Aces High Bulletin Board
General Forums => Aircraft and Vehicles => Topic started by: artik on December 13, 2003, 07:10:03 AM
-
Anybody has tables of wingload for AH planes?
Stall speeds?
Coner speeds?
We have exccelent graphs for Climb and Speed however I'd like also to have also information about wingload, stall/coner speed.
-
Hello there Artik
I have not seen this summed up in one particular but I'll give you a link with very good general information about most ww2 aircraft.
You should be able to figure it out from there. Of course wing loading varies with weight, so it's best to use empty weight as a comparative figure, - unless you can get typical operational weight (fighters fully armed and fuelled without ordnance for example). It's really a nice thing to put into Excel. then you can put max and min numbers and have it graphed out for instance.
As far as I know, the figures on these pages are correct, save possibly some climb numbers (maybe those are not using the same source so there is an error in the weight). But empty weight, full weight and wing area should be right.
Here is the link, best of luck:
http://www.xs4all.nl/~fbonne/warbirds/ww2indexpages.html
-
The important thing is liftloading. Only wingloading don't tell you much.
You can calculate liftloading by dividing wingloading with maximum lift coefficient; LL = Weight/(Wingarea*Max_Lift_Coeff.
Here are some numbers (although I cannot guarantee their validity since they are from a second hand source):
Aircraft / Weight [lb] / Aspect Ratio / Max. Lift Coefficient / Wing area [ft^2] / Liftloading [lb/ft^2]
Spit I / 6050 / 5.62 / 1.12 / 242 / 22.3
109E4 / 5600 / 6.0 / 1.48 / 174 / 21.7
P-51B / 9400 / 5.815 / 1.28 / 234 / 31.4
Spit9 / 7450 / 5.62 / 1.12 / 242 / 27.5
109G6 / 7159 / 6.0 / 1.48 / 171 / 28.3
-
Gsholz,
How are you calculating Cl max?
-
I have no idea. :confused:
-
Don't really how CL is found out. However, the CL formula sometimes collides with actual data.
Maybe an imperfect formula?
-
Huh? What do you mean?
-
I think what he means is that sometimes those "calculations" don't match real life.
For instance, the 109E having lower "Liftloading" (which I've never heard of) than the Spit I indicates what? That it should turn better?
-
Hi Urchin,
>For instance, the 109E having lower "Liftloading" (which I've never heard of) than the Spit I indicates what? That it should turn better?
Well, the Me 109E certainly should compare more favourably to the Spitfire I by lift loading than by wing loading because the Spitfire reaches a relatively low maximum lift coefficient only while the Me 109E reaches a comparatively high one thanks to the slats it uses.
(I'm not sure the quoted figures are correct, though - I thought the Spitfire got to around 1.22, for example.)
In any case, the immediate impact of lift loading only concerns instantaneous turn rate. Sustained turn rate is determined by the balance between power and drag.
On the other hand, wing loading has no immediate impact at all and can only be used to compare aircraft with identical wings :-)
Regards,
Henning (HoHun)
-
Gsholz,
The clmax thing is funny. The P-51 cl max you have is from a NACA report where it has no prop installed on the airplane. This always shows a much lower Clmax than real life because even when an airplane is flying with power off the prop is windmilling or idle this raises Clmax. Most flight manuals list stall speeds with power on/off clean condition and power off/on in landing condition which usually includes flaps. Also this is always for a specific weight.
The equation for Clmax is one of the easiest to learn because you don't need much data.
Weight * 391 / velocity^2 * wing area
When this is calculated it uses TAS for the stall speed/volocity and the 391 accounts for air density at sea level.
American A/C and British A/C are super easy because they all list stall speeds at specific weights in all conditions. European A/C are more challenging.
The F4U-1D stall clean idle power at 11,300LBS is 96.6MPH.
So
11,300* 391= 4418300 / 96.6^2 * 314= 2930110
4418300 / 2930110
Clmax= 1.5
If you check the same NACA report the P-51 Clmax came from the F4U's Clmax is even lower than the P-51 at 1.17.
If you find stall data for the 109 the numbers are easy to plug in and calculate.
-
Hi F4UDOA,
>The clmax thing is funny. The P-51 cl max you have is from a NACA report where it has no prop installed on the airplane.
If you're using lift loading as an indicator for manoeuvrability, then this might actually be the most appropriate value to use as the slipstream effect diminishes with speed. The problem is that it can only be found for a few aircraft types, which has an impact on comparability.
Here's some data from the graphical Me 109E vs. Spitfire comparison that has repeatedly been posted on several boards:
Spitfire (6000 lbs, 1050 HP @ 3000 rpm = 6.5 lbs/sqin, w = 24.8 lbs/sqft)
vs.
Me 109 (5600 lbs, 1200 HP @ 2400 rpm @ 12000 ft, w = 32.2 lbs/sqft)
Clmax table ("Assumed value of Clmax at full throttle"):
Gs Spitfire Me 109
1.0 1.87 1.95
1.5 1.65 1.70
2.0 1.52 1.60
2.5 1.47 1.52
3.0 1.45 1.49
4.0 1.43 1.47
5.0 1.42 1.45
6.0 1.38 1.44
You can see the effect of propeller slipstream dropping off with increased Gs, which of course coincedes with increased speed.
Regards,
Henning (HoHun)
-
Hi again,
>Clmax table ("Assumed value of Clmax at full throttle"):
I've just re-read NACA report "Stalling Characteristics of the Supermarine Spitfire VA Airplane":
"The maximum lift coefficient reached in turns from level flight with flaps up was 1.22."
(From the graphs, I'd say the turns for this test were done at around 3 G.)
Maximum lift coefficients from the report (gun ports covered/open):
Flaps up, gear up, throttle closed: 1.12/1.15
Flaps up, gear up, 3 3/4 lbs/sq in, 2650 rpm: 1.63/1.58
So judging from these tests, it seems that the Clmax assumptions for the Spitfire I posted above are a bit too high actually.
From van Ishoven's "Me 109", there are figures for the Me 109 (at 5580 lbs) that indicate a 1 G Clmax of 1.38 with slats open, flaps up (unfortunately, no throttle setting is given) and a Clmax of 1.92 slats open, flaps down. The source of his figures is not entirely clear though - as everything is in Imperial units, I'd say it must be RAE tests.
The figures are highly interesting in showing a 20 mph mismatch between indicated and calibrated air speed at high angle of attack. While the stall speed actually was 95.5 mph, the airspeed indicator showed just 75 mph. This effect makes it difficult to get accurate Clmax data from manual figures.
Regards,
Henning (HoHun)
-
I told you guys in my first post that my numers (not really mine) are NOT reliable. However my argument still stands that "liftloading" is more telling than "wingloading" to determine which AC turned better (which I think was the purpose of this thread). The formula should be good as long as you have good numbers to use in it.
-
Gsholz,
I know that data can be hard to come by. I do have a document that shows the 109J and the "V lande" to be 150KM at 3,000KG. I believe that is 93MPH at 6,613LBS giving a Clmax of 1.38. I don't know if this is power on or not or even if flaps are being used.
I will post the doc when I upload it to my webpage.
-
IMHO Clmax for 1g, liftloading for 1g and wingloading are all about as relevant (or useless) for turning performance comparisons. Generally instantaneous and sustained g loading during maneuvering is much more than 1 g; a plane can't turn at 1g stall speed. More relevant comparison might be clmax for say 3 g or complete v/g flight envelope based on real world tests just like RAE did with Spitfire I and Bf 109E.
gripen
-
Hi Gripen,
>More relevant comparison might be clmax for say 3 g or complete v/g flight envelope based on real world tests just like RAE did with Spitfire I and Bf 109E.
I guess you're referring to the same graph I was quoting the Clmax figures from? If you have any background information on it, it would be appreciated.
Regards,
Henning (HoHun)
-
HoHun,
I have the whole RAE report (RM No. 2361). Actually this is a version published by the Aeronatical Council after war; well printed and clean if compared to original (available from British library as well as many technical universities have this series). The flight envelope of the Spitfire is based fully on flight tests. In the case of the Bf 109 the flight envelope is partially calculated (stall speeds are tested). Stall tests of the Bf 109 gives Cl 1,4 with slots power off, slots came out at Cl 0,865 (these are tested values). Power on clean 1g Clmax is calculated as 1,95 (I quess you have same graph). The Plane tested was AE479 (captured in France), DG200 was captured after release of this report.
gripen
-
weight of an early, non mw50 G6 is 6922lbs (3140kg)
and not 7150lbs
wastel
-
Hi Gripen,
>I have the whole RAE report (RM No. 2361).
Do you happen to have it in electronic form? I'd just love to have a look at that report :-)
>The flight envelope of the Spitfire is based fully on flight tests.
That's interesting as it gives different Clmax values than the NACA report. (The impact of that difference is not as big as one would imagine since lift increases with velocity squared).
>Stall tests of the Bf 109 gives Cl 1,4 with slots power off, slots came out at Cl 0,865 (these are tested values). Power on clean 1g Clmax is calculated as 1,95 (I quess you have same graph).
I've got the graphs, and van Ishoven indeed quotes the same 1.4, which is rounded from the 1.38 I calculated from the test figures.
The 1 g clean Clmax would include extended slats, wouldn't it?
It seems NACA report "Calculated and Measured Turning Performance of a Navy F2A-3 Airplane as Affected by the Use of Flaps" applies the same method to the Brewster Buffalo.
Here's a comparison:
F2A-3 no flaps 13000 ft 900 HP: 25 s/360°
Spitfire (RAE test) 12000 ft: 19 s/360°
Me 109 (RAE test) 12000 ft: 25.5 s/360°
I was confused about which variant of Spitfire the RAE used for comparison, so I superimposed the "angle of climb" curve of Spitfire N.3171, a Mk.I with a Merlin III running at 6 1/4 lbs/sqin to the RAE graph:
Spitfire N.3171: 21.5 s/360°
(Weight of N.3171 was 6050 lbs, so I assume it didn't have pilot armour installed.)
Is it correct that Spitfire IA K.9791 was used by the RAE for the comparison? I'm not sure why it performs so much better than N.3171.
I don't think the Me 109E really had 1200 HP available, by the way. I wonder if that affected the calculations?
Regards,
Henning (HoHun)
-
CL is a figure for a certain square right?
So to produce total lift it is a function involving both CL and Wing area?
-
Yes, CL is a function that describes how efficient the wing is at producing lift not linked to wing area. A huge wing with low CL will still produce more lift than a tiny wing with high CL.
-
Hi Angus,
>So to produce total lift it is a function involving both CL and Wing area?
To be exact, total lift is proportional to the product of lift coefficient and wing area.
Lmax = Clmax * 1/2 * rho * v^2 * A
Lmax = maximum lift
Clmax = maximum lift coefficient
rho = air density
v = true air speed
A = wing area
Regards,
Henning (HoHun)
-
HoHun,
I just have paper copies from BL.
Naca did not test Spitfire at similar power settings as RAE (not just MAP but also rpm) and tested model is also different (a bit heavier). Otherwise I don't see much difference between Clmax values on NACA and RAE tests (clean power on values). IMHO they support each other very well given the differences on power settings (this is true also on aileron tests of Spitfire). Overall RAE and NACA tested planes with very similar methods and there were really lot of know how transit between these organisations (NACA F2A report actually claims RAE references and same references are also claimed in RAE Bf 109 report). In fact methods used by DVL appear to be also suprisingly similar.
RAE Clmax values of Bf 109 are with slats open but as noted they also measured at which speed (or Cl value) they came out.
I don't know which particular Spitfire was used for turn tests, report just claims that Stall boundary has been measured in flight. Which power setting was used on Spitfire N.3171?
gripen
-
You are great. Much information around much quicker than reading through piles of books.
The (lift) induced drag will then presumably always touch the subject of lift, right? The more total lift, the more lift-induced drag?
Really, lift induced drag is there as a function of TOTAL lift isn't it?
Just wondering..again....about something particular,,,will explain later
-
Hi Gripen,
>Naca did not test Spitfire at similar power settings as RAE (not just MAP but also rpm) and tested model is also different (a bit heavier).
Actually, aircraft weight doesn't influence Clmax as this is characteristic for the wing.
And in a turn, the difference between cruise and combat power would be hardly noticable:
"This value of maximum lift coefficient is closer to that reached from stalls in straight flight with power off than the value reached with power on because the slipstream effects in high-speed turns are relatively small."
(From the NACA report.)
>Which power setting was used on Spitfire N.3171?
6.25 lbs/sqin, compared to 6.5 lbs/sqin for the Spitfire on the graph.
Regards,
Henning (HoHun)
-
I dont really understand these............
wind tunnel tests with la7 at various AoA..the photos dont show a prop.............
(http://www.tilt.clara.net/pics/la7cl.gif)
Does this show a Cl of approx 1.4?
I have other similar graphs showing various straight line functions and one other inverse curved line graph.
-
Hi Tilt,
>wind tunnel tests with la7 at various AoA..the photos dont show a prop.............
Great scan! I wish we had data like that on any other plane! :-)
The pair of "rounded" lines show lift polars in the standard way (Cl vs. Cd, upper scale on horizontal axis).
The pair of "straight" lines show Cl vs. AoA (lower scale on horizontal axis).
I don't immediately recognize the two short parabolic graphs, though.
What does the Russian text say? :-)
Regards,
Henning (HoHun)
-
HoHun,
You are correct that weight does not affect Clmax but NACA tested Spitfire V and RAE tested Spitfire I.
Only comparable Clmax values in RAE and NACA tests are 1 g power on values ie not high speed turning. NACA claims Clmax 1,63 and 1,68 on 3,75lbs/2650rpm and 1,64 on 7lbs/2850rpm. RAE claims Clmax 1,87 on 6,5lbs/3000rpm. I don't know what is the real difference between engine output because engine models are different (Merlin III had lower SC gear ratio), I quess something like 100-150hp.
gripen
-
Looks like induced drag?
HiTech
-
The ac in question is the one and only La7 TK. which is a std La7 with 3rd stage super charger added.
I have 12 pages of text full of formulae I dont understand in Russian to accompany several pages of photographs and graphs similar to the one above. (graphs are straight [horizontal] line graphs referings to Cx and V and a negative sloped graph refering to m2 and angle)
The pictures show three shots for each AoA each with the exhaust vents at different apertures.
I believe this work was done on the 9/IX/44.
If its considered important I will scan and zip it to a site where it can be accessed.
Edit.
I assume the pairs of lines are with and without slats extended. (CL only really changes between them at higher AoA)..........
The Russian text idnetifies it propoerly on the graph if someone can translate.......
Could the other short curve be with flaps fully lowered?
-
Originally posted by gripen
I have the whole RAE report (RM No. 2361). Actually this is a version published by the Aeronatical Council after war; well printed and clean if compared to original (available from British library as well as many technical universities have this series).
gripen
Hi Gripen,
I'd like to try and get a copy of that report, can you give a full reference for it, and perhaps the details of the library that has a copy?
Thanks...
Badboy
PS HoHun, if I get a copy I'll be happy to duplicate it and snail mail to you.
-
Badboy,
My copy is ordered from the British Library (http://www.bl.uk/). They have a public catalogue (http://blpc.bl.uk/) there search for "Messerschmitt Handling" under category Reference Material only. You will get one result. After that follow the document order link in the BLPC main page and choose non registered customer. Then just fill the order form (you need a credit card). And that's it.
gripen
-
Originally posted by gripen
Badboy,
My copy is ordered from the British Library (http://www.bl.uk/). They have a public catalogue (http://blpc.bl.uk/) there search for "Messerschmitt Handling" under category Reference Material only. You will get one result. After that follow the document order link in the BLPC main page and choose non registered customer. Then just fill the order form (you need a credit card). And that's it.
gripen
Thanks, I managed to phone them just before they closed today and placed my order. Does that report only discuss the 109, or is the Spitfire covered also? I’d like to get the same info for the Spitfire, is that in a different document?
Did you find any similarly interesting documents there?
Thanks again…
Badboy
-
Guys,
On a similar note, since finding the different style of EM diagram sometimes seen in reports dated that far back, like the ones at this location:
http://www.fourthfightergroup.com/eagles/spit109turn.gif
I decided to reproduce the same type of analysis they have used and piggy back it onto the work I've already done for the Aces High aircraft. Now when I produce an EM analysis for any aircraft, I automatically get both types of diagram. There are advantages and disadvantages to both methods. The diagrams I've been producing were not conceived until the 1960s and they have the advantage that they can be overlaid with one another for a far easier comparison. The disadvantage with the type of EM diagram that originated in the late 30s is that they can't be overlaid. So for example, here is an overlay of the AH Spitfire MkI and the Me109e
(http://www.badz.pwp.blueyonder.co.uk/Files/Images/Spit1c.jpg)
The main advantage to producing the type of EM diagrams seen in those early reports is that they can be compared with the ones that exist for the real aircraft. For example, the Spitfire in the diagram above has this diagram:
(http://www.badz.pwp.blueyonder.co.uk/Files/Images/Spit1b.jpg)
But let's compare that with the diagram for the real Spitfire MkI.
(http://www.badz.pwp.blueyonder.co.uk/Files/Images/Spit1a.jpg)
Here we can see that both the real Spitfire and the AH Spitfire have the same corner velocity at that altitude and configuration, so let's compare a turn. Just for example I've selected a 5g turn at the corner speed of 250mph. I've indicated on the diagram for the real Spitfire that it would need to descend at 16 degrees below the horizon to sustain that turn and it would turn a full circle in about 14.5 seconds with a radius of about 850ft. You can see from the diagram for the AH Spitfire that it would also make the same turn in about 14.5 seconds with a radius of 850ft, and that it would need to descend at an angle of 23 degrees below the horizon, a descending turn only 6 degrees steeper than the real aircraft. But the turn rates and radii for the turn, along with the corner speed are amazingly close. The difference in the angle of descent is probably due to differences in engine power available at that altitude between the real world tests and Aces High, and perhaps some differences in weight.
It is interesting that both diagrams are essentially the same shape, and that they agree quite closely in many respects, indicating that the flight model in Aces High has accounted for all of the aerodynamic factors that would influence the shape of the curves to any significant degree. A worthy achievement indeed. Kudos to HTC.
This is even more significant, because I've made a similar comparison with the Spitfire and 109e from other simulations, and so far Aces High has first place for accuracy. I'm just thinking of writing up the whole comparison for an article on SimHQ.
Merry Christmas guys...
Badboy
-
Very NICE :) :) :) :) :)
Emm, now as wingloading will change according to A of A and Pitch as well, does anyone happen to have the easy formula for calculating that?
-
Hi Angus,
>Emm, now as wingloading will change according to A of A and Pitch as well, does anyone happen to have the easy formula for calculating that?
L = Cl (alpha) * 1/2 * rho * v^2 * A
L = lift
Cl (alpha) = lift coefficient as a function of angle of attack
rho = air density
v = true air speed
A = wing area
Cl (alpha) is an aircraft-specific function like the one Tilt posted for the La-7. It's based on a wing-section specific function, but application of a 2D wing section to a 3D aircraft inevitably modifies the lift coefficient function.
Regards,
Henning (HoHun)
-
Hi Badboy,
>The difference in the angle of descent is probably due to differences in engine power available at that altitude between the real world tests and Aces High, and perhaps some differences in weight.
Nice to see such accurate results! If I compare Spitfire Mk I N.3171 to the RAE test Spitfire, I'd say it had 100 HP less, which would slightly reduce the gap.
Note that the Aces High Spitfire's top speed is below that of the RAE test Spitfire, matching that of N.3171 almost exactly.
The Aces High Spitfire seems to have a sustained turn of 21 s/360°, which matches my estimate of 21.5 s/360° for N.3171 nicely.
The only area of difference seems to be the stall speed, which is well below 100 mph TAS for the RAE Spitfire but slightly above for its Aces High pendant.
Regards,
Henning (HoHun)
-
Badboy,
The RAE Bf 109 report contains above mentioned graph for Spitfire and some numerical values on charts. In addition there is discussion about mock combats and ailerons. You can find another RAE report on Spitfire by searching for "Spitfire Turning". Aeronautical Research Council published large amount of RAE reports and there is quite a lot interesting stuff. There is more RAE reports in the PRO but these in the BL are much better edited and copying in the BL is much cheaper.
BTW from where is that Spitfire graph? It's (about) same as in the Bf 109 report but I can see it's from a NACA paper.
HoHun,
Which report on N.3171 you are refering? Only one I can find is a propeller comparison by A&AEE.
gripen
-
Hi Badboy,
>PS HoHun, if I get a copy I'll be happy to duplicate it and snail mail to you.
Thanks, that would be very kind! :-)
Regards,
Henning (HoHun)
-
Hi Gripen,
>Which report on N.3171 you are refering? Only one I can find is a propeller comparison by A&AEE.
That's the one. I used the data from:
http://www.fourthfightergroup.com/eagles/spit1.html
because it had a constant speed propeller and 8 Browning guns. I believe it doesn't have armour, but I'm not quite sure of that.
N.3171 was also used as reference for the RAE evaluation of the Spitfire IIA, so I assume it can be considered to be representative for the Spitfire I.
Regards,
Henning (HoHun)
-
Hmm
The Spitfire in your link has a 2 pitch metal airscrew, not the CS one. The weights of all of these tests also indicate full combat loading.
-
Hi Angus,
>The Spitfire in your link has a 2 pitch metal airscrew, not the CS one.
Scroll down a bit :-) On top of the page is K.9793 with the two pitch propeller, the third table is N.3171 with a constant speed Rotol one. You'll see that it gains 1000 fpm initial climb rate, at the expense of 10 mph top speed. (Obviously the two-pitch propeller was optimized for high speed flight.)
>The weights of all of these tests also indicate full combat loading.
Hm, does that mean N.3171 did have armour?
Regards,
Henning (HoHun)
-
Oooops...my mistake.
Indeed, the performance increases a lot with a CS airscrew!
The weight keeps going up, so I belive the armour must have been there. Standard outfit basically
-
Originally posted by gripen
BTW from where is that Spitfire graph? It's (about) same as in the Bf 109 report but I can see it's from a NACA paper.
gripen
Hi Gripen,
That graph came from the Fourth Fighter Group’s web site, from the same location as the other one, here it is:
http://www.fourthfightergroup.com/eagles/spit1turn.gif
I have been through the NACA reports available on their server and can’t find it in any of them. However, there are some reports that I can’t find at all. For example, the report titled: Study of Turning Performance of a Fighter-Type Airplane Particularly as Affected by Flaps and Increased Supercharging. By J.W. Wetmore in a NACA report dated June 1942, doesn’t appear to be on the server.
So perhaps others are missing also?
Badboy
-
Originally posted by HoHun
Scroll down a bit :-) On top of the page is K.9793 with the two pitch propeller, the third table is N.3171 with a constant speed Rotol one. You'll see that it gains 1000 fpm initial climb rate, at the expense of 10 mph top speed. (Obviously the two-pitch propeller was optimized for high speed flight.)
Henning (HoHun)
I think it is worth mentioning that although increasing the solidity of a propeller was a good way to increase its power absorption, and that generally lead to better low speed acceleration and climb rates, it was always at the expense of maximum efficiency due to interference effects between the blades. When ever you look at propeller charts for two, three and four blade propellers of the same type, you will notice that the maximum efficiency drops as the number of blades increases.
Badboy
-
I presume both airscrews were 3 bladed, so that would not be the problem. Anyway, the Rotol CS screw enhanced the climb rate drastically, although seemingly at the cost of a little top speed. I wonder what it did to acceleration though.
-
Originally posted by Angus
I presume both airscrews were 3 bladed, so that would not be the problem. Anyway, the Rotol CS screw enhanced the climb rate drastically, although seemingly at the cost of a little top speed. I wonder what it did to acceleration though.
Nope, I actually checked, lists of MkI serials indicate that during these trials, K.9793 was fitted with a two blade propeller, and N.3171 had a three blade constant speed propeller. So additional solidity was an important factor that partially accounted for the improved climb rate and acceleration and the slight loss in speed as explained in my previous post.
The increase in acceleration would have been as obvious to the pilot as the improved climb rate, and there is an account written by a WWII pilot who describes the effect of his new constant speed propeller during mock combat by saying that he felt the acceleration was double what it had been previously.
Naturally, that sort of anecdotal evidence only serves to demonstrate that it indeed had an impact on the pilot, perhaps he was exaggerating slightly to make his point, but since climb rate and acceleration are linked, it is certain that an increase in climb rate would have a corresponding effect on acceleration.
Hope that helps.
Badboy
-
Hi Angus,
>I wonder what it did to acceleration though.
To add to Badboy's comments, acceleration is linear to climb rate (at the same speed). Going at best climb speed, the Rotol Spitfire would have felt a dramatic improvement of acceleration.
Off course this became less noticable at increased speed, and finally the two-pitch propeller would give a better acceleration near top speed. The two-pitch Spitfire couldn't have been faster else :-)
Regards,
Henning (HoHun)
-
Just a little question:
Why would the top speed be more for a manual 2 pitch propeller with 3 blades then a CS propeller also with 3 blades? Was the CS propeller not able to go to as course a setting as the manual one?
Were the Germans also using similar technology, or were their prop controls very much different?
-
Badboy,
Earlier NASA database (CASI) contained much more NACA papers than current (NTRS), but even CASI database did not contain so called "NACA confidental bulletins" which appear to be very interesting part of the NACA papers. Hopefully they will scan this part of NACA papers in the future or at least ad them to database. AFAIK NACA made something like 40000 papers (reports, memorandums, bulletins etc...). Currently they have scanned something like 10000.
gripen
-
Great discussion going on here.
Tilt - if the shorter parabolic lines were for flaps fully lowered then they would probably be similar and above the other curves since CLmax typically increases with flap deployment.
gripen - yeah, that's a tough one regarding the NACA ACR's/ Wartime reports. From what I can tell there isn't much going on in that respect in getting them digitized. I've found a local source in Houston but it requires knowing which ACR/Wartime report you are looking for since most of the stuff is mainly in storage as bound books and there is no way to have them all hauled out for browsing. I have enquired the NASA CASI folks regarding a listing of the titles for all the ACR/Wartime reports so that I can start picking a few out but what they gave me in reply was no help whatsoever.
Tango, XO
412th FS Braunco Mustangs
-
Talking about digitalizing WW2 material, i.e. photos, films, and documents, there is indeed not very much going on.
I am not sure what it is all about. The IWM has a free admission to even the photo and film arcives, but individual documents/films/photos have to be bought/licenced if you want to take those home with you.
The PRO has so much, and yet not all. Very little is digitalized, althoug on both places inquiries can be placed and answered by email, and a rough internet inquiry will lead you towards your research matter.
Maybe lack of funds or something like that. I do not know. However, in the long run, it would be a lot cheaper to digitalize the whole bunch right away. As it is, it´s using exactly the same storage and search technology as in the 40's for that sake.
Oh, IWM=Imperial War Museum, UK, and PRO=Public record Office, UK.
Both great places to visit, mind you!
-
Originally posted by dtango
Great discussion going on here.
Tilt - if the shorter parabolic lines were for flaps fully lowered then they would probably be similar and above the other curves since CLmax typically increases with flap deployment.
Tango, XO
412th FS Braunco Mustangs
Of course your right............ then I would assume that some how in these tests they formulated a curve for gear down?
-
By the way, - although wingloading does not have ALL to say about i.e. turning quality of an aircraft, it still has MOST to say.
AH aircrafts turn rates almost go paralell to their wingloading, with perhaps some exceptions though.
Oh, and I wish you all a good new year('s) ;)
-
This is an old thread, but in regard of some aerodynamic questions being asked on the forum, I belive it desreves to be punted.
So, risking the wrath of Pyro, I say:
PUNT
-
Thank you Angus.
This thread is right on target with Max CL and it effects on performance thread I started.
Can anyone explain further? So far the concensus in that thread has been that Max CL does figure into turning performance.
Question is just how much does it?
Crumpp