor and that is what bozon asked. 2D is used mostly for wing profile calculations and that has nothing to do with this thread.
Basicly you are showing as large confusion on Cl as you were showing in earlier thread (http://www.hitechcreations.com/forums/showthread.php?s=&postid=1368542#post1368542).
gripen
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Simaril, the P47 in AH is not modeled accurately then, because with flaps it's got BS float capabilities and doesn't stall at all.
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gripen, that formula is derived from "thin airfoil theory" and it does assume an infinite span.
The formula derived from "lifting line theory" includes a correction for the AR of the wing(ie: induced drag effect on lift).
CL = CLa * (AR/AR+2) * a
Where:
CL = 3D wing lift coefficient
CLa = 2D airfoil lift coefficient slope
AR = wing aspect ratio
a = angle of attack in radians
Obviously if AR approaches infinity it produces the same result as the other formula.
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Originally posted by Krusty
Simaril, the P47 in AH is not modeled accurately then, because with flaps it's got BS float capabilities and doesn't stall at all.
I'm not sure about your experience, but I definitely run into stall with the 47 even with flaps full out. If I get too much AoA, or get too heavy on controls at low speed, it definitely stalls....and I generally cant recover from the oscillating control loss at the low alts involved. If you mean that its too easy to fly, well, I cant testify to what it should feel like IRL at that speed so I cant tell if its realistic or not. FIn AH flaps can hold off a stall but you still have to work to manage the bird. I have won stallfighting badly flown Niks in a D25, but a well flown turner will own a perfectly flown jug in a stall fight. Period.
So if "BS float capabilities" means "I dont like it", I cant argue that...but if you mean that it never stalls and is impossibly stable, I've gotta disagree.
It seems to me that stall THRESHOLD and stall BEHAVIOR are 2 different things, and some posts blur the two together. At least one of these reports describes sudden and sharp stall characteristics for the 190 compared to the 47 -- but the stall speed is a different matter.
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ok, lets look at it this way:
1. power required: the energy loss rate to drag. We'll assume all drag is induced as this is the dominant type:
P = r S Cd V^3
where r - density, S - area, Cd - induced drag co-eff.
2. steady alt: lift needs to balance the weight with a bank angle a:
mg = r S Cl V^2 * cos(a)
3. centripetal force: since we want circular orbit:
m V^2 / R = r S Cl V^2 sin(a)
Assumptions:
We assume the thrust is horizontal (parallel to the velocity), it does not contribute to the lift or the centripetal force DIRECTLY. This depends on the fixed angle between the wings and the engine which we do not know and will just serve to complicate things. The angle off the velocity vector will be close to the AoA meaning less than 15 deg. If we try thrust vectoring more than that, we stall the wings since the angle between the thrust and the wing is constant. All thrust does here is allow us to maintain the speed.
Second assumption is that we neglect the viscous drag. Verying S will vary the viscous drag as well but only by a moderate amount (as it includes other parts of the plane as well).
Having 3 equations we can eliminate 2 factors. We are interested in R so lets eliminate the bank angle 'a' - by squaring eq.2 &3 and adding them up. Then we use eq.1 to eliminate the velocity 'V'.
We get a not-so-easy-to-type-here formula for R that STILL INCLUDE THE WING AREA 'S' in a way that larger S make R smaller monotoniously. R is roughly proportional to 1/S. Also we get that P make R smaller down to a minimum value - since we did not allow thrust vectoring where in practice we'd turn into a helicopter. Read the assumptions part again if you think this is a problem
Bozon
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Just one remark.
Wing area reduce the radius monotoniously here since I neglected viscous drag. If we include it, there will be an optimum wing area given all the other conditions constant.
Bozon
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Originally posted by Krusty
Simaril, the P47 in AH is not modeled accurately then, because with flaps it's got BS float capabilities and doesn't stall at all.
How much do you fly the P-47? I fly it alot , and i can assure you it STALLS,and does it often when low and slow. I'd sure like to fly the one that your flying .
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Hehehe, just out of curiousity I went and tried the p47 at low and slow offline :rofl Not only does it not stall, I could lift the nose up to over 60 degrees (starting speed of about 90 mph or so) and lower the airspeed under 50 mph until the stall indicator stops yelling.
And still the only thing the jug does is slightly lower its nose until the indicator starts yelling again. And for the whole time I've kept the stick in my blls and over 45 degree bank and maintained total control of the plane :rofl :rofl :rofl
I've flown AH since beta but never would I have thought that the stall was left out of the equation when you give full flaps. HAHAHAHA :rofl :rofl :rofl
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Originally posted by justin_g
gripen, that formula is derived from "thin airfoil theory" and it does assume an infinite span.
Yep, but we are dealing here with known wing areas so there is no need to go 2D. The only case we might need 2D is when the Clmax is determined from the wing profile data.
Generally there is no need to mix 2D to this discussion because Cl can be calculated from known wing areas with above simple formula and turn force, turn rate and turn radius can be calculated using the formulas hitech posted which again are very simple.
gripen
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Gripen....
Not one single person in this has ever disputed CL is not limitless. You made a wrong assumption.
Hey Bozon,
We sure we want to make these assumptions. All these forces do come into play and affect the aircraft.
We assume the thrust is horizontal (parallel to the velocity), it does not contribute to the lift or the centripetal force DIRECTLY.
Thrust does contribute to lift. For example:
Simply fly any plane in level flight and increase the throttle:
If the angle of attack were not coordinated (decreased) with this increase of thrust the airplane would climb. But decreasing the angle of attack modifies the lift, keeping it equal to the weight, and if properly done, the airplane still remains in level flight.
http://avstop.com/AC/FlightTraingHandbook/Thrust.html
(http://img142.potato.com/loc185/th_3fc87_Power_available.jpg) (http://img142.potato.com/img.php?loc=loc185&image=3fc87_Power_available.jpg)
At least one of these reports describes sudden and sharp stall characteristics for the 190 compared to the 47 -- but the stall speed is a different matter.
The FW-190 has two stalls. One, described above is based on the aeroelasticity of the wing underload and the other is when the wing is not deformed.
Very different stalls and behavior. Aileron adjust directly effects this behavior as well.
However I don't think a single player would want the P47 modeled off of Russian data. Or the Spitfire?
So why is it acceptable for an aircraft whose only major fault is the reports are not it English.
All the best,
Crumpp
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However I don't think a single player would want the P47 modeled off of Russian data. Or the Spitfire?
So why is it acceptable for an aircraft whose only major fault is the reports are not it english.
:aok :aok
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Originally posted by Crumpp
Not one single person in this has ever disputed CL is not limitless.
Eh... I can only quess you are trying to say that Cl is dimensionless, if so, you are finally learning.
Originally posted by Crumpp
As Justin pointed out however, there is a difference in 2D and 3D theory.
Well, that is what I'm saying too but 2D has nothing to with this discussion because we are dealing with known airframes.
BTW last time we discused (http://www.hitechcreations.com/forums/showthread.php?s=&postid=1346397#post1346397) about 2D and 3D you came up with numbers which you have not yet explained.
gripen
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2D has nothing to with this discussion
OO-K
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Originally posted by KAntti
Hehehe, just out of curiousity I went and tried the p47 at low and slow offline :rofl Not only does it not stall, I could lift the nose up to over 60 degrees (starting speed of about 90 mph or so) and lower the airspeed under 50 mph until the stall indicator stops yelling.
And still the only thing the jug does is slightly lower its nose until the indicator starts yelling again. And for the whole time I've kept the stick in my blls and over 45 degree bank and maintained total control of the plane :rofl :rofl :rofl
I've flown AH since beta but never would I have thought that the stall was left out of the equation when you give full flaps. HAHAHAHA :rofl :rofl :rofl
This puzzles me....not only because its different that what I've encountered when I fly the 47, but also because it isnt consistant with carefully documented AH2 data.
Kweassa's turn thread (http://www.hitechcreations.com/forums/showthread.php?s=&threadid=155592)
With full flaps, the P-47D25s turn radius was 190 meters at 120mph. I'm not sure what the radius would be at "45 degree bank angle at 50mph" but it has to be a lot smaller than that....so I gotta wonder about your results.
Love to see the film! I'll have to try this when I get home.
No doubt the stall of LW rides is much harder to fight, much more unstable. Just dont know what the truth was. In honesty, my aerodynamically uneducated self has to wonder of the difference should REEALLY be as extreme and sharp as it is in the FW and BF groups.
________________
While I understand the frustration at the underemphasis on german reports, I have to point out -- germany was run by frankly homicidal, unpredictable men who routinely ordered the impossible and expected it done. (I.e. any man who pulls back from the line as it now stands will be shot, etc) In the production system, the Reich was torn by splintered priorities taht shifted (sometimes monthly -- look at the design history of the Pfeil) Bureaucratic infighting and turf wars, intensified as resources got tighter, certainly could have affected the final reports' towards a desired outcome -- even if the scientists hated it when it happened. Anybody who's worked in a dysfunctional bureaucraacy can imagine what those pressures would have been like in the mess that was the Reich.
Its hard to be sure, consequently, where things have been buffed and polished ( and maybe stretched) for purrposes of self preservation.
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Originally posted by KAntti
Hehehe, just out of curiousity I went and tried the p47 at low and slow offline :rofl Not only does it not stall, I could lift the nose up to over 60 degrees (starting speed of about 90 mph or so) and lower the airspeed under 50 mph until the stall indicator stops yelling.
And still the only thing the jug does is slightly lower its nose until the indicator starts yelling again. And for the whole time I've kept the stick in my blls and over 45 degree bank and maintained total control of the plane :rofl :rofl :rofl
I've flown AH since beta but never would I have thought that the stall was left out of the equation when you give full flaps. HAHAHAHA :rofl :rofl :rofl
That's what I'm talking about, too.
Yes, it will stall under rare conditions, but it's never a stall, it's just a "oh, you can't climb any more" type of mush. I've been flying it lately and I've not run into any stall problems, just performance problems (getting myself into stupid situations)
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Most likely, an FW-190A8, could be an F8(lots of weight similar power) or an A5(3% less weight, 22.75% less power) too:
http://www.ww2.dk/oob/bestand/jagd/biijg300.html
Long dogfight:
(http://img15.potato.com/loc256/th_47b1d_ez42_jg300_testing_6.jpg) (http://img15.potato.com/img.php?loc=loc256&image=47b1d_ez42_jg300_testing_6.jpg)
FW-190A8 vs P47(most likely later P47 D series), nice turning fight:
(http://img143.potato.com/loc21/th_56586_fw190vs51.472.jpg) (http://img143.potato.com/img.php?loc=loc21&image=56586_fw190vs51.472.jpg)
Early FW-190G series vs early Mustang II (less power and a lot less weight) along with a wealth of opinion about the FW-190G series vs. Merlin 66 IX LF after his 30 minute flight by himself:
(http://img46.potato.com/loc255/th_c1c3e_pro_190_survey_c_3.jpg) (http://img46.potato.com/img.php?loc=loc255&image=c1c3e_pro_190_survey_c_3.jpg)
So while the P 51D series gained almost 2000lbs over the allison powered earlier versions and lot less power than the FW-190A series I am very curious to know where the perception comes from that the FW-190A8 was so unmanuverable.
In honesty, my aerodynamically uneducated self has to wonder of the difference should REEALLY be as extreme and sharp as it is in the FW and BF groups.
I think your right.
All the best,
Crumpp
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I can also give you an anecdote where mustangs hunted 190's upwards, caught them, caught them on the downward run and level-low.
Takes some typing.
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Originally posted by KAntti
Hehehe, just out of curiousity I went and tried the p47 at low and slow offline :rofl Not only does it not stall, I could lift the nose up to over 60 degrees (starting speed of about 90 mph or so) and lower the airspeed under 50 mph until the stall indicator stops yelling.
And still the only thing the jug does is slightly lower its nose until the indicator starts yelling again. And for the whole time I've kept the stick in my blls and over 45 degree bank and maintained total control of the plane :rofl :rofl :rofl
I've flown AH since beta but never would I have thought that the stall was left out of the equation when you give full flaps. HAHAHAHA :rofl :rofl :rofl
I just did some tests in a 47N 50% fuel no ord , mine has no problems dipping its left wing and doing a complete stall. do ya all have the stall limiter turned off?? LOL
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Originally posted by Crumpp
We sure we want to make these assumptions. All these forces do come into play and affect the aircraft.
Thrust does contribute to lift. For example:
Simply fly any plane in level flight and increase the throttle:
I knew that you'd remind me that thrust does contribute to lift, that is why I wrote a long paragraph explaining why I'm going to ignore it. It does not change the results - turn radius does depend on wing area. Not only on it but also on it.
Bozon
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Formula of the Cl (used for turning performance calculations) is simply (from NASA):
Cl = L / (A * .5 * r * V^2)
The area of the wing is used for the calculation so the wing span is finite (3D).
gripen, what I was saying before is that this is not true. This formula is 2d. It assumes an infinite wingspan. To calculate a 3d CL, you can use the equation derived from "lifting line theory", which uses aspect ratio(this accounts for a finite span, ie: AR = b^2/S) to alter the CL to account for losses due to induced drag.
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I am very curious to know where the perception comes from that the FW-190A8 was so unmanuverable.
It could be the "common knowledge" (incorrect) that the Fw 190A-8 was "designed" to combat bombers - same story for 109G. Alot of people believe this was the case. Also the heavier Sturmbock variant(R8?) may be confused with the normal A-8. Same for 109G and gondolas.
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Originally posted by justin_g
gripen, what I was saying before is that this is not true. This formula is 2d. It assumes an infinite wingspan. To calculate a 3d CL, you can use the equation derived from "lifting line theory", which uses aspect ratio(this accounts for a finite span, ie: AR = b^2/S) to alter the CL to account for losses due to induced drag.
No, infinite wing span means that wing area is also infinite and if you look formula I posted, you can see that known wing area is used for it so the formula is 3D.
Aspect ratio is not needed to calculate required Cl for any given wing area and lift combination.
gripen
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what does it matter how do you calculate CL?
Eventually you can throw all the correction for finit wing, thickness, twist, pigeon poop etc etc into an effective, include-all Cl coefficient and end up with the same formula:
Cl (A * .5 * r * V^2) = L
Why don't engineers include the 0.5 factor in Cl is beyond me. Perhaps they are not as lazy as physicists.
Bozon
P.S.
one needs also to scale the pigeon as the square root of A.
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gripen, read these webpages: Thin Airfoil Theory (http://www.aerospaceweb.org/question/aerodynamics/q0136.shtml) and Lifting Line Theory (http://www.aerospaceweb.org/question/aerodynamics/q0184.shtml) and Finite and Infinite Wing (http://www.aerospaceweb.org/question/aerodynamics/q0167.shtml)
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justin_g
I don't know what is the problem with this. If we wan't to know what Cl is required for known airframe at given 3D conditions (lift, speed, density, wing area), we can calculate it simply with the formula:
Cl = L / (A * .5 * r * V^2)
It gives the Cl which the wing must have at given conditions despite what ever is the geometry of wing. There is no need to know AR, wing twist, profile etc. at this point. If we want go further to induced drag analysis or AoA analysis then we need additional information.
gripen
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"Cl = L / (A * .5 * r * V^2)"
Is that it? The ultimate truth in determining Lift coefficient -> turn performance?
So why do they bother to make all kinds of complicated planforms and profiles if all you need for a fighter is as much area as possible?
:confused:
-C+
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ummm..............because there's more to being a fighter than turn performance?
(Like speed, energy retention, weight/power.....)
<----not an engineer, but this one looks like cherrypicking!
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Originally posted by Crumpp
....snip.....
I think your right.
All the best,
Crumpp
Crumpp,
I respect your knowledge of LW history, but I'm coming to have doubts about your intellectual honesty. I'm seeing you again select the parts you like and ignore the parts you dont.
You picked a comment at the end, but didnt respond to what went before. SO, I'm interested in your thoughts about the following questions I asked in posts above:
1) Why doesnt the heavy framing in AH serve as a reasonable programming expression of a cramped cockpit?
2) Can we acknowlege that there may be reasonable uncertainty about the objectivity of LW testing, given the bureacratic turf battling, central disarray, and homicidal tendencies of the Reich?
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Ummm, or maybe it is a lot more complicated, and as Gripen tried to point out that exact knowledge of turn performance requires the knowledge of a LOT more variables to determine the exact turn performance of a certain a/c. And that means that those calculations would be very much more complicated.
BTW, picking on 190 does not make you unpopular, Simaril, as you assume in the topic of this thread. Quite contrary. It makes you the part of the "winning team"... :aok
-C+
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I'll have go.
"1) Why doesnt the heavy framing in AH serve as a reasonable programming expression of a cramped cockpit?"
Because that can be impelemeted when determining the pilot movement limits. Thus the limits do not need to be implemented in c'pit framing. IMO that would be simply idiotic. The crampedness of a cockpit is relative. There was a Finnish pilot of 195cm who flew 109s. It sure was cramped for him, but I think any plane was cramped for him. And after all he did fit in 109...
BTW how is a cramped c-pit bad anyway? You can't breathe? Move? Lay down? What? That is what I call "picking".
2) Can we acknowlege that there may be reasonable uncertainty about the objectivity of LW testing, given the bureacratic turf battling, central disarray, and homicidal tendencies of the Reich?
Why can't we assume the same for allied testing, too, considering that the war was a "good business" as was reflected by many overly optimistic performance figures for certain combat aircarft which couldn't reach those numbers in operative equipment?
-C+
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Originally posted by gripen
justin_g
I don't know what is the problem with this. If we wan't to know what Cl is required for known airframe at given 3D conditions (lift, speed, density, wing area), we can calculate it simply with the formula:
Cl = L / (A * .5 * r * V^2)
It gives the Cl which the wing must have at given conditions despite what ever is the geometry of wing. There is no need to know AR, wing twist, profile etc. at this point. If we want go further to induced drag analysis or AoA analysis then we need additional information.
gripen
cc, I get you now. :o I was approaching it from the other end, so to speak...
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Simaril,
1) would it not depend pretty much on what is meant with "cramped"? IMO, it refers to less space for movement, but what is enough and what movements are required is also a relevant question. Why should the less movement be translated as less visibility?
Some previous threads have already discussed the effect of the missing armoured glass refraction. It is a major disadvantage for visibility -> SA -> ability to fight. The thicker the glass, the bigger the disadvantage from the missing refraction. In additionto that we already miss the "stereo view" of 2 eyes, which would already overcome some disadvantegae caused by the cockpit frames.
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but didnt respond to what went before.
It's covered. You picked an opinion.
Moving on:
I believe the P51 does benefit from refraction. In one thread pictures were compared with outside views of the framing in the Mustang. From the inside one of the frames seemed to disappear.
This is the effect of refraction. It is very noticable in the cockpit of Black 3. The framing from the armoured glass cannot be seen from the inside.
turn radius does depend on wing area.
No. Turn radius is a function of Power available to power required.
Wingloading is a reflection of that relationship in turn radius. It is not a good reflection of that relationship for turn rate.
Both components go into sustained turn performance of a fighter.
All the best,
Crumpp
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justin,
Your absolutely correct.
Gripen says:
It gives the Cl which the wing must have at given conditions despite what ever is the geometry of wing.
Gripen says:
If we want go further to induced drag analysis or AoA analysis then we need additional information.
The very fact your not considering the gemometry of the wing makes it 2d theory. Don't get confused justin because wing area alone is considered in the formula.
You posted the formula's for 3D wings and explaination. 3D theory takes into account indcued drag and AR by it's very nature. 2D theory does not.
http://www.aerospaceweb.org/question/aerodynamics/q0167.shtml
Gripen is wrong and does not understand the differences in the theory or terminology.
All the best,
Crumpp
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Actually I was wrong, in this application. I was actually thinking about calculating values of CL over a range of AoA, which is where the 3d theory will produce more accurate figures.
But if you just want the CL required to match the numbers for lift, speed, density and area then it is perfectly acceptable to use the formula gripen has listed. The page here (http://www.aerospaceweb.org/question/aerodynamics/q0252.shtml) has a worked example using real data.
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Aint seen Gripen slip much on the boards. Seems to know his stuff.
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Crumpp and Charge,
PLease dont misunderstand me. i am absolutely not on a mission either for or against any plane, and I'm certainly not a LW basher. I started with the Yak, then spent a pretty good chunk of time in the Dora in AH1. Tried to learn TnB in the old Spit IX/V. Best 'score" time came in the old G10 doing dedicated buff hunting. Tinkered with the 38 but wasnt ready skillwise, and now using a mishmash of 50cal planes to work on gunnery and SA. I'd bet I have more career kills in LW than any single other plane -- so I'm far from a basher.
I just love the variety of trying different things. I really like it when those things are historically representative ("representative" becaue you cant be "accurate" in front of a monitor).
I dont particularly like it when people are so focused on their agenda that it influences their search for "truth".
So, thanks for the clarification about the refractive effects of the armor glass. Thats an interesting point; was the glass convex to some degree to give a wide angle? Now that I think about it, if it wasnt convex, wouldnt that cause a LOSS of a correponding portion of the viusl field? (I'm not good at saying this, but if there was a refraction that gave a view without the framing WITHOUT concavity to widen the angle, then objects woudl take up the same angular size that would have been present without the glass. SO, every "extra" thing you caould see would have to be at the expense of something you couldnt see -- becasue the pilots overall angular visual field was unchanged and the size of objects was unchanged, still a 1:1 correspondence.) So, in effect, the lost visual field from the frames woudl STILL BE THERE with the only change being that you couldnt see the frame.
Or have I thought through this wrong?
The testing question is an interesting one. I didnt mean to argue that manufacturer's testing would be more reliable in a democracy; and certainly factors other than deciett can contribute to significant differences in test results (i.e. "clean" airframe, optimal tuniing, etc).
Instead, I was thinking about what pressures the military test arms had to contend with. There is no doubt that teh Reich's military had a higher risk of powerful -- and even lethal -- political pressures. Highest levels of command were unpredicatble and implacable, not susceptible to reason.
And, the military procurement system was not particularly rationalized. So, entirely apart form the self preservation aspects, with very tight resources and uneven (or irrational) distribution of those resources -- wouldnt it be pretty easy to see bureaucrats buffing results to avoid getting their programs cut? The combination of resource scarcity, overlapping and competing fiefdoms, and a "royal court" that could bestow favor or punishment at a whim just sounds like a recipe for fuedal behavior, doenst it? It just seems uncertain to me...maybe results woudl be straight up, maybe not.
The US just didnt have those pressures because the resources were abundant. They could afford to keep making P-39s when the planes were obviously substandard, because, well, they could. When the planning boiards were wrong, like with the US torpedos, the truth came out in spite of the career implications -- institutions liek the press and independent judicial style review branches werent cowed by political pressure. And you cant minimize the impact of national culture. The american sterotype is aggressive, results oriented, and willing to trample on tradition and some times institutions to get the job done. That's different than the european and germanic tradition, so might their have been less willingness to buck th einstitutions?
Just musing...not accusing.
Simaril
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But if you just want the CL required
No one has disputed the accuracy. CL is a dimensionless number.
What Gripen was referring too was my opinion of which theory is more accurate for analysis. Which has nothing to do with this discussion.
These equations are 2D. 3D is even more accurate.
The equation Gripen posted IS 2D theory.
The confusion comes from bozon question:
is your idea of CLmax include the area of the wing or is it unitless?
Which I took to mean:
"Area of the wing" = finite wing
"Unitless" = infinite wing
Because I know Bozon understands CL is dimensionless and it would be childish to imply otherwise. So it did not even enter my mind that he would be asking if CL was dimensionless!
Hitechs example in this discussion is correct and an accepted method of estimation. However the designers in WWII knew much more about aeronautical engineering and their own designs than ANYone on these boards or at HTC.
The entire wing loading gain of the FW-190 amounts is 6% to 7% with a 23% increase in horsepower over the lifetime of the design. The thrust increase is not including more efficient propellers.
You cannot get around the fact the Spitfire Mk XIV gained a much larger percentage of wing loading and equal power gains over the Spitfire Mk IX. In the air, to trained test pilots using domestic and familiar designs, the differences were imperceptible.
All the best,
Crumpp
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So, in effect, the lost visual field from the frames woudl STILL BE THERE with the only change being that you couldnt see the frame.
No the effect is you see around the supports. Light is bent around them.
Here is a good website with a nifty applet. Think of the support being the center of the axis. Light is bent around the support and you are looking behind it. Of course it only works to a point. The supports seem about 3/4 as thick as the AH cockpit on the FW-190 with nothing showing at the bottom nor can you see any of the armoured glass framing. You have a clear view of the nose. Our plane is level on supports now. Angle it upwards if it was on the gear and your view of the ground in front of you would disappear.
http://www.ps.missouri.edu/rickspage/refract/refraction.html
I really like it when those things are historically representative
So do I. None of the Focke Wulf pilots noticed any handling deterioration in the FW-190A8. They all say it was best performing fighter variant.
This is backed up by the science as well. The differences between an FW-190A3's turn ability and the FW-190A8's should be imperceptible from the cockpit.
Now people are being silly in defense of a game shape if they think anyone is trying to make the FW-190 a turn fighter. Just saying the same physics applies and these designers were not stupid. They knew much more about this stuff than we do.
All the best,
Crumpp
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Here we go again :D
You cannot see through metal...light does not pass through the metal framing.
Take out the glass - look at the feild of view from the pilots posistion.
Put the armored glass in and it will be the same image / same feild of view only 2" closer to the pilot. It would have the appearance of smaller frames due to the refraction, but no visable feild of view gains will happen.
You dont see around the supports.
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Here we go again
Come down and sit in the cockpit. You can check it out yourself. Nobody is claiming your seeing through metal. The light is refracted is all. It is no different than the properties an optical lense uses to manipulate field of view or magnification.
All the best,
Crumpp
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put 2 cents on the outside of the frame and tell me if you can see it. :D
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What a silly request, Waffle. Of course you would not see it behind the frame. However if you put a coin on the nose in front of the cockpit or back that same coin a few inches off the frame, you will certainly see it.
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What we have in the cockpit views in this game is not a simulation of the actual field of view taken from same perspective.
All the best,
Crumpp
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Originally posted by 38ruk
I just did some tests in a 47N 50% fuel no ord , mine has no problems dipping its left wing and doing a complete stall. do ya all have the stall limiter turned off?? LOL
38ruk, maybe I was a little of on my comments about the 47. What I mean was that even though the p47 does perform something that could by someone with great benevolence be seen as a stall, it nowhere near perform an actual stall nor spin.
What p47 D 25% without ord. does: U give full flaps and take off, when speed approaches 90 mphs u pull hard, but just enough to keep the wing from dropping (ending in app 50 - 60 %).
U wait until the stall horn stops yelling (50 mph-ish) and wait for the thing to stall. When the stall comes u keep that wing (most propably the left wing if ur controls are straight at the stall) from dropping by applying right aileron.
At this point the nose starts to gently come down from the sky, and the plane is still most definatively out of air, but you still have full use of your controls. If the wing continues to trouble you, aply some right rudder as well. In real life from this point on, at this altitude u would without a doubt go in to a spin and end up in a flat mark on the deck (the rudder being still in one piece is a possibility). But since this is AH and not even the Spit is able to perform the spin, what the heck, lets do it!
U apply the right rudder and your p47 enters in a sideslip (while your left wing is stalling, this is fun) and loses altitude very fast, but your wing still keeps up, which was the idea. Then u just wait until the nose approaches the horizon and the plane gathers some speed (u dont need much to let the rudder go), and voila! U have just done a manouver no aircraft (I know this is an overstatement but, maybe some extra 300 or somthin...) in the whole wide world is able to do and survive. U have actually stalled and done a sideslip during the stall under 300 ft (95 meters), yey!
If u call this a normal stall performance and lowspeed manouvering ability for the p47, I would like to see to what plane were the pilots referring to when they thought p47 has poor performance low and slow.
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nope - I'm pretty sure its a 90 degree feild of view....
But it's pretty fun zoomed in to 30-45 degrees with track IR. :D
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Crumpp,
The equation I posted is derived from 2D but it uses known wing area ie finite wing so it's purely 3D.
bozon asked if CLmax include the area of the wing or is it unitless. While unitless is not exactly right word, you should have understood the question if you actually understand what you are talking about. Anyone can draw his/her own conclusions from your answers...
gripen
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Waffle,
You already tried to argue against the refraction issue in this thread (http://www.hitechcreations.com/forums/showthread.php?s=&threadid=167723&perpage=50&pagenumber=2).
Again, no... one cannot see through the frame, but the refraction allows one to see partly around it! That makes a difference in available viewing angle and therefore a huge difference in what the extra blocking part covers in the distance.
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LOL.. it is mildly amusing how some people still have to try to build their egos and to diminish others by getting personal. Is it not enough to let the issues and facts do the arguing?
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"Highest levels of command were unpredicatble and implacable, not susceptible to reason. "
Simaril, I do understand what you are trying to say here and I have thought of it myself. However, even if at some administrative level there might have been some kind of political hassle I find it hard to belive that it would have gotten through to detailed technical or scientific documents. Which doesn't mean it is not possible.
I think those documents were simply out of the comprehension abilities of German high(-est) command. ;)
I have most doubts of the documents that are merely general impressions of things without even basic scientific approach. Just as the Jug/FW documents. Even if they say that FW was superior in slow speed I find it doubtful too.
IMO those documents have only implications of the nature of those a/c but not the actual performance.
-C+
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The equation I posted is derived from 2D but it uses known wing area ie finite wing so it's purely 3D.
NO it is not. Cut and dry it is 2D theory equation.
You confuse reference area with the influence of induced drag and AR.
http://www.aerospaceweb.org/question/aerodynamics/q0015b.shtml
That being said, while 3D theory is more accurate when used accordingly, the standard this particular 2D theory formula is fine and gives reasonable predictions. Some formulas in 2D theory are best if used only in specific circumstances and if used outside those parameters can give erroneous conclusions. Same applies with 3D theory.
There are quite a few theories of the mechanics of flight out there:
This BASIC computer program uses the classical monoplane equation from lifting line theory to solve for the lift and induced drag coefficients and the spanwise load distribution on a specified wing ( 3-D ). Lifting line theory assumes that a wing's behavior at any spanwise location where the equations are solved is essentially two-dimensional ( no spanwise flow ). It is also based on a model using a bundle of lift inducing vortices placed at the unswept quarter chord of the wing. The method is, therefore, only valid for wings with unswept quarter-chord lines and with moderate-to-high aspect ratio.
http://www.aoe.vt.edu/~marchman/software/
Here is a great paper on how designers can manipulate almost any wing design to mirror an elliptical shaped wing with no twist's induced drag production. This why nobody builds elliptical wings as they are much more expensive to manufacture while offering few benefits in the air. Goes back to the monsterously silly thread you linked, Gripen. The one you argued that woods formula was wrong.
http://www.mae.usu.edu/faculty/wphillips/MAE5500/JoA-Vol41-No1.pdf
(http://img129.potato.com/loc128/th_2f7ef_induced_drag.jpg) (http://img129.potato.com/img.php?loc=loc128&image=2f7ef_induced_drag.jpg)
All the best,
Crumpp
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Even if they say that FW was superior in slow speed I find it doubtful too.
It is interesting Charge that more than one flight test notes this same characteristic.
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Originally posted by hitech
Crumpp you are so far off on the discusion of power weight and lift as it applies to turn performance ill just throw out some basic numbers from spreed sheet I did.
Given a plane with a max turn of 2.3 g at 160 mph . (In the realm of a lot of war birds)
Would create a turn radius of 825 ft and a time around turn of 22.1 secs. I.E. Bank angle of 64.22.
Now lowering the weight of that plane. by 10 % would make a turn raidus of 727 with a circle time of 19.46, Bank Angle 66.96
Increasing power by 30% on the orignal weight would have the following effect.
Turn Radius 798 circle time rate 19.5 and a speed of 174. Bank Angle 68.59
Ill let you draw your own conclusions. They should be very entertaining.
HiTech
Tried to duplicate HT's spreadsheet:
Blue line is turn radius [ft]
Red line is turn rate [deg/s]
Starting from 2.3g, 160mph.
Weight has much greater influence than power.
(http://img.photobucket.com/albums/v424/timppa/Turn1.jpg)
(http://img.photobucket.com/albums/v424/timppa/Turn2.jpg)
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Crumpp, I give up. I showed you that turn radius does depend on wing area, if you want, through reducing the "power required", but you refuse to listen. Thank you for bringing this up since it was interesting and sorry again for my bad english confusing "unitless" and "dimentionaless" terms.
I'll add just one more thing which you may ignore - Gripen is not talking about calculating Cl on a computer, he's talking about measuring it. Hydrodynamic simulations on a computer 2D, 3D with or without thermodynamics are not the most reliable things especially when dealing with irregualr shapes and the interesting part is the generation and decay of vorticity. This is why engineers test everything very carfully on scaled models before actually trying to fly it.
KAntti: I would like to see to what plane were the pilots referring to when they thought p47 has poor performance low and slow.
Make the distinction between performance and handeling. P47 has very poor slow speed performance (turn radius/rate) even in AH if you look at kweassa's tests. It rivels the 190s for last place. Slow speed handeling is another issue. I don't know how good it was but the P47 was not known for poor slow speed handeling or nasty stalls like the F4U or the P51 or the 190. It is extremely hard to tell how the real thing handeled is these extreme conditions, so AH might be spot on or not.
Bozon
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Originally posted by Crumpp
No the effect is you see around the supports. Light is bent around them.
...snip...
All the best,
Crumpp
Crumpp,
I am not an engineer, so I cant evaluate aerodynamic claims. But, I do have a passing familiarity with refraction.
You, on the other hand, do not.
Refraction DOES NOT “bend” light around corners, it REDIRECTS linear light.The effect of a lens “bending light” occurs because the interface between differing optical densities (ie air and glass) takes place on a smoothly curved surface. I could link you to a site that might get the idea across, but for the purposes of this discussion I’ll limit myself to the armor glass question.
Waffle is 100% correct that the view from the near side of a flat surfaced block of armor glass will appear to show the precise view seen from the far side of the same homogenous block. This is exactly the principle underlying fiber optic technology. It also why framing "looks" smaller" through the block-- you're only seeing the part visible from the far surface of the glass.
Rather than draw the diagram, let me have you think of it logically: refraction happens when light’s incident angle is redirected at an interface between two substances of differing optical density, with the deviation the light’s previous path being proportional to the ratio between the two substances’ density. (as I remember.....)
What you have chosen to overlook is that light passing through the armor block goes through TWO such interfaces – AIR --> GLASS, then GLASS --> AIR. Since we’re talking about ratios, the mathematical outcome of these two angle ratios is…..ONE. There is no net redirection in the angle of light. The effect, rather, is that of displacing the viewing position. It’s a linear displacement, not a curved one – the light path mimics the shape of the German SS lightning bolt.
To “bend” light around an obstruction requires image distortion, unless you’re willing to trade unrefracted field of view for the new stuff you see. IN other words, without distortion, it’s a periscope -- you have the same angular field of view in a new direction. To take a, say, 6 cm surface and get 10 cm worth of view field, YOU HAVE TO DISTORT THE RELATIVE DIRECTIONS OF LIGHT TO INCREASE THEIR "SPREAD" . In other words, you make a lens.. and this kind of single lens will have distortion. With distortion, you can see more angularly– but you get a (conceptually) some degree of fish eye lens effect, which would be unacceptable for precision views like gunsights. If you want to argue this, I’ll be happy to do some research and explain it to you further....this stuff is off the top of my head, based on my understanding of the human lens.
Your talk of how these engineers were smarter than we are smacks of dogmatic worship, almost religious ardor. They were not smarter than us…they were good engineers using 1940s technology. In fact, the germans spent energy and limited resources developing “wonder weapons” whose practical impact could have been predicted to be minimal had anyone bothered to take the time to think about it – for example, the V2. An awful lot of effort and diversion of limited resources to deliver a 1 ton bomb….Meanwhile the backward allies spent technology on mass production techniques, chosing (for example) to keep less advanced designs in production to avoid drops in the supply stream. Who would you say was actually smarter?
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Bozon, I am not accusing only the p47 of being poorly modeled or something. I am telling u that the whole FM of AH is generally flawed because it totally lacks things like spin (and in this case stall as well).
For me this is not an big issue as I have allready accepted that this game has nothing to do with real life and that the plane set has been equalized by taking from the rich and giving it to the poor.
The thing that bothers me is that some people insist that this is not the case and actually try to make erratic cases to prove their point.
As you can see there is no case to be made by referring to actual events and testimonials from the era. I bet the only way one might get close is to sit couple of todays pilots in front of the game and let them tell what they think of it. There are lots of warbirds flying around, ask the pilots of them to visit AH convention or smthin and tell us (and HT) how a plane should or should not handle.
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Originally posted by BlauK
Waffle,
You already tried to argue against the refraction issue in this thread (http://www.hitechcreations.com/forums/showthread.php?s=&threadid=167723&perpage=50&pagenumber=2).
Again, no... one cannot see through the frame, but the refraction allows one to see partly around it! That makes a difference in available viewing angle and therefore a huge difference in what the extra blocking part covers in the distance.
You're totally missing the point....
Even if the canopy frame looks thinner (because it's shifted due to the refraction) you are not going to magically get more feild of view from a flat piece of glass.
So if you're looking through it - and you can see the frame..even if it looks super thin - you are still seeing the frame. From that point there is no feild of view growth from a flat piece of glass.
Also on the 109s the brackets that held the glass in are blocking alot of the refracted image from a center POV.
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Originally posted by Crumpp
NO it is not. Cut and dry it is 2D theory equation.
It uses finite wing so it's 3D. Please follow the link justin_g posted and see how it is used 3D.
Originally posted by Crumpp
You confuse reference area with the influence of induced drag and AR.
I wonder what you might mean, the equation is simply for the Cl.
Originally posted by Crumpp
Goes back to the monsterously silly thread you linked, Gripen. The one you argued that woods formula was wrong.
Hm... Actually I pointed out in that thread that Wood's formula for rectangular wing was used wrongly. It's not for other wing types nor for entire airframe.
gripen
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Originally posted by KAntti
I bet the only way one might get close is to sit couple of todays pilots in front of the game and let them tell what they think of it. There are lots of warbirds flying around, ask the pilots of them to visit AH convention or smthin and tell us (and HT) how a plane should or should not handle.
We have pilots playing the game. Including a Active duty F/A 18 pilot, don't remember is callsign though.:( As far as pilots flying 60 year old warbirds I would think that they are't racking them around the sky and most assuredly don't routinely ride around with the stall horn blareing. They only get one life.
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Waffle (.. and Simaril)
AFAIK, bending is not same as curving. Something bent can have a sharp angle.
(http://www.virtualpilots.fi/LLv34/kuvat/bk/109refract2.gif)
I claim that the current view (black line) offers less view and viewing angle than the refracted view (green line). Th erefraction makes one see "around the frame" and therefore it makes more field of view! It is all about the initial angle of meeting the inside surface of the glass... which is larger than without teh glass. There is no magic or curved lenses needed.
If you still claim otherwise, then explain the area between the black and green lines on the outside of the armoured glass!
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Blauk - thats nice in that drawing, but I'm fairly certain that they had bracing and brackets on the back side of the glass. :D
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Originally posted by Waffle BAS
Blauk - thats nice in that drawing, but I'm fairly certain that they had bracing and brackets on the back side of the glass. :D
Surely, and on the outside too! Ar yuo saying that there were more and wider bracings on the inside? I dont think so, because in such case one could not see any such difference in frame thickness as is visible in many photos.
I was simply talking about the phenomenon and the wider field of view it produces ;)
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Put it this way - it has to support the force from any pressure - be it wind / debris or impact. It has to support little force from the pilots side outward...unless the poor soul is trying to kick his way out through armored glass. :D Look at the 109 - you'll see 2 bars on the inside with bolts through them. I'm pretty certain they were inset and wider than the front exterior, as to give the glass more support.
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Sigh.
The drawing shows a nice green line, but its wrong.
Use the exact link you (crumpp) posted above. Choose any angle (I used 20 degrees). Set the density to air, and have the bottom density be glass. You'll get roughly 13.1 degrees.
Now set the top to 13.1 degrees, the density to glass, and have the beam pass to air density. You get the same 20 degrees you started with. Net effect is...NOTHING.
You're ignoring the fact that the near edge of the glass block takes up some physical space, and that the front face of the armor block covers up materials deep to it....one of those geometry things I dont feel like calculating, but you have a triangle. The lateral face of the block (the one to the side) forms the base. The line between the near corner of the block and the far side of the framing, extended from the view position till you reach plane of the frame, is the hypotenuse. The far face of the block and the front face of the canopy form the short arm of the right triangle.
Those angles define an invisble blind spot, invisible BECAUSE of the doubel refraction hiding the frame from view. You still have a blind spot, it just isnt a big black line. Ever try looking through that really thick glass at a bank drive through window? Have to move your head around to see all over....becasue of the refraction. In fact, most people find views through thick armor glass distorting and disturbing, not at all a view advantage.
You are right that the thickness of the block will increase view angles in a miniscule way -- precisely as if the canopy frame were farther from the viewer (and thus visbly smaller. BUT the separation between the actual and visible distance IS ONLY THE THICKNESS OF THE ARMOR GLASS. Pretty trivial.
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(http://www.dangreve.com/64.jpg)
Eyeball this pic....
Note the right side (as if you were sitting behind it) where the glass would join the exterior frame. Then look at the brace/bracket top and follow it's left edge. You can see that it's well inside of the line of where the exterior side of the glass meets the frame.
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Crumpp, I give up. I showed you that turn radius does depend on wing area, if you want, through reducing the "power required", but you refuse to listen.
Find where I disputed you on this bozon??
I haven't and your correct. It is exactly what I have said from the begining. Wingloading is a reflection of the power available to power required.
Only thing I claimed is that addition of thrust improves turn performance and a small increase in weight can be overcome with additional thrust. Designers were well aware of this.
Generally speaking, If you track the weight increases of most designs you will find they are accompanied by a power increase of appropriate magnitude.
The FW-190A8 gains 3.8% weight over the FW-190A5. It gains 22.7% more horsepower and a 10% more efficient propeller to increase it's effective thrust.
I have also said from the begining exactly what is in Perkins & Hage. Turning is a fundamental relationship of power available to power required. That relationship is the basis for turn performance. Not wingloading. Looking at wingloading alone is like looking at piece of the pie and not the whole thing.
Everybody keeps looking at this from the POV of which matters more, wieght or thrust. It's completely irrelevant. They both influence turn ability.
It uses finite wing so it's 3D.
Is not a finite wing. It's an area. Any shape can have an equal area. Finite defines the shape of the wing. Not just a random area.
If your not including the effects of induced drag along with the AR, it's not 3D.
Hm... Actually I pointed out in that thread that Wood's formula for rectangular wing was used wrongly. It's not for other wing types nor for entire airframe.
Right. Fortunately people can read the thread. If they want to muddle through it.
Even if the canopy frame looks thinner (because it's shifted due to the refraction) you are not going to magically get more feild of view from a flat piece of glass.
Nobody is claiming you are but the fact remains you can place a coin of the nose of the FW190 against the cockpit and see it. In AH, the bottom of the "frame shape" prevents this from happening. It's not the same FOV.
I don't think your an expert on the physics of light nor am I. I suspect those that built and designed the cockpit knew what they were doing inspite of what some gamers in this thread want to claim and that goes for all cockpits too, not just the Luftwaffe ones.
All the best,
Crumpp
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Note the right side )as if you were sitting behind it) where the glass would join the exterior frame. Then look at the brace/bracket top and follow it's left edge. You can see that it's well inside of the line of where the exterior side of the glass meets the frame.
When you put the glass in it, let me know! We can finish this discussion.
BTW, that is exactly the reason I have not participated in many of the "view threads". The view looked very close to the framing without the glass.
All the best,
Crumpp
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You put the glass in and the feild of view is blocked by the exterior frame Crumpp. You cannot see through and around metal....
The only thing that happens is that after the light bends through the glass -you are seeing the image which hits the exterior side - only it's 50-60mm closer to the pilot, which is what makes the rails look thinner due the refraction. The image is just shifted closer.
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Th erefraction makes one see "around the frame" and therefore it makes more field of view!
That is exactly the effect, BlauK.
Whatever the theory hunters want to claim. You nailed exactly the effect you see.
Good diagram.
All the best,
Crumpp
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Crump,
"they knew what they were doing" does not equate to "the AH canopy frame is wrong because it ignores armor block refraction."
Your explanation of refraction is in error. There IS a blind spot, it just isnt black liek framing. Its easier for AH to model a black line for framing, but it isnt unrealistic -- its just darker and more visible.
Forget whether there is glass in the frame Waffle posted or not -- you've been throwing aerodynamic calculations around freely, so you're good with numbers. Look at the angles I talked about, adn the results of the apllet you directed us to. Your explanation isnt correct.
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Originally posted by Crumpp
That is exactly the effect, BlauK.
Whatever the theory hunters want to claim. You nailed exactly the effect you see.
Good diagram.
All the best,
Crumpp
When you try to prove your point, its science; when we show something you dont like, we're "theory hunters"?
I agree that you see less black due to refraction, but THERE IS A BLIND SPOT that is covered with a "visible" refracted image. Just like your eye's blind spot, you dont know its there unless you test it -- otherwise its invisible.
The "I know what I see, I dont care what your calculations show", just gotta beleive approach is antithetical to your previous approach. I wonder why you've changed ....
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Look at the angles I talked about, adn the results of the apllet you directed us to. Your explanation isnt correct.
Where do you think the LOS picks up when it reaches the flat exterior surface?
Do you think it redirects to a new angle of vision independant of the LOS of the angle of entry on the interior glass?
Or do you think it keeps the same angle only it has been refracted to the exterior glass surface?
All the best,
Crumpp
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crumpp,
I thnk we're hitting a dead end here.
I was going to offer to take the hard data (which i'm sure ou have) about distance from the seat to the armor block, the thickness of the block, etc, and calculate the apparnet decrease in size of the framing caused by the refraction you're talking about. I'd also calculate the "invisible blind spot" caused by the refraction -- and I'd bet that'll be much bigger than the angular advantage of the refraction.
But there's no point. When you pointed out that I misread the dive distance, I was open and basically said "oops". You havent acknowleged the possiblity that you ...might....make....a... mistake, that your knowlege could possibly be anything less than encyclopedic.
Theres no point.
ONe last try at logic....if you're explanation is correct, why dont we make all glass as thick as possibel to widen the apparent view? Why dont we use glass block insterad of window glass?
We dont because empirically you know the idea is rediculous, that it wouldnt increase view and that it would increase distortion.
Never mind.
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THERE IS A BLIND SPOT
Sure there is a blind spot. It's not nearly as large as depicted in AH. I love the looks of the FW190 cockpit in AH, BTW. The reality would closer to inbetween the crappy thin line cockpit in AH1 and the new one.
When you try to prove your point, its science; when we show something you dont like, we're "theory hunters"?
I present practical experience only to get told it did not happen??
Might fly if I was not specifically looking at this issue of FOV. I was certainly curious after all the fuss over what I thought was pretty close. My biggest concern from a gaming POV was that the cockpits were relative not the specifics of the Focke Wulf.
Your theory hunters in this case unless you have sat in the FW-190's cockpit and investigated this exact issue. It has been around for a while.
All the best,
Crumpp
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crumpp, give me the actual dimensions we're talking about -- from the seat to the armor block, the width of the lateral framing, the width of the armor block. I'll do the trig and show you how much thinner the frame "looks" because of refraction. I'm betting its on the order of millimeters. The angular difference is rediculously small -- how many degrees separate the edge of the armor block from the ray that will pass just inside the outer edge of the canopy frame? We'l have to use seconds im afraid
Why don't you come down to the museum and YOU can do all that.
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Originally posted by Crumpp
Why dont YOU come down... and do all that
Crumpp, I'm done.
If you wont think about other perspectives, there's no point talking. You have lost my respect, because though I thought you we're knowlegable you've demonstrated that you are just a partisan with an agenda.
Goodbye.
Simaril
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If you wont think about other perspectives,
Check your PM and you might want to retract that last post. Unless you are unable to live up to your own standards.
I meant what I said about you doing the measurements.
Your field of view is from the viewpoint of game player whos is interested in the history.
Mine is similar as I play these games and enjoy them. However I have to consider the museum as well.
All the best,
Crumpp
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ONe last try at logic....if you're explanation is correct, why dont we make all glass as thick as possibel to widen the apparent view? Why dont we use glass block insterad of window glass?
Because it only works to a certain degree...like 90 degrees?
Nobody has made any ridiculus claims in here about the view either so just stop going off the deep end.
The actual view is better than what it is depicted as in AH. Pure and simple.
I offered my opinion from what I have seen.
No finite measurements have been put on it. I encourage you to come down and measure them!!
All the best,
Crumpp
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geeks
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Hi Simaril,
>Now set the top to 13.1 degrees, the density to glass, and have the beam pass to air density. You get the same 20 degrees you started with. Net effect is...NOTHING.
While you're right about the angles, you're wrong about the effect. The effect is a lateral displacement, yielding a parallel displaced beam.
As far as I can tell, Blauk's drawing is absolutely correct.
An optically flat plate should not be misunderstood as "virtually non-existing". As a practical example, the 500 mm mirror lens I use with my SLR camera is designed for operation with an internal filter. If I don't use the filter, I have to insert the special piece of optically flat clear glass that came with the lens instead of the filter, or I'll end up with a suboptimum picture because the flat plate does in fact make a difference.
Regards,
Henning (HoHun)
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Gripen is not talking about calculating Cl on a computer, he's talking about measuring it.
Not unless he is using instrumentation and a windtunnel.
All the best,
Crumpp
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Originally posted by Messiah
geeks
UberGeeks
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Waffle and Simaril,
I truly do not understand how the simple question can change so much :)
Could you, please, explain the area and angle difference between the green abd black line? Does it offer a wider view or not?
I gathered that Simaril already kind of agreed that the view is wider, but I dont get the idea about a blind spot? Does it refer to the side of the armoured glass? If it does, IMHO it is irrelevant, since the side is completely covered with metal anyways.
The issue here is about the uncovered and visible interior and exterior surfaces of that armoured glass. If the interior side bracing was so wide that it would cover the whole benefit of the refraction, the vertical frames would not appear thinner in the photos. Since they do appear thinner, the refraction offers a wider view.
In the photo below, you can fairly easily see how the bracings do not cover anything but the area already blocked by the exterior frames. You can see lots of them as well, but the main point, the more generous view is quite apparent.
(http://www.virtualpilots.fi/LLv34/kuvat/bk/cpit/109_ref_straight.jpg)
Waffle,
you keep on mentioning how the refraction only makes the view move/shift closer to the eye. Actually you metaphor has a point, but let me rephrase it as "The refraction is like moving the eye a bit closer towards the armoured glass". Right? ... and when the eye is closer to the glass it also gets a wider view in regard of the blocking frames!
If you guys cannot accept this from my mouth, please ask one of those you regard as acceptable and credible people and who usually agree with you.
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Originally posted by Crumpp
Is not a finite wing. It's an area. Any shape can have an equal area. Finite defines the shape of the wing. Not just a random area.
Well, you have a logical problem here, if wing span is infinite, then also area is infinite and if wing area is finite then also wing span is finite.
Originally posted by Crumpp
If your not including the effects of induced drag along with the AR, it's not 3D.
Here you have another logical problem, the formula:
Cl = L / (A * .5 * r * V^2)
Is simply for Cl in 3D because it assumes finite wing. There is no need to know induced drag nor wing geometry for calculating required Cl at given conditions.
Please follow the link (http://www.aerospaceweb.org/question/aerodynamics/q0252.shtml) justin_g gave and see how it is used to calculate 3D lift coefficient:
"We can use this relationship to rearrange the lift equation and apply it in a new way. Since lift must equal weight for the plane to fly level, lift becomes a known value that we can use to solve for the lift coefficient. The lift equation then becomes:
(http://www.aerospaceweb.org/question/aerodynamics/lift/eq07.gif)
We can again use the values provided above for the 747 to solve this equation.
(http://www.aerospaceweb.org/question/aerodynamics/lift/747-eq02.gif)
Lo and behold, the lift coefficient is 0.52, exactly the value provided in the original data. This application of the lift equation may seem backwards, but engineers often use it during the preliminary design process of a new aircraft. A cruise speed as well as an approximate weight and size are typically specified when the design effort begins. These values can be used in the above equation to solve for the lift coefficient necessary to maintain cruise flight at those conditions. Once that coefficient in known, designers can determine what wing shape and airfoil section will best provide that lift coefficient while minimizing drag. Other factors obviously come into play since an aircraft does not spend its entire flight at steady and level conditions, but this technique is a common first step in the initial sizing and design of a new flying vehicle."
Note that induced drag and AR (ie wing geometry) are not needed to calculate required Cl.
Originally posted by Crumpp
Right. Fortunately people can read the thread. If they want to muddle through it.
Well, fortunately the original thread is here (http://www.hitechcreations.com/forums/showthread.php?s=&threadid=129772) but to save time of readers, here are the relevant parts from Wood's book (Karl D. Wood (1935):"Technical Aerodynamics"). Wood described a system to estimate e factor of an airframe by splitting e factor to two parts:
ew = efficiency of the wing
ef = efficiency of the fuselage
The e factor being:
e = ew * ef
For the wing (ew) Wood gave following chart:
(http://www.onpoi.net/ah/pics/users/852_1138870299_wood1.jpg)
The formula seen in the chart is for rectangular wing and for wing only. The problem was that it was claimed that this formula can be used alone (without ef) to determine the e factor of an airframe which is wrong way to use it. After some discussion that was sorted out, except in the case of the Mr. Crumpp who apparently still believes that there is some kind of generalized formula to calculate e factor from AR alone.
Originally posted by Crumpp
Not unless he is using instrumentation and a windtunnel.
Yet another logical problem; required Cl can be calculated simply knowing the lift, speed, density and wing area without instrumentation or wind tunnel. See the 747 example linked above.
gripen
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Originally posted by Messiah
geeks
Originally posted by Grits
Ubergeeks
Actually, on reflection, I think I've been more of a jerk than a geek.
I offer my apologies to Crumpp in particular, but also to BlauK and to the AH community in general. I let irritation express itself in inappropriate ways, and I let it cloud my better judgement. (As usually happens in these situations, irritation came from other places and leaked into my BBS responses.) I'm a grown up, I've dealt with life and much more important things than this, and I should know better. Even in the most general terms, a human being is more important than some silly BBS argument. I screwed up, adn I will publicly take my medicine.
__________
After a nights sleep, with that subconscious processing that somehow takes place, I've also reconsidered the issues here. I really DO think that the refraction, by moving the viewer closer to the front canopy surface, would result in an apparently smaller frame obstruction. The Diagram is correct, and my first response to it was wrong.
With regards
Simaril
PS Grits, thanks for the "Uber." I've never before been uber anything in this game, and it feels good to have crossed the threshold!
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No problems Simaril, at least I did not notice any offence or anything personal :)
I am only wishing that HTC people would sometime have some time to update the 109 and 190 windshield/vertical frames models (others too that are affected)... Maybe in 2 weeks ;)
OK... what was the original issue of this thread....
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There is no need to know induced drag nor wing geometry for calculating required Cl at given conditions.
Wow!
the difference between a finite wing and an infinite wing is in that a finite wing has tips.
http://www.aerospaceweb.org/question/aerodynamics/q0167.shtml
Not just area.
http://www.aerospaceweb.org/question/aerodynamics/q0015b.shtml
So while the wing is "finite" under your definition. It does not fit the engineering defintion for 3D theory.
3D theory would be more accurate in this case for exactly the reason Justin posted.
Note that induced drag and AR (ie wing geometry) are not needed to calculate required Cl.
No and I never said you did need them. Unless your using 3D theory. If your not using using 3D theory then your correct.
The problem was that it was claimed that this formula can be used alone (without ef) to determine the e factor of an airframe
Gripen you can twist things however you want.
No matter what formula used our results remained the same when the same conditions of flight were used for both planes.
Things came out a little different when we did it your way by having the planes at different speeds or altitudes.
Yet another logical problem; required Cl can be calculated simply knowing the lift, speed, density and wing area without instrumentation or wind tunnel.
No your trying to claim I am saying you cannot calculate CL?????:huh
How ignorant is that.
All the best,
Crumpp
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I offer my apologies to Crumpp in particular,
No problem whatsoever. The stupid assumptions we all make on these boards leads to so many misunderstandings.
I certainly have to take a "hunk of the blame cookie" for it as well and offer my apologies for the attitude.
I meant that you are most welcome to come down to the Museum and make those measurements. I think it would be interesting!
All the best,
Crumpp
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Originally posted by Crumpp
Wow!
Well, your own post [2-01-2006 10:03 PM]:
"If your not including the effects of induced drag along with the AR, it's not 3D."
Which completely false statement. Lift coefficient (3D) can be easily calculated without knowing the AR or induced drag as pointed out several times above.
Originally posted by Crumpp
Not just area.
...
So while the wing is "finite" under your definition. It does not fit the engineering defintion for 3D theory.
Yet another logical problem in your thinking; if a wing has a finite area, it has also the tips despite what ever is the AR.
Originally posted by Crumpp
3D theory would be more accurate in this case for exactly the reason Justin posted.
Well, as you can see from the 747 example which justin_n posted, the equation I linked is 3D. It is accurate and exact.
Originally posted by Crumpp
No and I never said you did need them. Unless your using 3D theory. If your not using using 3D theory then your correct.
Well, let's quote your statement again:
"If your not including the effects of induced drag along with the AR, it's not 3D."
Which completely false statement. Required lift coefficient (3D) can be easily calculated without knowing the AR or induced drag as pointed out several times above.
Are you saying that the example justin_g posted is not 3D?
Originally posted by Crumpp
Gripen you can twist things however you want.
No matter what formula used our results remained the same when the same conditions of flight were used for both planes.
Things came out a little different when we did it your way by having the planes at different speeds or altitudes.
I have no idea what you are trying to argue. That thread (http://www.hitechcreations.com/forums/showthread.php?s=&threadid=129772) was about determining e factor and it was pointed out that supposed "generalized formulas" were actually not such but for specific wing shape and for wing only.
It was agreed that the best way to determine e factor is polar analysis.
Originally posted by Crumpp
No your trying to claim I am saying you cannot calculate CL?????:huh
I don't see such claim in my reply.
Generally you have problems to put up logical argument.
gripen
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Maybe this will help show what I'm trying to explain is happening.
first pic is an image of what would be hitting the the outside of the armored glass which view is blocked by the frame.
Second pic is that same image refreacted to the pilot side of the glass, say 2" closer. - Same feild of view.
(http://www.dangreve.com/images/1.jpg)
(http://www.dangreve.com/images/2.jpg)
Inside / outside
(http://www.dangreve.com/images/109.gif)
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Waffle, your picture would mean that the entrance and exit angles for the glass are not equal. Sorry, but that is not what they teach in schools.
Try drawing your picture from above and you will also realize it.
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lol - Don't have time to photchop everything to a T, nor would I want to try but you can get a general idea.
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Here's a rough top view of 109 construction, feel free to run refraction lines on it.
(http://www.dangreve.com/images/109a.jpg)
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Yet another logical problem in your thinking; if a wing has a finite area, it has also the tips despite what ever is the AR.
Can you point out the tips of the helicopter area or the 747 used in this example please and how the differences are accounted for in your formula by using raw area??
http://www.aerospaceweb.org/question/aerodynamics/q0015b.shtml
Assume two planes of equal weight, equal wing area, and equal speed flown in the same atmosphere.
One has an elliptical wing with no twist, and the other a square wing with no twist. The CL will calculate out exactly the same using that formula.
The shape of the wing is not considered, only the area. Not to be a Smart A, but you did have Geometry starting in early childhood development that taught you shapes, I am sure. Later in your education you should have had some more advanced geometry that taught you area.
Area is not shape nor does it define shape. It is just area.
For example a square with sides of 2 has the same area as a rectange with a=1 and b=4?
Area is equal but the shape is different, understand now?
http://www.gomath.com/htdocs/ToGoSheet/Geometry/area.html
Because your statement earlier:
required Cl can be calculated simply knowing the lift, speed, density and wing area without instrumentation or wind tunnel.
Is absolutely true.
It is not 3D theory, however as it does not account for the shape of the wing.
All the best,
Crumpp
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Originally posted by bozon
I don't know how good it was but the P47 was not known for poor slow speed handeling or nasty stalls like the F4U or the P51 or the 190. It is extremely hard to tell how the real thing handeled is these extreme conditions, so AH might be spot on or not.
Especially considering that 2 of the 3 planes you listed there are gentle as babies in the stall (p51 and f4u) where in fact they were monsters and both had severe handling problems (not modeled in AH)
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Sorry Waffle, I wont bite that picture :)
If the inside "attachment strips" were that wide the frames would not appear thinner in photos. I am beginning to wonder if you are trolling on purpose :)
Here is a pic from top for you (notice that there is still some more space for the inside strip):
(http://www.virtualpilots.fi/LLv34/kuvat/bk/cpit/refractB.gif)
You are assuming the refracted line of sight (LOS) goes along the dotted red line "A" and would offer equal angle with the black LOS without any armoured glass.
Instead the refracted LOS goes along the red line "B", which offers more viewing angle than the black line. The entrance and exit angles on opposite sides of the glass have to be same!
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Maybe this will help show what I'm trying to explain is happening.
What an excellent photo, Waffle!
Are the angles lined up exactly on that 2nd picture animation? If they are please notice the lattice work windows at the top and in the armoured glass view.
When your view minus the armoured glass is on, the pains do not line up. When the armoured glass is in place they do lineup accordingly.
I don't think there is really much to argue about on this subject. The designers of armoured glass were well aware of the optics, need for fighter pilots to be able to see as large a field of view as possible, and the need for that view to be accurate.
IIRC Zeiss manufactuers the armoured glass for most Luftwaffe birds.
I can verify that.
And this is not some Axis vs Allies crap. This is just normal technology of the day and the recessed armoured glass became the WWII standard.
All the best,
Crumpp
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Blauk -
look at this pic again
(http://www.dangreve.com/64.jpg)
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Instead the refracted LOS goes along the red line "B", which offers more viewing angle than the black line. The entrance and exit angles on opposite sides of the glass have to be same!
Exactly, that is why the "inside view" of waffles picture matches the "outside reality".
All the best,
Crumpp
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Originally posted by Crumpp
What an excellent photo, Waffle!
Are the angles lined up exactly on that 2nd picture animation? If they are please notice the lattice work windows at the top and in the armoured glass view.
When your view minus the armoured glass is on, the pains do not line up. When the armoured glass is in place they do lineup accordingly.
I don't think there is really much to argue about on this subject. The designers of armoured glass were well aware of the optics, need for fighter pilots to be able to see as large a field of view as possible, and the need for that view to be accurate.
IIRC Zeiss manufactuers the armoured glass for most Luftwaffe birds.
I can verify that.
And this is not some Axis vs Allies crap. This is just normal technology of the day and the recessed armoured glass became the WWII standard.
All the best,
Crumpp
No watermelon they wont line up, because I dont have the "image" of whats hitting the outside glass....lol
All I had was a reduced internal picture after the refraction, and blew that up 10% so what you're seeing is magnification... not reversed refractioN.
edit - should clarify - image was scaled to fit, which would be more / skew / enlargement with no "angular" correction.
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That is a nice frame Waffle. Is it yours or did you get the picture off ebay?
It's in pretty good condition for an original. Is it restored or reproduction?
All the best,
Crumpp
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No watermelon they wont line up, because I dont have the "image" of whats hitting the outside glass....lol
How did you make this film btw?
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pics from aero arts and parts, which I use for part reference for some skinning projects /personal 3d models.
EDIT: heres link: http://www.aeroart.de/en/
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Originally posted by Crumpp
Ok Waffle the canopy your looking through to view the top of the window panes is NOT armoured. You do know that?
Which pic?
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The bottom one.
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Waffle,
are yuo dodging the questions? A or B? ;)
I dont know what I am supposed to look at in the windshield frame photo. One thing I notice though, is that the inside strip seems pretty much aligned with the outside "strip". You notice that the framing gets wider towards back, right?
Still.. A or B in your opinion, and why?
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Just to be clear, your correct BlauK.
I am just curious about Waffles pics.
All the best,
Crumpp
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btw.
what animation and film are you talking about?
Am I just not seeing it with my browser?
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Blaunk -
The angle will be the same going through a piece of glass with parallel edges. Snell's law.
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Originally posted by Crumpp
Just to be clear, your correct BlauK.
I am just curious about Waffles pics.
All the best,
Crumpp
just two images turned into an animated gif.
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Originally posted by Waffle BAS
The angle will be the same going through a piece of glass with parallel edges. Snell's law.
And what does that give you A or B ?
Just say it :)
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Originally posted by Waffle BAS
just two images turned into an animated gif.
cc
now I saw it. Btw, notice how the vertical museum window bars get much closer to each other in the manipulated view than above the armoured glass.
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from the solid red line, going through the glass, I would say it should continue through the glass as "A" the red dotted line, if those are the same angle as they hit the glass from each side.
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Anyone know what type of glass the armored glass was made out of?
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The see through kind :) .
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Originally posted by Lye-El
We have pilots playing the game. Including a Active duty F/A 18 pilot, don't remember is callsign though.:( As far as pilots flying 60 year old warbirds I would think that they are't racking them around the sky and most assuredly don't routinely ride around with the stall horn blareing. They only get one life.
I'm not referring to any F/A 18 pilot, who the hell needs em in WWII simulation?
Stall is a very simple and rutine test any pilot does with any plane he flies. It is one of the very first tests one does when flyin a type of AC first time. In case you unintentionally stall, you really HAVE to know how the plane behaves.
As I said there are lots of 109's, p51's, spits flying around, go ask the pilots how the planes behave.
BTW I'll add this link for you and others interested in the actual characteristics of 109's. From the mouths of the pilots them selves:
(theres even an Stall performance report conducted by RAF Royal Aircraft Establishment (RAE) Farnborough handling trials.
http://www.virtualpilots.fi/feature/articles/109myths/ (http://www.virtualpilots.fi/feature/articles/109myths/)
I am generally not a 109 enthusiast, but I'd hate to think that ANY AC would be given LESS, OR MORE performance in AH than it in reality deserves.
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Since you guys like movies so much......
Here's one entitled "You Can't Fight Physics...Incidence and Refraction" :D
(http://www.dangreve.com/images/incidence.gif)
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Area is not shape nor does it define shape. It is just area.
All the physics and detail goes into Cl. Ugly physics is always in the dimentionless factors of any equation, All the factors with dimentions are almost always trivial - this is called dimention analysis. The the area is just a scale factor. It need not even be a real area of the wing, just a square of some well defined length of some part of the wing. Once you find out (no matter how) CL for specific shape of wing, it will be the same CL if you scale the wing size by factor of 2. The lift produced will be scaled by factor of 4 however through this length scale squared (dimention = area). You may choose to define it as the span, the width at half the span or the thickness.
Look at this simple example. We want lift which is a force, dimention = mass*length/time^2.
We know it should depend on the r = mass density of the air [mass/length^3], and on the V = velocity [length/time] and maybe another mysterious parameter...
To be able to produce something with force dimention we have to square the velocity to get the time^2 dimention, we have to multiply by density to get a mass dimention and the extra parameter has to be of length^2 dimention - lets call it S. So from dimentions alone I can guess that lift has to look like:
L = r * V^2 * S *(dimentionless coefficients)
Note that S does not have to be the real area of the wing, just a squared length scale. All the actual details of the exact shape of the wing and aerodynamics will go into dimentionless factors. Only thing to keep in mind when scaling things is that there might be other dimentionless numbers that need to be conserved (like the Rynolds number).
Bozon
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Sorry Waffle,
The right answer is B. The solid red line has the same angle on both sides of teh window.
:D
Why is the line of sight originating from different place inside of the cockpit with YOUR red and white lines. You are supposed to keep the eye in the same place in both cases to be able to compare them :)
Also your blocked FOW should be on the OUTSIDE of the cockpit, not inside.
Honestly Waffle... are you playing some major joke on me :).. candid camera somewhere? :)
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Which Is why i said "a - the dotted red line, or whichever angle is the same as the angle on the inside"
The blocked feild of view is representing what you would see....the inside of the frame...no light / sight passes through that. Hence the label "feild of view blocked by outer frame". So the pilots head would have to be to the left of the white line to see anything useful when the line is at the outer frame.
The reason the lines move is because a pilot can move his head, and also to show where the line of sight "from the outside looking in " would be. IE - where the pilot would have to have his head in order to see/ Also - it's not in scale at all..
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Yeah waffle............
The inner bars will define the window or orifice ......... .refraction will add a lenslike quality depending upon the angle of view.
In your animated giff the frame would be a constant but the field of view thru it would change depending upon the thickness and distance the head is held from it.
Because its flat the magnifying effect only occurs at the edges and is subject to the distance the head is held (generating the refractive angle ) from the glass.
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So what is your drawing presenting or claiming or proving? :)
- no light passes to the area you have marked grey? Not even from straight ahead? Must be a black hole or something :)
- you can move your head left, from red line to white line... and then with the refraction the frame block one's view from this better position (white) just as much as without refraction from the previous worse (red) position... eh? :)
Should we end here or should we keep on playing? Have you counted how many people in this and the previous threads have supported the theory you have presented? How many have agreed that the refraction offers more viewing angle and area?
Dont you think some other people would have already challenged the refraction drawings if I had just imagined them? Someone like gripen would surely have argued against them if there was something to challenge.
But maybe you already agree with the B-answer and will eventually see what it means. S!
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Originally posted by Crumpp
Can you point out the tips of the helicopter area or the 747 used in this example please and how the differences are accounted for in your formula by using raw area??
Nonsense. We need only know the reference area (usually wing planform area or what ever), geometry does not matter at all in the Cl calculation I linked. It simply gives the required Cl for given lift despite what ever is the geometry of the wing.
Originally posted by Crumpp
Area is not shape nor does it define shape. It is just area.
We don't need to know geometry of the wing to calculate required 3D lift coefficient.
Originally posted by Crumpp
It is not 3D theory, however as it does not account for the shape of the wing.
It's pure and plain 3D and no calculation gives more accurate result.
gripen
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Originally posted by BlauK
So what is your drawing presenting or claiming or proving? :)
- no light passes to the area you have marked grey? Not even from straight ahead? Must be a black hole or something :)
Light = sight....can't see without reflective light. Light wont pass through the metal frames.
so you're saying the pilots got a wonder woman plane and they can see throught the metal frame?
What it's proving is the basis of your drawing about suggesting there is magical feild of view growth, which there isnt. :D
Also you'll notice on the 45 degree drawing, when it's closest to the outer frame, the area thats not blocked by the inner braceing....
That would be the the view that would make the "rails" seem to be inset (ot thinner, as some would want to believe)
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Waffle,
-keep the eye in same place! We are not arguing about what one can see from one position compared to another. The question is about what one can see from one place with and without the armoured glass!
-make the inner attachment strip thinner like you can see in the photograph (it does not even precent seing the side of the armoures glass.. and if that is you point, let's not yet argue about it, just accept it for now)
-then compare the field of view OUTSIDE of the cockpit with and without refraction!
You got all the ingredients already, you are just confusing which pot to put them into!
Here is teh test for you:
Without the armoured glass one cannot see the green dot (P1) from the eye position marked with white! You can rotate the eye, but not move it to another place!
If one has the armoured glass with refractions, Can he see the green dot? Yes or No?
Please draw the answer on the pic below!
(http://www.virtualpilots.fi/LLv34/kuvat/bk/cpit/ref_test.jpg)
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(http://www.dangreve.com/images/ref_test1.jpg)
now we'll see what hapeens on rotation.
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Hi Waffle,
>The angle will be the same going through a piece of glass with parallel edges.
You're right with regard to the angle, but the displacement really makes a difference here.
Just imagine a pilot with a laser pointer mounted on his head.
Case A: No armour glass is installed. The pilot is pointing the laser beam at the very edge of the canopy frame. The beam just hits the frame, so you have a laser dot there, and that's it.
Case B: The armour glass is installed now. The pilot aims the beam at the same angle as before. The beam enters the glass now and is inevitably refracted towards the centre of the windshield. It's not as far out as the beam that was just stopped, so it's not stopped. Upon exiting, it is refracted outwards again back to its original angle.
As this original angle was too large to allow passage of the laser beam without the refractive armour glass, the laser beam is projected to a point that was obscured by the frame before.
The conclusion is that the armour glass does indeed result in a larger field of vision. (The geometry is the same regardless of the way the light passes through the glass.)
Does it sound logical if explained this way? :-)
Regards,
Henning (HoHun)
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If you take that white line, unedited, and rotate it at the eye-point, the end of it will touch the P1 and you still won't bump into the frame.
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(http://www.dangreve.com/images/ref_test2.jpg)
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Originally posted by Krusty
If you take that white line, unedited, and rotate it at the eye-point, the end of it will touch the P1 and you still won't bump into the frame.
but you're forgetting the refraction angle which will change as it goes through the glass.
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Originally posted by KAntti
BTW I'll add this link for you and others interested in the actual characteristics of 109's. From the mouths of the pilots them selves:
(theres even an Stall performance report conducted by RAF Royal Aircraft Establishment (RAE) Farnborough handling trials.
http://www.virtualpilots.fi/feature/articles/109myths/ (http://www.virtualpilots.fi/feature/articles/109myths/)
I am generally not a 109 enthusiast, but I'd hate to think that ANY AC would be given LESS, OR MORE performance in AH than it in reality deserves.
Interesting Virtual pilot site.
Again, this article is not and does not try to be a complete study. Far from it. It is fragmented and might seem as one sided.
That said what i found interesting was the opinions differ with pilots.
Visability sucked. Visability wasn't that bad.
Slats were good. Slats were bad.
109s could out turn spits during BoB but not later models of Spit.
The 109 was wonderful. The only good thing about the 109 was the cannon and engine.
109 turned great. 109 didn't turn well.
All from guys who flew them. Beauty is in the eye of the beholder apparently.
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Waffle,
I said, dont move the eye ;)
Only rotate it!
.. but anyways. You are already close to the solution. You already got more viewing angle. Congratulations!
In other words, what yuo see is what you get! Now look again at those pich where the vertical frames appear thinner!
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It's pure and plain 3D and no calculation gives more accurate result.
It is not Gripen. Your pushing pure baloney and acting like a child. If it does not consider the shape of the wing it is not 3D theory by definiton.
Calculation of CL alone is not 3D theory either, it is part of it. Unless you take the next step in the process and consider AR and efficiency.
For high angle of attack situations such as turn, 3D is more accurate than calculations based on CL alone. Why? It is an area were the dimensions ae not as trival.
Not to say that there are not other acceptable methods or other ways to do it as many conditions of flight the dimensions are trivial as bozon point out.
Anyone can work the following problem and see the difference in the theory:
Assume two planes of equal weight, equal wing area, and equal speed flown in the same atmosphere.
One has an elliptical wing with no twist, and the other a square wing with no twist. The CL will calculate out exactly the same using that formula.
These wings may have the exact same CL but they will not have the exact same abilities or characteristics.
All the best,
Crumpp
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Originally posted by BlauK
Waffle,
I said, dont move the eye ;)
Only rotate it!
.. but anyways. You are already close to the solution. You already got more viewing angle. Congratulations!
In other words, what yuo see is what you get! Now look again at those pich where the vertical frames appear thinner!
First pic - the eye didn't move..and you cannot see P1...
The only way to see P1 is to move the eye, which is illustrated in the second posted pic.
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nooo :cry , you were so close...
In first picture yuo did not rotate the eye and in 2nd yuo had to go and move it :(
Try one more time, please. Rotete, but dont move!
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Tell you what Blauk - you give me the angle from P1 - use dead center (1 pixel lines) to the outer frames edge (no-mans land - cant see nothing but frame mount)
Let me know that angle and post that pic.
It's not a simple as rotating to fit - theres a refraction angle in the glass which corresponds to the angle (LOS) that hits the glass. Thats what the second pic was about. Which is how seeing p1 results in having to move the eyepoint forward. As you rotate - you will also have to move the eyepoint forward some to see P1 due to the refraction angle changing in the glass.
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Waffle,
it is not really about the exact numbers, but about the principle.
Anyways, try 38,7 degrees. I dont know if yuo wil lbe able to fit the whol egreen dot, or just part of it, bu tin any case you can get a wider view than without teh armoured glass.
Here is the pic with 38,7 degs:
(http://www.virtualpilots.fi/LLv34/kuvat/bk/cpit/ref_test_38_7.gif)
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btw Waffle, what material are yuo using for the armoured glass?
I got interested in teh actual numbers, so I found this kind of values from net:
Air 1,0003
Plexiglass 1,51
Crown Glass 1,52
Light Flint glass 1,58
Dense flint glass 1,66
Your 40 angle refracts as 28,9, whereas I get even with the plexiglas a refraction of 25,2 degrees.. which allows more view than your 28,9 degs.
I really wonder if the density of the armoured glass would also be higher than that of normal glass... no idea.
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ding ding ding....lol
Thats why I was curious as to what type glass it was made out of. Actually this is kinda a moot point without that knowledge...
BTW - I ran the last pict with a 28 degree refraction...and the line ended up slightly behind the eyepoint...which would mean out of feild of view? or having to move back a small amount...lol
Anyway - I got crap to do today...wasted enough time today... :D
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Originally posted by Waffle BAS
BTW - I ran the last pict with a 28 degree refraction...and the line ended up slightly behind the eyepoint...which would mean out of feild of view? or having to move back a small amount...lol
Nope.. wrong interpretation. One does NOT have to MOVE BACK in order to see it. One CAN move back and STILL SEE IT! ;)
The blocked area is on the right side of the LOS, right?
Would this be enough to prove the point?
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Originally posted by Crumpp
It is not Gripen. Your pushing pure baloney and acting like a child. If it does not consider the shape of the wing it is not 3D theory by definiton.
Complete nonsense. The shape of the wing does not affect on required (3D) Cl for given lift. There is no physical nor aerodynamical reason for that. You simply can't understand that required Cl in 3D depends only on wing area, density, speed and lift.
Originally posted by Crumpp
Calculation of CL alone is not 3D theory either, it is part of it. Unless you take the next step in the process and consider AR and efficiency.
Complete nonsense. There is no physical reason to include AR or efficiency to Cl calculation because these are not needed to calculate required Cl in 3D.
Originally posted by Crumpp
For high angle of attack situations such as turn, 3D is more accurate than calculations based on CL alone. Why? It is an area were the dimensions ae not as trival.
Complete nonsense again. The equation I linked gives exact and accurate required Cl for any loading in turn and it's 3D. There is no method which gives more accurate Cl.
BTW please, try prove your claim with calculation if you can...
Originally posted by Crumpp
Anyone can work the following problem...
Required Cl for both wings are exactly same, regardless shape of the wing and the equation I linked gives exact and accurate required 3D lift coefficient for them at all loadings, in turn, level, dive or what ever flight condition.
gripen
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here's the pic:
So at 38.7 degrees - the eyepoint would have to be back...remember you said we couldn't move the head? :) so if it LOS was moved up to the eye posistion. - even at 38.7 degress - you still wouldn't see P1.
like I said it's all moot untill we find they type of glass / proper thickness and the refraction index of the glass.
Also - if you're getting a smaller angle - you said 25 to my 28 - that would result in a smaller view. I should say shifted instead...it would bring the angle on the exterior side inward.
(http://www.dangreve.com/images/28refrac.jpg)
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waffle, that only means that not only would you be able to see P1, you'd be able to see a bit past it. The line is the outer angle for your field of view.
Anything inside it is visible. Thus you could see P1 with refraction (but not without refraction).
The general conclusion I made from this thread is that the frames in the 109 (and 190?) should not be as thick, because in reality when you sit inside the cockpit the refraction makes them look thinner.
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Originally posted by Lye-El
Interesting Virtual pilot site.
That said what i found interesting was the opinions differ with pilots.
Visability sucked. Visability wasn't that bad.
Slats were good. Slats were bad.
109s could out turn spits during BoB but not later models of Spit.
The 109 was wonderful. The only good thing about the 109 was the cannon and engine.
109 turned great. 109 didn't turn well.
All from guys who flew them. Beauty is in the eye of the beholder apparently.
Of course I should have mentioned that this is not to show off 109 or compare it to any other aircraft. I tried by telling Im not into 109's but apparently I failed.
If you take a closer LOOK and forget your favorite AC and really look. WHERE can u see a mention anywhere there that 109 (never mind the variant) had other than superb or even adequate stall performance?
The overall picture the interviews offer is not what I am looking at. I want to know how the stall performance of AH 109 FM compares with what the pilots have to say. We have been and at least I am still talking only and solely of the stall performance. When the interviews and test reports are referring to as wonderful stalling performance, the AH 109 FM compared must be running in the woods at night with a sack over its head.
And truly, the beaty IS in the eye of the beholder as what u are referring to is the russians and others saying 109 was wonderful and finns that flew them saying it wasn't that good compared to the Fiat g.50's and Brewsters, please check them out:
http://hkkk.fi/~yrjola/war/faf/brewster.html (http://hkkk.fi/~yrjola/war/faf/brewster.html)
http://www.kotfsc.com/aviation/g50.htm (http://www.kotfsc.com/aviation/g50.htm)
The overall picture is very complex view to what 10 or so aces thought about the plane, but try to separate this small thing of stall performance from the overall picture and come back with something else than "They all contradict in performance compared to the spit"
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Originally posted by KAntti
And truly, the beaty IS in the eye of the beholder as what u are referring to is the russians and others saying 109 was wonderful and finns that flew them saying it wasn't that good compared to the Fiat g.50's and Brewsters, please check them out
Spot on
Beauty is very much in the eye of the beholder.
Thats the main reason that they don't build FMs based on anecdotal evidence.
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Holy helll we have a spitmaister here!
Even if it was equally accepted by any one as truth, regardless the side the plane was used Kev? U would actually trust the FM in hands of "trusted and absolutely non partial, non eye beholding" creator? Do you actually question anything that works in your favor Kev?
As I said before this is a game, AND if u dont believe anecdotes, there still are the real warbirds flying around.
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And todays fliers give anecdotes.
Some of the old ones still live though. But not many of them flew US, UK and LW planes. The selected who did that would almost exclusively at combat be Finns, then you have the others testing the enemy's stuff.
Oh, got one of them on my sig....goodness ;)
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Originally posted by Angus
And todays fliers give anecdotes.
Some of the old ones still live though. But not many of them flew US, UK and LW planes. The selected who did that would almost exclusively at combat be Finns, then you have the others testing the enemy's stuff.
Oh, got one of them on my sig....goodness ;)
Please tell me the performance data given to any AC is actually been confirmed at least by some flight tests done by a real human, please!!
I gather none of the interviewed flew US UK and LW planes, no where near. And if u still did not get it, my point is not to compare aircraft to each other, but to compare one AC to corresponding AH FM. The whole consept seems to be out of reach to you all who have been beating each other up so long that you dont even understand what I am saying.
This then might be the first time (not really but seems new to you) when 109's performance is not compared to other AC, but only to the FM of AH.
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Anecdotes..? Then here's the game for you:
(http://bellsouthpwp.net/w/o/wotans/FB_USA.jpg)
No math involved!
FM base on pilot's stories!
comes with .50 cal tiger killers...
(image originally posted on SimHQ by 15/JG52_Genie)
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HAHAHAHAHA:rofl :rofl :rofl
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Kantti:
I have some Anecdotes (from autobiographies mostly, - which I have) of pilots that tested RAF&LW, and vice versa with a topping of US.
It gets sour for many in this forum to swallow, that all I have matches nicely, be it a German pilot or an Englishman.
Anyway, if you want to compare the 109's performance to the AH, it's another thread, this one is about the 190's.
:D
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Oh, that picture above:
I knew a pilot who got into a scruffle with a 262. Him in a P51 together with a squadron.
262 got thirst for blood. He jumped the P51's and got one alone for himself, but the P51 actually outturned the 262, - by the time the 262 pilot aborted the turnfight it was too late, - the P51 shot him down. A 4 gun P51 BTW....Bruno, are you unemployed?
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Bruno, are you unemployed?
Hardly...
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Originally posted by KAntti
Holy helll we have a spitmaister here!
Even if it was equally accepted by any one as truth, regardless the side the plane was used Kev? U would actually trust the FM in hands of "trusted and absolutely non partial, non eye beholding" creator? Do you actually question anything that works in your favor Kev?
As I said before this is a game, AND if u dont believe anecdotes, there still are the real warbirds flying around.
Real warbirds, yup.
But in 'mock' combats theres not the desperation of knowing you could get shot down 'for real'.
Yup regardless of which side.
They are great for reading, but hardly a source of hard quantifiable data.
Not a question of believing or disbelieving anecdotes, you can't build an FM from them, they're not exact.
edit - Apart from that, there's enough disagreement when hard data is posted, imagine the chaos/accusations if FM's started to be built using anecdotes.
Don't fly IL2 so I can't comment, but from speaking to Skuzzy they don't think much of any of the FM's in it.
Apart from that, IL2 has zero to do with this game anyway.
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No one says anything about Cl. It's about theory.
Crumpp says:
Anyone can work the following problem...
Gripen says:
Required Cl for both wings are exactly same, regardless shape of the wing and the equation
Now we are making progress. That is because you have not applied shape to the wing yet, only area.
Before we get a turned around lets clarify some things.
The lift equation is a very powerful formula and can be used to analyze data to a point. It does return very good agreement but has limitations. It is not used by engineers for detailed analysis.
In effect it is a 3D CL as it measured actual lift force on a reference area but it is not 3D theory.
Getting back to our sample problem:
You get the same CL for both wings no matter what formula you use, correct?
In our above reference calculation our CL is finshed under the lift equation method and becomes the CL of the wings. Even though we both know an elliptical wing with no twist will have a higher lift than a rectangular one just due to the influence of induced drag.
Engineers use 3D theory. 3D theory uses a 2D CL and seperates the effects of AR and efficiency. Once these factors are applied our CL's will be different under the same conditions reflecting the shape of the wings.
http://www.grc.nasa.gov/WWW/K-12/airplane/kitedown.html
Which inspite of your claims is used on much more than rectangular wings. It was developed for that but has been expanded to cover other wing designs.
All the best,
Crumpp
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Originally posted by Crumpp
No one says anything about Cl. It's about theory.
Nonsense. You have been arguing all the time that the Cl equation:
Cl = L / (A * .5 * r * V^2)
is not 3D theory. It is 3D theory, it gives exact and accurate required 3D lift coefficient for any given airframe at any loading in 3D enviroment. 2D theory would result 2D lift coefficient ie Clo.
Originally posted by Crumpp
Now we are making progress. That is because you have not applied shape to the wing yet, only area.
Nonsense. We are talking about required lift coefficient, not about induced drag.
Originally posted by Crumpp
Before we get a turned around lets clarify some things.
The lift equation is a very powerful formula and can be used to analyze data to a point. It does return very good agreement but has limitations. It is not used by engineers for detailed analysis.
Complete nonsense. The Cl equation has no limitations and it can be used and is used by engineers for exact and detailed analysis.
Originally posted by Crumpp
In effect it is a 3D CL as it measured actual lift force on a reference area but it is not 3D theory.
Complete nonsense. You are trying make your own false definition of 3D theory.
3D theory simply handles finite wings and 3D lift coefficient (ie Cl) for any finite wing at given conditions can be calculated with the formula:
Cl = L / (A * .5 * r * V^2)
2D theory handles infinite wings and 2D lift coefficient is Clo which is usually determined in the wind tunnel.
Originally posted by Crumpp
You get the same CL for both wings no matter what formula you use, correct?
There is only one formula needed to calculate required Cl (3D) and the Cl will be the same for both wings.
Originally posted by Crumpp
In our above reference calculation our CL is finshed under the lift equation method and becomes the CL of the wings. Even though we both know an elliptical wing with no twist will have a higher lift than a rectangular one just due to the influence of induced drag.
We are not talking about induced drag.
Originally posted by Crumpp
Engineers use 3D theory. 3D theory uses a 2D CL and seperates the effects of AR and efficiency.
Complete nonsense.
3D theory uses 3D lift coefficient ie Cl.
2D theory uses 2D lift coefficient ie Clo.
Originally posted by Crumpp
Once these factors are applied our CL's will be different under the same conditions reflecting the shape of the wings.
Complete nonsense. The Cl (3D) at given loading is same in all cases despite what ever is the shape of the wings. Required 3D lift coefficient depends just on wing area, density, speed and lift regardless the shape of the wing.
Originally posted by Crumpp
http://www.grc.nasa.gov/WWW/K-12/airplane/kitedown.html
Which inspite of your claims is used on much more than rectangular wings. It was developed for that but has been expanded to cover other wing designs.
The link shows well the difference between 2D (Clo) and 3D (Cl) lift coefficient, you just can't undersstand how these are used.
Besides, I have not made any claims regarding that page in this thread.
gripen
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Waffle,
Krusty pretty much summed it up.
Also the smaller refraction angle would mean more shifting and therefore more viewing angle (not less). If the refraction angle gets smaller it allows a wider original (from eye) viewing angle and still manages to get by the frame at the outer surface of the glass.
In other words, the more dense material refracts more and makes a bigger shift and provides a wider view.
Thanks anyways for the argument. It made me refresh the old high school stuff on how the refraction is calculated. Maybe I will now try to put in the real numbers for 109 pilot's position etc. and figure out the previously mentioned 1-sided polygon approach in more detail for fixing the problem
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It is 3D theory, it gives exact and accurate required 3D lift coefficient for any given airframe at any loading in 3D enviroment. 2D theory would result 2D lift coefficient ie Clo.
No Gripen,
YOU have been arguing about CL, I have been arguing that 3D theory is more accurate.
3D theory simply handles finite wings and 3D lift coefficient (ie Cl) for any finite wing at given conditions can be calculated with the formula:
Cl = L / (A * .5 * r * V^2)
Find the CL for an elliptical shaped wing with no twist and an AR of 5:
L = 3000lbs
Area = 150sq ft
V = 400fps
r = 0.0023[slug/ft3]
Now find the CL for a rectangular shaped wing with no twist and an Aspect ratio of 7:
L = 3000lbs
Area = 150 sq ft
V = 400 fps
r = 0.0023[slug/ft3]
What is the CL going to be using the standard forumla??
The SAME!!! WE are done, right??
Yet we know the lift properties are going to be different for each of these wings so the CL should NOT be the same simply due to AR and induced drag production.
Well not if we want to include the shape of the wing. We start with a 2D CL and factor in the influence of Aspect Ratio and efficiency.
You can see the effect of aspect ratio on the lift produced by a wing quite clearly in the following graph.
(http://img132.potato.com/loc43/th_28c5e_lift.JPG) (http://img132.potato.com/img.php?loc=loc43&image=28c5e_lift.JPG)
http://www.aerospaceweb.org/question/aerodynamics/q0167.shtml
You can better understand the effects of induced drag and stall by studying the following graph.
(http://img146.potato.com/loc98/th_8e7f5_lift_tat.JPG) (http://img146.potato.com/img.php?loc=loc98&image=8e7f5_lift_tat.JPG)
http://www.aerospaceweb.org/question/aerodynamics/q0136.shtml
Our answer might be close to the original CL calculated using:
Cl = L / (A * .5 * r * V^2)
But it will not be the same.
Using 3D theory we will have two diffent CL for two different wings.
All the best,
Crumpp
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The general conclusion I made from this thread is that the frames in the 109 (and 190?) should not be as thick, because in reality when you sit inside the cockpit the refraction makes them look thinner.
That is correct!
All the best,
Crumpp
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The 190 frames look too thick too me just look at the pictues above.
The "anecdotes" usually refer to good view.
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Originally posted by Crumpp
YOU have been arguing about CL, I have been arguing that 3D theory is more accurate.
Nonsense. You have claimed several times that the formula I linked is not 3D theory and something which you can't specified is more accurate. These claims are completely false. The formula gives directly the exact and accurate required 3D lift coefficient (Cl not Clo) for any given loading at any given flight condition.
Originally posted by Crumpp
The SAME!!! WE are done, right??
Yep, we are done. We know (if you can actually do the calculation) what is the required Cl for this amount of lift at this flight condition. Required Cl (as well as lift) will be the same despite what ever is the shape of the wing.
Originally posted by Crumpp
Yet we know the lift properties are going to be different for each of these wings so the CL should NOT be the same simply due to AR and induced drag production.
Here we can see from where your confusion starts; AR nor induced drag have no any kind of effect to required Cl nor to required lift at this given flight condition.
Originally posted by Crumpp
Well not if we want to include the shape of the wing. We start with a 2D CL and factor in the influence of Aspect Ratio and efficiency.
The 2D lift coefficient (Clo) has absolute nothing to do with this. The formula gives directly the 3D lift coefficient (Cl) required for given lift.
Here is the 747 calculation:
(http://aerospaceweb.org/question/aerodynamics/lift/747-eq02.gif)
Please prove with calculation if the calculated lift coefficient is 3D (Cl as marked) or 2D (Clo) as you are trying to argue.
Originally posted by Crumpp
Our answer might be close to the original CL calculated using:
Cl = L / (A * .5 * r * V^2)
But it will not be the same.
Nonsense. The required Cl will be exactly same at given loading despite what ever is the geometry of the wing. There is no need to know the angle of attack.
If you want to prove otherwise, please do the math.
Originally posted by Crumpp
Using 3D theory we will have two diffent CL for two different wings.
Nonsense again, the Cl will be exactly same if the area, loading, density and speed are the same.
gripen
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Two different wings means two different airfoils right?
So, CL should be different, or could at least.
Well, in reality. Not sure of that theory.
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Originally posted by Angus
Two different wings means two different airfoils right?
So, CL should be different, or could at least.
Well, in reality. Not sure of that theory.
It does not matter if the airfoil is different. Exactly the same Cl will be required for a given lift regardless geometry or airfoil.
Try to think it this way; same amount of lift is needed at given wing area despite what ever is the geometry or airfoil, so the required Cl must be exactly same despite what ever is AoA or induced drag.
Basicly claiming something else is a physical impossibility because the lift and area remain the same.
gripen
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The required Cl will be exactly same at given loading despite what ever is the geometry of the wing. There is no need to know the angle of attack.
Who is talking about Angle of Attack??
The graph shows various angles of attack but the importance is the differences in the CL due to wing efficiency and Aspect ratio.
Are you not smart enough to compare them at 0 angle of attack listed on the chart?
Do you need me to point that out?
Ok, Gripen, look on the chart at the line marked "0" and compare the influence of induced drag and Aspect Ratio.
All the best,
Crumpp
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Gripen says:
The formula gives directly the exact and accurate required 3D lift coefficient (Cl not Clo) for any given loading at any given flight condition.
Yeah ok.
That is why NASA says:
Keep in mind that this equation for lift is only a very basic expression used to analyze the overall aerodynamic behavior of an entire vehicle. Engineers must use much more complex methods to do detailed design and analysis work.
http://www.aerospaceweb.org/question/aerodynamics/q0078.shtml
Throw some more nonsense in the thread, Gripen.
All the best,
Crumpp
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Originally posted by Crumpp
Who is talking about Angle of Attack??
The graph you posted above shows Cl vs angle of attack, but we don't need to know it.
Originally posted by Crumpp
The graph shows various angles of attack but the importance is the differences in the CL due to wing efficiency and Aspect ratio.
We are not interested what kind of angle of attack is required for the Cl required. Required Cl and lift will be the same regardless what ever AoA is needed at given flight condition.
Originally posted by Crumpp
Are you not smart enough to compare them at 0 angle of attack listed on the chart?
There is no need to know the AoA to calculate required Cl.
gripen
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Originally posted by Crumpp
That is why NASA says:
"Keep in mind that this equation for lift is only a very basic expression used to analyze the overall aerodynamic behavior of an entire vehicle. Engineers must use much more complex methods to do detailed design and analysis work."
It does not change the fact that the exact and accurate required Cl can be calculated easily with simple equation.
gripen
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It does not change the fact that the exact and accurate required Cl can be calculated easily with simple equation.
Yeah ok. Tell NASA.
It can right next to your theory on calculating wing efficiency off the wing twist distribution chart in Lednicers article.
All the best,
Crumpp
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Originally posted by Crumpp
Yeah ok. Tell NASA.
It can right next to your theory on calculating wing efficiency off the wing twist distribution chart in Lednicers article.
They allready know it as they know it in the Aerospace web. They also allready know that there is a strong correlation between e factor and lift distribution.
gripen
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Find the CL for an elliptical shaped wing with no twist and an AR of 5:
Now find the CL for a rectangular shaped wing with no twist and an Aspect ratio of 7:
What is the CL going to be using the standard forumla??
Of course it is the same, the formula is being used to calculate the CL required from the wing to create the required lift under a given set of conditions.
But what will differ, is the AoA, drag etc. of different wings. This is where the more advanced theories/calculations would be applied.
(http://img132.potato.com/img.php?loc=loc43&image=28c5e_lift.JPG)
Say you need CL = 1 to meet a given set of conditions. From the chart, you can see that the C172 only needs about 7º AoA, while the BAC Lightning would need about 20º AoA to get CL = 1. The Lightning would have higher drag as a result of the higher AoA and lower AR, requiring more thrust etc...
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"It is interesting Charge that more than one flight test notes this same characteristic."
That may be, but my point was that I wouldn't put much weight on anything that that document says without knowing something about the aircraft/s in question ie. Power/weight figures, wing profiles and planforms+area, flap configurations (if used in test) etc.
As I said: Merely implications of their true performance.
-C+
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ehh, Gripen:
"It does not matter if the airfoil is different. Exactly the same Cl will be required for a given lift regardless geometry or airfoil."
I recall HiTech explaining something similar. Bloody confusing.
Lift is a constant, - if you look at it that way.
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Of course it is the same, the formula is being used to calculate the CL required from the wing to create the required lift under a given set of conditions.
But what will differ, is the AoA, drag etc. of different wings. This is where the more advanced theories/calculations would be applied.
Justin sounds like he knows much more than I do however I will piggy back onto his point.
The equation to detemine Clmax is so simple that it encompasses all aspects of wing design without having to know almost anything about the aircraft. It could be a cardboard box you are measuring.
The calculation I use is
weight * 391(air density at sea level) / 1G stall speed ^2 * Wing area
There is no mention of aspect ratio, airfoil type or wing tip shape, why? Because these things are already factored into the equation in the form of stall speed. If the wing creates enough lift and the bird is not to heavy it will not stall. That is the same for a delta wing, Spitfire or 190. As long as you know the wing area, weight and 1G stall (power off) you know how this aircraft will handle.
What it does not tell you is Induced drag from lift. However an aircraft with lower wing loading will not have to pull as hard as one with high wing loading so it will naturally create less drag.
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f4udoa: Whats the 391 term?
HiTech
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Air density at sea level in hectograms/cubic yard?
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As I said: Merely implications of their true performance.
True and I completely agree. They are not useful for absolute performance.
Of course niether are performance graphs from different countries in the 1940's without a more detailed information than speed/climb.
The set up sheet for this particular report is available listing.
All the best,
Crumpp
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HT,
I'm an idiot!! 361 not 391!!
The 361 is air density multipier for sea level. At least this is how it was expalined to me.
If you remember Wells from the boards a few years back, I used to correspond with him to try to understand this stuff a little better.
For example
F4U-1
12,000 * 361 / 96mph^2 * 314
4332000 / 2893824
Clmax = 1.49
That is actually a little high but the stall is really closer to 96.5TAS.
From there you can multiply the square of the G factor * the 1G stall number to get the accelerated 3G stall.
3G Squared = 1.73 * 96MPH = 166.27MPH stall at 3G
When you compare these numbers to the actual numbers they are not just close they are amost exact. (the chart is IAS Knots)
(http://mywebpages.comcast.net/markw4/F4UG.jpg)
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Getting back to the discussion of the fundamental relationship of power available to power required.
Here is some food for thought in the form of the percentage weight gain of various USAAF Fighters:
(http://img14.potato.com/loc215/th_730d5_US_fighter_weight_growth.jpg) (http://img14.potato.com/img.php?loc=loc215&image=730d5_US_fighter_weight_growth.jpg)
Generally speaking, all of these weight gains accompanied a power available increase. I remind the participants that power available increase can come in many forms. More efficient propeller, drag reductions, etc...
Not solely from an increase in engine power.
Using the Rüstgewicht (empty service weight) the FW-190A BMW801D2 powered fighter variant series gained 5.9%.
All the best,
Crumpp
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Of course it is the same, the formula is being used to calculate the CL required from the wing to create the required lift under a given set of conditions.
Exactly Justin.
Keep in mind however it is only an estimate and not the absolute and correct CL. This sheet of comparing measurements to calculations provides a good example for various airfoils provides a clue to the margin of error:
(http://img124.potato.com/loc126/th_d2445_ecompare.jpg) (http://img124.potato.com/img.php?loc=loc126&image=d2445_ecompare.jpg)
So it is easy to see that while the calculated CL required gives good agreement in the majority of cases and provides for reasonable predictions it is not the absolute and correct CL as claimed.
All the best,
Crumpp
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Originally posted by Kev367th
Real warbirds, yup.
But in 'mock' combats theres not the desperation of knowing you could get shot down 'for real'.
Yup regardless of which side.
They are great for reading, but hardly a source of hard quantifiable data.
Not a question of believing or disbelieving anecdotes, you can't build an FM from them, they're not exact.
edit - Apart from that, there's enough disagreement when hard data is posted, imagine the chaos/accusations if FM's started to be built using anecdotes.
Don't fly IL2 so I can't comment, but from speaking to Skuzzy they don't think much of any of the FM's in it.
Apart from that, IL2 has zero to do with this game anyway.
Again I am not talking about comparing AC to annother so 'mock' combats are unnecessary. I am talking about 109's or any other AH AC's stall performance. U dont need any combat to perform such a test.
U really cant build an FM based on anecdotes I think so too, but you cannot calculate the behavior of an AC with just math. If that was the case, any test flight series would be totally useless. There are things a math cannot provide an answer to, thats why the tests are necessary.
In your opinion this would mean that no matter what the test pilot says about the performance, the engineers would dismiss the remarks as anecdotes.
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but you cannot calculate the behavior of an AC with just math.
Absolutely. Just look at the F-18.
All the best,
Crumpp
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Crumpp, it is an exact number. It is the exact CL required[/b] to meet a given set of conditions. See the B747 example from aerospaceweb.org, reproduced below:
Basic physics tells us that the lift and weight should be equal to each other for any aircraft in steady, level flight. If the two forces were not equal, the plane would not remain in level flight. Either the plane would climb to a higher altitude because the lift exceeded the weight and pulled it upward or the plane would descend due to the greater weight pulling it down.
We can use this relationship to rearrange the lift equation and apply it in a new way. Since lift must equal weight for the plane to fly level, lift becomes a known value that we can use to solve for the lift coefficient. The lift equation then becomes:
(http://www.aerospaceweb.org/question/aerodynamics/lift/eq07.gif)
We can again use the values provided above for the 747 to solve this equation.
(http://www.aerospaceweb.org/question/aerodynamics/lift/747-eq02.gif)
Lo and behold, the lift coefficient is 0.52, exactly the value provided in the original data. This application of the lift equation may seem backwards, but engineers often use it during the preliminary design process of a new aircraft. A cruise speed as well as an approximate weight and size are typically specified when the design effort begins. These values can be used in the above equation to solve for the lift coefficient necessary to maintain cruise flight at those conditions. Once that coefficient in known, designers can determine what wing shape and airfoil section will best provide that lift coefficient while minimizing drag. Other factors obviously come into play since an aircraft does not spend its entire flight at steady and level conditions, but this technique is a common first step in the initial sizing and design of a new flying vehicle.
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What effect does wingloading have on Pr in turns at Clmax?
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F4UDOA: Thanks just never have seen density combied with mph to fps conversion along with a 1/density instead of density combiened with the vel term and area term. Net wash is the same equations either way.
Had me confused for a sec.
Any way I belive you were correct with the 391 number .
1.4666 is mph to fps conversion
Should be = 1 / (1.4666 * 1.4666 * 0.5 * 0.00237)
HiTech
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Crumpp, it is an exact number.
Doah! For some reason I have turning on the brain. It will be the same for level flight. Got wrapped around the 2D vs 3D theory on which is better for analysis.
Other factors obviously come into play since an aircraft does not spend its entire flight at steady and level conditions,
Thanks,
Crumpp
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Other factors obviously come into play since an aircraft does not spend its entire flight at steady and level conditions,
The calculation for Cl required is absolutely accurate for any given flight condition; level, climb, turn, dive or what ever.
gripen
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Originally posted by Crumpp
I can just picture some German POW thinking:
"Why yes Mr interrogator, we hated the damn thing too. Always ran rough like that. In fact I was scared to death it was going to fall out of the sky on the flight over!"
That is purely speculative. There were Luftwaffe crew who were happy to help the allies. Men who didn't dig the Nazis and wanted them defeated. Remember the Ju 88 of 10./NJG3, crewed by Oblt Heinrich Schmitt, Ofw Paul Rosenberger and Ofw Erich Kantwill? They flew from Norway to Dyce in Scotland, gifting the British with a shiney new Lichtenstein radar, allowing the boffins to cut the strips of window to the right length, thus jamming German night fighters' radar and enabling Bomber Command to devastate Hamburg with few losses. So it's quite conceivable that a FW pilot would help the British with the 190. They would only need to find one man willing to help and I doubt they were so stupid as to be taken in by some guy feeding them nonsense. We're not talking about back engineering a UFO.
KD
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That is purely speculative. There were Luftwaffe crew who were happy to help the allies. Men who didn't dig the Nazis and wanted them defeated. Remember the Ju 88 of 10./NJG3, crewed by Oblt Heinrich Schmitt, Ofw Paul Rosenberger and Ofw Erich Kantwill? They flew from Norway to Dyce in Scotland, gifting the British with a shiney new Lichtenstein radar, allowing the boffins to cut the strips of window to the right length, thus jamming German night fighters' radar and enabling Bomber Command to devastate Hamburg with few losses. So it's quite conceivable that a FW pilot would help the British with the 190. They would only need to find one man willing to help and I doubt they were so stupid as to be taken in by some guy feeding them nonsense. We're not talking about back engineering a UFO.
Nice speculation on your part as well.
Facts are the rule is POW's resist. The exception is that they cooperate.
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But the real question, Crumpp, is whether you would have dismissed them if they said something you liked. That lies at the root of intellectual honesty, and separates the partisan from the investigator.
So while you feel safe in saying POWs as a rule resist, we can also say that interrogators as a rule understand that their subjects are unwilling and may be actively deceptive. Interrogators carefully seek corroboration and independent sources of information before reaching conclusions.
Why are you eager to trust the nature of german POWs but not the nature of their interrogators?
I have my suspicions.
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I think you are speculating quite a bit there. I did not make a snap judgement based on feelings or desires.
I think it is much more plausible to believe the BMW, Rechlin, and Focke Wulf reports on the technical aspects of the aircraft.
So it has nothing to do with speculation on the part of a POW's testimony.
Since the technical qualities discussed are not the technical qualities exhibited by the motor when set up properly. The engine did not vibrate excessively. In fact the Lufterrad was designed to uncouple from the shaft if it vibrated out of specified range.
All the best,
Crumpp
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Speculating that interrogators know their subjects are enemy combatants? That their loyalties likely lie with their homeland?
Seems a pretty safe bet....safer than, say, assuming that the interrogators would take eveything at face value...
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Well NASA had to reverse engineer the Kommandogeraet in the Fw 190 to see how it went together :D
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Speculating that interrogators know their subjects are enemy combatants? That their loyalties likely lie with their homeland?
Your leaving out the part of the equation and speculating that enemy prisoners will not resist by giving misleading answers. As opposed to assuming POW's will not resist by providing misleading information.
Seems a pretty safe bet....safer than, say, assuming that the interrogators would take eveything at face value...
Nobody has claimed such a silly thing. No statements were ever made about the interogators.
I think it is much more plausible to believe the BMW, Rechlin, and Focke Wulf reports on the technical aspects of the aircraft.
So it has nothing to do with speculation on the part of a POW's testimony.
Since the technical qualities discussed are not the technical qualities exhibited by the motor when set up properly. The engine did not vibrate excessively. In fact the Lufterrad was designed to uncouple from the shaft if it vibrated out of specified range.
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Well NASA had to reverse engineer the Kommandogeraet in the Fw 190 to see how it went together
I can see that most of you are looking at this from your gameshape view and how it will benefit your side.
Lets use some common sense, however.
You think it might be important on a very rare and very expensive motor to get settings correct that could destroy the whole motor if not done properly?
Especially when the company that originally built the device says they can no longer set it up?
All the best,
Crumpp
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Originally posted by Crumpp
Your leaving out the part of the equation and speculating that enemy prisoners will not resist by giving misleading answers. As opposed to assuming POW's will not resist by providing misleading information....
originally posted by Simaril
...safer than, say, assuming that the interrogators would take eveything at face value...
Originally posted by Crumpp
Nobody has claimed such a silly thing. No statements were ever made about the interogators.
Crumpp, this is what I mean. Let me explain the logical implications of your statements.
1)The interrogators are talking to the prisoners.
2)The prisoners try to fool the Brits. <----- This is your claim against the report
3)But, the interrogators' job is to find the truth.
THEREFORE By saying that the report took the lies for the truth, YOU are claiming that the interrogators took the lies at face value.
Its a fairly simple connection...hard to see why you argued it wasnt there.
You arent stupid, evidenced by your ability to discuss aerodynamics in numbing detail. But, you dont seem open to considering opposing ideas, even when they're about pretty minor points, and when they're logically kinda hard to argue against.
That implies either a blinding passion for the topic, or an arrogant heart that cant admit imperfection, or both.
I fully expect a defense will be mounted, but its pointless. Last time I said I'd lost respect it was out of frustration, but this time its from cool assessment of persistant behavior.
You might find that you got more respect...and that your valid points would be taken more seriously...if you openly admitted when you made a mistake.
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Hi Simaril,
>You might find that you got more respect...and that your valid points would be taken more seriously...if you openly admitted when you made a mistake.
I'm afraid the mistake is yours. Prisoners of War are an inaccurate and unreliable source of information, and any conclusions drawn from their statements are necessarily inaccurate and unreliable by themselves.
Crumpp's example simply illustrates the inherent inaccuracy of information acquired by interrogating prisoners. I can find nothing wrong with that.
Regards,
Henning (HoHun)
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THEREFORE By saying that the report took the lies for the truth, YOU are claiming that the interrogators took the lies at face value.
I said exactly what I wrote.
I think it is much more plausible to believe the BMW, Rechlin, and Focke Wulf reports on the technical aspects of the aircraft.
So it has nothing to do with speculation on the part of a POW's testimony.
Since the technical qualities discussed are not the technical qualities exhibited by the motor when set up properly. The engine did not vibrate excessively. In fact the Lufterrad was designed to uncouple from the shaft if it vibrated out of specified range.
You want to focus on the relevance of the POW's testimony. Having the benefit of hindsight, unlike the interrogator, we can cross-reference the POW's story with the many other sources.
It is a fact, that the BMW801 series did not run rough when properly set up. The RAE even got one to run smoothly on a bench after changing the plugs and settings. Unforturnately they never flew it.
The only trouble with vibration the Germans experienced was in the 5-6KM altitude range on daureleistung and this was solved.
But, you dont seem open to considering opposing ideas, even when they're about pretty minor points, and when they're logically kinda hard to argue against.
I am very much open to opposing ideas but I am not open to agendas.
I fully expect a defense will be mounted, but its pointless. Last time I said I'd lost respect it was out of frustration, but this time its from cool assessment of persistant behavior.
I suspect it would have been that way no matter what based on your behavior. Not being "arrogant" but I have some years of research into this aircraft behind me. I have put my dues in digging through archives.
It is unrealistic to expect someone to post a report or two gleaned off the Internet and expect for the floodgates of realization to open from my POV. Not to say I don’t appreciate it, the reports found on the internet are the most common and easiest reports to find.
Once more I even took the extra step by taking the time to PM you explaining exactly my position on your earlier request. Granted I misunderstood and you expected me to use charts/drawings.
I encourage you to come down and take the measurements.
I am not going to do it nor will have one of our employees do it without compensation.
You want a crew of guys stop what they are doing while I take measurements. In just few minutes time will cost quite a bit of money in just salaries paid out to have guys wait. Who is going to pay for that?
Now consider we are a NON-profit Organization. We live on donations and the generosity of our members. It is their money, given to us, to restore this aircraft and maintain the museum. Now we are stealing in my book because that money is being spent on pursuits OTHER than our charter.
Make Sense?
I told HTC the exact same thing. I will give you all the data you need to build the most realistic Focke Wulf FM around. All it would take is a donation for our time to a non-profit tax deductible organization.
Understand now why I will not just go do it?
So I would say I have been more than fair.
All the best,
Crumpp
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Originally posted by Crumpp
The RAE even got one to run smoothly on a bench after changing the plugs and settings.
Well, apparently you have not even read that report because it contains RAE test data on two BMW 801s which both did run fine after minor adjustment. And that was not the end of RAE tests on the 801...
gripen
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And that was not the end of RAE tests on the 801...
No it certainly was not. However they never flew one of those motors Gripen.
All the best,
Crumpp
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So, were they not getting full power out of the engine in the flight tests, or was it just the roughness?
Since they got the engines running nicely later on, why didn't they bother to take a ride again??????????
I remember Quill telling about testing the 190 himself, that must have been later than the "race" with Faber's 190. Sadly, in the book I have, he only mentions it and nothing more. There are more books from/about Quill. I wonder if there is some goodie around that none of us has seen.
Well, there are many, keep stumbling on them all the time.
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So, were they not getting full power out of the engine in the flight tests, or was it just the roughness?
Why don't you be the judge?
1. RAE tested performance is consistently on the low side of the percentage range of guarantee performance. Sometimes the RAE measured performance is outside of that range and never optimistic. All mention rough running motors and all are using allied natural petroleum AvGas.
2. The Luftwaffe, BMW, and Rechlin tests do not mention "rough" running motors except early 801's development. The flight tests consistently fall equally above and below the percentage range.
Where the Germans idiots who could not design an aircraft?
Where the allies trying to service an unfamiliar design during wartime?
All the best,
Crumpp
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Originally posted by Crumpp
1. RAE tested performance is consistently on the low side of the percentage range of guarantee performance. Sometimes the RAE measured performance is outside of that range and never optimistic.
as compared to what?
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RAE tested performance is consistently on the low side of the percentage range of guarantee performance. Sometimes the RAE measured performance is outside of that range and never optimistic. All mention rough running motors and all are using allied natural petroleum AvGas.
Waffle says:
as compared to what?
The Luftwaffe, BMW, and Rechlin tests do not mention "rough" running motors except early 801's development. The flight tests consistently fall equally above and below the percentage range.
Easier to understand?
All the best,
Crumpp
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Originally posted by Crumpp
No it certainly was not. However they never flew one of those motors Gripen.
RAE flew several other BMW 801s without particular problems. Just read Brown's comments on Fw 190.
There was no timing changes (as you have claimed in several boards) or what so ever large adjustments by RAE, only rough compensation of fuel gravity and the change of the plugs.
gripen
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Originally posted by HoHun
Hi Simaril,
...snip....
I'm afraid the mistake is yours. Prisoners of War are an inaccurate and unreliable source of information, and any conclusions drawn from their statements are necessarily inaccurate and unreliable by themselves.
...snip....
Regards,
Henning (HoHun)
Fair enough.
Simaril
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There was no timing changes (as you have claimed in several boards) or what so ever large adjustments by RAE, only rough compensation of fuel gravity and the change of the plugs.
Wow, it is intentional are you just not that smart?
From the very report YOU posted:
(http://img133.potato.com/loc156/th_a651e_RAE_Bench_Test1.jpg) (http://img133.potato.com/img.php?loc=loc156&image=a651e_RAE_Bench_Test1.jpg)
All the best,
Crumpp
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Originally posted by Crumpp
Wow, it is intentional are you just not that smart?
From the very report YOU posted:
"The effect of the "Rich-Weak" automatic control was investigated and magneto timings determined."
That means investigation and determining (ie amount of timings were measured) not change of the timings.
gripen
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Originally posted by Crumpp
Wow, it is intentional are you just not that smart?
From the very report YOU posted:
(http://img133.potato.com/loc156/th_a651e_RAE_Bench_Test1.jpg) (http://img133.potato.com/img.php?loc=loc156&image=a651e_RAE_Bench_Test1.jpg)
All the best,
Crumpp
Reads to me as they determined what the timing was...but doesn't say they adjusted it.
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Originally posted by Crumpp
Why don't you be the judge?
1. RAE tested performance is consistently on the low side of the percentage range of guarantee performance.
The "gaurentee performance"....thats what I wanted to know..
is that what the reichlen / luftwaffe / Beamer test are?
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is that what the reichlen / luftwaffe / Beamer test are?
Actually it is a specification sheet submitted to Rechlin.
All FW-190's leaving the factory have to be within certain performance specifications before being accepted into Luftwaffe service. Acceptance flights were conducted according to a checklist. Of course all the settings were at Stieg u Kampfleistung as the aircraft could not be operated at higher limits until after the initial 10 hour break in period.
Pretty much standard practice for all aircraft entering service in the world. the USAAF did it for their aircraft as well as the RAF. Nobody pays for something that does not work. Niether do they buy something without knowing what it will do.
Reads to me as they determined what the timing was...but doesn't say they adjusted it.
I don't know Waffle, seems to me if they determined the effect of mixture and timing then they might have to turn a screw or two on the Kommandogerät.
Sounds thin I know but just looking at the settings does not give you much of an idea of there effect unless I am just missing something.
:huh
All the best,
Crumpp
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Really thin :) the whole topic of that page lookks to be determining and investigating the engine and performance.
if there were changes made to the timing, i'm fairly certain it would be documented as the changes were to the spark plug type.
ehh -just my interpretation.
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Well, all I see is that somebody does speculations on these tests despite he has not even seen the report.
gripen
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if there were changes made to the timing, i'm fairly certain it would be documented as the changes were to the spark plug type.
Well our interpretation in rebuilding working 801 motors that run on modern gasoline is totally different.
The report reads:
First they found plugs that worked the best, then they determined timing and mixture settings, then they used those plugs. Perfectly logical.
Both allied and German fuels went through a number of changes during or shortly after these test's. Hence we see the "rough running" a common theme in allied testing.
In fact the allies had some difficulties in their own motors when the forumula for 130 grade was changed.
What your suggesting is actually pretty silly especially given the automatic nature of the engine controls which are set up for specific fuels.
All the best,
Crumpp
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Really thin the whole topic of that page lookks to be determining and investigating the engine and performance.
That is true it is determing engine performance both with 100/130 grade and C3.
The first portion of the report states they investigated performance of both fuels and determined the rough running was caused by fouling of the German plugs with allied fuels.
From there the pressure differences across the baffling and various cooling wind speeds was determined to ensure the new plugs would work and not overheat the motor.
The mixture and timing settings were determined for the new plugs.
Finally the plugs were fitted to the aircraft pending further flight investigations.
All a perfectly logical sequence of investigating engine performance with both fuels.
(http://img127.potato.com/loc160/th_e8d3c_RAE_Bench_Test3.jpg) (http://img127.potato.com/img.php?loc=loc160&image=e8d3c_RAE_Bench_Test3.jpg)
Improper mixture will certainly decrease power.
There are many variables that will determine the power output of an engine.
High on the list will be the ability of the fuel to burn evenly without
knock. No matter how clever the engine, the engine power output limit is
determined by the fuel it is designed to use, not the amount of oxygen
stuffed into the cylinder and compressed. Modern engines designs and
gasolines are intended to reduce the emission of undesirable exhaust
pollutants, consequently engine performance is mainly constrained by the
fuel available.
http://www.faqs.org/faqs/autos/gasoline-faq/part4/section-1.html
Whether future flight difficulties were due to the allies having problems of their own fuel or the changes in German settings is unknown. Nevertheless, problems existed in operating the engine that only the allied experienced and were not the providence of the BMW trained mechanics.
(http://img129.potato.com/loc24/th_97acd_leadincrease.jpg) (http://img129.potato.com/img.php?loc=loc24&image=97acd_leadincrease.jpg)(http://img145.potato.com/loc24/th_cfd38_leadincrease2.jpg) (http://img145.potato.com/img.php?loc=loc24&image=cfd38_leadincrease2.jpg)(http://img138.potato.com/loc24/th_b0161_lead_increase3.jpg) (http://img138.potato.com/img.php?loc=loc24&image=b0161_lead_increase3.jpg)
All the best,
Crumpp
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All I see is speculations after speculations.
gripen
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All I see is speculations after speculations.
Prove it is not true Gripen. You have all the answers so put your money were your mouth is at.
I only have access to working motors and years of research.
All the best,
Crumpp
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Well, as usual, it's up to you to prove that your speculations are true. No one needs to disprove them.
gripen
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It's obvious you have run out of intelligent arguments.
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CrumPWND!
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CrumPWND!
Need some catching up on the lingo. What in the world does that mean?
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Originally posted by Crumpp
It's obvious you have run out of intelligent arguments.
I wonder what you might mean. There is no need to argue against speculations.
gripen
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Ehhhh, Crumpp, there are some factors in this text of your's that you may not have considered.
"RAE tested performance is consistently on the low side of the percentage range of guarantee performance. Sometimes the RAE measured performance is outside of that range and never optimistic. All mention rough running motors and all are using allied natural petroleum AvGas.
2. The Luftwaffe, BMW, and Rechlin tests do not mention "rough" running motors except early 801's development. The flight tests consistently fall equally above and below the percentage range.
Where the Germans idiots who could not design an aircraft?
Where the allies trying to service an unfamiliar design during wartime?"
Firstly, a spelling issue.
"Where" should be "Were". But that's just a teaser......me not amreegan.
Ok, here goes.
1. The RAE flew a 190 straight from ops. I'd relly like to know how much flighttime they had with i.e. Faber's aircraft before the engine failed.
2. You have explained before that Faber's aircraft was derated. Ok. Not unique since it was a squadron service aircraft. So derated because of engine issues - on the line.
3. Bear in mind that in the WW2 Nazy Gemany, the environment for true reports is not always friendly, and up to leathal to the announcer. I keep wondering how many are total belivers in reports created in an environment where the wrong numbers could send you to the "rot front".
(Same goes with the USSR).
Think about it will you....
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The RAE flew a 190 straight from ops. I'd relly like to know how much flighttime they had with i.e. Faber's aircraft before the engine failed.
relly is spelled “really”. Flighttime is two words…Flight Time.
They did not have a usable quantity of C3 for flight testing and had to use 100/130 grade. Hence the bench test report above AFTER the conduct of the tactical trials.
You have explained before that Faber's aircraft was derated. Ok. Not unique since it was a squadron service aircraft. So derated because of engine issues - on the line.
All BMW801's are de-rated when new for the first 10 hours of operational use. This is called a "break in period."
Some BMW801D2's before June 1942 were locally "derated". Geschwaders operated both "normal" and de-rated engines side by side and the reporting of "de-rated" motors drops off the Beanstandungen's after June 1942.
Bear in mind that in the WW2 Nazy Gemany, the environment for true reports is not always friendly, and up to leathal to the announcer. I keep wondering how many are total belivers in reports created in an environment where the wrong numbers could send you to the "rot front".
Leathal should read “lethal”. Belivers is what? A small liver or do you mean “believers”.
As opposed to total believers in reports created in an environment where the wrong numbers could cause you to starve to death? Or destroy your family economically?
I don't think that is a very valid concern and implies that all Germans were lying.
If anything deceit would be much more dangerous than the truth.
It was a totalitarian government but a free market economy. The flaky reports are those dealing with race, religion, and Nazi party beliefs. Science, especially the more mundane aeronautics is hardly suspect.
All the best,
Crumpp
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There is no need to argue against speculations.
It's easy Gripen just use facts.
That is what I do.
All the best,
Crumpp
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Originally posted by Angus
3. Bear in mind that in the WW2 Nazy Gemany, the environment for true reports is not always friendly, and up to leathal to the announcer. I keep wondering how many are total belivers in reports created in an environment where the wrong numbers could send you to the "rot front".
(Same goes with the USSR).
Think about it will you....
umm Wily Messerchmitt should have been sent to teh Rot Front for designing that Me-210 lol. Lucky for him the Nazis kept him and gave him chance to improve tha 210 tio 410.
As for USSR... USSR's MiG beauro was not even given a chance to make new planes after the MiG-3 fiasco. their plans for a radial powered MiG was forced to pass it to LaGG beauro,
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FYI, A high caliber person like Adolf Galland was already confined with the subtle suggestion of taking poison. He spoke too clearly.
Willy Messerschmidt had a close shave with the "politicians" He was favoured by some, and some not.
Hugo Junkers got confined and humiliated, and died under Nazy control.
Werner Mölders was already having his horns against the "system". He quit wearing his iron cross.
To Galland again, - he actually ripped his decorations off at a time and flung them on the table. Göring's table I belive.
An Allied parallell would be interesting.
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Originally posted by Crumpp
It's easy Gripen just use facts.
That is what I do.
Well, anyone can read from above what you use for RAE tests.
gripen
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The idea that aero engineers and/or test pilots lie or tweak numbers for political reasons is pure bunk, imo - even in soviet russia.
Say FW lies and says the 190 is a super-plane - i think the LW + RLM might complain when the aircraft don't live up to their claims, hmm?
In Soviet Russia, the engineers + factories faced serious trouble if the a/c produced weren't up to scratch, so it would make much more sense to deliberately under-rate your designs so the production models can live up to the prototype numbers...
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You're right there, me bad :o
It rather applies to other cirkumstances. Well, there was a lot of hype, hush and push in the 3rd reich.
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Originally posted by justin_g
Say FW lies and says the 190 is a super-plane - i think the LW + RLM might complain when the aircraft don't live up to their claims, hmm?
Well, there is evidence on that.
gripen
(http://www.onpoi.net/ah/pics/users/852_1139222532_fwc.jpg)
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gripen,
Why is the top of that document missing? What is its title?
Are these design specs or measurements or what?
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:rofl
That is for the FW-190V5g and FW-190V5k.
Both developmental prototypes and those particular calcs are using the BMW801J series of turbocharged engines.
Big Conspiracy here!
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The speed claimed at 5,6km is far beyond the capabilities the airframe at given output (which is BTW less than claimed for the 801D).
gripen
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Was this the thread arguing about the 801? :)
Anyway, found this from Johann Schmitt...
"Toward the end of the war, we had a FW190 D powered by a Jumo 213 for a short while. I was suprised by how quite and vibration-free the the Jumo 213 was, much different than the BMW 801. Through all the testing I never really cared for the BMW 801. The engine ran rough and vibrated heavily."
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Also Crumpp - can you verify that the 801D was the last production of the 801s? From my understanding the 801E was supposed to go to production, but never did..and there was a "bastard" 801 instead which consited of 801E designed parts combined with 801 D parts.
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(which is BTW less than claimed for the 801D).
Actually it's similar to the BMW801D2 at this height.
Your making some huge assumptions off a little bit of information, Gripen.
First your whole premise is just stupid.
Your comparing an early developmental prototype trying to draw conclusions on the accuracy of Focke Wulf's predicitons.
These predictions were not reported to the RLM as official performance figures nor are they guarenteed. They are for a "new type" estimate. No one had ever done the type baffling and cooling fan combination found on the Focke Wulf nor was the power plant much more than a prototype on a bench. In fact it simply did not materialize and the FW-190V5g and FW-190V5k flew with the BMW-801C0.
With "New Type" aircraft, however, the error might be up to 6-7% in speed, and 200-250 ft./min. in climb.
(http://img131.potato.com/loc70/th_05c76_RAF_test_flight_standards.jpg) (http://img131.potato.com/img.php?loc=loc70&image=05c76_RAF_test_flight_standards.jpg)
The speed claimed at 5,6km is far beyond the capabilities the airframe at given output (which is BTW less than claimed for the 801D).
I imagine it is correct if you use the correct inputs and not try to misrepresent the weights.
(http://img141.potato.com/loc111/th_e039e_FW190A2_1.jpg) (http://img141.potato.com/img.php?loc=loc111&image=e039e_FW190A2_1.jpg)
All the best,
Crumpp
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Through all the testing I never really cared for the BMW 801. The engine ran rough and vibrated heavily."
I think you mean Johann Schmid 3/JG26?
If that is the case I would certainly understand as he flew in the Operational Test flight 190 and helped overcome many of the intitial problems.
Of course he was KIA during the war.
Johann Schmitt..do you have more information as too what unit he served and what aircraft he flew? Radials do vibrate much more than inline engines. That does not mean the BMW801 vibrated excessively in comparision to other radials. In fact the Lufterrad is designed to operate at the motors frequency of 700cps and will uncouple at disturbances of half that magnitude.
All the best,
Crumpp
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Also Crumpp - can you verify that the 801D was the last production of the 801s? From my understanding the 801E was supposed to go to production, but never did..and there was a "bastard" 801 instead which consited of 801E designed parts combined with 801 D parts.
The BMW801D2 was not the last production 801 series.
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nope Johann Schmitt...
Was in Hexengrund at the Torpedo Weapons Station. Presume - 44 untill end of war.
What was the last production run of the 801 series?
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The idea that aero engineers and/or test pilots lie or tweak numbers for political reasons is pure bunk, imo - even in soviet russia.
Say FW lies and says the 190 is a super-plane - i think the LW + RLM might complain when the aircraft don't live up to their claims, hmm?
In Soviet Russia, the engineers + factories faced serious trouble if the a/c produced weren't up to scratch, so it would make much more sense to deliberately under-rate your designs so the production models can live up to the prototype numbers...
Got to disagree there. Even in the corperate world today technology companies lie like dogs to front sell there products even at the expense of the common soldier. The fix it in the field mentality rules.
Rule number 1 of facist dictatorships.
Don't be the guy to give bad news, hence the phrase "don't shoot the messenger".
Would you want to be the guy to go to German high command in 1944 and tell them that you have a "small problem"? They weren't exacty living up to OCEA regulations back in the day.
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What was the last production run of the 801 series?
The BMW801E. Entered production in March 45. I highly doubt any made it on aircraft. It takes T3 around 6 months to build a reserve of motors before service adoption.
All the best,
Crumpp
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I read the the 801E was ready for production, but never made it into full production due to the shortage of machine tools late into the war. Hence them combining parts/components of the 801E and 801D into a "frankenstein" engine of sorts.
But since the 801E never made it onto an aircraft used in WW2.. I guess it's a moot point.
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Got to disagree there. Even in the corperate world today technology companies lie like dogs to front sell there products even at the expense of the common soldier. The fix it in the field mentality rules.
Problem is that the facts just do not bear out once you get past the new type development estimates. Even then it generally wildly over inflated the differences. For example FW-190V5k flew with a completely different motor from the estimate sheet Gripen posted. Those estimates do not apply.
However in flight the FW-190V5k did 714kph at 5.6km. Given instrumentation errors and a motor developing less power at that altitude I would have to conclude this estimate would have been conservative.
Here we see the Bf-109 production estimates compared with actual flight-testing:
For the estimate, comparing similar power output and altitude, in this case Steig u Kampfleistung at 0 meters we find the estimate given at 523kph using 1165PS.
http://www.beim-zeugmeister.de/zeugmeister/index.php?id=27&L=1
Actual flight testing, at Steig u Kampfleistung at 0 meters we find the measured speed at 526kph using the actual 1170PS.
http://www.beim-zeugmeister.de/zeugmeister/index.php?id=26&L=1
Well within the 1% standard for production estimates and highlighting the fact production estimates tend to be conservative.
That is not to say that mistakes do not happen. However the implication of a general trend towards optimistic production performance estimate is not true.
Neither is the conspiracy theorist notion of cooking the numbers to avoid punishment. You have to deliver a product and you will simply not be able to hide the fact your product is not what the customer bought.
nope Johann Schmitt...
He is certainly entitled to his opinion. It does differ from many of the Focke Wulf pilots whom I correspond with and the findings for Rechlin, BMW, Wright Aero Engine Company, and the RAE. In comparison to other radials the BMW801 properly set up does not vibrate excessively. The motor exhibits normal range of design frequency.
All the best,
Crumpp
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I read the the 801E was ready for production, but never made it into full production due to the shortage of machine tools late into the war.
There were quite a few other motors. Your thinking of the BMW-801Q2(TU), BMW801S1,S2 (TS-1, TS-2) and BMW801H1 (TH).
Those motors did make it into production begining in Dec 1943 and can be found on FW-190's after July 1944 in substantial quantity.
Hence them combining parts/components of the 801E and 801D into a "frankenstein" engine of sorts.
That is the BMW801Q2. All FW-190A8R11's were built with this motor as the increased armoured ring restored the CG limits with the R11 kit. If the aircraft mounted a BMW801H1 or BMW801S2 then the aircraft was designated FW-190A9/R11.
All the best,
Crumpp
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Originally posted by Crumpp
He is certainly entitled to his opinion. It does differ from many of the Focke Wulf pilots whom I correspond with and the findings for Rechlin, BMW, Wright Aero Engine Company, and the RAE. In comparison to other radials the BMW801 properly set up does not vibrate excessively. The motor exhibits normal range of design frequency.
He also said " Our engines were somewhat skeptical and called in experts from focke-wulf"
If a ground crew at a testing facility couldn't keep these engines running why did they have to call in experts from FW to come out?
BTW do you have Hauptmann Gollob's report on the FW 190 - Rechlin, Jan 1942?
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He also said " Our engines were somewhat skeptical and called in experts from focke-wulf"
You better clarify with him then. Sound to me like he is refering to inititial testing phase of the BMW801C0. The program came within a hair's breath of being cancelled.
During that first few months more than 40 design changes were enacted.
BTW do you have Hauptmann Gollob's report on the FW 190 - Rechlin, Jan 1942?
Yes I sure do. Also a BMW801C series.
All the best,
Crumpp
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What engine was in the a5 production wise?
Also, if you read that report....you will notice that the troubles made the 190 fall well short of the 109. Also from that report it looks like they were even trying to steer away from the 801c/d's and in favor of the db603.
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Originally posted by Crumpp
Actually it's similar to the BMW801D2 at this height.
The BMW 801D2 did about 1440ps + exhaust thrust at 5300m. Using NACA estimation methods, that means roughly 12-14% output increase ie equivalent shaft power was somewhat over 1600ps.
Originally posted by Crumpp
I imagine it is correct if you use the correct inputs and not try to misrepresent the weights.
Well, the V34 with BMW 801F weighed 3575kg, was unarmed clean A-5 airframe and did a bit less than 680km/h with 1,65ata 2700rpm at 5300m. The engine output was around 1700ps + exhaust thrust, shaft equivalent power being somewhere around 1900ps.
gripen
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Also, if you read that report....you will notice that the troubles made the 190 fall well short of the 109.
That is an 801C series motor not the BMW801D2. And yes at that time they sure did fall short of the 109.
Well, the V34 with BMW 801F weighed 3575kg, was unarmed clean A-5 airframe and did a bit less than 680km/h with 1,65ata 2700rpm at 5300m. The engine output was around 1700ps + exhaust thrust, shaft equivalent power being somewhere around 1900ps.
:rofl
Keep guessing. You’re never going to figure out what happened. And I think it is just too funny that your arrogant enough to assume the designers knew less than you.
All the best,
Crumpp
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Originally posted by Crumpp
Keep guessing. You’re never going to figure out what happened.
I have not quessed anything here.
Originally posted by Crumpp
And I think it is just too funny that your arrogant enough to assume the designers knew less than you.
I have not assumed anything about designer's knowledge here. FW was simply selling planes to RLM.
gripen
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Allow me to give you a big hint. Don't take it the wrong direction though.
From an allied report on the state of German Engines during the war:
(http://img120.potato.com/loc35/th_31eff_flight_geng51.jpg) (http://img120.potato.com/img.php?loc=loc35&image=31eff_flight_geng51.jpg)
Your talking about an early BMW801H series motor you know. You love comparing prototypes with no regard for their place in the line up or developmental sequence.
Comparing FW-190V34 to FW-190V5k is like comparing apples to oranges. Totally different aircraft with totally different specifications.
All the best,
Crumpp
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Originally posted by Crumpp
Your talking about an early BMW801H series motor you know. You love comparing prototypes with no regard for their place in the line up or developmental sequence.
It's output is known and far above 1430ps (turbo) at 5600m.
Originally posted by Crumpp
Comparing FW-190V34 to FW-190V5k is like comparing apples to oranges. Totally different aircraft with totally different specifications.
Actually I'm comparing the numbers of the larger airframe (18,3m2) to V34 which are quite similar and weighs are close.
gripen
-
It's output is known and far above 1430ps (turbo) at 5600m.
But it's drag is totally different Gripen.
All the best,
Crumpp
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Originally posted by Crumpp
But it's drag is totally different Gripen.
Why it should be totally different. The A-5 airframe was one of the cleanest Fw 190s. Infact installation of the turbo probably causes draggier airframe.
gripen
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Why it should be totally different.
This is why you constantly come to erroneous conclusions.
Which planes are we comparing? FW-190A5 to V34 or V34 to V5k?
All the best,
Crumpp
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Originally posted by Crumpp
Which planes are we comparing? FW-190A5 to V34 or V34 to V5k?
The V34 was an A-5 airframe and I'm comparing it to the larger version (V5g) with the BMW 801J in the datasheet.
gripen
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The V34 was an A-5 airframe and I'm comparing it to the larger version (V5g) with the BMW 801J in the datasheet.
In a nutshell,
V34 has much more drag than V5g. V34 has power production difficulties and in all likelyhood is not developing power like it should especially at altitude.
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Originally posted by Crumpp
V34 has much more drag than V5g. V34 has power production difficulties and in all likelyhood is not developing power like it should especially at altitude.
There is no way that the V34 had more drag than a V5g with turbocharged BMW 801J as specified in the spec sheet. The V34 was an unarmed clean prototype while the specified V5g with BMW 801J and the turbo required additional ducting.
Even if the engine of the V34 was not developing full specified power (100ps difference is claimed in the Fw ocumentation) it still had at least 300-400ps more equivalent shaft power over the BMW 801J powered V5g at 5600m.
Edit: Actually the engine of the V34 seem to had same or higher output at 5600m than specification because it's FTH at given setting (6000m with internal intake) was below claimed specification (7000m).
gripen
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Below is a Fw chart showing the performance of the V34 (internal intake) compared to the calculations for the armed plane (internal and external intake).
gripen
(http://www.onpoi.net/ah/pics/users/852_1139304926_v34-1.jpg)
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FW-190V5g was a clean unarmed plane.
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Originally posted by Crumpp
FW-190V5g was a clean unarmed plane.
There is no practical difference in drag between the clean unarmed V5g and the clean unarmed A-5 (as the V34); the A-5 has the fuselage extension and small bulges for the cannons (might had been removed from the V34) which can't have large effect, otherwise the airframes were almost identical.
But I'm comparing the V34 to the V5g type airframe with turbo charged BMW801J as given in the specsheet, which should have additional ducting for the turbo (as an example see Ju 388s with the turbo charged BMW 801s).
gripen
(http://www.kotfsc.com/aviation/graphics/ju388-photo1.jpg)
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There is no practical difference in drag between the clean unarmed V5g and the clean unarmed A-5 (as the V34); the A-5 has the fuselage extension and small bulges for the cannons (might had been removed from the V34) which can't have large effect, otherwise the airframes were almost identical.
There is a huge difference in drag between the types.
I sent Pyro some documentation highlighting the differences in performance for various setups a while back. All FW-190's are not created equal.
All the best,
Crumpp
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Originally posted by Crumpp
There is a huge difference in drag between the types.
It's up to you prove that that a V5g airframe as specified in the spec sheet (turbo requiring additional ducting) would have a lower drag than a clean unarmed A-5 airframe.
gripen
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It's up to you prove that that a V5g airframe as specified in the spec sheet (turbo requiring additional ducting) would have a lower drag than a clean unarmed A-5 airframe.
What an arrogant statement.
So we have to prove that Kurt Tank design team was wrong and you are right??
That's laughable.
You can easily check the Rechlin flight data I posted in the other thread. An armed production variant FW-190A5 could 680kph.
All the best,
Crumpp
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Originally posted by Crumpp
What an arrogant statement.
So we have to prove that Kurt Tank design team was wrong and you are right??
That's laughable.
Facts are your wrong and your just trolling for documents.
Well, the facts are that a clean unarmed A-5 airframe (Fw 190 V34) weighing 3575kg with around 1900ps shaft equivalent output did in flight test about 680km/h (TAS) at 5600m while the spec sheet for the V5g airframe (with additional ducting for turbo) weighing 3400kg with 1430ps output claims calculated speed 700km/h at 5600m.
Anyone can draw his/her own conclusions.
gripen
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Well, the facts are that a clean unarmed A-5 airframe (Fw 190 V34) weighing 3575kg with around 1900ps shaft equivalent output did in flight test about 680km/h (TAS) at 5600m
You have underestimated the FW-190V5 drag and overestimated the BMW801TH output I imagine Gripen. You can take my suggestion to relooking at it or not.
You have been wrong in every assumption you have made about Focke Wulf Performance in the past because you jump to conclusions without understanding the aircraft. Your doing the same thing again.
I noticed you got real quite after posting your sweeping claims about Focke Wulfs not being able to reach stated performance at 1.42ata in the other thread.
You need me to recalculate those FW-190/Spitfire comparisions with the new data?
All the best,
Crumpp
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Originally posted by Crumpp
The FW-190V5k has less drag and comparible power output Gripen. You can believe me or not.
I have not claimed anything about the V5k.
Originally posted by Crumpp
You have underestimated the FW-190V5 drag and overestimated the BMW801TH output I imagine Gripen. You can take my suggestion to relooking at it or not.
It's up to you to prove your claims, even a very conservative shaft equivalent output estimate gives 300-400ps advantage for the V34.
Originally posted by Crumpp
You have been wrong in every assumption you have made about Focke Wulf Performance in the past because you jump to conclusions without understanding the aircraft. Your doing the same thing again.
Well, anyone can read these threads and draw his/her own conclusions.
Originally posted by Crumpp
I noticed you got real quite after posting your sweeping claims about Focke Wulfs not being able to reach stated performance in the other thread.
All I see there is that someone picks the highest value (instead average) from the chart containing several values and tries to correct that with highest position error correction he can find.
Originally posted by Crumpp
You need me to recalculate those FW-190/Spitfire comparisions with the new data?
No thanks, I can honestly say than I don't need any kind of calculations because I have real world data in hand.
gripen
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All I see there is that someone picks the highest value (instead average) from the chart containing several values and tries to correct that with highest position error correction he can find.
The Focke Wulf specification sheet including the flight tested Rechlin figures are the guarantee performance figures. All speeds should fall within Focke Wulf, GmbH guaranteed percentages for performance of this chart until a new specification sheet is issued updating and replacing it .
I picked sea level and used a known FW-190A5 correction curve as an estimate. It was simple estimation to show the speeds gave good agreement and were well within the realm of guaranteed percentages for performance.
Somewhat conservative numbers as our flight test was only one aircraft and a small number of flights. The results give great agreement with Focke Wulf reported performance and Rechlin tested results coming within 1%. While the numbers might change that agreement stays steady within the 3%.
No thanks, I can honestly say than I don't need any kind of calculations because I have real world data in hand.
Sure. That's what makes you blatenly dishonest.
For example, you posted your claims of FW-190 performance with the C3-Einspritzung report in hand. That chart I posted is from that report. The one labeled in huge letters indicated airspeeds.
Either your a liar and do not have the whole report as you claim making a mistake of fact with incomplete information.
Or your a liar who is intentionally attempting to misrepresent FW-190 performance as conspiracy theory of unachievable numbers perpetuated by Focke Wulf on the RLM. And doing so without all the facts in your possession.
All for what Gripen? An advantage in game shape? Or are you just trying to provoke me and fishing for documents?
All the best,
Crumpp
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(http://www.dangreve.com/images/g190.jpg)
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Your refering to the BMW801C0 as listed in the specifications of that report. Yes it was unreliable.
(http://img102.potato.com/loc48/th_c5e52_801C_fixes.jpg) (http://img102.potato.com/img.php?loc=loc48&image=c5e52_801C_fixes.jpg)
And has absolutely no bearing on the BMW801D2.
All the best,
Crumpp
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5th Paragraph.....of the text in my post...read it aloud....slowly :)
Does ""interim solution" mean anything?
BTW - they were a5s with 801ds at the testing station. Wasn't a flight test facility - weapons testiing.
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BTW - they were a5s with 801ds at the testing station. Wasn't a flight test facility - weapons testiing.
Covered that one Waffle.
He is certainly entitled to his opinion. It does differ from many of the Focke Wulf pilots whom I correspond with and the findings for Rechlin, BMW, Wright Aero Engine Company, and the RAE. In comparison to other radials the BMW801 properly set up does not vibrate excessively. The motor exhibits normal range of design frequency.
You keep bringing up early developmental problems to prove the engine was unreliable it's whole lifespan.
Do those standards apply to the R-2800 series? Look up its design history. Durng it's teething period the motor was just as unreliable. However like all new motors the kinks were worked out.
(http://img133.potato.com/loc293/th_42397_PW2800story.jpg) (http://img133.potato.com/img.php?loc=loc293&image=42397_PW2800story.jpg)
http://www.enginehistory.org/NoShortDays/Introduction.pdf
If the BMW801 series early developmental problems had occurred in 1937 before the war, they would have been nothing but an obscure footnote in history as well.
The BMW801D2 by comparision to the C series only required operational checks every 200 hours and depot level maintenance at 2000 hours of operation.
Just as the RAE bench test showed much of the 801D2's vibration was caused by the knock limited performance of the fuel used.
(http://img140.potato.com/loc79/th_56107_fuelknock.jpg) (http://img140.potato.com/img.php?loc=loc79&image=56107_fuelknock.jpg)
The plugs the RAE used are German plugs authorized for use in the BMW801. One of two that the early BMW801D2's used.
They are one of many different types the BMW801 was authorized to use. Some are only for specific motor installations or set ups.
http://w4.siemens.de/archiv/en/geschichte/index.html
Looking at the Beanstandungen's it is obvious that early on in the BMW801D2 lifecycle some motors did exhibit knock limited performance and were de-rated. As knock will cause excessive vibration it only makes sense that some motors did vibrate excessively. To characterize this as a trait of a properly set up motor or a design feature is just not factual.
All the best,
Crumpp
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Originally posted by Crumpp
The Focke Wulf specification sheet including the flight tested Rechlin figures are the guarantee performance figures.
Nonsense, as an example A-5 chart is a plain calculation (assuming perfect surface condition) and so called Rechlin tests were not corrected for compressibility (at unknown conditions).
Originally posted by Crumpp
I picked sea level and used a known FW-190A5 correction curve as an estimate. It was simple estimation to show the speeds gave good agreement and were well within the realm of guaranteed percentages for performance.
You ignored the rest of the sheet showing lower performance and you certainly have other correction curves (the V34 is an A-5 airframe). Besides these values are not corrected for density.
Originally posted by Crumpp
Sure. That's what makes you blatenly dishonest.
So according to you using real world data makes me blatantly dishonest.
Originally posted by Crumpp
For example, you posted your claims of FW-190 performance with the C3-Einspritzung report in hand. That chart I posted is from that report. The one labeled in huge letters indicated airspeeds.
I wonder what you might mean. I have not claimed that those values are something else than indicated airspeeds; the speed marked as Va is indicated airspeed.
Originally posted by Crumpp
Either your a liar and do not have the whole report as you claim making a mistake of fact with incomplete information.
I have not claimed to have an whole report but the article. And it's clear on these issues.
Originally posted by Crumpp
Or your a liar who is intentionally attempting to misrepresent FW-190 performance as conspiracy theory of unachievable numbers perpetuated by Focke Wulf on the RLM. And doing so without all the facts in your possession.
Anyone can read above who cherry picks data here. Generally I'm interested about average plane, not the best possible.
Originally posted by Crumpp
All for what Gripen? An advantage in game shape? Or are you just trying to provoke me and fishing for documents?
I don't know what you are talking about, I've got enough documentation on Fw 190 for my needs, of course good real world data is allways most welcome.
gripen
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So according to you using real world data makes me blatantly dishonest.
You have calculation of V34 and parts of C3 endurance test. Hardly a pool of real world data.
I have not claimed to have an whole report but the article. And it's clear on these issues.
So your making judgements off incomplete data. figures.
I don't know what you are talking about, I've got enough documentation on Fw 190 for my needs, of course good real world data is allways most welcome.
Exactly, You’re fishing and trying to provoke because you do not have enough data for your agenda.
Generally I'm interested about average plane, not the best possible.
Which is exactly why your refuting Focke Wulf numbers presented to the RLM for guaranteed average performance with 3% for level speed.
Nonsense, as an example A-5 chart is a plain calculation (assuming perfect surface condition) and so called Rechlin tests were not corrected for compressibility (at unknown conditions).
What is so called about the numbers now? The testing facility whose job it is to independently verify and measure Luftwaffe aircraft performance is not acceptable?
Proof in point that there is no data for the Focke Wulf your willing to accept unless it fits your agenda. Even guaranteed average performance.
It’s fine with me if you want to consider the speeds in the brackets IAS. They will simply be faster. The speeds will remain within Focke Wulf guaranteed percentages by one percent only move to the optimistic side of the average.
I think you would be wrong in this particular aircraft’s case however.
Nonsense
The only nonsense is your agenda.
All the best,
Crumpp
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Originally posted by Crumpp
You have calculation of V34 and parts of C3 endurance test. Hardly a pool of real world data.
Hm... The V34 data is flight tested.
(http://www.onpoi.net/ah/pics/users/852_1139428615_v34d.jpg)
Originally posted by Crumpp
Which is exactly why your refuting Focke Wulf numbers presented to the RLM for guaranteed average performance with 3% for level speed.
Actuallly nothing proves that those calculations are something quaranteed. Below is something (Aa-3 for Turkey, a bit cleaner airframe than a normal A-3) which actually is quaranteed and fits to data pretty well except the speed seem to be without compressibility correction:
(http://www.onpoi.net/ah/pics/users/852_1139428675_fwq.jpg)
Originally posted by Crumpp
What is so called about the numbers now?
The data should be documented with corrections.
Originally posted by Crumpp
It’s fine with me if you want to consider the speeds in the brackets IAS. They will simply be faster.
That depends on conditions, near sea level TAS might be even slower at some conditions.
Originally posted by Crumpp
The only nonsense is your agenda.
Well, anyone can draw his/her own conclusions.
gripen
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Actuallly nothing proves that those calculations are something quaranteed. Below is something (Aa-3 for Turkey, a bit cleaner airframe than a normal A-3) which actually is quaranteed and fits to data pretty well except the speed seem to be without compressibility correction:
LOL get some more data Gripen. Common piece of Internet documentation that has been floating around for years. Sure it was for that airplane. And all the FW-190 series as well. You will find it is repeated on several documents. Average performance specifications will always be guarenteed over a percentage range and not as an absolute.
Pure smoke though for this particular argument and does not change the outcome.
Hm... The V34 data is flight tested.
Sure part of it is however your using the calculations for the mounting of different weapons effect on speed as the basis for your argument.
That depends on conditions, near sea level TAS might be even slower at some conditions.
We both know that is not the case with the Focke Wulf. So generalizations about the behavior of other aircraft are irrelevant.
More Smoke and mirrors. We are not discussing aircraft in general, we are discussing a specific aircraft.
Well, anyone can draw his/her own conclusions.
Sure can. Especially since even using your conditions does not lead to your conclusions.
Proof in point that there is no data for the Focke Wulf your willing to accept unless it fits your agenda. Even guaranteed average performance.
It’s fine with me if you want to consider the speeds in the brackets IAS. They will simply be faster. The speeds will remain within Focke Wulf guaranteed percentages by one percent only move to the optimistic side of the average.
I think you would be wrong in this particular aircraft’s case however.
Obviously you are running out of facts again.
All the best,
Crumpp
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Originally posted by Crumpp
Average performance specifications will always be guarenteed over a percentage range and not as an absolute.
None of those calculation sheet contains a mention about quaranteed performance.
Originally posted by Crumpp
Pure smoke though for this particular argument and does not change the outcome.
Hm... It's up to you to prove that something is quaranteed.
Originally posted by Crumpp
Sure part of it is however your using the calculations for the mounting of different weapons effect on speed as the basis for your argument.
Nonsense. I used directly flight tested V34 data to compare with claimed performance for the V5g airframe with BMW 801J (turbo charged).
Originally posted by Crumpp
We both know that is not the case with the Focke Wulf. So generalizations about the behavior of other aircraft are irrelevant.
Actually you don't know; it all depends on conditions and corrections even in the case of the Fw 190.
Originally posted by Crumpp
Sure can. Especially since even using your conditions does not lead to your conclusions.
Again, anyone can draw his/her own conclusions
Originally posted by Crumpp
Obviously you are running out of facts again.
Actually you have not posted anything which support that the V5g with BMW 801J would have reached claimed performance. But I have posted plenty of evidence that it's very unlikely.
gripen
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None of those calculation sheet contains a mention about quaranteed performance.
Where do you think it comes from?
Hm... It's up to you to prove that something is quaranteed.
Yeah it's up to me to prove everything unless it supports your agenda. Focke Wulf, Rechlin, even the allied reports are not good enough unless they support your version. Science and history be damned huh?
it all depends on conditions and corrections even in the case of the Fw 190.
It may vary a few mph Gripen but it will not vary that much. It certainly will remain a forward correction.
FW-190A3 Captured by the RAE WNr 313:
(http://img111.potato.com/loc132/th_2a66b_FW190A3f.jpg) (http://img111.potato.com/img.php?loc=loc132&image=2a66b_FW190A3f.jpg)
FW190G3 EB-104:
(http://img144.potato.com/loc132/th_a6e8e_EB_104correction.jpg) (http://img144.potato.com/img.php?loc=loc132&image=a6e8e_EB_104correction.jpg)
Nonsense. I used directly flight tested V34 data to compare with claimed performance for the V5g airframe with BMW 801J (turbo charged).
No Gripen. Your using the calculations for the mounting of different weapons effect on speed as the basis for your argument on the corrections without understanding the design changes between the Anton series.
The very fact you know exactly what I was talking about and will change the argument shows your lack of honesty.
Do I need to link the post?
But I have posted plenty of evidence that it's very unlikely.
:rofl
Where Gripen? Your comparison of a new type protoype with a completely different motor than what it was flown with to another new type prototype??
Where is the credibility in that?
All the best,
Crumpp
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Originally posted by Crumpp
Where do you think it comes from?
I wonder what you might mean; those are simply calculations based on perfect surface condition. There is no anykind claim about quaranteed performance range.
Originally posted by Crumpp
Yeah it's up to me to prove everything unless it supports your agenda. Focke Wulf, Rechlin, even the allied reports are not good enough unless they support your version. Science and history be damned huh?
You should know that if you claim an argument, you should be able to prove it. There is quite good agreement between the Aa-3 data, Rechlin tests at low altitude and allied tests.
Originally posted by Crumpp
It may vary a few mph Gripen but it will not vary that much. It certainly will remain a forward correction.
There is three corrections needed to calculate TAS from IAS:
1. Position error correction.
2. Density correction.
3. Compressibility correction.
Your argument is based just on first one, just calculate TAS varying temperature and density and you can easily find 10mph higher TAS than CAS at sea level.
Besides, the RAE correction curve is further evidence that you apparently purposedly posted highest position error curve you could find. There is probably even lower out there some where.
Originally posted by Crumpp
No Gripen. Your using the calculations for the mounting of different weapons effect on speed as the basis for your argument on the corrections without understanding the design changes between the Anton series.
Nonsense. The V34 data is flight tests of the unarmed and lightened A-5 airframe. It's well documented data with known corrections and known output.
(http://www.onpoi.net/ah/pics/users/852_1139460688_v34s.jpg)
Originally posted by Crumpp
Where Gripen?
Above.
gripen
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Gripen says:
Nonsense. The V34 data is flight tests of the unarmed and lightened A-5 airframe. It's well documented data with known corrections and known output.
Your lying again. Your argument is based off calculations as.
Gripen says in other thread:
The speed marked as x) is TAS calculated from the data (like polar , engine chart etc.) and the speed marked as xx) is calculated TAS without compressibility correction. Might look like a bit backwards system but apparently they needed TAS without compressibility correction for example for specsheets or such things.
It is based off calculations.
There is quite good agreement between the Aa-3 data, Rechlin tests at low altitude and allied tests.
Sure there is for 801D powered aircraft. FW-190Aa-3 is the export model and does not have a BMW801D2.
There is three corrections needed to calculate TAS from IAS:
1. Position error correction.
2. Density correction.
3. Compressibility correction.
Your argument is based just on first one, just calculate TAS varying temperature and density and you can easily find 10mph higher TAS than CAS at sea level.
NSS
Has nothing to do with the fact a correction was required to compare the new measuring system to the old measuring system.
The system comes with specific instructions for certain aircraft mounting it.
Besides, the RAE correction curve is further evidence that you apparently purposedly posted highest position error curve you could find. There is probably even lower out there some where.
The RAE chart is from an early FW-190A3. The chart I used is at least the same airframe as the FW-190A5.
Now it is perfectly OK to contradict the argument you presented:
Gripen says:
The location does not matter, there is allways variation even among similar installations.
Using either measurement does not alter the percentages and still gives good agreement.
So your argument is nonsensical and silly.
All the best,
Crumpp
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Originally posted by Crumpp
Your lying again. Your argument is based off calculations as.
The evidence is above believe or not, I don't care.
Originally posted by Crumpp
It is based off calculations.
Here you are trying mix an another chart to this discussion which I have posted to another thread (with the claim that the chart is a calculation).
Originally posted by Crumpp
Sure there is for 801D powered aircraft. FW-190Aa-3 is the export model and does not have a BMW801D2.
Claimed output matches well with rammed output of the D2.
Originally posted by Crumpp
Has nothing to do with the fact a correction was required to compare the new measuring system to the old measuring system.
The old and new measuring systems have nothing to with this discussion.
Originally posted by Crumpp
The RAE chart is from an early FW-190A3. The chart I used is at least the same airframe as the FW-190A5.
There is 2mph difference, ie there is variation. Another plane would have shown yet another curve.
gripen
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Here you are trying mix an another chart to this discussion which I have posted to another thread (with the claim that the chart is a calculation).
Cause we are talking about your claim on the corrections. Your whole argument has been based off assumptions from this test.
Claimed output matches well with rammed output of the D2.
Yeah according to you According to Focke Wulf it had a different motor and was an export version. Not one single country, Gripen, sells their very best military hardware to another country.
Why do you think it has a completely different designation? If it was just like an FW-190A3 it would have been designated an FW-190A3. Instead it is the FW-190Aa-3.
Once again your lack of knowledge on the design has led you to an erroneous conclusion.
There is 2mph difference, ie there is variation. Another plane would have shown yet another curve.
There is not enough of a variation to change the general conclusion. I have shown this variation in several threads as a point of fact on why these "my plane is faster than yours" comparisons are silly.
Facts are the general conclusion is the same. The flight-tested performance in all examined cases of operational aircraft aligns with published Focke Wulf figures within guaranteed percentages.
Actually you have not posted anything which support that the V5g with BMW 801J would have reached claimed performance. But I have posted plenty of evidence that it's very unlikely.
Using the FW-190A5 Rechlin flight test results for a normal finish FW-190A5at an altitude of 6300M:
(http://img146.potato.com/loc132/th_e25ba_FW190APerformance.jpg) (http://img146.potato.com/img.php?loc=loc132&image=e25ba_FW190APerformance.jpg)
Ballpark estimate:
FW-190A5 = 680kph (TAS) or 422mph (TAS)
FW-190V5g = 700kph (TAS) or 435mph (TAS)
We have a difference of 20kph or 13mph (rounding error).
Horsepower development off the sheet is 1430PS assuming it is not rammed for the FW-190V5g.
Using an FW-190A5 engine power development graph we see 1600hp for the BMW801D2.
Loss of speed for the FW-190A5:
2 mph for weight
3 mph for cooling gills
conservatively 14mph for weapon installation
Speed increase for FW-190A5
2 mph
2 + 3 + 14 - 2 = 17mph or 27kph speed decrease for the FW-190A5.
A 3.8% difference in speed which is well within the 5% - 6% range for new type development prototypes.
Thrust analysis:
The FW-190A5 generates 1137lbs of thrust to attain 680kph while the FW-190V5g generates 986lbs of thrust to attain 700kph.
A difference of 151lbs.
Calculating Cd (tot):
FW-190V5g Cd (tot) = .0177
FW-190A5 Cd (tot) = .024
A difference of .0063 due to design changes.
All the best,
Crumpp
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Originally posted by Crumpp
Cause we are talking about your claim on the corrections. Your whole argument has been based off assumptions from this test.
Now you try to change the subject, we are talking about the V34 and the V5g with BMW 801J. The calculated chart showing compressibility correction backwards has nothing to with this discussion.
My argument is based on flight tested data of the V34. I have posted above the results and even part of the flight log showing the corrections.
Originally posted by Crumpp
Yeah according to you According to Focke Wulf it had a different motor and was an export version.
The claimed output match the BMW data sheet as well as the A-5/A-6 manual. From Bookie's site:
"Turkey - Focke-Wulf 190 Aa-3
In the middle of 1942 the RLM issued an export order for FW 190s to be sent to Turkey. Turkey received 72 FW 190 Aa-3 (a for auslandisch - foreign) aircraft between October 1942 and March 1943. The first FW 190 Aa-3 was built in August 1942. The FW 190 Aa-3 received its own Werk Nummer block, 0134 101 - 0134 172 (although it is not known if W.Nr 110, 123, 146 and 148 were handed over). These aircraft were basically FW 190 A-3s, with BMW 801 D-2 engines, and FuG VIIa radios. However, they did not have FuG 25 radios, and had an armament fit of four MG 17s, with the option of installing two MG FF/M cannon in the outer wing position."
Originally posted by Crumpp
Using the FW-190A5 Rechlin flight test results for a normal finish FW-190A5at an altitude of 6300M:
Again, that data is not corrected for compressibility and the BMW 801D2 did about 1440ps + exhaust thrust at 5600m. Using NACA estimation methods, that means roughly 12-14% output increase ie equivalent shaft power was somewhat over 1600ps. That means over 150ps shaft equivalent output over the V5g airframe with turbo charged BMW 801J because turbo uses the exhaust energy. In addition turbo required additional ducting as seen below in the case of the Ju 388.
There is no way the V5g with turbo charged BMW 801J would had a lower drag than a clean A-5 airframe due to additional ducting.
gripen
(http://www.kotfsc.com/aviation/graphics/ju388-photo1.jpg)
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There is no way the V5g with turbo charged BMW 801J would had a lower drag than a clean A-5 airframe due to additional ducting.
Hint: It did not have a turbocharger at that time. The BMW801 was itself a practically a prototype. The BMW801J0 became the basis for the J1 and J2.
Glad you found a website to back up your claims. Me, I will trust Focke Wulf documents.
Again, that data is not corrected for compressibility and the BMW 801D2 did about 1440ps + exhaust thrust at 5600m.
Depends on the BMW801D2 and what timeperiod your talking about, Gripen.
All the best,
Crumpp
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"There is no way the V5g with turbo charged BMW 801J would had a lower drag than a clean A-5 airframe due to additional ducting."
What kind of external ducting did it have?
Did it have the same type of intake as some tropicalized versions had or what?
Are there any pictures of V5g?
-C+
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Originally posted by Crumpp
Hint: It did not have a turbocharger at that time. The BMW801 was itself a practically a prototype. The BMW801J0 became the basis for the J1 and J2.
I tend to believe Von Gersdorff & Co on engine questions. We are talking about calculation of the V5g with the BMW 801J and the calculation needs just supposed specs of the engine.
Originally posted by Crumpp
Glad you found a website to back up your claims. Me, I will trust Focke Wulf documents.
Well, you have used same site as a source. Besides, it's very common in the german documentation that the engine is described as the BMW 801D despite it actually was the D-2 (as an example A-5/A-6 manual).
Originally posted by Charge
What kind of external ducting did it have?
The spec sheet does not give details but it needed atleast intake as well outlet for the intercooler (picture of the Ju 388 gives an idea). The turbo of the BMW 801J is claimed to be aircooled so also that would have needed some additional air.
gripen
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I have plenty of pictures of FW-190V5g. I will post some.
All the best,
Crumpp
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FW-190V5g Cd (tot) = .0177
FW-190A5 Cd (tot) = .024
Can we say somthing dosn't pass a smell test?
You realy belive a 25% reduction in drag co on a like air frame with only small changes?
HiTech
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You realy belive a 25% reduction in drag co on a like air frame with only small changes?
Small changes?? If there where only small changes FW-190's would have been restricted to the airspace right above there own fields where they could glide to a landing after a few minutes of powered flight. FW-190V5g is a new type prototype.
In addtion to the exhaust reroute, Hitech, there were over 40 design changes to improve the cooling of the motor.
I would not call cutting new ducting, cooling fan, radiators, and rebaffling the motor small changes? Have you even noticed the external shape of the internal intakes blisters? They are different on the outside and very different on the inside.
Not to mention the addition of weapons with raised covers for all.
Hardly small changes. Notice the CD goes from very low for an aircooled motor to similar to most WWII radials?
Seems a rather major increase in cooling drag alone. While the actual drag reduction benefits were not realized the cowling was kept sufficiently tight to reducing the wet area. So even though the CD is normal, the aircraft remains realtively low drag.
Yes I find a 26.25% increase in the FW-190A CD(tot) believable with an understanding of the design changes.
All the best,
Crumpp
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Only parasite drag I presume?
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FW-190A5 Cd (tot) = .024
It's .022 BTW not .024.
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A reduction like that in parasite drag is stunning. If it was that reduction in total drag, it would be even more stunning. Are you really sure of this? This is easily the difference between 2 totally different airframes. Tells more than a hell lot of horsepowers.
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A reduction like that in parasite drag is stunning.
It's an increase not a reduction. Look at the FW-190 weapon installation. Blisters, wing covers, barrels, and all the changes to the motor compartment.
Have you even seen the FW-190V5 series? They were new type prototypes without weapons and the very first installation of the BMW801 series. The earlier prototypes had the BMW139.
Look at the P51 series. The P51D gains 11% more drag than the P51B. That is just adding two more weapons, engine changes, and a huge drag reducing canopy!
I find it extremely arrogant of some people who think they know more than the actual engineers who designed these aircraft. Especially using simple calculations that do not include the level of detail required for full analysis.
All the best,
Crumpp
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Bubble canopy increased drag on the P-51D. Also most B had the exact same engine - but the D was 5mph slower, I doubt -5mph = +11% drag.
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So you're comparing the cleanest to the dirtiest?
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Bubble canopy increased drag on the P-51D. Also most B had the exact same engine - but the D was 5mph slower, I doubt -5mph = +11% drag.
Not according to Dean's AHT. The P51D recieved extra guns and had a different motor. The bubble canopy was a drag reducing measure. Do you have something showing that it increased drag?
So you're comparing the cleanest to the dirtiest?
So your implying just the finish can effect it that much? You probably right, some planes did gain substantial benefits just improving the surface finish.
Maybe it is just cooling gill position that is causing a 10% drag variation. I wonder what the variation would be between having gills and not having them would be??
Lets look at some measured drag test's of the P51 series for variation. Keep in mind several of these are flight tested:
(http://img126.potato.com/loc271/th_10398_P51drag.jpg) (http://img126.potato.com/img.php?loc=loc271&image=10398_P51drag.jpg)
XP51:
(http://img138.potato.com/loc173/th_10399_Xp51_drag.jpg) (http://img138.potato.com/img.php?loc=loc173&image=10399_Xp51_drag.jpg)
Wow! We see a huge variation in some cases between the P51 variants.
I think it is a conspiracy between North American and the USAAF to hide the true performance of the aircraft. In reality the P51 must have performed much worse than published numbers. Just look at the huge variation in drag!
No way it could have anything to do with the level of detail of the calculations, flight tested aircraft set up, or solid science.
All the best,
Crumpp
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Not according to Dean's AHT. The P51D recieved extra guns and had a different motor. The bubble canopy was a drag reducing measure. Do you have something showing that it increased drag?
Initially, the P-51B and C had the Packard V-1560-3 engine. There were four hundred P-51B-1-NAs and 250 P-51C-1-NTs built. With the introduction of the P-51C-5-NT onto the Dallas production line and the P-51B-15-NA in the Inglewood production line, the Packard V-1560-7 engine was adopted as standard. Over 3000 P-51Bs and Cs were built.
The P-51D used the Packard V-1560-7.
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So it was built with both engines and both are correct. Moving on.
So we can eliminate the engine as a source of possible additional drag in the majority of P51B/C/D series.
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I was, too, under the impression that the bubble canopy was not necessarily a drag reducing factor. The movement of air became more turbulent behind the canopy so that a fillet had to be added in front of vertical stabilizer to make it more stable.
So I just made a assumption that the better rear view was well worth the increase in drag. Maybe it didn't affect the drag at all but only the stability?
-C+
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The P51B/C's had the same stability issues and it was caused by the propeller. The correction was the dorsal fin extension.
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I've lost you Crumpp:
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A reduction like that in parasite drag is stunning.
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It's an increase not a reduction. Look at the FW-190 weapon installation. Blisters, wing covers, barrels, and all the changes to the motor compartment.
Have you even seen the FW-190V5 series? They were new type prototypes without weapons and the very first installation of the BMW801 series. The earlier prototypes had the BMW139."
Thought you were talking about the drag on those two. That would roughly mean clean vs dirty. Never mentioned any finish.
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I've lost you Crumpp:
You have not lost me a bit. I do think your starting to see the holes in the:
Can we say somthing dosn't pass a smell test?
Argument.
I am sure it does smell rotten when you do not know the details of the design changes and assume you know more than the actual engineers.
All the best,
Crumpp
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So, please explain the types being tested and their differences A & B. Or is it buried somewhere earlier in the thread? Still looks like a big number to me but if it's "clean" vs "dirty" it should be ok...I think.
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See Rule #10
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First, I can no longer pull the graph. My firewall's screening its site.
It's probably not hosted anymore, being 3 years old
wrongway
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It only took him 3 years to do the math :D
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PJ_Godzilla = Crumpp?
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PJ_Godzilla = Crumpp?
Nah. "Or did I get this all wrong?" is not something Crumpp asks.
He has charts, you know.
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PJ_Godzilla = Crumpp?
The Rubber Lizard doesn't lurk behind other aliases. The Rubber Lizard wades through buildings toward the center of town.
Sorry about the belated response. The thread predates me and I'm almost exclusively an LW flyer so I'm always thinking about how to wring performance out of the 190s. I find the 109s to be much easier, honestly, and have taken a real shine to the G-14 lately. Of course, the K-4 is more capable in all but the flat turn but the G-14 is a sweet balance - as is the F-4. Too bad about the crappy dive performance. If it had that, it'd be perfect.
Anyway, I'm sure I went through all this in Aircraft Performance - I actually took that class from N.X. Vinh, former commander of the RVN Air Force, UM Prof after that.
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Anyway, I'm sure I went through all this in Aircraft Performance - I actually took that class from N.X. Vinh, former commander of the RVN Air Force, UM Prof after that.
You are a lucky guy, Nguyen X. Vinh was not only a pilot and aerospace engineer but also an outstanding mathematician. I've read some of his work, and own one of his books, but never met or communicated with him.
Badboy
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You are a lucky guy, Nguyen X. Vinh was not only a pilot and aerospace engineer but also an outstanding mathematician. I've read some of his work, and own one of his books, but never met or communicated with him.
Badboy
Indeed... he wrote me a letter of recommendation for my grad school trip out to Palo Alto. Not only was N.X. Vinh what you say, he was also a chain-smoking gambler who would never spend more than rock-bottom on a new car. I recall his new Escort wagon in 1985 - I didn't know you could delete the trim rings for credit.
Anyway, he was a fun-loving guy - from what I new of him. I always thought of him as a cross between a typical fighter pilot and a stereotypical Vietnamese: think of Maverick meets the VC Russian roulette player in the Deerhunter Tiger Cage.
He complained a bit about the Spitfire, btw. He said their turn rate was such that he was never sure on which side of the obstacle he needed to be. He depicted this, to a lot of laughter, in his heavy Vietnamese accent on the board via crude cartoons one day - jumping a stick figure from one side of a wall to another.