Aces High Bulletin Board
General Forums => Aircraft and Vehicles => Topic started by: gripen on September 28, 2005, 02:16:02 AM
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Raunio's article on Bf 109 controll forces is out now so here is DVL data on Bf 109 roll rates. I dug this out from the Deutsches Museum years ago and all those people who have got the report from me can do what ever they want with it from now on. It's free :)
The values in the chart are in rad/s and TAS (can be checked from the mach number if one wants to argue). Altitude is 3000 m.
gripen
(http://www.onpoi.net/ah/pics/users/852_1127891041_r1.jpg)
(http://www.onpoi.net/ah/pics/users/852_1127891105_r2.jpg)
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Thanks Gripen :aok
Neil.
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68 degrees/sec at 650 kph. I guess another myth died today. :)
Though it should be noted the tests were done on Bf 109F-2, so wing torsion effects should be stronger (ie. decreasing roll rate more at altitude) than with the 109G/K wings, which had reinforced main spar, ribs and skin.
Nice work making it public, Gripen.
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BOO! BOO! ....... oh wait, that's Milo's line.
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What are the stick forces at those speeds? My German is not nearly good enough to read German charts reliably or confidently.
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MeBwerte = measuted values
Umgerechnete werte = calculated value like extrapolated.
Anyway how do you read that thing. Well maybe I'd better zoom a bit more for a better reading.
And what 109????? 109F-2?
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Okay, from the perspective of somebody who doesn't do heavy research into that stuff.... My question is: "So what does that tell us? Does our AH model roll too fast? Just right? Too slow?"
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Krusty,
It depends on the stick forces required fpr those roll rates. They are higher than in AH, but AH limits stick forces to 50 or 60lbs as I recall, so if those are 90lb stick forces they don't mean anything to AH wheras if they ar 30lb stick forces they mean a lot.
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Okay, I gotcha on the stick forces. HT has mentioned that in the past. Okay, then, just from the rate of roll we have in AH now, regardless of stick force I take it the graph is saying the 109s rolled better? (just from a strict reading of the graph)
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Yes, much better.
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Raunio's article on Bf 109 controll forces is out
Where can I find the article?
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What are the roll rates in AH?
You should read the first graph BTW, the thick line (ymax=15) shows the roll rate at 15degrees stick deflection in radians.
The other line Em=15 shows the roll rate at 15 degrees middle value aileron deflection. The Bf 109`s ailerons deflected assymetrically, upwards 22 deg 40', dowards 11 deg 20', middle value being about 16. Appearantly this line shows the max possible deflection, so going by the max aileron deflection values (until limited by stickforce), we get :
Max roll rate of Bf 109F-2, at 30kg/66lbs stickforce :
200 kph = 45 deg/sec (0.8rad)
300 kph = 68 deg/sec (1.2rad)
400 kph = 83 deg/sec (1.45rad)
480 kph = 20kg/44lbs limit
500 kph = 88 deg/sec (1.55rad)
600 kph = 91 deg/sec (1.6rad) - peak value
700 kph = 56 deg/sec (0.98rad)
800 kph = 23 deg/sec (0.4rad)
Considering the aircraft reaches it`s peak roll rate at rather high speed, the stories about the set in cement, ineffective ailerons are really reaching.
To conver radians to degree:
Take the radian reading, divide it by 6.28 (ie. 2phi), then multiply with 360 to get the degree/sec value.
This pretty well agrees with both anecdotal evidence and other measured data :
"Roll performance is similar to a Hurricane or elliptical wing tipped Spitfire. A full stick roll through 360 degrees at 460kph takes 4 to 4.5 seconds without using rudder, and needs a force of around 20 lbf. One interesting characteristic is that rolls at lower speeds entered at less than 1g, such as a roll-off-the-top or half Cuban, have a markedly lower roll rate to the right than to the left. Therefore, I always roll left in such manoeuvres."
-Dave Soutwood on flying Black 6 (Bf 109G-2/trop), 109 Lair
http://109lair.hobbyvista.com/articles/airframes/black6/bk6_flight.htm
Ie.
4-4.5 sec for 360degree roll at 460kph = 80-90 degree/sec roll rate.
And also this doc states ~4.5sec for 360 degree roll at 450 kph, ie. ~80/sec :
(http://www.onpoi.net/ah/pics/users/715_1127927937_109g_aileron_stability.jpg)
The NNW-SSW lines show the stickforce limiting the available roll rate in kg. 20kg = 44lbs stickforce, 30kg = 66lbs stickforce. So if AH models with 60 lbs, the 30kg line is just about compatible, 6 lbs diffo won`t change much.
So is there a roll rate chart for the Bf 109F-G for AH to compare with?
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I don't know the actual roll rate numbers, but the metal aileroned Spitfires easily roll better then the Bf109s. The Hurricanes utterly dominate both the Spits and 109s in the roll. I personally think the Hurri is overmodeled in that regard, but haven't tried to dig up the evidence of it one way or another.
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Hi,
as gripen wrote, the datas are in TAS and as the document show the tests are made in H=3km (H = Höhe = altitude).
In in 3km alt :
600km/h TAS = around 510km/h IAS = 91°
700km/h TAS = around 595km/h IAS = 56°
800km/h TAS = around 680km/h IAS = 23°
This values are still better than the statements of absolute stiff alerons at 400mph(643km/h) IAS, but not much better than the datas i have for the 109E!
Actually i often wrote that even the statement of stiff alerons at 400mph(643km/h) are not very important, cause 643km/h (IAS) is far above Vmax of most 109´s. At normal combatspeed of 250-550km/h IAS noone ever wrote that the 109 had bad alerons, even the RAE wrote about very good alerons at this speeds.
That in 6000m alt 643km/h IAS are already 887km/h TAS (above mach 0,7) didnt disturb anyone.
It was a nice trick to let the 109 look worse, strangewise all did 'eat' it. Its like saying: the P51 roll good at 350mph (IAS), but at 550mph(IAS) the alerons are almost stiff, so the P51 cant get used as fighter anymore. Of course thats true at this speeds, but who care, its not the common speed.
Greetings, Knegel
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Out of curiosity, how did you convert TAS to IAS, with what variables?
I am still not sure if this is IAS or TAS.
It`s pretty hard to be sure given the rought Mach/kph scale, and that it`s quite effected by tempereture, humidty and altitude...
Simply there`s too much margin for error.
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Originally posted by Kurf�rst
You should read the first graph BTW, the thick line (ymax=15) shows the roll rate at 15degrees stick deflection in radians.
Isegrim,
Wouldn't the measured performance data provide a more accurate picture than the calculated data?
.
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It isn`t calculated, it`s extrapolated from measured data for max deflection.
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Originally posted by Kurf�rst
It isn`t calculated, it`s extrapolated from measured data for max deflection.
Ah, okay. Any ideas why max deflection wasn't measured?
.
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IIRC the test plane had to be given back or it was destroyed, something like that. The report is concentrating on theoretical study about wing flexing effecting roll rate, via a practical example, so it wasnt the main thing - I guess the 109F roll rate wasnt someting new to them in 1944. DVL was (is) the German equivalent of NACA.
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Originally posted by Kurfürst
Out of curiosity, how did you convert TAS to IAS, with what variables?
I am still not sure if this is IAS or TAS.
It`s pretty hard to be sure given the rought Mach/kph scale, and that it`s quite effected by tempereture, humidty and altitude...
Simply there`s too much margin for error.
Hi,
here is a nice true airspeed calculator: http://www.csgnetwork.com/tasinfocalc.html
Its for sure TAS! Look to 600km/h (lower picture), its close to Mach 0,5. If the km/h would be in IAS, it would be 708km/h TAS, but thats a 'bit' more than mach 0,5 (Mach1 in air is roundabout 1220km/h, depending to the temperature).
Greetings, Knegel
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Originally posted by Kurfürst
I guess another myth died today.
Hm... The data actually confirms what is allready known about the aileron characters of the Bf 109 ie the forces and effectiveness are normal at low speeds but at high speeds the forces are very high.
At 3000 m (about 10k) the TAS value is roughly 20% higher than IAS value depending on conditions. As an example 400 mph IAS is about 770 km/h TAS. If some body want's to make comparison with the NACA data (http://naca.larc.nasa.gov/reports/1947/naca-report-868/index.cgi?page42.gif), the speed should be converted to IAS and mph and stick force should be converted to 50 lbs.
Also it should be noted that the calculated peak roll rate of this particular plane was about 80 deg/s when elasticity of the wing and linkage was counted.
gripen
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charts are for an 109F2. Would be interesting to know whether later wings were stiffer.
In any case the 109 can hold it´s own against contempory fighters, comparing this chart to NACA chart for example
niklas
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Later wings of the 109 went stiffer I think,- so less twisting.
As the engines went more powerful, rolling into the torque would also become heavier.
As you would not trim the plane at any speed to balance the torque (outside trim), there is a certain speed where the aircraft rolls rougly equally into both directions. So, with ultimate power/speed it will need a boot on the rudder to keep it level, and to apply more force in one direction, and less in the other.
The airscrew pumping out 1000-2000 hp will definately give some aid or trouble to a human arm working to haul a 2-3 tonne aircraft from one side to the other.
So is the chart an avrage figure, - or isn't there so much difference between left and right at all?
Just me....:p
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Well, the 109F-4 wont do 400 TAS at 10k in level flight, but...
Took up a 109F-4, 10k, 400 TAS (from a 2k dive), rolls 180 degress in @ 2-3 seconds.
So if somebody could let me know what all the fuss is about later, that would be cool. The film does not show fractions of seconds, so you have to guesstimate.
Go ahead and see for yourselves.
Has to be a myth 1st before it can die. Personally I have never heard of the 109 being unable to roll well at 400mph at a low alt like 10k. A6M5 Zero maybe...
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Just the 109E model had problems rolling at high speed AFAIK.
At really high speeds all controls grew heavy on later models, but all in HArmony. ;)
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Upon seeing some of the other charts it would seem that you need a set value of stick force pounds to compare properly, but like I say, the 109F-4 rolls very nicely from my tests. Maybe somebody else can do a better analysis.
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"but the metal aileroned Spitfires easily roll better then the Bf109s"
I wonder where that claim comes from?
Hmm, which of them suffered more of wing flexing?
Did the Brits manage to build a large and rigid wing?
Small wing is more rigid and that is what was an advantage in German fighters. But then again the wingloading was high.
Wing flexing works against roll rate, U know....
-C+
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Originally posted by gripen
Also it should be noted that the calculated peak roll rate of this particular plane was about 80 deg/s when elasticity of the wing and linkage was counted.
Do you mean the highest line on the chart, the extrapolated one that peaks at 1.6 rad, about 90 degrees, doesn't take account of wing flexing?
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Charge: Karnak was talking about the aircraft as they perform in AH, not any real life data.
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Originally posted by justin_g
Charge: Karnak was talking about the aircraft as they perform in AH, not any real life data.
I was, but Allied tests from WWII found the same thing. The metal aileroned Spits handily outrolled the captured Bf109s in their tests. The question is, were those Bf109s in good enough condition to make the tests valid? The fabric aileroned Spits (Mk I, Mk II, early Mk V) rolled very much worse than the metal aileroned Spits and there was little to choose between a Bf109E and Spit I in the roll. Both had serious defiencies in that area. The Bf109F and metel aileroned Spitfires both improved roll performance over their predecessors, however the both still had problems at higher speeds.
The wing twisting that Charge was refering to is something that plagued the Spitfire until the wing was redesigned in the Spitfire F.21. That was mostly a problem at higher speeds though and at lower speeds the Spitfire's roll rate was unimpeded. You can feel the model of this in AH when the Spit's roll rate goes to crap above 350mph to the point where you can't really roll at all at 500mph or above.
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Originally posted by Nashwan
Do you mean the highest line on the chart, the extrapolated one that peaks at 1.6 rad, about 90 degrees, doesn't take account of wing flexing?
The lines with greek character "xi" and m give the roll rate with given average aileron deflection and these include wing flexing. But also the aileron linkage had some elasticity and therefore the average aileron deflection decreased with given stick movement when the speed increased. The line with greek character "phi" and max gives calculated roll rate with max stick movement. The chart below gives an idea how the average aileron deflection decrease when the dynamic pressure increase.
gripen
(http://www.onpoi.net/ah/pics/users/852_1128017315_r3.jpg)
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Originally posted by gripen
If some body want's to make comparison with the NACA data (http://naca.larc.nasa.gov/reports/1947/naca-report-868/index.cgi?page42.gif), the speed should be converted to IAS and mph and stick force should be converted to 50 lbs.
I've made a guesstimate of where the line for 50lbs(22.7kg) stick force would lie, and overlaid it on the NACA graph. It's not "gospel", but ppl can get a basic idea of the 109's comparitive performance.
(http://i22.photobucket.com/albums/b311/qwejibo/NACA-109ROLL.gif)
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Looks about right, the Zero is going to be slow at high speeds, with the Fw190 being the fastest, and everybody else somewhere in between.
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Originally posted by justin_g
I've made a guesstimate of where the line for 50lbs(22.7kg) stick force would lie, and overlaid it on the NACA graph. It's not "gospel", but ppl can get a basic idea of the 109's comparitive performance.
As noted above you should use the line for max stick deflection. In my own calculations I have used peak roll rate 85 deg/s at 500 km/h TAS for the G but it's more like a compromise based on this and other data (all data contain some oddities including this). At 400 mph IAS the Bf 109F should roll a bit over 20 deg/s with 50 lbs stick force.
gripen
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So above 330mph IAS the normal span Spit rolls better than the 109 and the clipped wing Spit has a MUCH greater rollrate than the 109.
Am I reading the graph correctly?
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"The question is, were those Bf109s in good enough condition to make the tests valid?"
I've never heard that 109s demanded anything special to keep up their roll rate as 190s did, so I'd imagine that they were OK to be used as comparison for roll rate???
-C+
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These numbers represent maximum roll rate, but not roll acceleration. Time from 0 to 180 degrees per speed applying # lbs starting from a no-roll state would be much more useful, as well as the same but starting with an opposite roll movement.
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Originally posted by MANDO
These numbers represent maximum roll rate, but not roll acceleration. Time from 0 to 180 degrees per speed applying # lbs starting from a no-roll state would be much more useful, as well as the same but starting with an opposite roll movement.
That is true, but I can't think of any such charts that I have seen.
The test pilots would have hated the test programs and performance documentation that we flight simmers would have had them do.:p
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Originally posted by MANDO
These numbers represent maximum roll rate, but not roll acceleration. Time from 0 to 180 degrees per speed applying # lbs starting from a no-roll state would be much more useful, as well as the same but starting with an opposite roll movement.
Something like below?
gripen
(http://www.onpoi.net/ah/pics/users/852_1128025032_r4.jpg)
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Originally posted by MANDO
Time from 0 to 180 degrees per speed applying # lbs starting from a no-roll state would be much more useful
Any kind of this data out there for P47 , P51, oh and P38 of course?
niklas
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Hi,
here is a nice page for documents!
http://mitglied.lycos.de/luftwaffe1/
There is also a SpitVa test, with metal covered alerons!
(http://www.raf-roy.com/share/knegel/Screenes/SpitV_roll.JPG)
According to this test the Spitfire dont got close to the 105°/sec, shown in the document above, at least not with 50lb, this would need around 70lb.
Unfortunately they show as max entry the 1.2rad/sec line, but it looks like with 50lb, the max rad/sec would be at around 230mph, while rooling to the right side. I estimate around1.4rad/sec. While rolling to the left side the peak is at around 190mph and max rollratio must be still around 1.4rad/sec.
Greetings, Knegel
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If it was a Spit Va it should have had fabric ailerons as they were all very early Mk Vs. It is possible it was being used as a test bed though. I'll see what I can dig up about that when I get home.
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I believe the NACA test is of a Spit V with metal ailerons. Guppy posted some info about it here some time ago
originally posted by Guppy35
This is the NACA tested Spit Va W3119 a very early Spit V with the external armored windscreen, flat canopy etc.
For anyone who has read Robert Stanford Tuck's biography "Fly for your Life" By Larry Forrester, this is also the Spit that Tuck did his little airshow at Wright field with.
To quote from the book "It happened that Wright Field had the only Spitfire in America-a Mark V. Unfortunately almost every pilot in the Air Corps had had a go on her and like a car that had too many drivers, she was the worse for wear...'She was very tired, very sloppy-she'd had the guts caned out of her all right.'"
W3119 was at Wright Field first in April of 41 and NACA saw her in July of 41.
With Stanford Tuck describing W3119 as "tired and very sloppy" while at Wright Field, you have to wonder how she was when NACA had her after this.
Now the Tuck biography has some errors too, such as mentioning Mustangs being tested with Merlin engines at Wright at the same time. While the Mustang I was around, the first Merlin conversion wasn't until October 42 in England, but it's a direct quote of Tuck on the condition of that Spit when he flew it so take it for what it's worth
http://www.hitechcreations.com/forums/showthread.php?s=&threadid=109977&highlight=caned
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Hi,
its with metal alerons!
(http://www.raf-roy.com/share/knegel/Screenes/SpVa_1.JPG)
This results are better than what i have for teh SpitI+II!
Greetings, Knegel
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Originally posted by gripen
The lines with greek character "xi" and m give the roll rate with given average aileron deflection and these include wing flexing. But also the aileron linkage had some elasticity and therefore the average aileron deflection decreased with given stick movement when the speed increased.
[/B]
Aileron linkage was done with metal rods, not cables like on the Spitfire, there was no 'linkage elastacy'.
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Originally posted by gripen
Hm... The data actually confirms what is allready known about the aileron characters of the Bf 109 ie the forces and effectiveness are normal at low speeds but at high speeds the forces are very high.
[/B]
*Very high* - compared to what? Not any higher than for the majority of WW2 fighters I have seen.
Let`s see in comparision, speeds up to max. aileron deflection could be maintained with 50 lbs stickforce :
Bf 109F-2 : up to 550 kph / 340 mph
Spit V : 140 mph (with 40 lbs)
P-47C : 230 mph
Typhoon : 250 mph
F4F : 235
P-63 : 280 etc.
I don`t see any particularly heavy forces compared to the others, its perfectly normal for a WW2 airplane.
Perhaps the only exception is the Mustang, which had very low deflection for the ailerons - and consequently low force/good roll rate at high speed, as well as poor low speed roll rate where it would really count.
At 3000 m (about 10k) the TAS value is roughly 20% higher than IAS value depending on conditions. As an example 400 mph IAS is about 770 km/h TAS. I
*Roughly?* Oh, now I see why it was important to switch it to IAS. Your usual handling of the primary data gripen, it gives something, then you adjust it to suit your own needs. Displacing the chart *roughly* by a whole 20% and decreasing the actual values they measured... But as Kneagel pointed out, the DVL roll chart is for IAS, not for TAS, thus it`s directly comparable to the NACA chart.
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Originally posted by Karnak
I was, but Allied tests from WWII found the same thing. The metal aileroned Spits handily outrolled the captured Bf109s in their tests. The question is, were those Bf109s in good enough condition to make the tests valid?
[/B]
The only direct comparisions with the Spitfire vs. 109G were done against that 'Wilde Sau' nightfighter Bf 109G-6 with the 20mm gondolas. These weighted some 250 pounds each, and the more weight on the wing carried, the worser the roll rate bocomes, as there`s far more intertia - see fighters like the P-38, Me 110 etc that all had engine gondolas in the wings, and even with boosted ailerons, the inertia remained a problem.
One other thing that report notes with comparision flight of the 109G/Spit is that the AFDU didn`t deflect the ailerons, and were rather cautious to use them. OTOH, if you compare them indirectly, ie. the 109/Tempest comparision, which was done with a 'clean' 109G-2, and the Spit/Temp comparision, oddly they note for both fighters that they fall behind the Tempest in roll at 350mph IAS in both cases.
The wing twisting that Charge was refering to is something that plagued the Spitfire until the wing was redesigned in the Spitfire F.21. That was mostly a problem at higher speeds though and at lower speeds the Spitfire's roll rate was unimpeded. You can feel the model of this in AH when the Spit's roll rate goes to crap above 350mph to the point where you can't really roll at all at 500mph or above. [/B]
Indeed, too bad the NACA report with that roll chart isn`t quoted entirely, for it says the wing twist would reduce the Spit roll rate at high speed by 65% (P-47 :35%, stiffer wings).
Note that both 190/Spit`s roll curve is totally different than any other roll curve on the NACA graph.It very much appears the NACA Spit/190 chart do not show at all the effect of wing twisting, the curves are totally straight, they would be curved if it was an actual measurement and showing the elastacy effect of the wing and linkage. I guess they were rough calculations based on a few measured points. Nashwan has the report, but for some odd reason, he would not show the conditions of the planes and testing methods, only some part of it. I wonder why. ;)
See below, actual testing of the Spit/Hurri roll rate with metal ailerons, vs. the 'spiked/straight' curves of the P-36/P-40 that were shown for comparasion, and were done by using only known aileron effectiveness at a single speed and stickforce. Same thing.
(http://www.onpoi.net/ah/pics/users/715_1094126808_rollratespithurrip40p36.jpg)
Now if I compare that one for the Spit which I knew it was coming from fully measured datapoints, using 30 lbs stickforce for both planes I get (using 200mph IAS = 386kph TAS and 15kg force for the 109, just to make Gripen happy):
at 200mph IAS/10k :
109F-2 : 73 deg/sec
SpitV : 63 deg/sec (metal ailrons)
Hardly any difference, and that`s exactly what Dave Southwood said about the roll rate of the 109G/non-clipped Spit.
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Originally posted by gripen
Something like below?
gripen
(http://www.onpoi.net/ah/pics/users/852_1128025032_r4.jpg)
This 109 data is with 7.6 ie. half stick throw though, so not very compatible, but should give some idea.
Here`s some for the Spit :
(http://www.onpoi.net/ah/pics/users/thumbs/715_1119443335_dsir23125625.jpg) (http://www.onpoi.net/ah/picpopup.php?ImgId=22432)
Edited, picture too big.
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Hihi, this tickled me a bit:
"Let`s see in comparision, speeds up to max. aileron deflection could be maintained with 50 lbs stickforce :
Bf 109F-2 : up to 550 kph / 340 mph
Spit V : 140 mph (with 40 lbs)
P-47C : 230 mph
Typhoon : 250 mph
F4F : 235
P-63 : 280 etc."
Firstly, the position in the 109 cockpit didn't allow much leverage. 50 lbs was about as much as you could do.
(Oh, I still remember you mentioning that a shorter stick allowed more force to be applied)
Secondly the comparative Spit there is at 40 lbs. Of course a full span aircraft. Not that it matters a lot, for I remember you also claiming that the clipping had very little effect.
Comes into my mind also from a similar thread that back then you used an extended Mk VIII (?) Spit for comparison.
On your list here there is no P51, no F4U and of course no 190, - why ruin the 109F's top seat.
There is no 109E for obvious reasons......
Then this one:
"Perhaps the only exception is the Mustang, which had very low deflection for the ailerons - and consequently low force/good roll rate at high speed, as well as poor low speed roll rate where it would really count."
So suddenly performance at low speeds becomes more important? Why do you think the P51 was set up this way?
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Do you have a point Angus, or you're just ranting as usual?
"There`s no 109E for obvious reasons"
Yep. It would make the contemporary Spit I look awfully poor, and that`s more than you can generally bear. :D
And yes, I do think low speed roll rate is more important. After all, rolls are most needed at dogfight speeds of typically 2-300mph.
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Note that both 190/Spit`s roll curve is totally different than any other roll curve on the NACA graph.It very much appears the NACA Spit/190 chart do not show at all the effect of wing twisting, the curves are totally straight, they would be curved if it was an actual measurement and showing the elastacy effect of the wing and linkage. I guess they were rough calculations based on a few measured points. Nashwan has the report, but for some odd reason, he would not show the conditions of the planes and testing methods, only some part of it. I wonder why.
I don't have the report on the Spitfire roll rates. The results, and brief descriptions of them, are in the FW 190 roll rate that Crumpp has, and I believe he's posted the whole thing in the past.
They are certainly measurements, the report goes into some detail on how they were obtained, and says that measurements obtained with a stopwatch are innacurate because of the short times involved.
Here's the relevant page:
(http://www.onpoi.net/ah/pics/users/282_1128078793_roll2m.jpg)
Once agaqin, this is from a report into the FW 190, and does not go into detail on the Spitfire tests, it merely provides them for comparison.
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You know perfectly well that the curves for a Spit I actual roll rate and a 109E actual roll rate are very similar. Post the chart if you like.
The stickforces are higher in the Spit I while more force can be applied due to the stick setup, so it basically boils down to the pilot.
And since you say that low speed roll rates are more important, well, I have something to remember :D
In that case the 109E beats the SpitI, hehe.
Does that apply to other performance as well?
Anyway, glad you took the bait :D
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OOps, the answer was for Kuffie, not you Nash :eek:
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Hi,
Angus,
"Firstly, the position in the 109 cockpit didn't allow much leverage. 50 lbs was about as much as you could do."
If you look to the 1st document in this theatre, you will see that the test was made with 30kg = 66lb.
"The stickforces are higher in the Spit I while more force can be applied due to the stick setup, so it basically boils down to the pilot." Why more force can be aplied?? Are british pilots more strong??
Kurfi,
"But as Kneagel pointed out, the DVL roll chart is for IAS, not for TAS, thus it`s directly comparable to the NACA chart."
Iam unsure which one is the DVL chart, but if you talk about the 1st both charts in this theatre, i did point out they are in TAS!!
But you be right that the 109 wasnt a bad rolling plane, it was absolute normal, at some speeds better at some speeds less good than most other planes, but at highspeed it did need much manpower.
Here is the NACA comparison with corrected 109F curves and the 50l SpitVa curve.
(http://www.raf-roy.com/share/knegel/Screenes/NACA-109ROLL.gif)
Greetings, Knegel
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Originally posted by Nashwan
They are certainly measurements, the report goes into some detail on how they were obtained, and says that measurements obtained with a stopwatch are innacurate because of the short times involved.
Here's the relevant page:
(http://www.onpoi.net/ah/pics/users/282_1128078793_roll2m.jpg)
Once agaqin, this is from a report into the FW 190, and does not go into detail on the Spitfire tests, it merely provides them for comparison.
Originally posted by hop2002:
Is it a flight test or a rough calculation with "rule of thumb" methods ? It seems to be latter, ie. notice that both aircraft have perfectly straight roll lines - which point to that wing and control elastacy was not taken into account at all
It's a fully instrumented flight test. It says so clearly in the FW 190 roll rate report where the figures are used:
http://www.onpoi.net/ah/pics/users/282_1128078793_roll2m.jpg
Read the last paragraph.
Appearantly not a fully instrumented test, Hop. It appears exactly what it seemed at the first glance, a rough calculation with "rule of thumb" methods.
Your paper says on the middle about how they arrived on the data :
"Kb2 has been calculated from the the stick force measurements; it`s value is -0.11, approximately constant over the range of tests."
In the last paragraph, they noted the exact same way was used to calculate the roll rate of Spit, Mustang, Typhoon as on the FW 190.
So appearantly it`s a calculation that hypothesizes the aileron effectiveness is constant over the whole speed range - but it isn`t, wing flexing reduced this considerably at high speed especially with the Spitfire, the NACA 878 report notes 65% reduction from wing torision, and the aileron reversal point is rather low as well. The FW 190 should suffer from this as well, even though it`s wing structure must have been more rigid with the two spar design that carried heavy loads.
They simply took a constant aileron effectiveness, and displayed how much this constant would yield if it`s only limited by the stickforce. This doesn`t take wing elastacy into account,that`s why they got those perfectly straight lines going up, than beyond stickforce limit, down. That`s theoretical value, with 100% rigid wings, which no planes of the era had.
This isn`t how it looks like in real life, enough to look on the 109 roll curves, the NACA roll curves for all the other aircraft, the NACA Spitfire tests, the RAAF Spitfire tests - they are all much more smoothened out because of the wing`s flexing. The effect varies from plane to plane, and we know the Spit had too much wing flexing at hand, until it's wings were redesigned with the Mk21 and later.
Basically you dismiss all measured data from the RAAF, NACA, in favour of higher figures coming from a simplified calculation that doesn`t even consider all factors. But if you insist to compare theoretical 100% wing rigidity roll data - do it with all planes, not just the one you like.
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"and the Spit/Temp comparision, oddly they note for both fighters that they fall behind the Tempest in roll at 350mph IAS in both cases."
The Tempest has more optimum placement of aileron (pretty much like in Spit F.21) so it's not a surprise it's better in roll than standard wing Spit and 109.
Angus take a look at Spitfire's/Hurri's controller and lets talk about leverage...
-C+
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Originally posted by Knegel
"The stickforces are higher in the Spit I while more force can be applied due to the stick setup, so it basically boils down to the pilot." Why more force can be aplied?? Are british pilots more strong??
Actually it seems strange too. The Spit stick leverage was very short, only the upper part could be moved for the aileron - about 20 cm at best, giving very poor leverage vs. a normal flight stick. Outright stupid if you ask me, the least effective way to convert the pilot`s muscles into force.
Ie. silicon graphics representation, viewed from the back, pilot throwing the stick to the right :
Spit`s fligth Stick:
leverege:
<->
...O
./
.I
.I
.I
.I
Most other WW2 fighters :
leverage
<---->
..... //
...../
..../
.../
../
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It's seems Charge has the same thing on mind as I do. Simply no leverage on the Spit to turn that muscle into force easily. Even the NACA report notes the max. force the pilot could apply was 40 lbs in the SpitV, and that was enough to deflect ailerons fully up to 140mph ias, no more.
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Haven't been able to stick my head into a Hurry's cockpit yet, but into a Spitfire cockpit yes, so I can easily understand what the Pilots refer to.
The only thing I have from SpitI and HurryI is anecdotes,- they claim the Hury rolled much much easier,- controls were much lighter.
Was the leverage more favourable as well?
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Same thing I read from reports from 1940 on Spit/hurri relative roll, too. They say the hurri was ligther - I wonder the reason, perhaps because the washout on the Spit. Its effect on stickforces was raised early in its development, but mitchel turned it down.
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The Hurry in 1940 would probably still have had fabric ailerons as well,- or on second thought, maybe not? There were many many kinds of wings in service, metal gradually becoming the norm.
Could be the washout, size, or more factors perhaps.
It's elevators were heavier,- however it was reported to turn on it's tail. Very balanced controls and easy to fly.
Landed 7 kills in a Hurry last night :D
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Originally posted by Kurfürst
Actually it seems strange too. The Spit stick leverage was very short, only the upper part could be moved for the aileron - about 20 cm at best, giving very poor leverage vs. a normal flight stick. Outright stupid if you ask me, the least effective way to convert the pilot`s muscles into force.
Ie. silicon graphics representation, viewed from the back, pilot throwing the stick to the right :
Spit`s fligth Stick:
leverege:
<->
...O
./
.I
.I
.I
.I
Most other WW2 fighters :
leverage
<---->
..... //
...../
..../
.../
../
Hi,
leverage dont count here!!
We have results with different stickforces, so the leverage dont count. 50lb at the handgrip are 50lb, no matter what leverage!
The lbs dont get measured at the bottom of the stick!
The leverage only is worth a look, if we wanna try to explain why planes had different rollratios, but wingarea, wingaspectratio, size, form and position of the alerons are far more important, at least if we assume that the constructors gave the pilot as much movement and as much leverage as the cockpit did allow(long stick = big leverage but smal variation = good for highspeed manouvers, short stick = smal leverage but much variation = good for slowflight manouvers, boosted alerons are different again).
On the page i did post some posts before is a complete HurriII test!
I did add the 50lb roll curve to the NACA document above!
The Hurri was ok at highspeed, but the max rollratio was rather poor.
According to the test the Hurri did need smal stickforces to get 0.4-0,8rad/sec, but above a special aleron delfection the stickforces got very big, thats why the max rollratio is bad, but the highspeed roll is ok.
Greetings, Knegel
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So, a longer stick with the same lbs makes more lbs on the control cables right. Hence the U.S. Fighters with their geared down control, - a larger travel to do the same force. So, the Spitty was set up worse in that way, - more power was needed on the cables to inflict the same roll as a 109. Howewer.....
The Spit pilots usually jabbed their elbow to the fuselage side, - it fitted quite well, - thereby being able to apply more force to the stick, - that's what I mean.
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Hi,
dont you think the 109, FW190 , P47, Yak1 or whatever pilots didnt use such 'tricks' to get a greater stickforce??
The thing is: While a hard combat, they had to roll right left right, at same time with turning and using siderudder. At highspeed such tricks are for sure good, where most rollratios was very slow anyway, but at combatspeed (150-350mph IAS) light sticks was a big advantage. They didnt clipped the Spitwings cause it looks more agressive!
Greetings, Knegel
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"Actually it seems strange too. The Spit stick leverage was very short, only the upper part could be moved for the aileron - about 20 cm at best, giving very poor leverage vs. a normal flight stick. Outright stupid if you ask me, the least effective way to convert the pilot`s muscles into force."
The RAF used the style of stick you are describing in ALL of its fighter a/c, there was nothing wrong with the design.
At wars end in 1945, the Spit XIV and Tempest used the same style of control stick they did in 1939...there was no need to change the basic design. Or they would have.
The P-51 (Mustang III) doesnt use it because the P-51 was manufactured in USA, same with other lend lease a/c, and they did not replace the control columns as policy.
The Spitfires wing, like all other fighters wings, had good, and bad attributes to them...like all the other fighters in WW2. None of them turned like an A6M Zero but rolled like an Fw190, as the flight data clearly shows...
"The Bf109 had a poor rate of roll because of its narrow cockpit, you couldnt move the control stick all the way to one side" - See, I dont need any sources at all to just fire off a baseless claim. Its easy! :huh
Regards.
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If the British stick setup was good, why then is it no longer in use while the German/American one is?
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What do you mean?
The rollrate was, if anything, enhanced with the way a Spitfire stick was set up. Make it shorter and yo will suffer.
And the wing clipping was made to meet the high rolling 190, NOT the 109.
Well, there may be some here who think the 109 and 190 rollrate is in the same ballpark maybe,- Crumpp, - where are you?
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Originally posted by Angus
What do you mean?
The rollrate was, if anything, enhanced with the way a Spitfire stick was set up. Make it shorter and yo will suffer.
The moving part of the Spit's stick in the roll axis was shorter than the 109's stick. It was also very inharmonic having long stick leverage in the pitch axis, but short stick leverage for roll.
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Originally posted by Kurfürst
Aileron linkage was done with metal rods, not cables like on the Spitfire, there was no 'linkage elastacy'.
This is what DVL measured:
(http://www.onpoi.net/ah/pics/users/852_1128017315_r3.jpg)
Try to live with that.
Originally posted by Kurfürst
*Very high* - compared to what? Not any higher than for the majority of WW2 fighters I have seen.
At 400 mph IAS and with 50 lbs stick force, the Bf 109 had the lowest roll rate if compared to other planes in the NACA chart (http://naca.larc.nasa.gov/reports/1947/naca-report-868/index.cgi?page42.gif) ie the forces were very high.
Originally posted by OttoJ
The moving part of the Spit's stick in the roll axis was shorter than the 109's stick. It was also very inharmonic having long stick leverage in the pitch axis, but short stick leverage for roll.
The charts above tell directly the roll rate with given stick force. The amount leverage is irrelevant for this discussion.
gripen
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I'm not into "your" discussion. I'm correcting Angus' mistaken belief that the Spit had more roll stick leverage than the 109.
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The Harvard trainer the RAF and RCAF used for advanced flight training used the same style control yoke with student pilots.
...the Tornado uses the same style of yoke, where only the top portion rotates for bank. So it is still used.
Its an ergonomic design choice, just like cockpit instrumentation and canopies are (some are hinged, some slide back, ect ect). You can find any number of "yoke types" in all kinds of a/c, both civil and military. They are not uniform by any stretch of the imagination.
The P-38 used a "yoke style", the Bf 110 used a standard "stick style", the Mosquito used a "bomber style" yoke in the bomber version and an RAF "fighter style" in the fighter version. They all worked just fine.
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What?! I can't believe they would use such a stick in the Tornado.
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Originally posted by OttoJ
I'm not into "your" discussion. I'm correcting Angus' mistaken belief that the Spit had more roll stick leverage than the 109.
Well, even in that case you are talking about force and movement, so the thing to look for is amount of movement, not directly the leverage because the aileron linkage change the movement ratio.
BTW the Do 335 had functionally quite similar stick as British planes.
gripen
edit: Image added from Aeroflight pages
(http://aeroflt.users.netlink.co.uk//profile/d335-72.gif)
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Mig-29, F-16, Tornado.
They all use different styles and designs, and all work just fine too.
British cars have the steering wheel on the right side, doesnt mean they are inferior. Just different.
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hi,
Originally posted by gripen
The charts above tell directly the roll rate with given stick force. The amount leverage is irrelevant for this discussion.
gripen
Looks like this is somewhat difficult to understand. lol
You be right that the 109F got heavy stickforces at high IAS, thats one reason why it was a very good high alt fighter.
In 6,1km alt 300mph are 420mph TAS, while a combat, where the enemys took notice of each other, the speed did decrease fast after the 1st turn. 400mph IAS rarely got reached(edit: in this alt), fighting at such speeds was difficult in all WWII planes, actually most planes would have broken while a hard movement at this speeds.
The P51 had its adjusting, cause it was adjusted to bring the pilot home at 1st! It wasnt adjusted to bring the best performence while a dogfight, cause the US HQ saw very early that most kills from 1941 onward was made while sneaky fast attacks and if the attack wasnt successfull it was better to be able to get away than to turnfight.
Angus,
"What do you mean?
The rollrate was, if anything, enhanced with the way a Spitfire stick was set up. Make it shorter and yo will suffer.
And the wing clipping was made to meet the high rolling 190, NOT the 109.
Well, there may be some here who think the 109 and 190 rollrate is in the same ballpark maybe,- Crumpp, - where are you?"
As you pointed out, and as you can see in the document above, the Spitfire wasnt better(regarding rolling) than the Bf109F at combat speeds, therefor i guess the clippled wing spit was not only needed vs the FW190, specialy the SpitV did suffer speedproblems, so i guess every advantage was welcome.
Since most planes had enough power to make the blackout, in big degrees, to the turnlimit, the rollratio is the most important axe while evading a attack and while following a evading enemy.
If a rollratio setting is good or bad depends to the way the pilots had to fight. Down low, while tight slow turnfight the P51 had a bad setting, while the 109 had a bad setting for highspeed.
btw, i realy would like to see the direct testcurve for all the planes in the NACA comparison.
Greetings, Knegel
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Originally posted by Squire
Mig-29, F-16, Tornado.
They all use different styles and designs, and all work just fine too.
British cars have the steering wheel on the right side, doesnt mean they are inferior. Just different.
Yes they are inferior! ;)
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Originally posted by Knegel
You be right that the 109F got heavy stickforces at high IAS, thats one reason why it was a very good high alt fighter.
Actually DVL planned to test this plane also at 6 km, but:
"Die messungen in 6 km Höhe konnten jedoch nicht mehr durchgeführt werden, da der Versuchsträger infolge Feindeinwirkung vernichtet wurde."
BTW please check the charts Abb. 11 and Abb. 4 and correct your chart.
gripen
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I seem to recall that at some alt it was troublesome to push the 109 into a blackout condition at all. That would more likely have to be high alt yes?
Anyway"As you pointed out, and as you can see in the document above, the Spitfire wasnt better(regarding rolling) than the Bf109F at combat speeds, therefor i guess the clippled wing spit was not only needed vs the FW190, specialy the SpitV did suffer speedproblems, so i guess every advantage was welcome.
Since most planes had enough power to make the blackout, in big degrees, to the turnlimit, the rollratio is the most important axe while evading a attack and while following a evading enemy. "
It's new news that the Spitfire clipping occured to counter the uber-rollrate of the 109. Wonder what the 190 guys say about that.
And for the rollrate factor, - try it in AH :D
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Hi,
Gripen, you be right, curves adjusted!
Angus,
in every alt it was troublesome to push any WWII fighter into a blackout, if the speed was low.
I dont know any WWII fighter which had a limited sustained turn due to a blackout, but from 1941 onward the pilots in general did avoid to make close slow turnfights(somewhere i did read that 80% of all planes got shot down by a suprise attack anyway).
I dont told that they clipped the wings cause the 109, i wrote it was helpfull, specialy for the relative slow SpitV´s also vs the 109´s.
In low and medium alt the CW Spit still could turn good enough, so why should they keep the wingtips? Good pilots didnt need the smooth stall, but a much better rollratio and more speed is always welcome.
btw, only you talk about a uber-rollrate of the 109.
Greetings, Knegel
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Originally posted by Squire
...the Tornado uses the same style of yoke, where only the top portion rotates for bank. So it is still used.
The A-4 Skyhawk used that type of stick too.
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I seem to recall that the Hurri II could sustain a constant 5G
Later model Spits could sustain 6 or 7.
Found it in an audobiography, there was a chapter about G suits.
I'll look it up.
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That's just BS Angus. No prop-fighter has enough power to sustain such G loads. 3-4 G's max.
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Dug it up
The Hurry COULDN'T sustain 5G's long enough to make the G suit a practical thing. So, shame on me.
The later spits could keep enough to put you asleep (that's 5 g's for 5 secs as measured in a centrifuge, RAF test 1940's), but not much longer.
However the use of the suits in a Spit VIII unit were cancelled, for it meant extra 4-5 minutes for scramble, which was a cost of some 20.000 feet.
Climb for the aircraft (initial I presume) is quoted as 5000 fpm, and top speed 420 mph, so when on ready, too much was found to be lost by the bulky suits.
But they were tested and worked quite well.
The LW tested some suits as well I think. In 262's??
I recall Rall mentioning that blackouts were not a problem, - sometimes he would black out, but not enough to lose conciousness. Mostly it was tunnel vision.
The G suit issue is however on a tougher scale, - when your blood start pooling and eventually you faint.
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Originally posted by gripen
At 400 mph IAS and with 50 lbs stick force, the Bf 109 had the lowest roll rate if compared to other planes in the NACA chart (http://naca.larc.nasa.gov/reports/1947/naca-report-868/index.cgi?page42.gif) ie the forces were very high.
Quite silly way of expressing your hatred to the 109.
First, 'the stick forces were very high at 400mph' - of course. So were on every other plane appearantly. You told nothing, effectively.
Second, Roll rate doesn`t tell much about stickforces. It`s effected by the available aileron deflection, aileron effectiveness, the behaviour of ailerons at high speed, and wing flexing. Stickforces are just one factor that may effect it.
Third, factually you are wrong about the lowest roll rates, for appearantly there`s not much difference in high speed roll between the 109 and Spit, F4F, F6F, P-39, and its much better than the Typhoon or Zero.
The Spitfire (metal a.) for example, required well over 75 lbs/~35kg to deflect the ailerons sufficiently to develop as slow roll rate as 45 deg/sec according the British tests. Above 40 lbs was required to deflect them fully up to 140 mph only.
Finally, it`s hardly makes sense to come up with extreme speeds and make comparisons at like 400mph IAS, something like 750 kph TAS, that was near or above the Vne of most of these planes, and wouldn`t even be reached at 3000m in full powered level flights - doesn`t makes sense unless one who hates a plane wants to pick one plane, put it under extreme conditions and say it`s BAD BAD, when in fact at all practical combat speeds, the roll rate and stickforces were entirely satisfactory.
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Ahhh:
"Second, Roll rate doesn`t tell much about stickforces. It`s effected by the available aileron deflection, aileron effectiveness, the behaviour of ailerons at high speed, and wing flexing. Stickforces are just one factor that may effect it"
Well, I thought it did. In some way. So, - that's why some designers geared the ailerons through the stick, just like lifting a stone with a long plank.
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Not to get into the argument and all about which plane rolled better, but you can't compare RAF ww2 stick controls to that of the tornado IDS or the mig21 or the a4 skyhawk or anything.
In ww2 they didn't have hydraulics or fly by wire electronic servos controlling the surfaces. In ww2 it was direct force on the surface, so it's a totally different ballpark. Can't compare it to modern iterations of the same type of stick.
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That's why you'd use gearing, - i.e. more stick travel for an equal deflection like on the Curtiss for example, right?
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I'm of that impression, yes, but I'm going to stay out of it :P
I was just pointing out the wrong way of comparing things some people have :)
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I have not read through this whole thread but I can say that RAE 1231 was a measured flight test.
The instrumentation and data acquisition is explained in the report. This data is then used to compare with various calculations.
Calculations were done to compare with the ADM standard measurements. The measured results were also compared to gun camera footage.
Calculations were also done to find the loss of rate from wing torsion based of the measured results.
It is easily provable by cross-referencing the aileron adjustment regulations of the FW190 series with the report that the aircraft tested suffered from out of ailerons in need of adjusting and does not represent the top rolling ability of the series.
they would be curved if it was an actual measurement and showing the elastacy effect of the wing and linkage
Generally speaking a "curved" graph of roll rate only shows the ailerons were not at full deflection. Usually this is due to stick forces being too high for the pilot to achieve full deflection.
In the case of the NACA test's this would mean that full deflection was possible only with a force above 50lbs.
(http://www.onpoi.net/ah/pics/users/503_1128202515_aileronrollsforcelimits.jpg)
All the best,
Crumpp
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Originally posted by Kurfürst
Quite silly way of expressing your hatred to the 109.
I wonder what do you mean? The Bf 109 was one of the most important types of the FAF and I have been collecting data on it for years because I'm honestly interested about the type.
If you don't like the data I have dug out and presented here or my postings overall, just ignore me.
Originally posted by Kurfürst
First, 'the stick forces were very high at 400mph' - of course. So were on every other plane appearantly. You told nothing, effectively.
At 400 mph IAS, the Bf 109 had lower rate of roll at given stick force (50 lbs) than all other planes in the NACA chart. See Mr. Knegel's presentation.
Originally posted by Kurfürst
Second, Roll rate doesn`t tell much about stickforces. It`s effected by the available aileron deflection, aileron effectiveness, the behaviour of ailerons at high speed, and wing flexing. Stickforces are just one factor that may effect it.
The DVL and NACA graphs show roll rate at given stick force and these include wing and linkage elasticity. Basicly all factors are included because all these are based on flight tested data.
Originally posted by Kurfürst
Third, factually you are wrong about the lowest roll rates, for appearantly there`s not much difference in high speed roll between the 109 and Spit, F4F, F6F, P-39, and its much better than the Typhoon or Zero.
As noted above, at 400 mph IAS all these planes had better rate of roll with 50 lbs stick force than Bf 109. Again, see Mr. Knegel's presentation.
Originally posted by Kurfürst
Finally, it`s hardly makes sense to come up with extreme speeds and make comparisons at like 400mph IAS, something like 750 kph TAS, that was near or above the Vne of most of these planes, and wouldn`t even be reached at 3000m in full powered level flights - doesn`t makes sense unless one who hates a plane wants to pick one plane, put it under extreme conditions and say it`s BAD BAD, when in fact at all practical combat speeds, the roll rate and stickforces were entirely satisfactory.
The red line speed for the Bf 109 at 3000m was 750 km/h IAS and 400mph IAS is only about 650 km/h IAS so 400 mph IAS is well within normal flight envelope and easily reachable in diving maneuvers.
gripen
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Originally posted by Krusty
Not to get into the argument and all about which plane rolled better, but you can't compare RAF ww2 stick controls to that of the tornado IDS or the mig21 or the a4 skyhawk or anything.
Sure you can, the A-4 also had old fashioned cable backups for the hydrolic systems, so that stick had to work just like a WW2 plane if the hydrolics failed. The only reason I pointed that out about the A-4's stick was it was said that that type of control was not a good one, and some of us gave examples of other (yes newer) planes that use identical sticks.
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Well the stick type may be good for planes with automated controls (and A4 might have been a pig to fly on manual backups, too), but doesn't mean earlier planes were "good" as well :P
Regardless, "good" or "bad", they simply.. "were".
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Originally posted by gripen
At 400 mph IAS, the Bf 109 had lower rate of roll at given stick force (50 lbs) than all other planes in the NACA chart.
400 mph IAS is an extremely high speed, only achievable in a dive and at that speed your only concern would be to level out.
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Originally posted by OttoJ
400 mph IAS is an extremely high speed, only achievable in a dive and at that speed your only concern would be to level out.
Hm... as noted above 400 mph IAS (about 650 km/h IAS) is not even close normal flight limitations of the Bf 109 at 3000 m ie 750 km/h IAS.
BTW RAE had no problems to test Fw 190 Roll rate at 409 mph EAS (EAS is IAS with type specific corrections) at 10k and all other planes (Typhoon, Mustang I and Spitfire) in the same test were tested same way:
(http://www.onpoi.net/ah/pics/users/852_1128229617_r8.jpg)
In the case of the Mustang III, RAE went even further and tested ailerons up to about 470 mph EAS at 10k:
(http://www.onpoi.net/ah/pics/users/852_1128229687_r9.jpg)
Generally 400 mph IAS at 3000 m is not particularly high speed and easily reachable for all planes mentioned in the NACA chart.
gripen
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Originally posted by gripen
I wonder what do you mean? The Bf 109 was one of the most important types of the FAF and I have been collecting data on it for years because I'm honestly interested about the type.
If you don't like the data I have dug out and presented here or my postings overall, just ignore me.
Yeah Gripen, we`ve all seen your posts, you are always showing one sided stories about both the FW 190 and Bf 109, which later you can`t support with anything for even your own docs don`t support you, then you stubbornly repeat the same over and over again. Don`t fed us with BS about your honesty, please. You are hypocrite, and for some reason you hate LW planes, everyone knows it.
Originally posted by gripen
At 400 mph IAS, the Bf 109 had lower rate of roll at given stick force (50 lbs) than all other planes in the NACA chart. See Mr. Knegel's presentation.
...
As noted above, at 400 mph IAS all these planes had better rate of roll with 50 lbs stick force than Bf 109. Again, see Mr. Knegel's presentation.
As noted to you, to which your response is only silly parrotting - how can I take your claims seriously?
Again, the FACT is the DVL doc shows 55deg/sec roll rate 375mph IAS, which is better than the Zero, Typhoon, Spitfire, P-39, F4F, and almost as good as the P-47 or F6F. As usual it is the case that gripen claims something with reference to a document, but the document doesn`t shows what gripen says it say.
Besides, it appears that Kneagel got the wrong IAS/TAS conversion got some problem, which effects the roll data very strongly, hence the margin of error is very great. You know this as well, you just being a hypocrite again.
The DVL and NACA graphs show roll rate at given stick force and these include wing and linkage elasticity. Basicly all factors are included because all these are based on flight tested data.[/B]
Again, you repeat the same sillyness like a parrot. I can`t take you seriously with 'arguements' like this.
If you really wish to prove the 109 had higher stickforces than others, why not posts stickforces themselves vs. other planes?
I already looked that up with the available data, and they don`t support your claim at all.
The NACA says the Spit having troubles with stickforces already at 140 mph IAS, above which full deflection is not possible.
Another Spit (metal) doc (AVIA 6/10126) shows the aircraft needs 71 lbs stickforce to deflect the ailerons only by 4.5 degree at 400 mph IAS.
Whereas your doc shows that FULL aileron deflection (avarage 15 degree, almost four times more) can be reached on the 109 with only 66 lbs stickforce up to 330 mph IAS. With a comparable 40 lbs stickforce as in the NACA`s Spit tests, the 109 can deflect ailerons fully up to about 265 mph IAS. So what are you talking about, I ask.
The red line speed for the Bf 109 at 3000m was 750 km/h IAS and 400mph IAS is only about 650 km/h IAS so 400 mph IAS is well within normal flight envelope and easily reachable in diving maneuvers.
gripen [/B]
Easily reachable? That`s merely an opinion of yours. Basically you say that at speeds that wouldn`t even be reached by 90% of all WW2 fighters at 10k ft, the roll rate of the Bf 109 is bad. Quite irrelevant really, dogfights featuring wild barrell rolls near Vne speeds only exists in your fantasies, in fact most plane manuals strictly forbid such hard rolling manouvers at high speeds anyway.
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Originally posted by Kurfürst
Yeah Gripen, we`ve all seen your posts, you are always showing one sided stories about both the FW 190 and Bf 109, which later you can`t support with anything for even your own docs don`t support you, then you stubbornly repeat the same over and over again. Don`t fed us with BS about your honesty, please. You are hypocrite, and for some reason you hate LW planes, everyone knows it.
It's not a public problem if you don't like my postings. Why don't you do just like Mr. HoHun and add me to your ignore list? And if you want to express your feelings about me even more, just add me to your signature to promote me in your every post.
Originally posted by Kurfürst
Again, the FACT is the DVL doc shows 55deg/sec roll rate 375mph IAS, which is better than the Zero, Typhoon, Spitfire, P-39, F4F, and almost as good as the P-47 or F6F. As usual it is the case that gripen claims something with reference to a document, but the document doesn`t shows what gripen says it say.
It's not a public problem if you can't make DVL and NACA data comparable. At 375 mph IAS and with 50 lbs stick force, the Bf 109 is about equall with the Zero and Typhoon as Mr. Knegel's presentation shows. At higher speeds the Bf 109 is worse.
Originally posted by Kurfürst
If you really wish to prove the 109 had higher stickforces than others, why not posts stickforces themselves vs. other planes?
It's not a public problem if you can't read the NACA chart, it gives directly the roll rates with given stick force (50 lbs).
Originally posted by Kurfürst
Easily reachable? That`s merely an opinion of yours. Basically you say that at speeds that wouldn`t even be reached by 90% of all WW2 fighters at 10k ft, the roll rate of the Bf 109 is bad.
400 mph IAS at 10k is not particularly high speed, even the Bf 109E and Spitfire I were tested up to that speed by RAE much earlier than DVL test. And as noted above, it's well below normal flight limitations at 10k.
gripen
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Yep, HoHun is right. I must admit I admire his ability to put as much faith in the public`s common sense that it can filter the true facts from the silly mantra of an self-proclaimed 'expert on all'.
HoHun is right. Who the f. cares what gripen mumbles. He can post his sillyness for himself and be always right in that. :rofl
You don`t worth an answer.
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Hi,
the 109 roll very bad at highspeeds over 350mph, but up to 280mph the rollratio was ok for its time and even up to 340mph it was good, although the stickforces was pretty high.
If we consider that the best sustained turnspeed of the powerfull La7 was 200-210mph(320-340km/h) IAS at sea level and only 175-180mph(280-290km/h) IAS in 5000m alt (less powerfull planes, had best sustained turn speeds good below that of the La7!), we can get a imagination what speeds IAS was common while a combat. Next to this there must be a reason why the Brits tested the SpitfireVa and HurriII only up to 300mph.
So the people who wanna see the Be109 in a bad light dont will stop to point to the bad highspeed behaviour, while the people who wanna show the Bf109 in a good light, will point to the advantage over the Spit and Hurri at slow to medium speeds.
Btw, i would like to know where the very high 'Spitfire (normal wing)' datas in the NACA document comes from.
Did they made more changings to the metal covered alerons to obtain such a rollperformence?
And it also would be interesting to see the original tests of the other planes next to 109G and K roll tests.
Greetings, Knegel
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I belive the Spitfire was under constand "edit" in the rollrate field from MkV onwards.
So, was the 109.
BTW, some WW2 monsters reach 400 mph at SL, so, you'd want them to be able to bank.
Now for Kuffie, - ease off a bit will you.:p
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Hi,
Kurfi, cant you accept german testdatas too?? The 109F was bad at highspeed roll in comparison to ALL other WWII fighters shown in the NACA test. Where is the problme?? Most planes was more bad up to 200mph.
Angus, at 400mph the 109 still could bank 90° with 2,3sec, although high stickforces are needed, this is far away from not manouverable, if we consider that one turn manouver let fall the speed fast much below Vmax! If the pilot would need to bank many times at 400mph the limited constant manpower would be a real problem for sure.
The 109F simply wasnt made to fight at such speeds and i guess the 109G10 and 109K4 made this job better.
I think the results of the 109F in combat show pretty good that the rollratio same like the other flightperformences wasnt its handycap, rather its armament.
Greetings, Knegel
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Originally posted by gripen
In the case of the Mustang III, RAE went even further and tested ailerons up to about 470 mph EAS at 10k:
EAS? Estimated Air Speed?
470 mph IAS at 10k is ~564 mph TAS. Did they put rockets on this Mustang?
Are you sure about these numbers?
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Kneagel I think you took the IAS/TAS conversion wrong.
Here`s my version. I used a Rechlin flight test that lists both IAS and TAS for 3000m, so it`s more accurate to show German conditions. IAS conversion is effected by a lot of factors, and standard day conditions are different from country to country, so even small errors can lead to big differences, see below.
I used 1 IAS = 0.861 TAS conversion, not the scientific gripen :lol "roughly 20%". It should reflect German IAS conversion standards.
(http://www.onpoi.net/ah/pics/users/715_1128252798_bf109roll-50lbs.gif)
ERRATA : The blue "30 lbs" (I don`t know if it`s conversion quality error or typo) is showing the 50 lbs line for the Bf 109, not 30 lbs !
I don`t really see how the roll rate bad. It`s about avarage on the whole range in the group.
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Butch made some interesting comments on the other thread, I think it`s wortwhile to qoute him :
This document (which i own as well) is nothing new nor does it contradict the other German documents i have pertaining to 109 Roll rate. Actually it is much worse that the calculated data i have which for instance give the 109F a roll rate of 95°/s at 480km/h....
Second a 66lb stick for is something which can be achieved easily by someone trained and fit. I used to be an archer when i was younger and used a classic bow rated at... 66lb. It is straining at first but with training and excercise and an healthy life you could maange it easily. Sure if you suffer from a serious hang-over it will definitely put some strain on your shoulder
On a Warbird one must distinguish the left side roll from the right side roll, the later if measured single handled is usualy worse because of :
THe cramped space impeding proper arm movement
The lesser power achievable by the muscles in such a movement.
The left roll is easier due to upper torso muscles being used to full extent.
Now is 66lb achievable on a constant basis, definitely NO. It is straining and could be achieved for short amount of time and can be repeated a few dozens of time during a day. This provided you are well trained and healthy. I insist on hte later point since i could experience the effect of not being well feed or having drink too much the day before competitions... :x
On a punctual basic one can achieve much larger effort for small amount of time. 100lb or more can be achieved due to adrenalin boosting your muscles. The day after won't be one you'll be wishing to fly because your arm will most likely be sore. Once again that's something i experience when training my upper body muscles.
Frankly the 50lb limit usualy seen in documents is more for comparison than a physical limit. THe only physical limit it may represent is tiredness. At 50lb you do not tire much provided you are used to such efforts. Given the training the flying cadets had to undergone, i believe they should not have much trouble pushing/pulling 50lb ever way and doing this repeatidly.
That's my .02$ worht of comments.
Ie. butch`s other doc gives 95 deg/sec roll rate at 480 km/h, ours give at this speed 80 deg/sec. I guess it comes down to variations between individual planes. The NACA/RAE chart shows the highest values for any Spit in roll I have seen so far (and I seriously doubt the clipped figures would come from flight tests, all other documents contratics such a great and linear change), so it`s probably a better example of the aircraft.
BTW Spitfire fans always complain about that 1941 NACA test on the SpitV, dismissing the results completely based on Nashwan`s claim that it was 'very tired', now I wonder what`s in the case of the 109F-2, which was built in late 1940, and tested in late 1944, a four years old machine.. still, it did quite well imho.
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Originally posted by OttoJ
EAS? Estimated Air Speed?
470 mph IAS at 10k is ~564 mph TAS. Did they put rockets on this Mustang?
Are you sure about these numbers?
EAS=Equivalent Air Speed. It is TAS with compressibility correction.
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Kurfy, in pursuit of your agenda 109 you have sunk all time low. You have become a true believer now. Only a true believer can twist the presented data as you are now doing. Sad.
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Originally posted by Kurfürst
HoHun is right. Who the f. cares what gripen mumbles. He can post his sillyness for himself and be always right in that.
You don`t worth an answer.
So why don't you stop your never ending personal attacks and ignore me?
Originally posted by Knegel
the 109 roll very bad at highspeeds over 350mph, but up to 280mph the rollratio was ok for its time and even up to 340mph it was good, although the stickforces was pretty high.
Well, I don't see much difference to my opinion; "The data actually confirms what is allready known about the aileron characters of the Bf 109 ie the forces and effectiveness are normal at low speeds but at high speeds the forces are very high."
Originally posted by Knegel
Next to this there must be a reason why the Brits tested the SpitfireVa and HurriII only up to 300mph.
Actually that is NACA data, they tested a Spitfire, Hurricane and Mosquito which RAF had given to USAAF for eveluation. Infact RAE send critics to NACA because NACA did not test planes at higher speeds.
Originally posted by Knegel
Btw, i would like to know where the very high 'Spitfire (normal wing)' datas in the NACA document comes from.
These values come from a large fighter aileron comparison by RAE. The tested planes were Fw 190, Mustang I, Typhoon and Spitfire V with standard and clipped wings. These tests were fully instrumented and the planes were tested up to and over 400 mph IAS. For details get DSIR 23/12865 and 23/12506 from the PRO (there are also other docs with data from these tests).
Originally posted by Knegel
Did they made more changings to the metal covered alerons to obtain such a rollperformence?
Tested planes were standard Spitfire Vs. The most probable reason for the difference between NACA and RAE data is that there appear to be plenty of loosenes in the aileron linkage of the NACA tested Spitfire and Hurricane; the roll rate curves does not show typical sharp edges when the stick force limit is reached. The RAAF data on Spitfire V shows quite good agreement with RAE data given the different stick force and the both data sets show typical sharp edges.
Originally posted by Knegel
And it also would be interesting to see the original tests of the other planes next to 109G and K roll tests.
There is some data around on the Bf 109G but not as well instrumented as this DVL test. The ailerons are basicly same in the Bf 109F, G and K and stick forces are also about the same, the differences come from somewhat stiffer wing in the later models.
Originally posted by OttoJ
EAS? Estimated Air Speed?
470 mph IAS at 10k is ~564 mph TAS. Did they put rockets on this Mustang?
Are you sure about these numbers?
EAS = Equivalent air speed, IAS corrected with type specific corrections (not TAS!).
The Mustang III was red lined 505 mph IAS, so 470 mph IAS is well within normal flight envelope and easily reachable in dive. You can see the test points from the dataset.
Regarding Butch2K's comment; AFAIK about half of the internet has got this DVL data during past (from me or they have dug out it from the DM like me, or NASM), I have given the doc about every reasonable person who has shown interest (tens of people including several writers and game developers). The only restriction I have asked from them was to keep silence until Raunio's article comes out and generally that has been worked out well except one case when a person started to distribute it in AAWII board (Butch's board).
And the mentioned calculation showing the 95 deg/s roll rate is exactly that ie a calculation.
gripen
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Originally posted by pasoleati
Kurfy, in pursuit of your agenda 109 you have sunk all time low. You have become a true believer now. Only a true believer can twist the presented data as you are now doing. Sad.
Can you elaborate on how do I "twist" the data so that I can correct ?
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BTW the RAE Spitfire roll rates shown on the NACA curves are quite suspicious especially when we compare them to other RAE tests.
Ie. RAE`s comparision of Mustang and Spitfire roll rate (AVIA 6/10126) notes the following (from 1942) :
(http://www.onpoi.net/ah/pics/users/715_1128259573_spitrollat400mph.jpg)
Ie. to achieve a 45deg/sec roll rate on the Spitfire, 71 lbs stickforce is required at 400mph ias. However the NACA chart claims 40 deg/sec achived with 50 lbs stickforce, ie. 2/3s the force of that, it just doesnt match with any other dataset.
Appearantly the NACA chart values are for either some very good example of the Spitfire, or it just some kind of a calculation or prototype with a new type of aileron. Coincidentaly, a Spitfire V was tested at that time with spring tab ailerons, I guess that`s what the RAE test shows - which is probably the reason why Nashwan doesn`t show the test details.
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Originally posted by gripen
There is some data around on the Bf 109G but not as well instrumented as this DVL test. The ailerons are basicly same in the Bf 109F, G and K and stick forces are also about the same, the differences come from somewhat stiffer wing in the later models.
gripen
If you have these, why not show the results gripen?
After all, from your telling it appears that dataset is better, but you want to stick to the lowest dataset done on a four year old airframe.
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Originally posted by Kurfürst
If you have these, why not show the results gripen?
I have all ready claimed the calculated result (from timed values) above ie peak roll rate about 85 deg/s at about 500 km/h TAS.
gripen
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Why not show the 109G instead gripen? It would be interesting for all of us.
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Why?
gripen
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BTW that 85 deg/s is calculated from Bf 109G results.
gripen
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Because perhaps it would be interesting to see a 109G and not a four year old 109F test result.. you bothered about a worn, but relatively new Spitfire tested by the NACA, but not about a rather old 109F airframe? We could see how they differ, especially when the major model was the Gustav with stiffer wings improving roll rate at high speeds.
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Regarding stickforces :
Spitfire, RAE tests :
71 lbs required for 45 deg/sec roll rate at 400mph IAS
109F, DVL tests :
66 lbs required for 40 deg/sec roll rate at 400mph IAS
I don`t see huge difference, if any.
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Gripen, Raunio says (in his first article in the ongoing series) that EAS is based on TAS but with compressibility correction included.
And I provided copies of that aileron doc with the same restriction that you did, i.e. not to publish it before Raunio´s article. And I wasn´t the first one to refer to that report either.
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EAS is definately based on IAS.
For example, the RAE dive tests on the Spitfire give figures like:
alt (ft) EAS TAS Mach
39,690 136 274 0.408
20,080 371 510 0.730
(These were not done with standard instruments)
Coincidentaly, a Spitfire V was tested at that time with spring tab ailerons, I guess that`s what the RAE test shows - which is probably the reason why Nashwan doesn`t show the test details.
This is getting boring. I've shown you all the details I have. I have some of an Fw 190 report, which includes a comparison with other results. It does not go into details of the other results. Ask Crumpp, he has the report.
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Lol this
"Regarding stickforces :
Spitfire, RAE tests :
71 lbs required for 45 deg/sec roll rate at 400mph IAS
109F, DVL tests :
66 lbs required for 40 deg/sec roll rate at 400mph IAS
I don`t see huge difference, if any."
There isn't much difference of stickforce there. If you'd calculate onwards in percentage flat the 109 is slightly higher.
What matters is the ergonomic position of applying the force and where in that ergonomic position you hit the ultimate maximum.
BTW..
What model of Spitfire though?
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Angus, I don`t really get this "LOL-109mustbehigher-ergonomyposition" thing. The point was the Spitfire and 109 are again extraordinarly evenly matched in both stickforce and roll rate - neither really good at high speed btw.
I suppose even you wouldn`t call the Spitfire or the 109 an especially ergonomic plane to sit in.
As for the Spit model, I`ll look up if I can find the details. Definietely a later model though from mid-1942, a V or IX.
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Originally posted by Nashwan
This is getting boring. I've shown you all the details I have. I have some of an Fw 190 report, which includes a comparison with other results. It does not go into details of the other results. Ask Crumpp, he has the report.
OK, so you don`t have ANY details on the Spitfire roll rate test, possible modifications done, or wheter the aircraft was an avarage, above/below avarage example? So it`s a set of data which happens not to match any other data. Could it be an experimental machine?
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These weighted some 250 pounds each, and the more weight on the wing carried, the worser the roll rate bocomes, as there`s far more intertia - see fighters like the P-38, Me 110 etc that all had engine gondolas in the wings, and even with boosted ailerons, the inertia remained a problem.
This is an incorect assumption. Stead state roll rate is not effected by inertia. And at medium and above speeds roll acceleration (i.e. the time it takes to reach max roll rate) is almost none existant.
HiTech
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Originally posted by pasoleati
Gripen, Raunio says (in his first article in the ongoing series) that EAS is based on TAS but with compressibility correction included.
EAS as used by RAE in their documentation is not the same EAS as used in current litterature. RAE just made IAS values comparable by adding type specified corrections.
gripen
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Originally posted by Kurfürst
OK, so you don`t have ANY details on the Spitfire roll rate test, possible modifications done, or wheter the aircraft was an avarage, above/below avarage example? So it`s a set of data which happens not to match any other data. Could it be an experimental machine?
Get the document's (DSIR 23/12865 and 23/12506 from the PRO), these give all the details you need to know.
gripen
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OK, I will check them out, but until then I think I remain sceptical.
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Hey Gripen, have you been around the PRO?
Live in England or Frequent traveller?
I've been there, - to get deep into the stuff they have I would need a year off ;)
And for you Kuffie, there seems to be a lot of data around about many many Spitfires to be compared with some tatty stuff about some 109's. Why do the most quoted values have to be allied values or estimations of the 109? And BTW, I did have my thoughts about the gondie effect of the 109G,- now as HiTech has replied, I expect you to challenge him on the subject or bring something unknown to the fray.
Then this:
"Angus, I don`t really get this "LOL-109mustbehigher-ergonomyposition" thing. The point was the Spitfire and 109 are again extraordinarly evenly matched in both stickforce and roll rate - neither really good at high speed btw.
I suppose even you wouldn`t call the Spitfire or the 109 an especially ergonomic plane to sit in. "
I always smell your "109mustbehigher-ergonomyposition" thing. I remember you debaiting the cockpit size of a 109 vs a P51.
Read up in Rall's book. It will do you good ;)
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Originally posted by Kurfürst
OK, I will check them out, but until then I think I remain sceptical.
Well, feel free to remain skeptical but I think no one cares if you are sceptical or not. You can also easily save some work and just read the page (http://www.onpoi.net/ah/pics/users/282_1128078793_roll2m.jpg) Nashwan posted:
"This course has been adopted in Fig. 6 which shows the results obtained for the F.W.190, Mustang, Typhoon and Spitfire V (metal covered ailerons) with both standard and clipped wings. On all these aircraft instrumental recors of rolling performance have been obtained at the R.A.E. similar to those under discussion for the F.W.190."
Originally posted by Angus
Hey Gripen, have you been around the PRO?
Live in England or Frequent traveller?
I've visited PRO couple times and I'm just a frequent traveller.
gripen
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Originally posted by Kurfürst
Kneagel I think you took the IAS/TAS conversion wrong.
Here`s my version. I used a Rechlin flight test that lists both IAS and TAS for 3000m, so it`s more accurate to show German conditions. IAS conversion is effected by a lot of factors, and standard day conditions are different from country to country, so even small errors can lead to big differences, see below.
I used 1 IAS = 0.861 TAS conversion, not the scientific gripen :lol "roughly 20%". It should reflect German IAS conversion standards.
ERRATA : The blue "30 lbs" (I don`t know if it`s conversion quality error or typo) is showing the 50 lbs line for the Bf 109, not 30 lbs !
I don`t really see how the roll rate bad. It`s about avarage on the whole range in the group.
Hi,
i dont think i got the calculation wrong!
Lets take the 30lb(13,6) peak value.
We miss this exact line, but i estimate it at almost exact 1.2 rad, 400km/h TAS.
400km/h = 248,6mph TAS, your 30lb IAS peak show a much greater IAS than TAS, so you probably was in a 3000m deap valley!
If i take your factor of 1 IAS = 0.861 TAS.
248,6mph x 0,861 = 214mph, my graph show 208mph, i think thats a pretty smal error. The Airspeedcalculator use factor 0,8492 for 3000m alt.
Sometimes the will to find a wanted result lead us to make bad mistakes! I realy would have liked to find a better 109 rollratio, and my initial wrong interpretation made me believe that, but the result simply show what is long time well known!
btw: "I used a Rechlin flight test that lists both IAS and TAS for 3000m." Could you please show this test, if you realy took your 30lb line from a Rechlin test, i wonder why your 66lb line fit to mine?
never theless, this 109F test is only one, and as you see, we have already 3 different Spitfire metal aleron curves, plus the Mustang/Spitcomparison, and all show different results.
Would be interesting, if they made tests with other aleron adjusting.
Yep gripen, i simply agreed to you, regarding the rollratio.
Yes, some NACA tests show comparisons up to 400mph and more, NACA tests of the HurricaneII (L-565) and the SpitfireVa(L-334), next to the Spit/Hurri/P36/P40 comparison, stop at 300 eg. 320mph. Looks like they dont thought that tests above this speed are of any use. I only wanna show that the rollratio at highest speeds shouldnt get overvalued!
Greetings, Knegel
Edit: Just understood your "errata" message! Your 30lb/50lb line is the 30lb line in a 3000m deap valley, you took 248 / 0,861 = 285mph, instead of 248 x 0,861 = 214mph.
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Originally posted by gripen
Tested planes were standard Spitfire Vs. The most probable reason for the difference between NACA and RAE data is that there appear to be plenty of loosenes in the aileron linkage of the NACA tested Spitfire and Hurricane; the roll rate curves does not show typical sharp edges when the stick force limit is reached. The RAAF data on Spitfire V shows quite good agreement with RAE data given the different stick force and the both data sets show typical sharp edges.
gripen
Any flying times of the 109F2 known? Was it factory fresh, or also used for other tests earlier?
We should never forget that this report was NOT made to determine the highest rolling velocity of the 109 series, especially not of factory fresh aircrafts, but to confirm theoretical models!
Furthermore we should never forget that tests were down in 3 different countries, everywhere maybe with different instrumentation, TAS/ IAS is different, power setting was different, and so on. 109F was always flying with full tanks too.
When SpitVA was flown quite often than it´s great data, isn´t it? I mean it represents aircrafts in service condition, probably after higher G-loads. And why should loseness affect stick force?
The spit was a light plane for it´s size, one would assume a rather flexible wing. Ok, the "sharp edge" in the naca chart is at low speeds, nevertheless i´d assume even there the influence of wing twist like in other curves that is not shown. I have my doubts about it, seriously, and i consider the naca chart way more realistic.
Oh btw - it is well known that the 190 curve is the worst they measured out of three. So if you intentionally take the worst of the enemy, you take what ? The best of your own of course!
niklas
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Hehe, - this:
"The spit was a light plane for it´s size, one would assume a rather flexible wing"
FYI, the wing was flexible, as were other WW2 fighter wings. However the Spitfire wing was VERY strong and much stronger than many other. So, while I know it was made stiffer in later models, I rather doubt it flexed any more than most.
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Originally posted by Angus
FYI, the wing was flexible, as were other WW2 fighter wings. However the Spitfire wing was VERY strong and much stronger than many other
Probably one more of your theories that you can only backup by some stories (in best case) i suppose. Actually you probably don´t even know about what stiffness we are speaking.
niklas
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Oh btw - it is well known that the 190 curve is the worst they measured out of three. So if you intentionally take the worst of the enemy, you take what ? The best of your own of course!
No, I think it's the only one they measured. What they said was:
It should be pointed out, however, that where Frise ailerons are used, there is liable to be a variation in the feel of the control from aircraft to aircraft. Our pilots, who have now flown three Fw 190s, have, in fact, noticed this variation; they report that the machine on which the measurements were made had rather heavier ailerons than the other two.
I don't know how comfortable you are with English, but the tense of the last sentence implies the tests were made before the other aircraft were flown, and that the other aircraft have been flown but not fully tested.
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You´re right in this case. But why did they take the heaviest one for testing when they knew about 2 better ones?
niklas
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I don't think they knew about the 2 lighter ones until after the tests.
The test was of Pe882, I believe. That was captured after it landed in Britain in error on 17th April 1943 (according to Brown). The report is dated July 1943, and obviously the tests took place before that.
The 2 others refered to in the report are probably those that landed in Britain on the 20th May and 20 June 1943.
I should think the tests were run some time in April or May, either before the 2nd plane was captured, or before they became aware there were aileron differences between the aircraft.
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Originally posted by niklas
Any flying times of the 109F2 known? Was it factory fresh, or also used for other tests earlier?
As you allready know, the report does not give much details about the test plane. It's just described as a "sample" and it was a prepared test bed with special instrumentation. Probably it was one of those planes which these organizations used for various tests. Anyway, nothing indicates that it was in bad condition.
From earlier discussion you probably remember that the only oddity I can see is mean average deflection which is not same as given in the specs (when measured without load). That might be measurement error or just normal production variation.
Originally posted by niklas
We should never forget that this report was NOT made to determine the highest rolling velocity of the 109 series, especially not of factory fresh aircrafts, but to confirm theoretical models!
Yep, it can be seen that the tested sample did very close to theoretical models ie it's condition was very close to what it was supposed to be.
Originally posted by niklas
When SpitVA was flown quite often than it´s great data, isn´t it? I mean it represents aircrafts in service condition, probably after higher G-loads. And why should loseness affect stick force?
The loosenes "might" affect on stick forces by increasing the stick movement for given aileron deflection ie in a way there is more leverage at the speeds where the full stick deflection can't be reached. But that depends on geometry of the linkage.
Originally posted by niklas
The spit was a light plane for it´s size, one would assume a rather flexible wing. Ok, the "sharp edge" in the naca chart is at low speeds, nevertheless i´d assume even there the influence of wing twist like in other curves that is not shown. I have my doubts about it, seriously, and i consider the naca chart way more realistic.
It can be easily seen that in the case of the NACA tested Spitfire V, the aileron linkage (probably too low tension in the controll cables) start to show large amount of elasticity at low speeds before the stick force limit is reached and removing the typical sharp edge when the stick force limit is reached (the roll rate still increase after a small edge). That indicates poor mainteance because other tests by RAE and RAAF show logical sharp edge (ie the roll rate decrease after the sharp edge). Service planes probably showed same kind of symptons but that is arguable and depends on mainteance.
Notable thing regarding the wing twist is that RAE comments on the NACA report on Spitfire claim:
"Stability and control in a high speed dive. This was not touched, since the highest speed attained during the tests was 295 m.p.h. Vi. Neglect of the vital speed region round 400 m.p.h. Vi resulted in erroneous conclusions being drawn from the measurements at lower speeds. For example it is stated that "there was very little reduction in aileron effectiveness either by separation of flow near minimum speed or by wing twist at high speed." Actually, of course, loss of aileron power due to wing twist at high speeds is one of our biggest problems on the Spitfire - at 400 m.p.h. Vi about 65% of the aileron power is lost thereby."
Originally posted by niklas
Oh btw - it is well known that the 190 curve is the worst they measured out of three. So if you intentionally take the worst of the enemy, you take what ? The best of your own of course!
AFAIK they made instrumented tests just with one plane and that just happened to have heaviest ailerons of the three.
Originally posted by Nashwan
The test was of Pe882, I believe. That was captured after it landed in Britain in error on 17th April 1943 (according to Brown). The report is dated July 1943, and obviously the tests took place before that.
Yep quite probably the PE882, the report on it claims that:
"Perhaps owing to rigging, the lateral control, though still good, was not nearly so light at high speeds as in former aircraft."
The "former aircraft" means the MP499.
gripen
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Originally posted by niklas
Any flying times of the 109F2 known? Was it factory fresh, or also used for other tests earlier?
[/B]
Well considering the tests was done in June 1944, and the 109F-2 was only produced between November 1940 - August 1941, the machine itself was 3-3.5 years old.
Originally posted by niklas
Furthermore we should never forget that tests were down in 3 different countries, everywhere maybe with different instrumentation, TAS/ IAS is different, power setting was different, and so on. 109F was always flying with full tanks too.?
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Yep. Even though if the instrumentation would be just as good everywhere, the power would strongly effect the rate of roll (the 109F-2 was only flown at continous power), and the RAE typically did it`s trials without guns and ammo, half fuel load.
The most serious issue in comparing with the NACA chart is IAS/TAS conversion, it would displace the original graph left or right on the speedscale, and even small conversion differencies can have big effect.
The spit was a light plane for it´s size, one would assume a rather flexible wing. Ok, the "sharp edge" in the naca chart is at low speeds, nevertheless i´d assume even there the influence of wing twist like in other curves that is not shown. I have my doubts about it, seriously, and i consider the naca chart way more realistic.
niklas [/B]
Yep, that`s my line of thinking as well. NACA 868 notes some 65% reduction of roll rate for the Spitfire due to wing twist, but curiously, there is no sign of that on the RAE curves they copied. I guess there`s more in the original report on that, it`s just a bit 'filtered'.
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Originally posted by Angus
Hehe, - this:
"The spit was a light plane for it´s size, one would assume a rather flexible wing"
FYI, the wing was flexible, as were other WW2 fighter wings. However the Spitfire wing was VERY strong and much stronger than many other. So, while I know it was made stiffer in later models, I rather doubt it flexed any more than most.
Read NACA 868.
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Originally posted by Kurfürst
Yep. Even though if the instrumentation would be just as good everywhere, the power would strongly effect the rate of roll (the 109F-2 was only flown at continous power), and the RAE typically did it`s trials without guns and ammo, half fuel load.
Actually not, the measured value is peak roll rate so weight has no effect. Read hitech's post above.
Originally posted by Kurfürst
The most serious issue in comparing with the NACA chart is IAS/TAS conversion.
Well, rough and good enough IAS to TAS conversion in standard atmosprehe is very easy to do. Infact only you have had serious problems with it in this thread.
Originally posted by Kurfürst
NACA 868 notes some 65% reduction of roll rate for the Spitfire due to wing twist, but curiously, there is no sign of that on the RAE curves they copied. I guess there`s more in the original report on that, it`s just a bit 'filtered'.
Actually that 65% value comes from RAE tests as noted above and RAE curves for the Spitfire V contain this. Notable thing is that NACA choosed to use RAE data on NACA 868 report instead their own measurements and the reason is quite obivious; RAE measurements are better made.
Regarding wing twist it should be noted that there is not much difference in aileron reversal speeds of the Spitfire V and the Bf 109F.
gripen
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Originally posted by gripen
Well, rough and good enough IAS to TAS conversion in standard atmosprehe is very easy to do. Infact only you have had serious problems with it in this thread.
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Don`t make me laugh gripen. You 'very easy' IAS/TAS conversion is an utterly primitive and error prone method of simply assuming "IAS is roughly 20% smaller than TAS at 3000m" as you have already told us.
To me it seems there is only one person with problems here, it`s you and your ego. But as I said, I couldn`t care less about what some egomaniac posts who was already judged to be unworthy of reading by posters who otoh earned the respest of everyone for their honesty.
Notable thing is that NACA choosed to use RAE data on NACA 868 report instead their own measurements and the reason is quite obivious; RAE measurements are better made..
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Only you think things are that simple. You are telling the same mantra for yourself, and you are also the only one believing it.
In the, you are mumbling and nodding to yourself. To outsiders, it looks quite weird. :lol
Regarding wing twist it should be noted that there is not much difference in aileron reversal speeds of the Spitfire V and the Bf 109F.
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Yes of course Gripen, of course.
But let`s see the facts, when the USAAF tested a Bf 109F, to their surprise they found the 109 wing being just as rigid as their own two-spar designs. I guess the rather massive main spar coupled with a box spar worked rather well.
The aileron reversal speed for the Me109 can be derived in FB 1951 and is around 611 mph while the Spitfire had only 510 mph (source avia report 6/10126 from the RAE).The supposedly rugged P47 has a reversal speed of only 545 mph (source NACA report 868). The NACA report notes 35% reduction of roll rate at high speed for the two spar P-47C, but as high as 65% for the Spitfire.
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Originally posted by Angus
"FYI, the wing was flexible, as were other WW2 fighter wings. However the Spitfire wing was VERY strong and much stronger than many other. So, while I know it was made stiffer in later models, I rather doubt it flexed any more than most. "
The flexing happens because the wing had big area and it was thin. The 109 has a smaller and thicker wing so it was more rigid.
Spitfire's tubular wing spar was very strong but is has not much to do with torsional rigidity of a wing. The wing's planform shaping structure defines more of this quality.
This is why I think that new and used Spits may have had quite different rolling charactreristics, whereas 109s and 190s had prolly more uniform performace despite their service age.
-C+
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Originally posted by Kurfürst
Don`t make me laugh gripen. You 'very easy' IAS/TAS conversion is an utterly primitive and error prone method of simply assuming "IAS is roughly 20% smaller than TAS at 3000m" as you have already told us.
Feel free to laugh but quick and dirty 20% conversion is better than yours, see Knegel's comment on your calculations.
Originally posted by Kurfürst
To me it seems there is only one person with problems here, it`s you and your ego. But as I said, I couldn`t care less about what some egomaniac posts who was already judged to be unworthy of reading by posters who otoh earned the respest of everyone for their honesty.
Only you think things are that simple. You are telling the same mantra for yourself, and you are also the only one believing it.
In the, you are mumbling and nodding to yourself. To outsiders, it looks quite weird. :lol
So why don't you just ignore my postings then?
Originally posted by Kurfürst
The aileron reversal speed for the Me109 can be derived in FB 1951 and is around 611 mph while the Spitfire had only 510 mph (source avia report 6/10126 from the RAE).
Actually FB 1951 gives the reversal speed in TAS and RAE data gives it IAS (or EAS). Feel free to convert values comparable. The RAE 1231 (DSIR 23/12865) gives reversal speed 580 mph EAS for the Spitfire V with standard wings and that value is calculated from flight test results.
gripen
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Originally posted by gripen
Feel free to laugh but quick and dirty 20% conversion is better than yours, see Knegel's comment on your calculations.
[/B]
Yep the mantra again. And frankly, if I have to choose between the IAS/TAS conversions of E-Stelle Rechlin (which is the one I use), you, or Kneagel, I choose E-Stelle Rechlin.
E-Stelle Rechlin`s engineers vs. 'quick and dirty 20% conversion'.
Yes I laugh at you.
Originally posted by gripen
So why don't you just ignore my postings then?
I enjoy having another lapdog next to Milo, who keeps barking at me, toothless.
The aileron reversal speed for the Me109 can be derived in FB 1951 and is around 611 mph while the Spitfire had only 510 mph (source avia report 6/10126 from the RAE).The supposedly rugged P47 has a reversal speed of only 545 mph (source NACA report 868).
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Originally posted by Kurfürst
Yep the mantra again. And frankly, if I have to choose between the IAS/TAS conversions of E-Stelle Rechlin (which is the one I use), you, or Kneagel, I choose E-Stelle Rechlin.
What mantra? IAS is simply the pressure difference between pitot tube and static port. Conversions in standard atmosphere are very easy make and no need to dug something from Rechlin papers.
Originally posted by Kurfürst
I enjoy having another lapdog next to Milo, who keeps barking at me, toothless.
Well, if you want make yourself laughable, it's not my problem.
Originally posted by Kurfürst
The aileron reversal speed for the Me109 can be derived in FB 1951 and is around 611 mph while the Spitfire had only 510 mph (source avia report 6/10126 from the RAE).The supposedly rugged P47 has a reversal speed of only 545 mph (source NACA report 868).
Let's have look to RAE 1231:
(http://www.onpoi.net/ah/pics/users/852_1128420347_r10.jpg)
Now just use your favorite method to convert EAS (IAS with type specific corrections) to TAS.
gripen
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Kurfi,
slowly you drive me Nuts!
Your personel attacks to gripen miss any base!!
He present arguments while you offer polemics after you think your arguments fail!
The calculation from TAS to IAS is pretty easy, if factor 0,849 or 0,861 dont make that a big different at all, althought i have to agree that 0,8 is far off!
If you have a Rechlin Be109F rolltest, which show IAS, please offer it! I would for sure like to see a faster rolling Bf109!!
After recomparing your data curve, the DVL data curve in the 1st post and my data curve, i got aware of a other mistakes on my side!
1. I took 610km/h TAS as last "30kg max stickvariation value", instead of 620km/h (wrong estimation, probably at that moment i thought the vertical lines are in 50km/h steps).
2. While estimating the 30lb and 50lb values i took the kg lines as linear increasement, but its not! The middle between 10kg and 20kg is NOT 15kg, its rather 13,6kg!! Therfor the 30lb(13,6kg) peak is now at 223mph, instead of 210mph, and the 50lb peak is now at 287mph, instead of 274mph!!
Nevertheless your 30lb line show the flat angle of the 30lb line, therefor i still think its the wrong calculated 30lb line. Mistakes are fast made and can show significant differents!
Anyway, the Bf109F is bad in rolling at highspeed, if we compare it to most other fighters in this graphic!
btw, the SpitVa test i have, show a max stickdeflection with 50lb only up to 145mph, therfor we dont find a 'max deflection' line in this graph, which start at 160mph.
The Hurri II test show a max stickdeflection with 50lb up to 165mph, so we dont will see the typical sharp edge too.
Looks like the linkage of this both planes was setup for better highspeed movements! This explain the relative low slowspeed rollratios and the relative good highspeed results.
Another btw: I would like to know to which direction the 109F did roll in the DLV test and to what direction the other planes did roll?
I just took notice that the SpitVa and Hurri II show the slower roll to the right side! The 50lb peak value of the SpitVa(rolling left) would be around 75°/sec at around 220mph, the Hurri II have a peak value of around 69° at around 280mph(the 50lb rollratios to the left are comparable with the 60lb rollratio to the right side).
And another btw: Iam not sure if the loadout of the planes (weapons/fuel) dont influence the rollratio! More weight = more yaw moments and more weight outside of the rollcenter. For a middle or shoulder wing plane this wouldnt count that much, but in a low wing plane, with wingmounted guns, the weight of this guns is far outside of the rolling center, therfor they probably will cause some problems. Specialy if realy the guns, not only the amunition was left and the tank was half full. This would bring around 400kg weight, this would decrease the needed AOA and would result in total different behaviour!
If the high result of the Spitfire in the NACA comparision realy was made without guns and half fuelload, if would explain much!
The HurricaneII in my test had 7014lb, thats 200lb more weight than normal gross weight, but the SpitVa had only 6237lb and was flown with 6184lb, thats almost Spit1a level!!
And another btw: Although the Spitwing was big, it had only a aspectratio of 5,6, while the Bf109F had 6,1. Therfor the Spit wing in general could be more thin without to lose stability in relation to the Bf109 wing!! Next to this the 109 had a higher wingload by default, therefor the wing was under higher stress in general!
How it realy was only tests can show, i only want to negate the agrument of a big + thin wing = less stable. The aspectratio much to often get forgotten, not only regarding the lift and drag!
Greetings, Knegel
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Originally posted by Knegel
The calculation from TAS to IAS is pretty easy, if factor 0,849 or 0,861 dont make that a big different at all, althought i have to agree that 0,8 is far off!
Well I actually said that:
"TAS value is roughly 20% higher than IAS value depending on conditions. As an example 400 mph IAS is about 770 km/h TAS."
It means IAS to TAS and inverting results (rough) TAS to IAS correction factor 0,844 (650/770).
Originally posted by Knegel
Looks like the linkage of this both planes was setup for better highspeed movements! This explain the relative low slowspeed rollratios and the relative good highspeed results.
I don't think so; the roll rate curve should have a sharp corner when the stick force limit is reached. More likely reason is loose linkage because it explains the unlogical curve. In addition movements mentioned in the report are normal.
Originally posted by Knegel
If the high result of the Spitfire in the NACA comparision realy was made without guns and half fuelload, if would explain much!
The report does not specify the weight or condition but I don't see a reason why should RAE made a large fighter aileron comparison with non standard planes (even gun camera films from real combat were studied). Besides, the Bf 109F report only claims full tankage.
BTW if you are interested to see "the stuff" just give the address (send a privat message).
gripen
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Hi ,
770km/h TAS with the (still low factor) of 0,844 is 404mph, not 400. With factor 0,849 its 406mph, with Kurfis 0,86 its 411,5mph.
11,5mph = 18,5km/h, thats not a bit in such a comparison!
If the IAS/TAS factor realy was 8,6 when the test got recalculated to TAS, we should use it! I took 0,849!
Anyway,
"I don't think so; the roll rate curve should have a sharp corner when the stick force limit is reached. More likely reason is loose linkage because it explains the unlogical curve. In addition movements mentioned in the report are normal."
What stick force limit?? As i wrote, the original test show that they couldnt reach the max stickvariation from 145mph onward, so the sharp corner isnt visible on the NACA comparison, cause it start with 160mph.
But i mixed it up, its a slowspeed setup, with a smal leverage, that explain why the max stickvariation only can get reached up to 145mph with 50lb. A longer leverage would increase the rollratio at highspeed.
They wrote: "It may be comcluded, therefor, that there was very little reduction in aleron effectiveness eighter by seperation or flow near minimum speed or by wingtwist at highspeed."
Private message is send! :)
Greetings, Knegel
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Originally posted by Knegel
770km/h TAS with the (still low factor) of 0,844 is 404mph, not 400. With factor 0,849 its 406mph, with Kurfis 0,86 its 411,5mph.
I don't see much point to argue about 10 mph differences. 2% per 1000 ft is pretty much universally used quick and dirty IAS to TAS conversion factor. We are not talking about exact values here because the exact conditions are not known and I have not made any exact claims about the values during this thread.
Originally posted by Knegel
What stick force limit?? As i wrote, the original test show that they couldnt reach the max stickvariation from 145mph onward, so the sharp corner isnt visible on the NACA comparison, cause it start with 160mph.
Actually you are continously mixing NACA and RAE comparisons.
The NACA comparison (http://mitglied.lycos.de/luftwaffe1/aircraft/usaaf/rollrate.pdf) was done with 30 lbs stick force limit. The Fig. 2 shows roll rates with 30 lbs stick force and the notable thing is that curves of the Spitfire and Hurricane does not typical sharp corners as can be seen in the P-40 and P-36 (RAE and RAAF comparisons also show this):
(http://www.onpoi.net/ah/pics/users/852_1128467483_r5.jpg)
Most probable reason for this is that the tested Spitfire and Hurricane had plenty of loosenes in aileron linkage. The curves can be compared also to RAAF comparison with same 30lbs limit:
(http://www.onpoi.net/ah/pics/users/852_1128465874_r6.jpg)
It can be seen that the NACA data misses the peak (probably due to loosenes) but otherwise the curves are quite similar showing about 50-60 deg/s at about 100 mph IAS and bit over 20 deg/s at 400 mph IAS (aproximated).
Basicly, if the NACA tested Spitfire have had no loosenes in the aileron linlage, it would have reached about same peak rolling performance (about 80 deg/s) as RAAF tested with 30 lbs stick force.
The 50 lbs curves in the NACA 868 (http://naca.larc.nasa.gov/reports/1947/naca-report-868/index.cgi?page42.gif) come from the RAE fighter aileron comparison (RAE 1231 is one of the report produced). Notable thing is that if you aproximate the 30 lbs curve from the RAE 50 lbs curve, it will be quite close RAAF curve.
Originally posted by Knegel
But i mixed it up, its a slowspeed setup, with a smal leverage, that explain why the max stickvariation only can get reached up to 145mph with 50lb.
The leverage is irrelevant in all these tests because these all give the roll rate with given stick force. And all these tests had a standard Spitfire V, the differences are caused by different stick forces and probably the loosenes in the aileron linkage of the NACA tested Spitfire as can be seen from the curve.
Originally posted by Knegel
They wrote: "It may be comcluded, therefor, that there was very little reduction in aleron effectiveness eighter by seperation or flow near minimum speed or by wingtwist at highspeed."
That has nothing to with leverage and it is a wrong conclusion as pointed by RAE in their comments on NACA tests on the Spitfire:
"Stability and control in a high speed dive. This was not touched, since the highest speed attained during the tests was 295 m.p.h. Vi. Neglect of the vital speed region round 400 m.p.h. Vi resulted in erroneous conclusions being drawn from the measurements at lower speeds. For example it is stated that "there was very little reduction in aileron effectiveness either by separation of flow near minimum speed or by wing twist at high speed." Actually, of course, loss of aileron power due to wing twist at high speeds is one of our biggest problems on the Spitfire - at 400 m.p.h. Vi about 65% of the aileron power is lost thereby."
gripen
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Hi,
"I don't see much point to argue about 10 mph differences. 2% per 1000 ft is pretty much universally used quick and dirty IAS to TAS conversion factor. We are not talking about exact values here because the exact conditions are not known and I have not made any exact claims about the values during this thread."
11mph make a huge different if shown in the NACA comparison graphic!
"Actually you are continously mixing NACA and RAE comparisons."
I talk about the NACA SpitVa test, the rollratios i did include in the NACA comparisons.
(http://www.raf-roy.com/share/knegel/Screenes/NACA-109ROLL.gif)
Page to D/L the Spit test is here: http://mitglied.lycos.de/luftwaffe1/
"......the notable thing is that curves of the Spitfire and Hurricane does not typical sharp corners.................. .
Most probable reason for this is that the tested Spitfire and Hurricane had plenty of loosenes in aileron linkage. The curves can be compared also to RAAF comparison with same 30lbs limit:"
There is the typical sharp corner! Look to 100mph for the Spitfire, this is what the SpitVa test say: " With a stickforce of 30 pounds, full deflection of the alerons could be obtained only at speeds lower than 110 miles per hour." and " The excessive forces required to reach high rolling velocitics and the impossibility to obtain maximum aileron deflection much above 140mph miles per hour are also illustraited."
"The leverage is irrelevant in all these tests because these all give the roll rate with given stick force. And all these tests had a standard Spitfire V, the differences are caused by different stick forces and probably the loosenes in the aileron linkage of the NACA tested Spitfire as can be seen from the curve."
The leverage is not irrelevant, if we try to explain why a plane have a special behaviour and why the different Spitfires have different behaviour. Thats what i did try. SpitVa test and the P36,P40, Spit,Hurri comparison show similar results, while the 30 lb and 50 lb comparison show that a other leverage must got used!
"That has nothing to with leverage and it is a wrong conclusion as pointed by RAE in their comments on NACA tests on the Spitfire:"
Thats right, it was only another point to show.
Greetings, Knegel
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Originally posted by Knegel
11mph make a huge different if shown in the NACA comparison graphic!
Well, we don't know the exact conditions so we can't claim any exact IAS value. What we do know is that in the RAE comparison the values are corrected to EAS, which, at least in some degree, gives comparable values. Infact values used Kurfürst might contain type specific corrections making them less comparable.
Originally posted by Knegel
I talk about the NACA SpitVa test, the rollratios i did include in the NACA comparisons.
Yep, thats exactly the same plane as used for the NACA comparison between Spitfire, Hurricane, P-36 and P-40 and it shows same unlogical roll rate curve.
Originally posted by Knegel
There is the typical sharp corner! Look to 100mph for the Spitfire, this is what the SpitVa test say: " With a stickforce of 30 pounds, full deflection of the alerons could be obtained only at speeds lower than 110 miles per hour." and " The excessive forces required to reach high rolling velocitics and the impossibility to obtain maximum aileron deflection much above 140mph miles per hour are also illustraited."
Yes, there is a corner but unlike RAE and RAAF test, the roll rate increase still after corner. No other plane in the charts with frise type ailerons show similar curve (except Hurricane in the NACA test, which probably got similar mainteance). The most likely explanation for this is loosenes in the linkage.
Besides it should be noted that NACA choosed to use RAE values for the Spitfire instead their own test values in their after war summary of lateral control research (NACA 868). IMHO for a good reason.
Originally posted by Knegel
The leverage is not irrelevant, if we try to explain why a plane have a special behaviour and why the different Spitfires have different behaviour. Thats what i did try. SpitVa test and the P36,P40, Spit,Hurri comparison show similar results, while the 30 lb and 50 lb comparison show that a other leverage must got used!
No, the charts give directly the stick force. Regarding the leverage, only meaningfull measurement is amount of the stick movement, longer movement giving the better leverage. All these tested Spitfire Vs (NACA, RAE and RAAF tested) had exactly same leverage (even the clipped winged Spitfire V), the differences are caused by different stick forces used for the test, normal variation between planes and also probably the condition of the plane (specially in the case of the NACA test).
gripen
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Hi,
if the leverage was the same, how do you explain that one Spitifre can keep full stickvariation with 30lb up to 160mph, while in the other Spit the max stickvariation stop with ALSO 30 lb below 110mph?? Highspeedproblems are not relevant here!
Loosens in the lincage that make a different of 40mph i would count as bad damage and would be pretty good visible in the 'initial roll curve', but its not!
The increasing rollratio up to 220mph, in the rollratio curve of the SpitVa, is caused by the fact that the stickforces dont increase linear with the alerondeflection.
The test say: "The alerons were relatively light for smal deflections, but the slope of the curve of the stick force against deflection increased progressively with deflection, so that about five times as much force was required to fully deflect the alerons as was needed to reach one-half of the maximum travel. The effectiveness of the alerons increased almost linearly with deflection all the way to the maximum position."
(of course at the measured speed of max 300mph, as you stated, the other test show that at higherspeeds this was different).
As result we get a increased rollratio up to 220mph!
Before 220mph the still big deflection of the alerons caused a greater stickforce in relation to its influence to the roll speed. At 220mph with same stickforce the aleron deflection was only a bit smaler than with 200mph, but the effectivity did increase linear, so the rollratio increased. Above 220mph the 'crossline' is reached, so the same static stickforce wasnt enough to let the plane roll faster.
Imho the two tests show that the leverage relation in the SpitV was absolutly messed up, therfor iam sure they changed it in later Spitfires, which gave a much better result, cause they was able to obtain greater alerondeflections at higher speeds.
btw, the stick itself dont need to get changed to change the leverage, this can get changed by a part in the wings or below the stick.
Greetings, Knegel
Edit: The Hurri had same behaviour, here is what the test say:
"It is interesting to to note that the force requiered to attach the rolling velocity of 0,6 or 0,8 radian per sec decreased as the speed was increased from 100 to 200miles per hour. This unusual condition results from the rapid increase of stickforce near maximum deflection"
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Originally posted by Knegel
if the leverage was the same, how do you explain that one Spitifre can keep full stickvariation with 30lb up to 160mph, while in the other Spit the max stickvariation stop with ALSO 30 lb below 110mph??
Where do you see a Spitfire keeping full stick movement up to 160 mph IAS with 30 lbs stick force?
If I use (rough) linear estimates, the RAE tested Spitfire V (normal and clipped wing) would have reached full stick movement up to about 140-150 mph IAS with 30 lbs stick force. These values are about same as tested by RAAF.
Originally posted by Knegel
The increasing rollratio up to 220mph, in the rollratio curve of the SpitVa, is caused by the fact that the stickforces dont increase linear with the alerondeflection.
Actually that is further evidence that there was something wrong in the aileron linkage of the NACA tested Spitfire; RAE and RAAF data shows quite linear increase in stick force.
Generally feel to believe what ever test data you want to believe but to me it's quite obivious that the NACA tested Spitfire had problems in the linkage and probably in airframe over all due to extensive flying in the states. And that seem to be also the opinion of the NACA because they choosed to use RAE data for their later works.
gripen
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Originally posted by gripen
Infact values used Kurfürst might contain type specific corrections making them less comparable.
[/B]
I`ve got another version. Gripen doesn`t like the Bf 109 too much. The greater conversion difference between IAS and TAS, the worser the Bf 109 will look like. So gripen argues for the highest possible difference value so the plane would worser than the actual data, despite being shown that his conversion was wrong.
Now explain us how this makes any sense, ie. how does Me 109 type specific corrections invalid for the Me 109..?
Yep, thats exactly the same plane as used for the NACA comparison between Spitfire, Hurricane, P-36 and P-40 and it shows same unlogical roll rate curve..
[/B]
What makes it unlogical ? The Hurricane displayed exactly the same
It`s a bit funny, becasue I remember you arguing that the relatively high values for the P-40 in test are invalid, but back then you argued the reverse way, that the 'spikes' on roll rate curves show it`s not from testing. Now you argue the exact opposite that the spikes should be there, why is that, back then you didn`t liked the P-40 rolled faster than the Spit, now you don`t like the NACA made independent tests on the Spit, too?
Yes, there is a corner but unlike RAE and RAAF test, the roll rate increase still after corner. No other plane in the charts with frise type ailerons show similar curve (except Hurricane in the NACA test, which probably got similar mainteance). The most likely explanation for this is loosenes in the linkage.
Perhaps because no other plane had as serious problems with wing flexing like the Spit.
Besides it should be noted that NACA choosed to use RAE values for the Spitfire instead their own test values in their after war summary of lateral control research (NACA 868). IMHO for a good reason.
Yep, the NACA test did not included 50 lbs tests results, so their own 30 lbs results wouldn`t be comparable with other 50 lbs results. Btw it`s interesting to note that the NACA test takes notes that the pilot was unable to effect more than 40 lbs force on the stick, making the RAE results at 50 lbs a bit hypothetical isn`t it?
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Originally posted by Kurfürst
Gripen doesn`t like the Bf 109 too much. The greater conversion difference between IAS and TAS, the worser the Bf 109 will look like.
Actually I originally gave this data without any kind of conversion except claiming that speed is TAS and roll rate rad/s.
Originally posted by Kurfürst
Now explain us how this makes any sense, ie. how does Me 109 type specific corrections invalid for the Me 109..?
EAS is IAS cleaned from type specific corrections ie comparable with other EAS values while IAS values might not be.
Originally posted by Kurfürst
What makes it unlogical ? The Hurricane displayed exactly the same
The shape of the curve makes it unlogical. And as noted above the NACA Hurricane had been in the similar use and mainteance as NACA Spitfire.
Originally posted by Kurfürst
It`s a bit funny, becasue I remember you arguing that the relatively high values for the P-40 in test are invalid, but back then you argued the reverse way, that the 'spikes' on roll rate curves show it`s not from testing. Now you argue the exact opposite that the spikes should be there, why is that, back then you didn`t liked the P-40 rolled faster than the Spit, now you don`t like the NACA made independent tests on the Spit, too?
The P-36 and P-40 curves does not show a sign of wing twist while the later measurement with P-40 show wing twist (see P-40F curve in the NACA 868).
Originally posted by Kurfürst
Yep, the NACA test did not included 50 lbs tests results, so their own 30 lbs results wouldn`t be comparable with other 50 lbs results.
The 50 lbs curve can be easily calculated from the data given in the Spitfire report and NACA did that at least in the case of the F4F and P-39 (ie the original reports give 30 lbs curves).
Originally posted by Kurfürst
Btw it`s interesting to note that the NACA test takes notes that the pilot was unable to effect more than 40 lbs force on the stick, making the RAE results at 50 lbs a bit hypothetical isn`t it?
Feel free to use double standards if you believe that it increases your credibility.
gripen
-
Hi,
If i dont look wrong the Spitfire have a max aleron deflection on 160mph in the picture, with 30 lb!
(http://www.onpoi.net/ah/pics/users/852_1128465874_r6.jpg)
Even 140-150lb is not close to as tested by RAAF!!! 100-110mph to 140-150mph, thats a lost of minimum 30-50mph!! To explain this with a loose linkage cant fit. Look to the 'initial roll curve' , there we would see this 'loose' linkage, in form of a big delay in the beginning, but there isnt a delay!
With "something wrong in the aileron linkage" you get close to it, cause wrong or messed up is the leverage setting to alerons.
Here again what the Hurri II test say to this phenomen:
"It is interesting to to note that the force requiered to attach the rolling velocity of 0,6 or 0,8 radian per sec decreased as the speed was increased from 100 to 200miles per hour. This unusual condition results from the rapid increase of stickforce near maximum deflection"
If the leverage setting now got adjusted to provide a smaler 'max aleron deflection', the max stickvariation can get reached on higher speeds and the "flat curve effect" get minimized(smaler aleronvariation = smaler rapid increase of stickforce near maximum deflection and more max force at higher speed on the alerons, due to the longer leverage).
Iam still sure the leverage did change from the early SpitfireVa to later models! If the lincage would be loose, the rollratio would be less good all over, but the SpitVa show similar values at 320mph like the later Spit.
Actually i only wanna explain why the later Spit´s rolled faster!
Greetings, Knegel
-
btw, the german test is given in TAS, therfor IAS = EAS!!
TAS dont need any correction!
-
Originally posted by Knegel
If i dont look wrong the Spitfire have a max aleron deflection on 160mph in the picture, with 30 lb!
Ah, that look's something like 160 mph, I did just a quick look an it looked like a bit over 150 mph IAS.
It's still quite close aproximated value for the RAE tested plane and it actually indicates that the slope of the force curve did not increase progressively. At 400 mph IAS the values (30 and 50 lbs) are almost linear as well as shape of the curve is almost linear.
Originally posted by Knegel
Look to the 'initial roll curve' , there we would see this 'loose' linkage, in form of a big delay in the beginning, but there isnt a delay!
Actually I wrote above that at 100 mph IAS the curves are quite similar and the loosenes start to show above that ie the tension of the cables might be wrong.
Originally posted by Knegel
With "something wrong in the aileron linkage" you get close to it, cause wrong or messed up is the leverage setting to alerons.
I wonder how many times it should be pointed out: There is no difference in leverage between these planes, AFAIK stick geometry and aileron movements were same in all production Spitfire Vs.
gripen
-
Originally posted by Knegel
btw, the german test is given in TAS, therfor IAS = EAS!!
TAS dont need any correction!
That's what you and me did, but I don't know from where the value Mr. Kurfürst used came from ie if it contains type specific corrections.
Still we don't know the conditions the TAS was measured.
gripen
-
Originally posted by gripen
Actually I originally gave this data without any kind of conversion except claiming that speed is TAS and roll rate rad/s.
[/B]
Oh yeah - you were constantly arguing that the IAS conversion from Rechlin should not be used, and your rought 20% conversion is correct, which of course would yield worser numbers.
The shape of the curve makes it unlogical. And as noted above the NACA Hurricane had been in the similar use and mainteance as NACA Spitfire.
[/B]
Nope, there is no such thing about use and maintaince in the NACA report, it was made up you, and also the worn Spitfire theory was made up on this board.
The P-36 and P-40 curves does not show a sign of wing twist while the later measurement with P-40 show wing twist (see P-40F curve in the NACA 868).
[/B]
Funny, the NACA 866 P-40F curve which now you claim to include wingtwist, is exactly the same shape as the NACA`s previous trials.
That`s means the RAE Spitfire tests do not included the effects of wingtwist, while the NACAs do, hence the difference, as was suspected before.
The 50 lbs curve can be easily calculated from the data given in the Spitfire report and NACA did that at least in the case of the F4F and P-39 (ie the original reports give 30 lbs curves). )
[/B]
That`s merely your claim, nothing supports it.
Feel free to use double standards if you believe that it increases your credibility.
gripen [/B]
Only you apply double standards here.
-
Originally posted by Kurfürst
Oh yeah - you were constantly arguing that the IAS conversion from Rechlin should not be used, and your rought 20% conversion is correct, which of course would yield worser numbers.
Feel free to use what ever conversion factor you ever like to use but the factor you now use might contain type specific stuff.
Originally posted by Kurfürst
Nope, there is no such thing about use and maintaince in the NACA report, it was made up you, and also the worn Spitfire theory was made up on this board.
The evidence is in the curves which show unlogical shape and it's know that the planes spent long time in the Wright Field before NACA.
Originally posted by Kurfürst
Funny, the NACA 866 P-40F curve which now you claim to include wingtwist, is exactly the same shape as the NACA`s previous trials.
Feel free to compare. Early measurement from Spitfire, Hurricane, P-36 and P-40 comparison:
(http://www.onpoi.net/ah/pics/users/852_1128467483_r5.jpg)
The P-40F measurement:
(http://www.onpoi.net/ah/pics/users/852_1128512343_r11.jpg)
Originally posted by Kurfürst
That`s means the RAE Spitfire tests do not included the effects of wingtwist, while the NACAs do, hence the difference, as was suspected before.
Actually, as pointed above, the RAE tests certainly contain wing twist:
(http://www.onpoi.net/ah/pics/users/852_1128420347_r10.jpg)
Originally posted by Kurfürst
That`s merely your claim, nothing supports it.
Just check the corresponding reports.
Originally posted by Kurfürst
Only you apply double standards here.
Well, IMHO planes should be compared with similar stick force limits. Apparently you disagree.
gripen
-
Hi gripen,
"It's still quite close aproximated value for the RAE tested plane and it actually indicates that the slope of the force curve did not increase progressively. At 400 mph IAS the values (30 and 50 lbs) are almost linear as well as shape of the curve is almost linear."
If you realy think that 50mph are a close aproximated value for the RAE tested plane, we also can assume that a other Bf109F2 have the same curve like the 109F2 at 50mph higher speeds, but thats rubbish. The late Spit show a 50% greater speed of max stick deflection, thats far outside of close!
Sure are the curves at 400mph almost linear, cause the aleron deflection is very smal! Dont we talk about the somewhat strange results between 110mph and 220mph of the SpitVa and HurriII??
"Actually I wrote above that at 100 mph IAS the curves are quite similar and the loosenes start to show above that ie the tension of the cables might be wrong."
The "stickforce / aleron deflection" tests are made at 108mph, 190mph and 295mph. And, yes, the tension of the cables is wrong, but what cause a different in the tension?? The leverage!!
If the cables of the old SpitVa would be loose, the speed of max stickdeflection would be higher than that of the later Spit (dont mix it up with max aleron deflection, did it myself several times)!!
"AFAIK........................ .."
Yes, thats it! I would say the testresults show that the leverage did change.
Actually i dont know exact what they did change, but the tests obvious show a significant different in leverage force from the handgrip to the alrons. Actually i call it strange, if the leverage wasnt adjustable somehow!
Geetings, Knegel
-
Originally posted by gripen
Feel free to use what ever conversion factor you ever like to use but the factor you now use might contain type specific stuff.
I feel free as it`s certainly to better than guessing the atmospheric or standard conditions which could significantly vary, or using "roughly 20%" which is just about useless if you want accurate results.
Originally posted by gripen
The evidence is in the curves which show unlogical shape and it's know that the planes spent long time in the Wright Field before NACA.
[/B]
What evidence are you talking about? Your own posts prove your own posts?
Originally posted by gripen
Feel free to compare. Early measurement from Spitfire, Hurricane, P-36 and P-40 comparison:
(http://www.onpoi.net/ah/pics/users/852_1128467483_r5.jpg)
The P-40F measurement:
(http://www.onpoi.net/ah/pics/users/852_1128512343_r11.jpg)
[/B]
It looks like the later P40F measurement has very similiar results as the NACA`s own Spitfire measurement, the curve is very similiar. And you say the early P-40 test didn`t have wing torsion added.
The only conclusion that can be derived that the RAE Spitfire/190 test doesn`t show wing torsion effects, just like the early NACA P-40 report - the similiarity in curve shape is striking.
Originally posted by gripen
Actually, as pointed above, the RAE tests certainly contain wing twist:
(http://www.onpoi.net/ah/pics/users/852_1128420347_r10.jpg)
[/B]
Where does it say that? Can you qoute the line? For again I can see you claim a document saying something, but when I look at the document it doesn`t say anything what you claim. This happens quite often.
Now, considering the later NACA P-40F tests include wing torsion effects, and are very similiar to NACA Spit tests, we can conclude the RAE tests which are rather dissimilar to either do not include wing torsion.
Probably that`s why the RAE tests show abnormally high values, and in conflict with both the NACA`s test results, and in fact even other RAE test results :
(http://www.onpoi.net/ah/pics/users/715_1128259573_spitrollat400mph.jpg)
Just check the corresponding reports. [/B]
Ok, until then there is agreement that gripen claimed something, and then couldn`t back it up.
Well, IMHO planes should be compared with similar stick force limits. Apparently you disagree.
gripen [/B]
Appearantly you have reading comprehension problems gripen for I said the RAE roll rates of the Spit are a bit hypotethical, considering they show performance at a stickforce that according to the NACA was not possilbe to be used in the Spit cocpit (50 vs. 40lbs usable) :
To qoute myself :
"Btw it`s interesting to note that the NACA test takes notes that the pilot was unable to effect more than 40 lbs force on the stick, making the RAE results at 50 lbs a bit hypothetical isn`t it? "
I wonder how can one deduct that I suggest planes should not be compared with similiar stick limits. I said the RAE results are hypothetical, given they are both using stick forces above real values, and they don`t take into account the wing twist of the aircraft, hence their values are higher than any other test, by far.
-
Originally posted by Kurfürst
I feel free as it`s certainly to better than guessing the atmospheric or standard conditions which could significantly vary, or using "roughly 20%" which is just about useless if you want accurate results.
We have no idea about the conditions the DVL data was measured, only the temperature can be derived from the mach number. Basicly there is no way to give more than rough estimates without knowing the exact conditions of the original test.
Originally posted by Kurfürst
What evidence are you talking about? Your own posts prove your own posts?
The curves show unlogical shape which is not supported by other measurements:
(http://www.onpoi.net/ah/pics/users/852_1128467483_r5.jpg)
In addition even NACA choosed to use RAE data in their later works.
Originally posted by Kurfürst
It looks like the later P40F measurement has very similiar results as the NACA`s own Spitfire measurement, the curve is very similiar. And you say the early P-40 test didn`t have wing torsion added.
The early measurement shows linear curve up 280 mph IAS where the stick force limit is reached ie no sign of wing twist. Later measurements show wing twist above 200 mph IAS ie the curve start to bend downwards.
Apparently you can't read the graphs.
Originally posted by Kurfürst
The only conclusion that can be derived that the RAE Spitfire/190 test doesn`t show wing torsion effects, just like the early NACA P-40 report - the similiarity in curve shape is striking.
Here we have further evidence that you can't read the graphs, RAE curves show clearly wing twist as well as data in the report gives the aileron reversal speed.
Originally posted by Kurfürst
Ok, until then there is agreement that gripen claimed something, and then couldn`t back it up.
F4F report can found from PRO as DSIR 23/12325 and P-39 report from here (http://mitglied.lycos.de/luftwaffe1/aircraft/usaaf/P39D_flying.pdf).
Originally posted by Kurfürst
Appearantly you have reading comprehension problems gripen for I said the RAE roll rates of the Spit are a bit hypotethical, considering they show performance at a stickforce that according to the NACA was not possilbe to be used in the Spit cocpit (50 vs. 40lbs usable) :
Well, not according to RAE and also NACA moved to 50 lbs limit later.
gripen
-
Here is the curves showing wing twist for the Fw 190 from the RAE test, all other planes in the test were tested same way.
gripen
(http://www.onpoi.net/ah/pics/users/852_1128517348_r13.jpg)
-
Originally posted by gripen
We have no idea about the conditions the DVL data was measured, only the temperature can be derived from the mach number. Basicly there is no way to give more than rough estimates without knowing the exact conditions of the original test.
[/B]
That`s true for most of the other tests as well, so?
The reason you argue about IAS/TAS conversion is because you want the actual DVL data look worser.
The curves show unlogical shape which is not supported by other measurements:
http://www.onpoi.net/ah/pics/users/852_1128467483_r5.jpg
[/B]
Well that`s merely a claim, nothing more. It is not supported by anything, and will be not, knowing gripen.
In addition even NACA choosed to use RAE data in their later works.
[/B]
That`s another unsupported claim again.
The early measurements shows linear curve up 280 mph IAS where the stick force limit is reached ie no sign of wing twist. Later measurements show wing twist above 200 mph IAS ie the curve start to bend downwards..
[/B]
Exactly like RAE`s curves for the Spit. Those also show a linear curve up 200 mph IAS where the stick force limit is reached ie no sign of wing twist.
Obviously, neither NACA and RAE test that exhibits the very same curve shape contains the effects of wing twists. They are a simpliefied set of data.
The case is quite clear, neither the P-36/P40 or the RAE Spit grahps include wing twist in the results.
Apparently you can't read the graphs..
[/B]
Appearantly you can`t discuss in a normal manner just froth in the mouth.
Here we have further evidence that you can't read the graphs, RAE curves show clearly wing twist as well as data in the report gives the aileron reversal speed..
[/B]
Stop frothing in the mouth, it is not very convincing except for the case that you are unable of normal discussion.
The RAE curves show the exact same thing as the NACA curves which you have already admitted that they don`t show wing twist at all. Hence why the RAE report doesn`t agrees with any other test :
(http://www.onpoi.net/ah/pics/users/715_1128259573_spitrollat400mph.jpg)
The RAE clipped/nonclipped curve shows 40 deg/sec at 400mph EAS with 50 degree force, and does not include wing twist.
Actual testing also by RAE show the requirement for 40 degree/sec roll rate at 400mph, 71 lbs - 50% greater force!
The difference is due to the fact that greater for is required if you also have to overcome the wing twist, which is not included in the first RAE roll graph.
Well, not according to RAE and also NACA moved to 50 lbs limit later.
gripen [/B]
NACA says 40 lbs is the maximum a pilot could exert in a Spitfire. That makes 50 lbs curves somewhat of a suspect, and hypothetical.
Again you claim something using credible names, but actually checking those source reveals nothing what you claim from them.
In other words, you make bogus claims using credibly institutes to make up for your own lack of credibility.
-
Originally posted by gripen
Here is the curves showing wing twist for the Fw 190 from the RAE test,
Actually it shows theoretical 100% rigid wing vs. measured figures on the poorest of the 3 FWs.
all other planes in the test were tested same way. [/B]
Again you claims something that is not actually told by your sources. Showing a FW 190 curve hardly proves anything else other than for the FW, now does it?
If you want to prove the Spitfire curve is similiar, why you wouldn`t post the similiar Spitfire curve?
The answer is quite simple, you don`t have anything from the Spitfire tests, you are simply making guesses on the conditions, and as usual, taking the best case for your beloved plane, worst case for the plane you hate.
-
Originally posted by Kurfürst
That`s true for most of the other tests as well, so?
Well, no one has argued here that the data in other tests is some how exact but in the RAE data the results are made comparable at least some degree, by giving them in EAS.
Originally posted by Kurfürst
The reason you argue about IAS/TAS conversion is because you want the actual DVL data look worser.
As pointed out above, I have given the data originally without anykind of conversion.
You are the one here to argue about the IAS/TAS conversion.
BTW in the beginning you were claiming that the DVL data is in IAS.
Originally posted by Kurfürst
Well that`s merely a claim, nothing more. It is not supported by anything, and will be not, knowing gripen.
The charts are posted above several times, any one can compare the curves.
Originally posted by Kurfürst
That`s another unsupported claim again.
The 50 lbs chart from the NACA 868 has been posted above several times even by yourself.
Originally posted by Kurfürst
Exactly like RAE`s curves for the Spit. Those also show a linear curve up 200 mph IAS where the stick force limit is reached ie no sign of wing twist.
The curves show start of bending and the chart in the report gives reversal speed.
Originally posted by Kurfürst
Appearantly you can`t discuss in a normal manner just froth in the mouth.
Can't you see the bending of the curve in the P-40F graph?
Above you claim that:
"Funny, the NACA 866 P-40F curve which now you claim to include wingtwist, is exactly the same shape as the NACA`s previous trials."
Originally posted by Kurfürst
Stop frothing in the mouth, it is not very convincing except for the case that you are unable of normal discussion.
Well, any one can check your discussion abilities from this thread.
Originally posted by Kurfürst
The RAE curves show the exact same thing as the NACA curves which you have already admitted that they don`t show wing twist at all.
No, RAE curves show the wing twist.
Originally posted by Kurfürst
NACA says 40 lbs is the maximum a pilot could exert in a Spitfire. That makes 50 lbs curves somewhat of a suspect, and hypothetical.
Couple years later NACA choosed RAE data on Spitfire over their own measurements and, in addition, used 50 lbs limit in their research summary.
Originally posted by Knegel
If you realy think that 50mph are a close aproximated value for the RAE tested plane, we also can assume that a other Bf109F2 have the same curve like the 109F2 at 50mph higher speeds, but thats rubbish. The late Spit show a 50% greater speed of max stick deflection, thats far outside of close!
The Spitfire V is not a late Spitfire and difference between NACA and RAE/RAAF measurements is probably caused by condition of the plane.
Originally posted by Knegel
The "stickforce / aleron deflection" tests are made at 108mph, 190mph and 295mph. And, yes, the tension of the cables is wrong, but what cause a different in the tension?? The leverage!!
Actually more simple and logical answer is out of spec tension of the cables.
Originally posted by Knegel
If the cables of the old SpitVa would be loose, the speed of max stickdeflection would be higher than that of the later Spit (dont mix it up with max aleron deflection, did it myself several times)!!
Actually that depends on geometry of the linkage.
Originally posted by Knegel
"AFAIK........................ .."
Yes, thats it! I would say the testresults show that the leverage did change.
Believe what ever you want to believe but to make others to believe it, you should have evidence. At least Morgan's and Shacklady's bible does not claim control changes.
gripen
-
Originally posted by Kurfürst
Actually it shows theoretical 100% rigid wing vs. measured figures on the poorest of the 3 FWs.
That means that measured values contain wing twist.
And this has quite little to do with stick forces.
Originally posted by Kurfürst
Again you claims something that is not actually told by your sources. Showing a FW 190 curve hardly proves anything else other than for the FW, now does it?
Here is the quote again:
"This course has been adopted in Fig. 6 which shows the results obtained for the F.W.190, Mustang, Typhoon and Spitfire V (metal covered ailerons) with both standard and clipped wings. On all these aircraft instrumental records of rolling performance have been obtained at the R.A.E. similar to those under discussion for the F.W.190."
gripen
-
If you want to prove the Spitfire curve is similiar, why you wouldn`t post the similiar Spitfire curve?
The Spitfire curves are included in NACA 868.
What the RAE test says:
The best method of comparison of the rolling performance of different aircraft is based on the steady rate of roll a pilot can generate using a definite stick force, say 50 lb., or full aileron if this requires less than 50 lb. on the stick. This course has been adopted in Fig.6 which shows the results obtained for the F.W.190, Mustang, Typhoon, and Spitfire V (metal covered ailerons) with both standard and clipped wings. On all these aircraft instrumental records of rolling performance have been obtained at the R.A.E, similar to those under discussion for the Fw 190. In this connection it is worth noting that "instrumentation" is essential when obtaining the curves of Fig.6. Stop-watch measurements of time to bank on fighters are rarely of sufficient accuracy, since the times to be measured are so small.
There is little.to chose between the Fw 190 and the clipped wing Spitfire over the whole speed range, although both show a considerable improvement on the standard Spitfire V. The Mustang .comes out top at 400 m.p.h. EAS but falls away appreciably below 350 m.p.h.; while the Typhoon has a comparatively poon rolling performance, at all speeds.
Now, the RAE report states clearly that these are measured results, so they have to include wing twisting. And the RAE is including them for comparison purposes, so there's little point in including a non standard Spitfire, especially without saying so. Note how they point out that the Fw 190 is the worst of the 3 samples they have.
-
Hi again,
quote:
--------------------------------------------------------------------------------
Originally posted by gripen
The Spitfire V is not a late Spitfire and difference between NACA and RAE/RAAF measurements is probably caused by condition of the plane.
--------------------------------------------------------------------------------
Since the slowspeed and highspeed results of the SpitVa and the late SpitV( i cal it 'late', cause the SpitVa was the 1st SpitV) are pretty similar, i would like to know what conditions can make a plane only in the middle speed so much more bad??
If the SpitVa condition was more bad, we would see this specialy at highspeeds, but here it actually show better results than the late SpitV!
quote:
--------------------------------------------------------------------------------
Originally posted by gripen
Actually more simple and logical answer is out of spec tension of the cables.
--------------------------------------------------------------------------------
What "out of spec tension of the cables"?? Do you think the SpitVa cables have a to strong tension?? Only this would explain why the late SpitV can reach a higher speed with max stickvariation, if the leverage is the same.
quote:
--------------------------------------------------------------------------------
Originally posted by gripen
Actually that depends on geometry of the linkage.
--------------------------------------------------------------------------------
Now i start to think you make jokes with me! A different geometry of the linkage HAVE A DIFFERENT LEVERAGE AS RESULT!!!!
Thats what i try to explain since some posts.
quote:
--------------------------------------------------------------------------------
Originally posted by gripen
Believe what ever you want to believe but to make others to believe it, you should have evidence. At least Morgan's and Shacklady's bible does not claim control changes
--------------------------------------------------------------------------------
I have some original Spitfire wing drawings of the A and C wing, which isnt allowed to offer here, they realy dont show the same lincage, which would give a different leverage.
Actually the both testresults and a bit knowledge of the physical law are evidence. You already did agree to it without to realize it, with your statement above. A different geometry of the linkage = different leverage!
Greetings, Knegel
-
Hi Nashwan,
donmt you think something is fishi with the ' Fig. 47, NACA Report No.868?
On the bottom they state 30lb stickforce, but the Spitfire(normal wing) show a much greater rollratio than in other sources with 30lb, while the typhoon, for exampel, show the exact 30lb curve of a other test, and also the P51B is similar to the MustangIII with 30 lb and the F6F-3 show the spring tab aleron curve at 30lb.
Your quote of a NACA comparison state a "Fig.6" where the 50lb comparison get displayed, do you have this "Fig.6" ??
Would be very interesting to see it.
Greetings, Knegel
-
Fig 47 Naca 868 shows 50 lbs stick force, not 30lbs.
Here's the RAE Fig 6 (Thumbnailed because it's a big pic):
(http://www.onpoi.net/ah/pics/users/thumbs/282_1094123825_roll11.jpg) (http://www.onpoi.net/ah/picpopup.php?ImgId=12355)
NACA 868 uses these RAE figures for the 190 and Spit, and (I think) for the Mustang and Typhoon.
-
Originally posted by Knegel
Since the slowspeed and highspeed results of the SpitVa and the late SpitV( i cal it 'late', cause the SpitVa was the 1st SpitV) are pretty similar, i would like to know what conditions can make a plane only in the middle speed so much more bad??
I don't know, it seems that loosenes in the linkages affects mainly in large deflections.
Originally posted by Knegel
What "out of spec tension of the cables"?? Do you think the SpitVa cables have a to strong tension?? Only this would explain why the late SpitV can reach a higher speed with max stickvariation, if the leverage is the same.
I can't say anything about the tension of the cables without looking the manual. The curve shows only that there is no large difference at very low speed and at very high speed ie at low pressure and/or at small aileron deflection.
Originally posted by Knegel
Now i start to think you make jokes with me! A different geometry of the linkage HAVE A DIFFERENT LEVERAGE AS RESULT!!!!
Thats what i try to explain since some posts.
Well, if you would say that under pressure the leverage changes at higher aileron deflections due to loosenes in the linkage. That might explain the unlogical shape of the curve.
Originally posted by Knegel
I have some original Spitfire wing drawings of the A and C wing, which isnt allowed to offer here, they realy dont show the same lincage, which would give a different leverage.
Actually the both testresults and a bit knowledge of the physical law are evidence. You already did agree to it without to realize it, with your statement above. A different geometry of the linkage = different leverage!
If you have the evidence, I'm more than willing to believe because that would at least partially explain the difference between the curves.
gripen
-
Hi,
if the linkage would be somehow loose, the rollratio would decrease, like the picture show, but at same the speed of max stick deflection would INCREASE, not decrease!!
A decreased speed of max stickdelfection and a decreased rollratio, at same time, only can have a different leverage as reason!
Loose linkage and bad tension etc would let minimize the aleron variation at a given speed, therfor the pilot could keep the max stick variation at higher speeds.
According to the test torsion of the wing wasnt a problem up to 300mph!! The other test only state that wing torsion was a problem at 400mph!
Nashwan,
do you have the Spit 50lb test somewhwere? A 25degree/sec roll increasement due to 20lb more stickforce is pretty outstanding.
Greetings, Knegel
-
Originally posted by Knegel
if the linkage would be somehow loose, the rollratio would decrease, like the picture show, but at same the speed of max stick deflection would INCREASE, not decrease!!
No, that depends on the geometry of the linkage and how the geometry changes due to loosenes. While the stick movement for the given deflection might increase, the angles of the forces in the linkage might change to less optimal direction and the increased movement (leverage) or force might be used just to bend linkage or cables instead to deflect control surface.
Originally posted by Knegel
According to the test torsion of the wing wasnt a problem up to 300mph!! The other test only state that wing torsion was a problem at 400mph!
As RAE comments note, NACA just made erroneous conclusion due to speed range and apparently also due to condition of the plane. Below is a graph from RAE report No. B.A. 1667 "Aileron tests on Spitfire". The tested plane is a Spitfire I with canvas covered ailerons and the graph shows that at 300 mph the wing lost roughly 40% of the rollinperformance due to twist.
gripen
(http://www.onpoi.net/ah/pics/users/852_1128592804_r14.jpg)
-
Originally posted by gripen
Here is the curves showing wing twist for the Fw 190 from the RAE test, all other planes in the test were tested same way.
gripen
(http://www.onpoi.net/ah/pics/users/852_1128517348_r13.jpg)
Thx for bringing it up. Is this from one of the 2 later fw-190?? It says "Measured rate of roll". Difficult to say what stickforce was applied, but probably not more than 70lb. Maybe only 50lb too? Any further informations?
In any case the 50lb limit of the RAF/NACA chart is at too low speed and contradicts all pilot accounts.
niklas
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Originally posted by niklas
Thx for bringing it up. Is this from one of the 2 later fw-190?? It says "Measured rate of roll". Difficult to say what stickforce was applied, but probably not more than 70lb. Maybe only 50lb too? Any further informations?
It's from the RAE 1231 and tested on same plane as other data (very probably PE882). The data gives rate of roll per degree aileron deflection so it's not collected from full deflection or full available force data so that graph does not tell anything about used stick forces; graph would have been pretty similar in all their Fw 190s. Note that it does not tell anything about elasticity of the linkage either.
The graph below gives an idea about the stick force used in the tests.
gripen
(http://www.onpoi.net/ah/pics/users/852_1128229617_r8.jpg)
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Nashwan,
do you have the Spit 50lb test somewhwere? A 25degree/sec roll increasement due to 20lb more stickforce is pretty outstanding.
No, the RAE test of the Spitfire is included in the report on the FW 190 for comparison purposes, but it doesn't go into details of the test, apart from the paragraphs Gripen and I have posted on this thread.
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Originally posted by gripen
No, that depends on the geometry of the linkage and how the geometry changes due to loosenes. While the stick movement for the given deflection might increase, the angles of the forces in the linkage might change to less optimal direction and the increased movement (leverage) or force might be used just to bend linkage or cables instead to deflect control surface.
If the linkage is loose, it mean the alerons cant get its best deflection with the used stick variation anymore. Ok??
As result of course the max roll ratio decrease! Ok??
As result the max presure onto the alerons decrease, cause smaler aleron deflection.
As result the pilot can keep the stick at higher speeds in its max position.
As long as the planes have the same linkage and leverage, the only way, how the aleron deflection get minimized and at same time the the stick force increase, is, if the alerons are mechianically blocked. But this we for sure would see on the full range of the curve, not only in the middle. And the testers would have took notice of such abig problem!
Originally posted by gripen
As RAE comments note, NACA just made erroneous conclusion due to speed range and apparently also due to condition of the plane. Below is a graph from RAE report No. B.A. 1667 "Aileron tests on Spitfire". The tested plane is a Spitfire I with canvas covered ailerons and the graph shows that at 300 mph the wing lost roughly 40% of the rollinperformance due to twist.
gripen
(http://www.onpoi.net/ah/pics/users/852_1128592804_r14.jpg)
This should proof that the Spitfire and the FW190 curve in the test are not measured, cause the increase of roll with constant alerondeflection(max stickdeflection) is almost linear!
Originally posted by Nashwan
Thx for bringing it up. Is this from one of the 2 later fw-190?? It says "Measured rate of roll". Difficult to say what stickforce was applied, but probably not more than 70lb. Maybe only 50lb too? Any further informations?
In any case the 50lb limit of the RAF/NACA chart is at too low speed and contradicts all pilot accounts.
niklas
It must have been a constant aleron deflection, not constant stickforce in this test. The calculated max roll ratio was around 115degree/sec at 255mph, while the NACA comparison show a bit over 160degree/sec at same speed.
So i guess with max stickdeflection the wingtwist would be even bigger, therofr the 190 curve in the Naca test, same like the Spit curve looks even more strange!
If the NACA guys wasnt able to see that the Spit wing have wingtwist, they maybe made more strange mistakes!
Greetings, Knegel
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Originally posted by Knegel
If the linkage is loose, it mean the alerons cant get its best deflection with the used stick variation anymore. Ok??
As result of course the max roll ratio decrease! Ok??
As result the max presure onto the alerons decrease, cause smaler aleron deflection.
As result the pilot can keep the stick at higher speeds in its max position.
The last sentence might be right or wrong depending the geometry of the linkage and where the loosenes is located. The pilots input might go to bend the linkage or cables.
Originally posted by Knegel
As long as the planes have the same linkage and leverage, the only way, how the aleron deflection get minimized and at same time the the stick force increase, is, if the alerons are mechianically blocked.
No, the loosenes might cause changes in the leverages inside the linkage and even waste large amount of control force to linkage itself.
Originally posted by Knegel
This should proof that the Spitfire and the FW190 curve in the test are not measured, cause the increase of roll with constant alerondeflection(max stickdeflection) is almost linear!
No, the RAE curves show slight bending before the force limit is reached and the report states clearly that the curves are based on flight tested data. There is not much bending below 250 mph EAS even in the case of the Spitfire I.
BTW you are following Mr. Kurfürst's road now.
Originally posted by Knegel
It must have been a constant aleron deflection, not constant stickforce in this test.
No, the steady rate of roll per degree aileron can be calculated from any measured rate of roll at any aileron deflection when the both are measured simultaneously as was done in the RAE tests.
Originally posted by Knegel
The calculated max roll ratio was around 115degree/sec at 255mph, while the NACA comparison show a bit over 160degree/sec at same speed.
No, the calculation is rather easy; the max aileron deflection was +-17 deg and steady rate of roll per degree aileron about 9,5 deg/s at 255 mph EAS and that results about 160 deg/s (there was very little elasticity in the linkage).
gripen
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Ehmm
"If the linkage is loose, it mean the alerons cant get its best deflection with the used stick variation anymore. Ok??
As result of course the max roll ratio decrease! Ok??
As result the max presure onto the alerons decrease, cause smaler aleron deflection.
As result the pilot can keep the stick at higher speeds in its max position.
As long as the planes have the same linkage and leverage, the only way, how the aleron deflection get minimized and at same time the the stick force increase, is, if the alerons are mechianically blocked. But this we for sure would see on the full range of the curve, not only in the middle. And the testers would have took notice of such abig problem!"
At first glance I'd figure you're right. If you have sloppy cables for instance, then eventually you will be able to push the stick as far as it goes without so much happening. Deflection will be less for the same movement if under stress. But a max position would also require quite some strength.
Now, the testers should however notice as you point out, and there is some person called a rigger as well. Comes with the aircraft in Squadron service. ;)
So, I'm lost here. Where is the max position and limited by what? Were cables an issue and why? And so on.
But at the end of the day, what many seem to be missing is simply that it's the roll-rate which is in question, - the actual real life roll rate, and stick forces do not have to go linear with it because of the cockpit ergonomy.
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Originally posted by Angus
So, I'm lost here. Where is the max position and limited by what? Were cables an issue and why? And so on.
The early NACA roll rate curve for the Spitfire V shows unlogical shape which is not supported by other measuremants. The rest here is speculation, it might be caused by loosenes or different linkage or something else (one possibility is that the aileron itself is physically different than in later measurements).
gripen
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Spit V's were rogue anyway, - no two the same.
Do you know when they stiffened the wing? I seem to recall that it was with the VIII model, but can't find the info on it.
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The wing of the Spitfire got step by step (From I to IX) thicker skin, just like the Bf 109, which increased the torsional stiffnes. I don't know the exact numbers and the thickness of the skin sheet varied from root to tip.
The final solution did not come until the Mk. 20 series which had completely redesigned wing. The VIII type airframe was something between original and Mk 20 series. The VIII had for example shorter span ailerons.
gripen
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Originally posted by gripen
The last sentence might be right or wrong depending the geometry of the linkage and where the loosenes is located. The pilots input might go to bend the linkage or cables.
No, the loosenes might cause changes in the leverages inside the linkage and even waste large amount of control force to linkage itself.
gripen
What you describe is again the physical law!
Originally posted by gripen
No, the RAE curves show slight bending before the force limit is reached and the report states clearly that the curves are based on flight tested data. There is not much bending below 250 mph EAS even in the case of the Spitfire I.
No, the steady rate of roll per degree aileron can be calculated from any measured rate of roll at any aileron deflection when the both are measured simultaneously as was done in the RAE tests.
No, the calculation is rather easy; the max aileron deflection was +-17 deg and steady rate of roll per degree aileron about 9,5 deg/s at 255 mph EAS and that results about 160 deg/s (there was very little elasticity in the linkage).
gripen
I think now you messed up the reading of the graphic.
As far as i can see the graphic show the rollratio with constant alerondeflection. In the vertical i can see degree/sec (high -1), so if there stand 10 it mean 100degree/sec, if there stand 15 its 150degree/sec.
The strait (linear) line is the rollratio without wingtwist in degree/sec , while the other line show the rollratio with wingtwist also in degree/sec. The constant round curve show that never the max stickdeflection got reached.
At 330mph the measured rollratio is roundabout 110°/sec, same like in the naca comparison, so here the stickforce is 50lb. Before this point the stickforce is smaler, behind this point the stickforce increase.
As you (maybe) can see, with increasing presure on the alerons the wingtwist increase.
So with max delection of alerons the wingtwist also should increse much with increasing speed, and this at much smaler speeds, cause the greater aleron variation cause more early a big wingtwist, but this effect i simply cant see in the naca comparison.
The incredible roll increasement of 25°/sec due to 20lb more stickfore and the linear roll increasement of the Spitfire let me doubt that this test was realy measured! But maybe this Spit had a different wing than the other Spitfire, where the 30lb test was made with.
Maybe its the stiffned wing of the VIII model(?) like Angus mentioned. But i still doubt a that linear increasement at all.
Would be nice to see the correlating test.
Originally posted by gripen
BTW you are following Mr. Kurfürst's road now.
I would say this is the start of the polemical way. :(
I dont have a problem to offer my conclusion, although Kurfi got the similar conclusion. If you think this is bad, you lose the path of a agrue based discussian, not me.
Greetings, Knegel
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Originally posted by Knegel
What you describe is again the physical law!
I'm merely saying here that we don't know for sure what would be the effect of the loosenes in the linkage. The graph shows similar values at low deflections as other tests but at higher deflection the graph show different and unlogical values. The rest is speculation.
Originally posted by Knegel
As far as i can see the graphic show the rollratio with constant alerondeflection. In the vertical i can see degree/sec (high -1), so if there stand 10 it mean 100degree/sec, if there stand 15 its 150degree/sec.
No, the graph (Fig. 3) [edited, I forgot the Fig number] gives the steady rate of roll per degree aileron and for example at about 255 mph EAS the plane did about 9,5 deg/s/degree aileron and with full 17 deg deflection that results about 160 deg/s.
(http://www.onpoi.net/ah/pics/users/852_1128517348_r13.jpg)
Originally posted by Knegel
The strait (linear) line is the rollratio without wingtwist in degree/sec , while the other line show the rollratio with wingtwist also in degree/sec. The constant round curve show that never the max stickdeflection got reached.
No, the straight line is also rate of roll per degree aileron as stated in the right side of the graph ie deg/s/degree aileron. The round curve shows (as stated in the right side of the graph) the measured rate of roll per degree aileron which can be calculated from any known steady roll rate and aileron deflection combination. Note that the straight line is calculated from the round line.
Originally posted by Knegel
I would say this is the start of the polemical way. :(
I dont have a problem to offer my conclusion, although Kurfi got the similar conclusion. If you think this is bad, you lose the path of a agrue based discussian, not me.
Well, I have said several times in this thread that it's up to you to choose which data you want to believe. But all I see here is that you have problems to understand the Fig. 3 in the RAE 1231.
The report as well as the graph text state directly that the values are measured in the flight test and therefore the wing twist is included and report also states that the Spitfire, Mustang and Typhoon were measured similar way. Here you can choose Mr. Kurfürst's road or believe what the report and graph actually say.
gripen
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Well, Gripen, you beat me to it.
From Knegel:
"As far as i can see the graphic show the rollratio with constant alerondeflection. In the vertical i can see degree/sec (high -1), so if there stand 10 it mean 100degree/sec, if there stand 15 its 150degree/sec."
It got me pondering, - you read the graph wrong, for there is hardly no rollrate of a WW2 fighter that insane!!!
And as I did point at before, - no matter how deep you get into stickforce math, deflections, stretchings and so on, it is the actual roll rate at the receiving end that counts.
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Hi,
Now its getting funny. :)
Originally posted by gripen
I'm merely saying here that we don't know for sure what would be the effect of the loosenes in the linkage. The graph shows similar values at low deflections as other tests but at higher deflection the graph show different and unlogical values. The rest is speculation.
gripen
You dont know for sure what is the reason for the different result, but you 1st was sure that the leverage is not the reason, but the linkage, then the geometry(leverage) did change cause a loose linkage.
There is no loose linkage, which have 15°/sec roll performence decreasement as result. A mechianic would call this damaged and i doubt that they made excessive test with a damaged plane.
If cou would know a bit about the physical law in general and special linkages, you would know that this different results only can happen due to a wanted different leverage.
I have enough education and experience in this field, its not a speculation!
Originally posted by gripen
No, the graph (Fig. 3) [edited, I forgot the Fig number] gives the steady rate of roll per degree aileron and for example at about 255 mph EAS the plane did about 9,5 deg/s/degree aileron and with full 17 deg deflection that results about 160 deg/s.
No, the straight line is also rate of roll per degree aileron as stated in the right side of the graph ie deg/s/degree aileron. The round curve shows (as stated in the right side of the graph) the measured rate of roll per degree aileron which can be calculated from any known steady roll rate and aileron deflection combination. Note that the straight line is calculated from the round line.
gripen
Next to the strait line and the other line you clearly can read rate of roll, rate of roll get measured in degree/sec, not in degree/sec/degree.
Steady rate of roll per degree aleron, this mean a constant aleron deflection. They didnt wrote "Steady rate of roll per x degree aleron", and of course this wouldnt make sence in relation to different speeds. We would have two variables, its pretty not usefull to display such things.
With a constant aleron deflection and a rigid wing the roll ratio increase linear with the speed. Thats what the strait line show.
They was up to show the influence of the wingtwist, therfor they did calculated strait line, with rigid wings. This they did before the flight or after the flight, but they didnt need the measured curve for this.
Originally posted by gripen
Well, I have said several times in this thread that it's up to you to choose which data you want to believe. But all I see here is that you have problems to understand the Fig. 3 in the RAE 1231.
gripen
I dont need to believe, i take the tests like they are and try to explain why they are different, thats all. That we shouldnt believe we can see in the mistake that the NACA testers made regarding the wingtwist.
Originally posted by gripen
The report as well as the graph text state directly that the values are measured in the flight test and therefore the wing twist is included and report also states that the Spitfire, Mustang and Typhoon were measured similar way. Here you can choose Mr. Kurfürst's road or believe what the report and graph actually say.
gripen
The other NACA test also state clearly that the wing dont twist!
I dont know if the tests are realy measured, but i would like to know why the different Spitcurves dont fit to each other.
I dont say the Spit didnt roll that fast, i only wanna know what they did change or if the testers made mistakes again.
Angus,
i only did try to explain that the leverage in the different Spits did change(similar to the P36 to P40). Its important to know that there was changuings to be able to say which spit did roll with what speed.
Greetings, Knegel
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Originally posted by Knegel
You dont know for sure what is the reason for the different result, but you 1st was sure that the leverage is not the reason, but the linkage, then the geometry(leverage) did change cause a loose linkage.
There is no loose linkage, which have 15°/sec roll performence decreasement as result. A mechianic would call this damaged and i doubt that they made excessive test with a damaged plane.
We do know that the NACA tested Spitfire V had unlogical roll rate curve if compared to RAE and RAAF tested planes. We also know that the plane saw extensive flying in the US. It's my speculation that this is caused by loose linkage because at low speed and/or low aileron deflections reached values are normal. At high aileron deflection values differ considerably from the other tests and show characters which are not seen in other tests.
Originally posted by Knegel
I have enough education and experience in this field, its not a speculation!
I have no idea about your education or experience, but I can draw conclusions from your postings.
Originally posted by Knegel
Next to the strait line and the other line you clearly can read rate of roll, rate of roll get measured in degree/sec, not in degree/sec/degree.
No, let's have look:
(http://www.onpoi.net/ah/pics/users/852_1128517348_r13.jpg)
First the text in the bottom: STEADY RATES OF ROLL PER UNIT AILERON ANGLE
Which means the steady rate of roll per degree aileron angle because the aileron angle is given in the degrees in the report. So it can be written:
(rate of roll)/(aileron angle)
Or with units:
(deg/s)/deg
Same is said with a bit other words in the left side of graph: STEADY RATE OF ROLL PER DEGREE AILERON (DEG.SEC^-1)
And same is said directly in the text: "The variation of steady rate of roll per unit aileron angle with speed is shown in Fig.3"
Lets take an example: What steady rate of roll at 350 mph EAS can be reached with max available aileron deflection with 50 lbs stick force assuming flexible wing?
First we must take a look to stick force graph:
(http://www.onpoi.net/ah/pics/users/852_1128229617_r8.jpg)
We can read from the stick force graph that at 359 mph EAS max aileron deflection is about 8 degrees with 50 lbs and at 308 mph EAS about 12 degrees so we can estimate that at 350 mph EAS we can reach roughly 8,8 deg aileron deflection. So now we can simply read from the Fig. 3 what kind rate of steady rate of roll per unit aileron angle can be reached at 350 mph EAS and the graph gives about 11 (deg/s)/deg for flexible (ie measured) wing so the rate of roll would be:
8,8deg x 11(deg/s)/deg = 96,8 deg/s
Note that unneeded degs "eat each other" and disapear :)
If we assume rigid wing, the Fig. 3 gives about 15 (deg/s)/deg and that results:
8,8deg x 15(deg/s)/deg = 132 deg/s
Now we know that if the roll rate curve gives about 97 deg/s at 350 mph EAS it contains wing twist and if it gives about 132 deg/s, the wing is assumed to be rigid. So let's have look to Fig. 6:
(http://www.onpoi.net/ah/pics/users/852_1128714314_r15.jpg)
The chart gives about 97 deg/s so it contains wing twist. Lets look the NACA chart:
(http://www.onpoi.net/ah/pics/users/852_1128714360_r16.jpg)
It gives the same value ie 97 deg/s so it contains wing twist too. Lets read what RAE 1231 says about the test data:
"The best method of comparison of the rolling performance of different aircraft is based on the steady rate of roll a pilot can generate using a definite stick force, say 50 lb., or full aileron if this requires less than 50 lb. on the stick. This course has been adopted in Fig.6 which shows the results obtained for the F.W.190, Mustang, Typhoon, and Spitfire V (metal covered ailerons) with both standard and clipped wings. On all these aircraft instrumental records of rolling performance have been obtained at the R.A.E, similar to those under discussion for the Fw 190. In this connection it is worth noting that "instrumentation" is essential when obtaining the curves of Fig.6. Stop-watch measurements of time to bank on fighters are rarely of sufficient accuracy, since the times to be measured are so small."
So now we have 100% certainty that the RAE test data on the Fw 190, Spitfire, Mustang and Typhoon include wing twist. And the meaning of the grahs should be clear for all.
Originally posted by Knegel
The other NACA test also state clearly that the wing dont twist!
So it's says but RAE data proves that claim errorneous:
(http://www.onpoi.net/ah/pics/users/852_1128592804_r14.jpg)
Note that again the steady rate of roll is given per degree aileron deflection just like in the wing twist graph of the Fw 190.
gripen
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Well maybe it depends on the aileron angel for which the rollrate was measured. Assuming a linear dependence of aileron angle and rollrate is maybe not realistic.
Or the measured rollrate was too high for some guys in the RAF...
niklas
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Ah yeasssh.
The 109 rolled so well it couldn't be measured.
The 190 rolled nicely also. Almost as well. :D
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Hi,
with increasing aleron variation and increasing speed, at same time, the steady rate of roll(rigid wing) dont would increase linear!!!
The curve would go upward, cause the force due to increasing speed and increasing alerondeflection together would let increase the rollratio
progressively !!
Yes its the steady rate of roll per 1 unit aleron delfection, not per x unit alerondelfection!!
How do you think they will measure a linear increasement of alerondelfection and speed at same time?? Thats simply not possible!
You will realy tell me that they had exact 10° alerondeflection at 230mph and 13° at 300mph??
Thats rubbish! And dont make sence!! We would have the speed, the alerondeflection and the rollratio as variable, thats simply not usefull!
To show the influence of the wingtwist they need a constant alerondeflection with increasing speed. Otherwise we cant read anything!
With a constant aleron deflection (one unit, the exact value isnt important) the physical law say that the rollratio increase linear with the speed(up to roundabout mach 0,75).
With different aleron deflections we dont know the exact curve, cause the effectiveness of the alerons with different alreon variations depends much to the aerodynamic of the wing and alerons.
Therfor it dont make sence to make wingtwist tests with a variable alerondeflection, specialy not, if the speed change at same time.
If you dont understand that, we can stop here!
Greetings, Knegel
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btw, the DLV made the same tests with the 109F2, this is what they write:
"Um den Einfluß der elastischen Flügelverdrehung auf die Drehgeschwindigkeit zu untersuchen, ist es jedoch erforderlich, die Abhängingkeit der Rollgeschwindigkeit von der Fluggeschwindigkeit für konstante Querruderausschläge zu kennen."
Translated:
"To investigate the influence of the elastic wingtwist to the roll speed, its needed to know the dependence of the roll speed to the flight speed for constant aleron deflections."
And if you look here, to the 3° or 6° aleron deflection line, it looks almost the same like the FW190 and Spit line with constant alerondeflection.
(http://www.onpoi.net/ah/pics/users/852_1127891041_r1.jpg)
Greetings, Knegel
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Well, the 109F chart says the peak rollrate is at higher speed for lower deflection. This shouldn´t be surprising. The difference looks minor on the other hand, less than 100km/h.
So a single chart for all aileron deflection is at least for higher speeds (non-linear characteristics) a simplification.
Furthermore aileron angle is a bad base for such a chart because the aileron angle get lower due to elastic deformation at higher speeds, see that F2 chart. I think it would have been better to base it on stick angle. Or does the mean aileron angle is the theoretical angle without elastic deformation? Is it a corrected one for this influence?
niklas
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Originally posted by Niklas
Well maybe it depends on the aileron angel for which the rollrate was measured. Assuming a linear dependence of aileron angle and rollrate is maybe not realistic.
Or the measured rollrate was too high for some guys in the RAF...
The data set was measured with quite wide variety of aileron angles (roughly from 2,5 to 14 deg) and generally the RAE report praises the ailerons of the Fw 190 as well as pretty much all other British sources. In addition report notes that the tested plane had rather heavier ailerons than other two they had.
Originally posted by Knegel
with increasing aleron variation and increasing speed, at same time, the steady rate of roll(rigid wing) dont would increase linear!!!
I must honestly say that I have no anykind of interest to know if the curve for the rigid wing is right or wrong, I'm merely interested about the measured roll rates at measured aileron deflections. If you are not happy with curve for the rigid wing, you have got the data and the field is open for your analysis. But maybe you should open a new thread for that because this very little to do with the subject of this thread.
Originally posted by Knegel
Yes its the steady rate of roll per 1 unit aleron delfection, not per x unit alerondelfection!!
No one has claimed otherwise here except that you claimed above that:
"As far as i can see the graphic show the rollratio with constant alerondeflection. In the vertical i can see degree/sec (high -1), so if there stand 10 it mean 100degree/sec, if there stand 15 its 150degree/sec."
Is there a remote possibility that you could admit that you did not understand the Fig. 3 until I explained it to you?
Originally posted by Knegel
How do you think they will measure a linear increasement of alerondelfection and speed at same time??
What they did was simply that they flew at given speed (205, 257, 308, 359 and 409 mph EAS), rolled the plane and recorded the aileron deflection, steady rate of roll and stick force (and probably many other things too) and repeated that several times at all tested speeds. The steady rate of roll per unit (degree) aileron can be easily calculated from any known aileron deflection and steady roll rate combination simply:
steady roll rate per unit = (measured steady roll rate)/(measured aileron deflection)
And to keep units with:
(deg/s)/deg = (deg/s)/deg
As an example, if measured roll rate at given speed is 160 deg/s and measured aileron deflection was 17 deg, the steady rate of roll per unit (degree) aileron is simply:
(160deg/s)/(17deg) = 9,41 (deg/s)/deg
Originally posted by Knegel
To show the influence of the wingtwist they need a constant alerondeflection with increasing speed. Otherwise we cant read anything!
No, they just needed to collect enough test points and fit the curve. There is some thirty measured data points in the set.
(http://www.onpoi.net/ah/pics/users/852_1128229617_r8.jpg)
Originally posted by Knegel
If you dont understand that, we can stop here!
Well, the understanding problem is in your side.
gripen
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Hi,
you be right, it did need a bit, but now i got it! :)
This graph show the "roll effectiveness"(rate of roll per aleron delfection) of the wing.
The entrys 'measured rate of roll', 'rate of roll with rigid wings' and 'loss of rate of roll due to wing torsion' drove me to the wrong conclusion!
This describtions are simply wrong. Thes curves display the 'wing torsion factor' related to the 'measured rate of roll' and 'wing torsion factor' of a rigid wing, the different of both display the 'loss of roll effectivity' due to wing torsion(decreased drill rigidity).
All three wrong describtions whould have been measured in degree/sec, thats why i did stumble.
Out of this factors, as you wrote, we can calculate the rate of roll, with different aleron deflections.
So the FW190A curve is the measured one.
Greetings, Knegel
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Btw.
what i find to be very strange is that they assume a absolute rigid linkage.
Up tp 60lb stickforce the alreron deflection increase absolute linear with the stickforce(double stickforce = double alerondeflection).
The 109F did show a smooh decreasing of the alerondeflection with the speed. This had a roll ratio lost of 15°/sec as result on the huighest peak (roundabout max 80 °/sec to 95°/sec).
If the measured of course include the softness in the linkage, so the Different to the rigid wing curve include the softness of the linkage too. But its wrong to calculate from this curve to a curve at higher speed or higher alerondeflection, cause the the influence of the softness of the linkage differ with the speed and/or alerondeflection.
Since it looks like they did calculate the 50lb curve out of the tested curves, its possible that they dont include the softness of the linkage at given speeds with max aleron deflection, cause they assume a absolute rigid linkage! (if there was a softness in the linkage at all).
Dont we have a german FW190 roll test, similar to the DLV one? They did split all this influences into different tests.
Greetings, Knegel
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Originally posted by Knegel
what i find to be very strange is that they assume a absolute rigid linkage.
Up tp 60lb stickforce the alreron deflection increase absolute linear with the stickforce(double stickforce = double alerondeflection).
The report claims directly:
"Stick forces for various aileron angles and speeds are given in Fig. 4 where it will be seen that the stick force is roughly proportional to the aileron angle applied, and also follows the 'speed squared law'; there is thus no increase of -Kb2 with speed. This is probably due to the fact that an effort has been made to cut distortion to a minimum, both by using a small rib spacing and by employing a push-pull rod control circuit. The latter is effective mainly by reducing the variation of the upfloat of the ailerons with speed, from 200 mph ASI to 400 mph ASI the upfloat (measured on starboard aileron) was sensibly constant at 1 deg."
And:
"(iv) -Kb2 for the ailerons is -0,11, and does not vary apprediably over the speed range 200 mph to 400 mph EAS or angular range +-10 deg."
The elasticity of the linkage is there and it was measured to be very small ( 1 deg upfloat would mean 0,5 deg for mean aileron deflection assuming upfloat). Notable thing is that FW specification for the aileron movement was 18 deg up and down so the elasticity was actually about same amount as production variation or measurement error.
It should be noted that even the DVL report on the Bf 109F-2 is a bit strange in this respect; the claimed average deflection in the report is 17,5 deg ( ie 23 deg up and 12 deg down) and the measured average deflection with no load was about 15,5 deg. The manufacturers specified average deflection was 17 deg ie 22,7 up and 11,3 down.
In the case of the Spitfire I the report gives the stretch for used stick force range and the loss of aileron movement with 50 lbs stick force was about 2 deg:
(http://www.onpoi.net/ah/pics/users/852_1128936283_r17.jpg)
Generally you can spend the rest of your life nit picking the data but IMHO that is not purpose of this thread.
gripen
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Hi,
the DLV test dont clain that the 109F had 23 deg up and 12 deg (17,5°) down aleron variation, thats the max range for the measuring instrument.
I only found a max displayed aleron deflection of 15,5°(very slow speed).
With the same stickvariation the 109F lost roundabout 2,7° aleron deflection due to a soft linkage. :eek:
If , like you say, the by the manufacturers specified average deflection was 17 deg, we can assume a loose/worn linkage.
Actually i wonder why they made such tests with a outdated plane in 1944 anyway.
I find it very usefull to discuss this tests to get a better idea of the testresults.
Greetings, Knegel
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Notable thing is that FW specification for the aileron movement was 18 deg up and down so the elasticity was actually about same amount as production variation or measurement error.
The specification for FW190 aileron movement is 17 degrees (+-2 degrees).
(http://www.onpoi.net/ah/pics/users/503_1128968712_flapsettings2.jpg)
If you check the aileron adjustment regulation for the FW190 and cross reference for the speed and altitude given in RAE1231 it is easy to see that the ailerons were out of adjustment. The stick forces are simply out of range and would not have passed the Fiesler Force meter checks. This is not a linkage adjustment and does not effect the amount of aileron movement.
It adjust the amount of space between the aileron and wing. In otherwords the aerodynamic balance of the Frise ailerion. With the adjustment block full forward, you still get 17 degrees of aileron movement.
The adjusting blocks attach to the mounting blocks of the aileron.
Additionally the FW-190 mounted 3 types of ailerons with different hinge axis.
(http://www.onpoi.net/ah/pics/users/503_1119051605_alierontype1.jpg)
(http://www.onpoi.net/ah/pics/users/503_1119051646_ailerontype2and3.jpg)
So even though the RAE test pilots noticed something was up with the aircraft:
(http://www.onpoi.net/ah/pics/users/503_1119051559_pilotscomments.jpg)
We can cetainly say that RAE 1231 represents the "at least" performance of an FW190A4 with ailerons in need of adjustment.
Of which aileron type, we do not know.
All the best,
Crumpp
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Originally posted by Knegel
the DLV test dont clain that the 109F had 23 deg up and 12 deg (17,5°) down aleron variation, thats the max range for the measuring instrument.
Ah, that's my error, the chart says "gerät", you are correct.
Anyway, the Mtt documentation gives following specs for the ailerons of the Bf 109F:
(http://www.onpoi.net/ah/pics/users/852_1128976680_r18.jpg)
I have not found tolerances for the 109F but the K had tolerance +1 and -2 up and +- 1 deg 30' down, so apparently 15,5 deg is within normal tolerances.
Originally posted by Knegel
I only found a max displayed aleron deflection of 15,5°(very slow speed).
Hm... let's have look to the chart:
(http://www.onpoi.net/ah/pics/users/852_1128017315_r3.jpg)
It shows 15,5 deg at zero speed ie no dynamic pressure.
Originally posted by Knegel
With the same stickvariation the 109F lost roundabout 2,7° aleron deflection due to a soft linkage. :eek:
Is there a reason to think that it's not a normal value?
Originally posted by Knegel
If , like you say, the by the manufacturers specified average deflection was 17 deg, we can assume a loose/worn linkage.
Well, you can assume what ever you want but the chart shows logical linear elasticity of the linkage just like Spitfire I chart. In addition, the roll rate chart shows typical logical curve for the frise type aileron and the roll rate values are very close to calculated values in the test. At least I don't see signs of loose or worn linkage nor other problems with structure.
Originally posted by Knegel
Actually i wonder why they made such tests with a outdated plane in 1944 anyway.
That should have been asked from DVL but I don't see a reason why the tested aircraft should not have been in normal condition.
Originally posted by Crumpp
The specification for FW190 aileron movement is 17 degrees (+-2 degrees).
The manual gives +-17 so you are right. I have two separate sources claiming +-18 degrees like chart below (for the A-5), anyway, that's within normal tolerance:
(http://www.onpoi.net/ah/pics/users/852_1128976749_r19.jpg)
Originally posted by Crumpp
So even though the RAE test pilots noticed something was up with the aircraft:
That has been pointed out several times during this thread and actually I have quoted (http://www.hitechcreations.com/forums/showthread.php?s=&postid=442473#post442473) that in this BBS before you were even member here.
gripen
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Hi,
quote:
--------------------------------------------------------------------------------
Originally posted by gripen
Is there a reason to think that it's not a normal value?
--------------------------------------------------------------------------------
I dont say its not normal, rather i find the assumption of a rigid linkage for the FW190 and Spitfire not normal. At least the FW190 curve got calculated with a rigid linkage.
The soft BF109F2 linkage start to show significant decreasing results above 200mph IAS, with full aleron deflection, but specialy here the picture dont show test results for the FW190. Is there another picture, with testresults with full alerondeflection and/or max stickforces?
If i see the exact linear max stick deflection roll curve of the Spitfire(normal wing), the Spit wing and linkage must have been absolut rigid.
-
Originally posted by Knegel
I dont say its not normal, rather i find the assumption of a rigid linkage for the FW190 and Spitfire not normal. At least the FW190 curve got calculated with a rigid linkage.
I don't see such assumption in the RAE reports. Given the claimed 1 deg upfloat in the case of the Fw 190, such small elasticity (smaller than normal production variation) is difficult to see from the graphs and also difficult to calculate out from the rough charts. They measured it and I don't see a reason why they should have not included it.
Originally posted by Knegel
The soft BF109F2 linkage start to show significant decreasing results above 200mph IAS, with full aleron deflection,
Actually the full aileron deflection curve is a calculation and the full stick deflection curve is a calculation as well.
Originally posted by Knegel
but specialy here the picture dont show test results for the FW190. Is there another picture, with testresults with full alerondeflection and/or max stickforces?
It shows test points and upfloat was measured as noted in the report. You have got the all the data I have on these tests and the field is open for your own search. These tests are so far the best instrumented and documented data I have found (since early nineties). But there might be better stuff out there, so why don't you just start start digging instead nit picking?
Originally posted by Knegel
If i see the exact linear max stick deflection roll curve of the Spitfire(normal wing), the Spit wing and linkage must have been absolut rigid.
The Spitfire V reached the force limit at so slow speed that bending is not particularly visible; there appear to be some bending but the Fig.6 is rough anyway. And based on measurements on the Spitfire I, the Spitfire seem to have a somewhat more rigid aileron linkage than Bf 109F.
We do know that:
"This course has been adopted in Fig.6 which shows the results obtained for the F.W.190, Mustang, Typhoon, and Spitfire V (metal covered ailerons) with both standard and clipped wings. On all these aircraft instrumental records of rolling performance have been obtained at the R.A.E, similar to those under discussion for the Fw 190."
So all these planes were tested same way and the elasticity (wing and linkage) was measured and I don't see a reason why these should have not been included to the curves.
gripen
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Oh,
you have problems to believe that the SpitVa wing and linkage was normal standard, but you dont have problems to believe that the Spit in the NACA comparison have absolute rigid wings and linkage up to 207mph and that the FW190 had a absolute rigid linkage as well??
"I don't see such assumption in the RAE reports. Given the claimed 1 deg upfloat in the case of the Fw 190, such small elasticity (smaller than normal production variation) is difficult to see from the graphs and also difficult to calculate out from the rough charts. They measured it and I don't see a reason why they should have not included it."
Yes, they claimed this, but made tests mainly only with around 5°(+/-3°) alerondeflection. Nevertheless they did insert a linear line, and calculated the 50lb roll performence out of the roll result with smal alerondeflection and the aleron effectiveness.
With only5° initial aleron deflection(4,5° constant stickdeflection) the Me109F2 also only lost roundabout 0,8° between 200 and 400mph IAS.
With 12,2° initial aleron deflection(11,8° constant stickdeflection), the different was already 2°!!
And also very important to know is that the softness of the linkage have most influence below 200mph!!
And even if we believe the testers, and the FW190 was that stiff all over, a 0,5° reduction of alerondeflection would let decrease the max roll rate to 157°/sec!!
You can call this nit picking, but i saw already many so called test results, where the testers made mistakes(one very nice, well known, is the RAE turnperformence comparison, 109E3 vs Spit1, where the result was calculated only by the wingload).
If we wanna get a credible conclusion out of all tests, we need to understand how the testers got the results and if they made mistakes.
We are not in a church, we can understand this tests and we can see mistakes. To believe results like they are, without to understand the used procedure, dont seems to be logical to me.
Iam gathering flight tests, but as you know, there are only a few roll performence tests available. I already was in some german museums, but dont found more than i already had.
Greetings, Knegel
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Originally posted by Knegel
you have problems to believe that the SpitVa wing and linkage was normal standard,
As noted several times the NACA test on Spitfire V shows unlogical shape of the roll rate curve.
Originally posted by Knegel
but you dont have problems to believe that the Spit in the NACA comparison have absolute rigid wings
No, as pointed out above several times with RAE data and quote, the conclusion by NACA was simply wrong. Besides NACA choosed to use RAE data for their later works.
Originally posted by Knegel
and linkage up to 207mph and that the FW190 had a absolute rigid linkage as well??
No, as pointed out several times above the report clearly states that upfloat was measured.
Originally posted by Knegel
Yes, they claimed this, but made tests mainly only with around 5°(+/-3°) alerondeflection.
No, as pointed out above, the measurement range was roughly from 2,5 to 14 deg.
Originally posted by Knegel
And even if we believe the testers, and the FW190 was that stiff all over, a 0,5° reduction of alerondeflection would let decrease the max roll rate to 157°/sec!!
At least I can't read the grahs with such accuracy that I can find reliably 5 deg differences ( note that I have used pretty much allways rough values during this thread).
Originally posted by Knegel
You can call this nit picking, but i saw already many so called test results, where the testers made mistakes(one very nice, well known, is the RAE turnperformence comparison, 109E3 vs Spit1, where the result was calculated only by the wingload).
I have not seen such RAE test, the RAE report on the AE479 contains flight tested Clmax data which was used for comparison calculations. Maybe you should start a new thread on that topic?
Originally posted by Knegel
Iam gathering flight tests, but as you know, there are only a few roll performence tests available. I already was in some german museums, but dont found more than i already had.
Happy hunting! Hopefully you have enjoyd the stuff I gave to you.
gripen
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Originally posted by gripen
As noted several times the NACA test on Spitfire V shows unlogical shape of the roll rate curve.
gripen
I disagree. In case you think there happened too much elasticity: Remember the chart is for 6000ft only. Density in 6k is higher than in 10k, so stress on the ailerons is higher, thus more tension.
Does a plane roll faster or slower at lower alt? I expect at least a faster roll acceleration, in case of banking tests i expect it to roll faster after all.
It only looks so strange because high stickforces are reached already at verly low speeds. Normally you would expect a decrease of rollrate when max. stickforce is reached to achieve max. deflection, the SpitV in this test was able to roll still a bit faster when reducing stick deflection due to force limit. But the same can be observed in the naca868 chart (F6F-3, or P47-C being at the peak).
When the constant rollrate curves in fig.28 reach a minimum, then there is the point reached where a further increase of speed will result in an decrease of rollrate, when a max. constant stickforce is given. This is for high stick deflection somewhere between 190-220mph and fits nicely to the RAF Measurement
niklas
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Originally posted by niklas
I disagree. In case you think there happened too much elasticity: Remember the chart is for 6000ft only. Density in 6k is higher than in 10k, so stress on the ailerons is higher, thus more tension.
Feel free to disagree but my speculation is based on assumption that the elasticity might change the leverage to the worse direction.
Originally posted by niklas
Normally you would expect a decrease of rollrate when max. stickforce is reached to achieve max. deflection, the SpitV in this test was able to roll still a bit faster when reducing stick deflection due to force limit. But the same can be observed in the naca868 chart (F6F-3, or P47-C being at the peak).
The shape of the curve is completely different if compared to the RAE measurements.
Originally posted by niklas
When the constant rollrate curves in fig.28 reach a minimum, then there is the point reached where a further increase of speed will result in an decrease of rollrate, when a max. constant stickforce is given. This is for high stick deflection somewhere between 190-220mph and fits nicely to the RAF Measurement
Hm... deflection is not particularly high at 190-220 mph IAS with 50 lbs, the right roll about 1,2 rad/s at 200 mph IAS ie about 69 deg/s (using Spitfire I charts, separate for left and right) which means roughly 60% deflection and the left roll might be around 1,3 rad/s ie 75 deg/s which means roughly 75% deflection. The RAE data gives full deflection at 200 mph IAS at 10k ie 105 deg/s and the fig. 28 indicates that full deflection would have needed around 80-100 lbs at 6k. I don't see a good fit here, density difference between 6k (about 1,02 kg/m3) and 10k (about 0,9 kg/m3) does not explain the difference. At higher speeds the curve seem to come close RAAF data ie at low deflections there appear to be better fit and also the fig. 28 seem to give normal shape of the roll rate curve at low deflections.
Anyway, feel free to believe what ever data you prefer.
gripen
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Originally posted by gripen
As noted several times the NACA test on Spitfire V shows unlogical shape of the roll rate curve.
gripen
Who say that the shape is unlogical? Its different to later Spits, but it show a similar shape like many other planes(F6F, F4F, P47). And as i pointed out before, it looks like a different leverage(geometry of linkage).
Originally posted by gripen
No, as pointed out above several times with RAE data and quote, the conclusion by NACA was simply wrong. Besides NACA choosed to use RAE data for their later works.
gripen
Conclusions and testresults are two different pair of shoes. We have measured curves for both spits, the conclusion that the wing was rigid was probably wrong, but not the measured curve.
Originally posted by gripen
No, as pointed out several times above the report clearly states that upfloat was measured.
Originally posted by gripen
No, as pointed out above, the measurement range was roughly from 2,5 to 14 deg.
gripen
Yes, but they only have 1 measured point at 14° and 1 at roundabout 11°, all over they display only 30 points, most of them are with around 5°(+-3) aleron deflection.
There is no way to get results with high aleron deflection out of the testresults!
Originally posted by gripen
At least I can't read the grahs with such accuracy that I can find reliably 5 deg differences ( note that I have used pretty much allways rough values during this thread).
gripen
We dont need to calculate to see that they dont took the 'soft' linkage into account, we see a absolute linear behaviour in their 'Stickforce/aleron' graphic, growing up from the zero point.
Originally posted by gripen
I have not seen such RAE test, the RAE report on the AE479 contains flight tested Clmax data which was used for comparison calculations. Maybe you should start a new thread on that topic?
gripen
Compare the results of the resulting calculated min radius with the wingload relation and you will see it fit. The Clmax relations for sure vary much from the wingloadrelations.
http://mitglied.lycos.de/luftwaffe1/Carson/Carson.html
You can open a new theatre if u want, i dont see the need. :)
Originally posted by gripen
Happy hunting! Hopefully you have enjoyd the stuff I gave to you.
gripen
For sure i enjoy it, same like the discussian with you! Thank you very much! :)
Greetings, Knegel
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Originally posted by Knegel
Who say that the shape is unlogical? Its different to later Spits, but it show a similar shape like many other planes(F6F, F4F, P47). And as i pointed out before, it looks like a different leverage(geometry of linkage).
Hm... no other plane shows roughly 40% stick force decrease for given rate of roll when the speed increases. The P47 curve show slightly increased (say 1-2%) roll rate after the force limit is reached before it starts to decrease. The curves of the F4F and F6F seem to show just the wing twist because the original curves were for 30 lbs stick force, it should be also noted that F6F curve is for spring tab ailerons.
Notable thing is that none of the many RAE measurements on Spitfire with various type of ailerons nor RAAF measurements show this kind of curve.
Originally posted by Knegel
Conclusions and testresults are two different pair of shoes. We have measured curves for both spits, the conclusion that the wing was rigid was probably wrong, but not the measured curve.
I wonder why you just keep repeating that rigid wing argument? Only source which claims rigid wing is NACA report on Spitfire V and that claim is errorneous as pointed out several times. All RAE data mentioned here assumes wing twist which is calculated from the tested roll rates. If the RAE data had been derived from rigid wing values, the roll rate curve would have shown well over 120 deg/s at 200 mph EAS.
Note also that in the RAE reports the curve for the rigid wing is calculated from the measured results so there is simply no logic in your argument.
Originally posted by Knegel
Yes, but they only have 1 measured point at 14° and 1 at roundabout 11°, all over they display only 30 points, most of them are with around 5°(+-3) aleron deflection.
There is no way to get results with high aleron deflection out of the testresults!
There is a simple way, just the same as used by DVL, values can be extrapolated with good enoug accuracy.
Originally posted by Knegel
We dont need to calculate to see that they dont took the 'soft' linkage into account, we see a absolute linear behaviour in their 'Stickforce/aleron' graphic, growing up from the zero point.
The results show roughly linear increase of stick force (despite the scatter) so linear assumption is not far off. You can test it your self, just fit the lines to data.
Originally posted by Knegel
Compare the results of the resulting calculated min radius with the wingload relation and you will see it fit. The Clmax relations for sure vary much from the wingloadrelations.
I wonder what do you mean, the RAE results are based on measured Clmax data (flight tested for both planes with similar instrumentation) not just wingloading. Please, read the report and open a new thread if you like to argue.
gripen
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Originally posted by gripen
Hm... no other plane shows roughly 40% stick force decrease for given rate of roll when the speed increases. The P47 curve show slightly increased (say 1-2%) roll rate after the force limit is reached before it starts to decrease. The curves of the F4F and F6F seem to show just the wing twist because the original curves were for 30 lbs stick force, it should be also noted that F6F curve is for spring tab ailerons.
Notable thing is that none of the many RAE measurements on Spitfire with various type of ailerons nor RAAF measurements show this kind of curve.
gripen
Yes, no other Spit did show this curve cause they had a other leverage(linkage geometry) so they didnt show this curve, cause the point of max stick deflection was at much higher speeds. Its also possible that they made other, aerodynamical variations on the alerons on later Spitfires, to arcive a other performence. The SpitVa test state why the stickforce decrease with increasing roll speed.
Originally posted by gripen
I wonder why you just keep repeating that rigid wing argument? Only source which claims rigid wing is NACA report on Spitfire V and that claim is errorneous as pointed out several times. All RAE data mentioned here assumes wing twist which is calculated from the tested roll rates. If the RAE data had been derived from rigid wing values, the roll rate curve would have shown well over 120 deg/s at 200 mph EAS.
Note also that in the RAE reports the curve for the rigid wing is calculated from the measured results so there is simply no logic in your argument.
In this case i didnt repead anything, i just was telling that the wrong conclusion, regarding the rigid wing, dont make the measurement wrong.
Originally posted by gripen
There is a simple way, just the same as used by DVL, values can be extrapolated with good enoug accuracy.
The DVL made roundabout 50 testpoints only for 11,8° stick deflection, 50 points for 7,6° stick deflection and roundabout same number of measured points for 4,5° stickdeflection. From this resulting directly measured lines its not difficult to calculate the 15° stickdeflection results! If the DLV would have had only the 4,5° stickdeflection results, they dont would have been able to know what happen at higher aleron deflections!
Originally posted by gripen
The results show roughly linear increase of stick force (despite the scatter) so linear assumption is not far off. You can test it your self, just fit the lines to data.
I dont know where do you see this, the test results are in most cases far away from the concluded line, we even could assume lines.
(http://www.raf-roy.com/share/knegel/Screenes/Stickforce.JPG)
This entry fit in the same way to the measured points like the assumed linear entry´s.
Originally posted by gripen
I wonder what do you mean, the RAE results are based on measured Clmax data (flight tested for both planes with similar instrumentation) not just wingloading. Please, read the report and open a new thread if you like to argue.
gripen
Strange, so the CLmax of the Spit and 109E was the same, what a odd luck.
Greetings, Knegel
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Im trying to think why cable stretch would have any impact on roll rate.
The only time I can see it change the roll rate , is if the stick is limited by full throw and not by force. If it is just limited by stick force then the same force would still be at the ailaron no mater how much the cable streatches, only the stick would move slightly further. But the angle of the ailaron would still be the same.
HiTech
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I don't think it's cable stretch either. Altough in gripen's world it's possible that even metal connect rods - like on the 190, 109 or P-47 - would stretch, for the rest of us it seems quite unlikely - even the NACA report that gripen appearantly didn't read before qouting from it states that calbe stretch is not really a factor for fighter sized aircraft, rather more of an issue with bombers etc. ;)
I'd believe though the reason for more limited deflection is the wing twist. If the wing bents a bit, the distance the rod has to cover between the aileron and the stick will change, and this may well effect the amount of aileron deflection vs. stick deflection.
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Hi hitech,
you be right, and if you look to most rollratio curves you will take notice that the pilots in many planes did reach max stickvariation up to 200-230mph IAS. In the case of the SpitVa you be absolutly right, a lose linkage dont would minimize the rollratio, cause max stick deflection dont get reached at best rollratio!
But with max stickdelfection only with a rigid linkage the max aleron delfection get reached, of course the plane with more rigid linkage have a advantage.
Kurfi,
if you would read the 109F2 rollratio test, you could take notice that this plane lost roudnabout 15°/sec roll ratio due to a soft linkage! Its true that metal connect rods can strech, althoug probably not the metal itself, but the "hinges" and bended rods(due to vibrations and presure) cause a similar result. At least the 109F2 test show clearly that the linkage was 'soft'.
Softness in the linkage is absolutly normal, same like wing torsion, thats why i dont understand the linear Spit rollratio increasement with max stickdeflection.
Edit: Aleron torsion can cause a reduced alerondeflection, even with a absolute rigid linkage!
Greetings, Knegel
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Originally posted by Knegel
Yes, no other Spit did show this curve cause they had a other leverage(linkage geometry) so they didnt show this curve, cause the point of max stick deflection was at much higher speeds. Its also possible that they made other, aerodynamical variations on the alerons on later Spitfires, to arcive a other performence. The SpitVa test state why the stickforce decrease with increasing roll speed.
Hard to say where the speculations starts; there are many possibilities:
- different linkage
- different ailerons
- condition of the plane
- all above
- something else
Not much reason to argue without facts.
Originally posted by Knegel
In this case i didnt repead anything, i just was telling that the wrong conclusion, regarding the rigid wing, dont make the measurement wrong.
No one has argued here that the measurement itself is some how wrong. But you claimed above that:
"but you dont have problems to believe that the Spit in the NACA comparison have absolute rigid wings"
Actually I have said that wing twist conclusion by NACA is errorneous which pretty much opposite than your argument.
Originally posted by Knegel
I dont know where do you see this, the test results are in most cases far away from the concluded line, we even could assume lines.
There is no need to assume anything, there is no signs of systematic bend in the data, data points scatter steadily around the linear line. Despite the scatter, the aileron response factor (-Kb2) can be calculated for all given speeds and these can be compared. RAE found out that the -Kb2 was "approximately constant over the range of the test". Note that even one value is enough to calculate -Kb2, in this data set there is some 30 values at wide hinge moment range and stick force range which all give roughly same -Kb2 and also roughly linear increase of stick force with aileron angle.
Overall this is not exact science but a practical fighter aileron comparison with good enough methods.
Originally posted by Knegel
Strange, so the CLmax of the Spit and 109E was the same, what a odd luck.
Nonsense, the Clmax values are different. Please, read the report and start a new thread if you have something to whine bout.
Originally posted by hitech
Im trying to think why cable stretch would have any impact on roll rate.
Below is a very simplified way to show how leverage can change due to stretch in the aileron circuit which is geared to give differential movement ( more up than down like 15deg up and 10deg down):
(http://www.onpoi.net/ah/pics/users/852_1129146132_r20.jpg)
Just imagine that the other cable stretch and the leverage in the linkage will change as well as movements of the aileron. If we assume further that both aileron are connected to this circuit, the stretch will change the relative movements ie the force balance between ailerons will also change (in the frise type ailerons up going aileron balances down going aileron).
Note that this is plain speculation but atleast theoretically possible.
gripen
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Hi,
Originally posted by gripen
Hard to say where the speculations starts; there are many possibilities:
- different linkage
- different ailerons
- condition of the plane
- all above
- something else
Not much reason to argue without facts.
gripen
But you didnt stop to assume a loose linkage for quiete a time in this theatre.
Originally posted by gripen
No one has argued here that the measurement itself is some how wrong. But you claimed above that:
"but you dont have problems to believe that the Spit in the NACA comparison have absolute rigid wings"
Actually I have said that wing twist conclusion by NACA is errorneous which pretty much opposite than your argument.
gripen
I was talking about the obvious rigid wing/linkage of the Spit(normal wing) in the NACA comparison!! Even the FW190 show a very smooth curve(even with rigid linkage), while the Spit(normal wing) is absolut linear.
You call the SptVa curve strange(actually same like the testers and they gave a clarification), but you dont find the Spit(normal wing) curve strange.
So one time you believe the testers, the other time not. Thats what i find strange. I dont want to believe, i want to know, if i dont know, i try to find a clarification for the results, if i dont find one, i dont stop to call the results not credible until someone give me a clarification. If the results fit to my knowledge, i use the tests as credible(not as universal, if the test show bad linkage setups like in the SpitVa) , until someone show me a mistake.
My current conclusion is: The 190 and Spit(normal wing) miss some datas to explain the calculated 50lb curves, therfor it dont make sence to me, to compare them with the other 50lb curves where we have exact datas.
So i will stick with the 30lb curves, at least here the possible failsure rate is smaler.
The SpitVa test show a bad leverage setup, iam sure it could reach much better results, specialy at slow/medium speeds, with a other setup(the other curves show that this got fixed in later spits), therefor i also dont would use this test as normal Spitv roll performence.
Originally posted by gripen
There is no need to assume anything, there is no signs of systematic bend in the data, data points scatter steadily around the linear line. Despite the scatter, the aileron response factor (-Kb2) can be calculated for all given speeds and these can be compared. RAE found out that the -Kb2 was "approximately constant over the range of the test". Note that even one value is enough to calculate -Kb2, in this data set there is some 30 values at wide hinge moment range and stick force range which all give roughly same -Kb2 and also roughly linear increase of stick force with aileron angle.
Overall this is not exact science but a practical fighter aileron comparison with good enough methods.
gripen
Iam unsure what exact is Kb2, is it PB/2V??(dont found any source regarding it).
PB/2V only can get calculated for all speed in relation to the alerondefflection, not in relation to the stickdeflection!
They did calculate Kb2 out of the stickforce measurement and althought they found that there is a variation of at least 0,5° they still assume a linear behaviour of the linkage in relation to the speed, althought they never made usable tests with high aleron deflections.
As my example with the curves show, the curves can look much different at high speed due to a soft linkage. The linear increasement is only a assumtion!
I would assume curves at least a bit like they got it for the SpitVa.
(http://www.raf-roy.com/share/knegel/Screenes/SpVa_2.JPG)
As you can see, PB/V2(Kb2??) is linear, althought the stickforce/alerondeflection are not!
Not exact sience?? If someone wanna comapare something it have to be exact, specialy if 0,5° different aleron variation result in 5,5° roll speed different. What if the linkage at highspeed had deflection different due to softness in the linkage of 1 or 1,5°??
This dont seams to got measured, and if this is the case, then good by to a worthy comparison with high alerondeflections.
Originally posted by gripen
Nonsense, the Clmax values are different. Please, read the report and start a new thread if you have something to whine bout.
gripen
I dont whine, sounds more like you do, so if u have to offer something start the new theatre. :)
Greetings, Knegel
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I see what you trying to say Gripen but a slight streching in a wire is hardly noticeable unless the leverage is really small, which I doubt it wasn't.
And a braided(?) wire will stretch, where as a strech in a rod linkage would be very very small.
BTW your picture is symmetrical, so the ailerons have the same movement both ways. It should have either a non centered axle, or one of the wire attachment point should be closer to the axle to give it a non-symmetrical movement.
Edit: "Edit: Aleron torsion can cause a reduced alerondeflection, even with a absolute rigid linkage!"
IIRC this is documented in NACA 868, too.
-C+
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Gripen: I had considered that, but decided it's effect would be a very small and the leverage change wasn't worth trying to describe.
Btw: The streatch could also make the leverage go up. Depending on where the 90 deg lever arm point was.
HiTech
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so i tried to get rollrate out of the naca test. Make you own conclusions.
(http://de.geocities.com/stefan_l_01/fzg/spitvarolling.gif)
It should be noted that i entered table values only once, before drawing the chart. This means the almost linear characteristic up to 240mph is not "adjusted" by myself afterwards. Maybe it was just luck to have picked the values in a way that a linear characteristic was the result.
In any case i consider these rollrates way more realistic than the RAF one´s if one considers:
- ailerons don´t reach up to the tips
- light wing structure
- elastic cables
- wing area covered by ailerons is not extraordinary high
- percentage of aileron area in the aileron section is not extraordinary high
- design of mid 30ies after all (nose shape, wing shape)
niklas
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Interesting, niklas. It seems to be a very similair curve than that of the 109F-2 in the DVL test.
And what gives, Southwood who flew the 109G-2/trop, stated :
"Roll performance is similar to a Hurricane or elliptical wing tipped Spitfire. "
The RAE curves that gripen claims to have came from tests do not agree with this, whereas your curves from the NACA paper we KNOW coming from tests, do...
There is also no explanation for the ultra-high, and linear increase in the roll rate of the 'clipped wing' Spit. It looks like to be mechanically 50% higher at any speed. Appearantly, it's just a calculation like the other curve, but it's characteristics doesn't match any of the half a dozen Spitfire tests with clipped wings, which all state that :
a, clipping the wings doesn't give that much of a roll rate increase, and is not recommended.
b, clipping the wings only helps production aircrafts with poorly matched ailerons, and the increase is only pronounced at higher speeds.
c, it doesn't agree with the RAE comparision of the Mustang and Spit, which states 45 degree roll at 400mph EAS would require 71 lbs force, not 50 lbs.
In short, the RAE curves for the Spit doesn't agree with any other test, and in fact there's no evidence at all that these were tested values, not rough calculations. And the people who claim it's a test refuse to show the test conditions and details - if there is such....
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Originally posted by Knegel
But you didnt stop to assume a loose linkage for quiete a time in this theatre.
Actually I'm talking about that with others. It should be noted that we have at least anecdotal evidence on condition of the airframe from Stanford Tuck:
"It happened that Wright Field had the only Spitfire in America-a Mark V. Unfortunately almost every pilot in the Air Corps had had a go on her and like a car that had too many drivers, she was the worse for wear...'She was very tired, very sloppy-she'd had the guts caned out of her all right."
Originally posted by Knegel
I was talking about the obvious rigid wing/linkage of the Spit(normal wing) in the NACA comparison!!
I have allready told you that:
NACA comparison (http://mitglied.lycos.de/luftwaffe1/aircraft/usaaf/rollrate.pdf) is comparison made by NACA and the tested planes were the P-36, P-40, Hurricane and Spitfire. The tested Spitfire was same as used for flying qualities tests and no wing twist was errorneously claimed for this plane by NACA in the report on flying qualities.
RAE fighter aileron comparison (RAE 1231 and other reports) is an aileron comparison made by RAE and amount of wing twist was measured for all tested planes and these roll rate curves can be found also from NACA 868.
Originally posted by Knegel
Even the FW190 show a very smooth curve(even with rigid linkage), while the Spit(normal wing) is absolut linear.
That is because the chart is rough and wing bends quite steadily when the speed increases:
(http://www.onpoi.net/ah/pics/users/852_1128592804_r14.jpg)
Calculation to check if the twist is there at 200 mph EAS (roughly):
Rigid wing and linkage: 22deg x 6(deg/s)/deg = 132 deg/s
Elastic wing and linkage: 20deg x 5(deg/s)/deg = 100deg/s
Originally posted by Knegel
You call the SptVa curve strange(actually same like the testers and they gave a clarification), but you dont find the Spit(normal wing) curve strange.
So one time you believe the testers, the other time not.
I wonder what do you mean? The roll rate curve is indeed strange but I have no problem to believe if it is about correct for this particular plane at given condition. And the RAE curve might look strange due to rough nature of presentation but there is 100% certainty that the curve contains the twist as well as elasticity of the linkage.
Originally posted by Knegel
My current conclusion is...
Feel free to conclude what ever you want, but note that most of last 50 messages in this thread are caused by your misunderstandings.
Originally posted by Knegel
Iam unsure what exact is Kb2, is it PB/2V??
pb/2V is helix angle of the roll ie angle of the wing tip motion during the roll.
-Kb2 (or Kb2 with negative values) is aileron response factor ie relation between stick force and aileron angle.
If you are interested, following RAE report describe it:
"Handling Tests on the Curtiss H-75, and Comparative Aileron Tests on the Curtiss H-75, Spitfire and Gloster F.5/34" RAE report No, B.A. 1583.
Originally posted by Knegel
Not exact sience?? If someone wanna comapare something it have to be exact, specialy if 0,5° different aleron variation result in 5,5° roll speed different.
There is no need to be exact, 5 deg differences in the roll rate are neglible and given the amount of data, the error is probably less than 5 deg.
Originally posted by Knegel
I dont whine, sounds more like you do, so if u have to offer something start the new theatre. :)
Why don't you just go and read the RAE report on Bf 109E before you claim something about it.
Originally posted by Charge
BTW your picture is symmetrical, so the ailerons have the same movement both ways. It should have either a non centered axle, or one of the wire attachment point should be closer to the axle to give it a non-symmetrical movement.
It gives differential motion:
(http://www.onpoi.net/ah/pics/users/852_1129230823_r21.jpg)
In the old days before the computer radios this was the linkage we used to use to get differential aileron motion in the RC-planes.
Originally posted by hitec
Gripen: I had considered that, but decided it's effect would be a very small and the leverage change wasn't worth trying to describe.
In the middle positions the strech has a very little effect but in extreme positions even a small strech or loosenes can cause large differences in motion and also changes in leverage.
Originally posted by hitec
Btw: The streatch could also make the leverage go up. Depending on where the 90 deg lever arm point was.
Yep, I've said that in my reply to Niklas few days ago; it depends on geometry of the linkage.
gripen
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amount of wing twist was measured for all tested planes and these roll rate curves can be found also from NACA 86
Actual Roll Performance was measured in RAE 1231. Twist was calculated by comparing measured results with a theoretical rigid wing.
All the best,
Crumpp
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"It gives differential motion:"
I don't get it. If you move it to the other direction the movement looks the same?
-C+
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Originally posted by Crumpp
Actual Roll Performance was measured in RAE 1231. Twist was calculated by comparing measured results with a theoretical rigid wing.
Yep, my mistake, wrong wording.
Originally posted by Charge
I don't get it. If you move it to the other direction the movement looks the same?
Think cables as pushrods going directly to the ailerons. Due to round movement of the linkage, the pushrod going towards ailerons has shorter directional movement than the pushrod going outwards.
gripen
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Originally posted by gripen
Actually I'm talking about that with others. It should be noted that we have at least anecdotal evidence on condition of the airframe from Stanford Tuck:
"It happened that Wright Field had the only Spitfire in America-a Mark V. Unfortunately almost every pilot in the Air Corps had had a go on her and like a car that had too many drivers, she was the worse for wear...'She was very tired, very sloppy-she'd had the guts caned out of her all right."
This count mainly for the wingtwist, but the cables for the linkage can get adjusted, they dont get more soft cause they are old. If a real lose linkage would have caused this incredible different, they would have had 5° or more 'deadzone' for the stick, but thats of course BS. And again, a lose linkage cause a increased speed of max stick deflection, not a decreased.
Originally posted by gripen
I have allready told you that:
NACA comparison (http://mitglied.lycos.de/luftwaffe1/aircraft/usaaf/rollrate.pdf) is comparison made by NACA and the tested planes were the P-36, P-40, Hurricane and Spitfire. The tested Spitfire was same as used for flying qualities tests and no wing twist was errorneously claimed for this plane by NACA in the report on flying qualities.
RAE fighter aileron comparison (RAE 1231 and other reports) is an aileron comparison made by RAE and amount of wing twist was measured for all tested planes and these roll rate curves can be found also from NACA 868.
I was talking about the NACA comparison, which include the FW190.
Originally posted by gripen
That is because the chart is rough and wing bends quite steadily when the speed increases:
(http://www.onpoi.net/ah/pics/users/852_1128592804_r14.jpg)
Calculation to check if the twist is there at 200 mph EAS (roughly):
Rigid wing and linkage: 22deg x 6(deg/s)/deg = 132 deg/s
Elastic wing and linkage: 20deg x 5(deg/s)/deg = 100deg/s
How do you know the aleron deflection??
We also could calculate this:
Rigid wing and linkage: 18deg x 6(deg/s)/deg = 108 deg/s
Elastic wing and linkage: 16deg x 5(deg/s)/deg = 80deg/s
Originally posted by gripen
I wonder what do you mean? The roll rate curve is indeed strange but I have no problem to believe if it is about correct for this particular plane at given condition. And the RAE curve might look strange due to rough nature of presentation but there is 100% certainty that the curve contains the twist as well as elasticity of the linkage.
But you have problems to believe it was normal.
Originally posted by gripen
pb/2V is helix angle of the roll ie angle of the wing tip motion during the roll.
-Kb2 (or Kb2 with negative values) is aileron response factor ie relation between stick force and aileron angle.
If you are interested, following RAE report describe it:
"Handling Tests on the Curtiss H-75, and Comparative Aileron Tests on the Curtiss H-75, Spitfire and Gloster F.5/34" RAE report No, B.A. 1583.
gripen
Aha, thanks for the clarification. But you realy think they was able to get credible results out of TWO measured points with a bit high alerondeflection, while we see how bad the mesurements fit to the linear curve?? Calculations to even more alerondeflections they only can make if they have a worthy number of measured points for at least three different aleron delfections. But they only have one aleron deflection with many measured points. The linear increasement stay a assumption without base.
Originally posted by gripen
There is no need to be exact, 5 deg differences in the roll rate are neglible and given the amount of data, the error is probably less than 5 deg.
5° with the not used 0,5° different aleron delfection between 200 and 400mph, based on the few measered points! If it was 1° with 17° aleron deflection at 257mph, the different would be already 10°/sec.
Originally posted by gripen
Why don't you just go and read the RAE report on Bf 109E before you claim something about it.
Probably its made in best position for the Spit, and in badest position for the 109, like most of the tests, made with that 109E, to show how bad the 109 was.
I only know this often offered results.
Minimum radius of turn without loss of height......... ft. 696(Spit) 885(E3)
Cooresponding time to turn through 360 deg........ sec. 19(Spit) 25(E3)
But anyway, i dont think it make much sence to look to the british turn tests of this 109E3, the french tests with this planes show particular big differents, what show that the engine was under bad conditions, but with a bad engine the turntime would also decrease much(same like the climb).
Originally posted by gripen
In the old days before the computer radios this was the linkage we used to use to get differential aileron motion in the RC-planes.
Still the same if only one servo get used.
Originally posted by gripen
Yep, I've said that in my reply to Niklas few days ago; it depends on geometry of the linkage.
gripen [/B]
This could explain the relative good results at highspeed, but not the extreme low speed of max stick delfection! A lose linkage would let increase the speed of max stickdeflection!
Niklas,
the Spit5a rollcurve show a speed of max stick deflection only up to 130-140MPH, above this speed the stick deflection isnt constant!! Therfor the curve can have many different results, depending to the leverage and aleronbehaviour(the increasing rollratio with constant stickforce is not common).
The Spit roll curve, where i cant understand a linear increasement, have a speed of max stick deflection of 200mph! So the stick position was constant. To show a linear roll increasement with a constant stickposition, the linkage and wing must have been rigid.
Even at the highest point, where the stick forces and aleron forces are most big, there is nothing to see(even the FW190 show this, due to wingtwist).
If you insert the roll curve into the NACA comparision(with FW190), you will see that the SpitVa curve inst linear too in that relationI did this some days before, unfortunately with the more slow, right roll).
Greetings, Knegel
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Originally posted by Charge
"It gives differential motion:"
I don't get it. If you move it to the other direction the movement looks the same?
-C+
Hi,
maybe this help:
(http://www.raf-roy.com/share/knegel/Screenes/852_1129230823_r21.jpeg )
Greetings, Knegel
-
Originally posted by Knegel
This count mainly for the wingtwist, but the cables for the linkage can get adjusted, they dont get more soft cause they are old.
Is there evidence that the linkage was adjusted properly? Apparently not based on Tuck's writings.
Originally posted by Knegel
I was talking about the NACA comparison, which include the FW190.
The NACA 868 is a summary on lateral control research and the values for the Fw 190 (and Spitfires, Mustang and Typhoon) in there come from RAE fighter aileron comparison. I have told (http://www.hitechcreations.com/forums/showthread.php?s=&postid=1820189#post1820189) you allready this once; only NACA tested comparison claimed here is this (http://mitglied.lycos.de/luftwaffe1/aircraft/usaaf/rollrate.pdf).
Originally posted by Knegel
How do you know the aleron deflection??
That's easy, I just check the values from the report:
(http://www.onpoi.net/ah/pics/users/852_1129281061_r22.jpg)
The mean aileron deflection is then (25+19)/2 = 22 deg assuming rigid linkage. Note that there is some variation on values, as an example NACA aileron comparison (P-36, P-40, Spitfire and Hurricane) gives 26,5 deg up an 21 down but that's within +-2 deg tolerances and the measurement system might had been different than used by the Brits. Another RAE report gives 24 up and 20 down, again within tolerances.
The report gives elasticity of the linkage with increasing stick force:
(http://www.onpoi.net/ah/pics/users/852_1128936283_r17.jpg)
With 50 lbs stick force the mean aileron deflection decreased 2 deg ie 22 deg - 2deg = 20 deg.
Originally posted by Knegel
But you have problems to believe it was normal.
Well, no other measured Spitfire shows similar roll rate curve. And it should be noted that at low deflections the curve seem to be normal, only at high deflections and high stick forces the curve shows strange shape. One explanation for this is cable stretch because in the differential aileron linkage the stretch shows up exactly there ie at high deflections and high stick forces.
And again it should be noted that there is evidence on condition of the plane.
Originally posted by Knegel
Aha, thanks for the clarification. But you realy think they was able to get credible results out of TWO measured points with a bit high alerondeflection, while we see how bad the mesurements fit to the linear curve??
Actually much higher hinge moments were measured at higher speeds and data gives no indication that a bit higher deflection would have resulted somehow different results. There is scatter but nothing indicates that the fitted linear lines are bad. If they have tested say 10 planes of same type, the differences between the planes would have been probably much larger than the error in this measurement.
Originally posted by Knegel
Probably its made in best position...
Read my lips: Get the report and start a new thread if you have something to say about it.
Originally posted by Knegel
This could explain the relative good results at highspeed, but not the extreme low speed of max stick delfection!
Actually the stretch in the linkage is fully valid for low speed results too because low load means low stretch. It's still speculation but it gives logical explanation for the strange results at high deflections and high stick forces.
gripen
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Originally posted by gripen
Is there evidence that the linkage was adjusted properly? Apparently not based on Tuck's writings.
Of course we have! Look to the Stickforce/alerondeflection and pb/2V curve, for ecxample. If there would be a real loose linkage, which cause 60mph different speed of max stick deflection, we could see that, cause this would cause a real deadzone and so the curves dont would start a zero.
A soft linkage cant cause this results, only a real loose linkage, but such a different would count as damaged! Only a wanted different leverage can explain this results.
Originally posted by gripen The NACA 868 is a summary on lateral control research and the values for the Fw 190 (and Spitfires, Mustang and Typhoon) in there come from RAE fighter aileron comparison. I have told (http://www.hitechcreations.com/forums/showthread.php?s=&postid=1820189#post1820189) you allready this once; only NACA tested comparison claimed here is this (http://mitglied.lycos.de/luftwaffe1/aircraft/usaaf/rollrate.pdf).
[/B]
Who care who realy made this tests, on the 50lb datasheat i can read NACA, and i was talking about this tests.
Originally posted by gripen That's easy, I just check the values from the report:
(http://www.onpoi.net/ah/pics/users/852_1129281061_r22.jpg)
The mean aileron deflection is then (25+19)/2 = 22 deg assuming rigid linkage. Note that there is some variation on values, as an example NACA aileron comparison (P-36, P-40, Spitfire and Hurricane) gives 26,5 deg up an 21 down but that's within +-2 deg tolerances and the measurement system might had been different than used by the Brits. Another RAE report gives 24 up and 20 down, again within tolerances.
The report gives elasticity of the linkage with increasing stick force:
(http://www.onpoi.net/ah/pics/users/852_1128936283_r17.jpg)
With 50 lbs stick force the mean aileron deflection decreased 2 deg ie 22 deg - 2deg = 20 deg.
[/B]
Aha, so there are more datas regarding the Spitfire in the 50lb comparison??
Originally posted by gripen
Well, no other measured Spitfire shows similar roll rate curve. And it should be noted that at low deflections the curve seem to be normal, only at high deflections and high stick forces the curve shows strange shape. One explanation for this is cable stretch because in the differential aileron linkage the stretch shows up exactly there ie at high deflections and high stick forces.
And again it should be noted that there is evidence on condition of the plane.
[/B]
The testers gave a clarification why the curve look that strange, later spits had a different leverage setup.
Originally posted by gripen
Actually much higher hinge moments were measured at higher speeds and data gives no indication that a bit higher deflection would have resulted somehow different results. There is scatter but nothing indicates that the fitted linear lines are bad. If they have tested say 10 planes of same type, the differences between the planes would have been probably much larger than the error in this measurement.
[/B]
Once you say they found at least 0,5° variation(aleron deflection) and then you say the linear lines are not bad??
If they would have tested 10 planes to compare them with others planes, all this 10 planes would show at least roundabout a 5°/sec to fast rollratio.
The complete picture would be wrong. 5° in relation to the peak value maybe isnt much, but this minus 5° would influece almost the complete curve. So specialy at high speeds it would show badly wrong results.
Originally posted by gripen
Read my lips: Get the report and start a new thread if you have something to say about it.
[/B]
Is it a free D/L?
Originally posted by gripen
Actually the stretch in the linkage is fully valid for low speed results too because low load means low stretch. It's still speculation but it gives logical explanation for the strange results at high deflections and high stick forces.
gripen [/B]
Wake up, 60mph smaler speed of max stickdeflection!! A loose or soft linkage only can result in a higher speed of max stickdeflection. To decrease this speed, the linkage must have got more solid, actually more short! A to short general leverage setup have the displayed curve as result, specialy if its a not linear leverage like your picture show. This explain why smal aleron deflections need unexpected smal stickforce in relation to high deflections, this also explain why the rollspeed increase with constant stickforce up to a special speed and why the speed of max aleron deflection was that slow.
The HurricaneII show very similar results, i guess the leverage of this planes was adjusted to give more constant good performence at all speeds, not only one high peak.
Why exact this curve happen, of course, can have many reasons, a loose or soft linkage cant have this extreme differents as result.
Greetings, Knegel
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Originally posted by Knegel
Of course we have! Look to the Stickforce/alerondeflection and pb/2V curve, for ecxample.
The charts show simply that at low speeds roll rate is about that what it should be. When the speed rise, the roll rate curve starts show unlogical shape ie the stick force decrease about 40% for given roll rate when the speed increases. Basicly the shape of the curve speaks about problems (stretch or something else) not about properly made mainteance.
Originally posted by Knegel
Who care who realy made this tests, on the 50lb datasheat i can read NACA, and i was talking about this tests.
No one understands you if it's unclear what test you mean.
Originally posted by Knegel
Aha, so there are more datas regarding the Spitfire in the 50lb comparison??
As has been told earlier, these come from RAE tests on Spitfire I, which have basicly same wing and same aileron movement.
Originally posted by Knegel
The testers gave a clarification why the curve look that strange, later spits had a different leverage setup.
The testers simply tell the results, the leverage change is your speculation.
Originally posted by Knegel
Once you say they found at least 0,5° variation(aleron deflection) and then you say the linear lines are not bad??
I have no idea what you are trying to argue.
Originally posted by Knegel
Wake up, 60mph smaler speed of max stickdeflection!!
I wonder if you have missed all written so far in this thread; I'm looking for sensible explanation and I can't find any sense from your writings.
I can see from the graphs that the problem existed only with combined high stick forces and large deflections. The stretch fits well here because it happens due to high stick forces and the differential linkage fits also well here because it explains the problems in high deflections.
gripen
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Hi,
so you use Spit1 datas, where the alerons was different and maybe the linkage too, to explain the 50lb curve?? Nothing to add here.
I dont know what you did learn, but a stretched linkage result in smaler aleron deflection, so far so good, but also in a higher speed of max stickdeflection. There is NO way that a strech can result into a decreased speed of max stickdeflection.
My assumption is same logical, like if conclude out of the weight and performence datas of the 109E and 109G, that the 109G must have had more thrust.
Thats not a speculation, thats basic knowlege of the physical law, in our case knowledge of the leverage law.
If there would be a unexpected high strech, specialy the differential linkage would keep the leverage relative high, therfor the speed of max stick deflection would increase even more, but the tests show a decreased speed of max stick deflection.
A to extreme differential linkage, where smal aleron deflection need very smal stickforces but high aleron deflection need much much more stickforces explain the testresults (5 times higher stick force to aquire full delfection than half deflection). This also explain the strange curve.
Greetings, Knegel
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Originally posted by Knegel
so you use Spit1 datas, where the alerons was different and maybe the linkage too, to explain the 50lb curve?? Nothing to add here.
The aileron movements and areas are the same. If there is a difference (increased rigidity or something), it would make Spitfire V roll relatively better.
Originally posted by Knegel
I dont know what you did learn, but a stretched linkage result in smaler aleron deflection, so far so good, but also in a higher speed of max stickdeflection. There is NO way that a strech can result into a decreased speed of max stickdeflection.
Actually it can if the control force is wasted to bend or stretch something inside linkage instead moving the ailerons. And the change of the relative movement of the ailerons can also change forces for given mean deflection.
Note that NACA did not actually record position of the ailerons during flight (only stick position) and they actually claim flexibility in the aileron control system.
Originally posted by Knegel
Thats not a speculation, thats basic knowlege of the physical law, in our case knowledge of the leverage law.
Actually assuming changed leverage (or geometry) is speculation because many other things can have same effect ie progressively increasing control force. There is evidence on poor condition of the plane but no direct evidence on changed geometry.
Note that NACA claim almost linear rise of the aileron effectiveness just like RAE measurements up to about 250 mph EAS
Originally posted by Knegel
A to extreme differential linkage, where smal aleron deflection need very smal stickforces but high aleron deflection need much much more stickforces explain the testresults (5 times higher stick force to aquire full delfection than half deflection). This also explain the strange curve.
Now you are mixing the aileron differential to the aileron expotential which are completely different things. If there had been purpose built expotential in the aileron circuit, also the effectiveness curve would have been expotential. But in reality it was linear.
gripen
-
Originally posted by Knegel
Niklas,
the Spit5a rollcurve show a speed of max stick deflection only up to 130-140MPH, above this speed the stick deflection isnt constant!
Knegel
I know. Isn´t it interesting that though a reduced stick deflection the rollrate still increases linar?
Well actually you can observe at 140mph in my chart a little spike, so tendency below that speed seems to be progressive with speed.
Maybe a reduced stick deflection has a strange effect for the spitfire: it produced less aileron forces, thus less tension/bending, maybe also less wing twist, after all the loss due to the reduced stick deflection is not proportional to the stick deflection.
Unfortunatly it is not said whether the deflection in the chart is aileron deflection or stick deflection (the text mention aileron deflection) and when it´s aileron deflection, whether aileron elasticity etc. is taken into consideration.
In any case this characteristic raises the question whether the peak in other aircraft curves is the 50lb limit or whether they reached also the force limit earlier
EDIT: Maybe the cause for the progressive tendency up to 140mph is the high AoA of the aircraft at low speeds. It seems to get more efficient when flying at a more flat AoA, what shouldn´t be a surprise. The Naca chart begins at 160mph, thus this progressive speed range is not visible. Maybe other aircraft would show the same characteristics. But below 160mph rollrate isn´t of great importance for dogfighting anyway. Furthermore the reduced stabillity of the whole machine at these low speeds probably don´t allow correct measurments without influence of slip etc.
EDIT2: Added RAF (naca868) curve to the table.
(http://de.geocities.com/stefan_l_01/fzg/spitvarolling_2.gif)
niklas
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Originally posted by niklas
Unfortunatly it is not said whether the deflection in the chart is aileron deflection or stick deflection (the text mention aileron deflection) and when it´s aileron deflection, whether aileron elasticity etc. is taken into consideration.
The NACA report on Spitfire V explains the the issue quite directly in the page 4:
"The instrument recording the angular position of the three control surfaces was attached to the control linkages near the cockpit. Tests made on the ground showed that errors in the recorded angles due to stretch in the control system were small enough to be negligible in the case of the elevator and rudder controls. A slight amount of flexibility was noticeable in the aileron system but, inasmuch as no simple means was avalable for determining the error introduced, no correction was applied to the recorded aileron angles."
The RAE comparison claims device named "rat" used for recording aileron angles. Probably the same device is described in the Spitfire I report:
"A standard RAE control movement recorded was used to measure the aileron displacement. It was fitted in the wing and connected to the aileron control system at the aileron end, thus making correction for the cable stretch unnecessary."
In addition tested plane was fitted with camera for "continuous photographic record of a well defined line painted chordwise on the wing at the mid aileron position". That data was used for determining wing twist.
Edit: The RAE report on P-51B describes yet another device:
"Aileron Angle A Desynn transmitting instrument was mounted on each wing and linked directly to the inboard end of each aileron respectively."
gripen
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ok, ok. i only read quickly over the test result phrase for my judgment... have better things to do currently instead of reading through x pages of outdated stuff...
niklas
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Well, the notable thing is that they claim "slight amount of flexibility" apparently with no particular load on aileron circuit. That supports Tuck's opinion on that plane.
gripen
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I´d say: This Spit example demonstrates very well the difference between a factory fresh, well prepared and adjusted, "best case" aircraft and a service condition aircraft.
Furthermore it shows very well how few importance a test of a single aircraft alone has. A single machine simply can not speak for a whole series!
So, coming back to AH, what is modelled: The "best case" spitfire rollrate and the worst case service condition fw-190 rollrate, because it is MENTIONED in the RAF test report that 2 other 190 had lighter ailerons what would result in a higher rollrate at med to high speeds. BAH!
Oh, in case of the 109, what about the influence of this single tested 109E, oh....
niklas
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Originally posted by niklas
I´d say: This Spit example demonstrates very well the difference between a factory fresh, well prepared and adjusted, "best case" aircraft and a service condition aircraft.
I'd say that the NACA tested Spitfire V was poorly maintained.
Originally posted by niklas
Furthermore it shows very well how few importance a test of a single aircraft alone has. A single machine simply can not speak for a whole series!
RAAF tested Spitfire V did roughly same or better than RAE tested with normal wing.
Originally posted by niklas
So, coming back to AH, what is modelled: The "best case" spitfire rollrate and the worst case service condition fw-190 rollrate, because it is MENTIONED in the RAF test report that 2 other 190 had lighter ailerons what would result in a higher rollrate at med to high speeds. BAH!
The results RAE measured with that tested plane (PE882) were still very good and it ailerons might have been within normal variation.
gripen
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The results RAE measured with that tested plane (PE882) were still very good and it ailerons might have been within normal variation.
Gripen,
The deflection was within normal variation. However the ailerons were out of adjustment. We can cross reference the Fiesler Force Gauge limits as stated in the regulations with the forces, altitude and airspeed given in RAE 1231. These will shows that RAE 1231's FW190A4 exhibited forces that were out of the range limits. They were close but still out of specification. The Luftwaffe manual gives a clear range, accounting for the natural variation of Frise type ailerons. The RAE chalked up the difference in feel between the FW190's as this natural variation. It was a mistake.
If the FW190 tested by the RAE had been in front of a Luftwaffe maintenance crew, and they were shown the data, work would have started adjusting the ailerons.
It adjusts the amount of gap between the aileron/wing and how much of the Frise horn is in the slipstream.
Not surprising as the Luftwaffe had difficulty maintaining adjustment. It is rather silly to expect a foreign service unfamiliar with the design to be able to do it.
All the best,
Crumpp
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Originally posted by Crumpp
The deflection was within normal variation. As stated before, simply look in the aileron adjustment regulations and you can see RAE 1231 represents an FW 190 with out of adjustment ailerons. Adjustment had nothing to do with aileron deflection. It adjust's the amount of gap between the aileron/wing and how much of the Frise horn is in the slipstream.
Hm... I did not mean deflection (which is within tolerances) but stick force and for stick forces I don't know any reference value to compare with. AFAIK it's not known which ailerons (of at least three types you listed) the tested plane had.
gripen
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Hm... I did not mean deflection (which is within tolerances) but stick force and for stick forces I don't know any reference value to compare with. AFAIK it's not known which ailerons (of at least three types you listed) the tested plane had.
The regulations are the same for all three as are the force tolerances.
Get a copy of the regulations, they are listed there.
They have been posted in several threads.
All the best,
Crumpp
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Hm... I have no idea what regulations you are talking about. Could you simply list what should have been the aileron deflection at given speed and stick force (or what ever yard stick they used for regulations)?
gripen
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The range is 10-14kg at 8 degrees of aileron deflection with a speed of 400mph at 10,000 feet. The forces exhibited must be with 1 Kg for each aileron.
At that speed with properly adjusted ailerons a reduction of forces in the first centimeter of travel is normal but cannot be less than 1Kg. Otherwise the pilot will experience trouble holding the ailerons steady and may experience a knocking of the stick.
All the best,
Crumpp
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is that 400mph IAS or TAS?
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It is IAS.
All the best,
Crumpp
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Originally posted by Crumpp
The range is 10-14kg at 8 degrees of aileron deflection with a speed of 400mph at 10,000 feet. The forces exhibited must be with 1 Kg for each aileron.
Found the source for this from the Fw 190 A-5/A-6 manual (part 3):
"Bei Va = 650km/h in 3000 m Höhe: 10 bis 14 kg Handkraft bei 2 cm Knüppelweg."
The full deflection of the stick to each side appear to be 17 deg (34 deg total movement) according to Fw 190D manual (supposing the movement being the same for the Fw 190A) and the lenght of the stick is about to 50 cm so full movement is about 15cm to each side. So 2 cm movement of the stick means about 2,3 deg aileron deflection.
The RAE tested values are give about 30 lbs at 400 mph IAS for this deflection and the fitted line seem to give about 20 lbs so the RAE measurements seem to be very close normal values for the Fw 190.
gripen