Aces High Bulletin Board
General Forums => Aircraft and Vehicles => Topic started by: niklas on January 03, 2001, 05:38:00 AM
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(http://www.freenet.de/luftwaffeln/nacaroll.gif)
[This message has been edited by niklas (edited 01-03-2001).]
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Nice data! Any more like it? Where did it come from?
Thanks.
Andy
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Cheesus! That is one hell of a piece of data! I haven't seen any roll rate information never ever on any book or in net!
From where did you got this?
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jochen Gefectsverband Kuhlmey I/SG 5
Sieg oder bolsevismus!
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Ok, lets look at the data...
Fw 190 rules as excepected, so it does in AH.
Spitfire seems to lock up aileron badly on high speeds, something that I havent find true on AH unless it has been changed recently.
Clipped wing Spitfire would be verrrry nice addition!
Someone has some testing to do...
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jochen Gefectsverband Kuhlmey I/SG 5
Sieg oder bolsevismus!
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Someone sent me this picture, but look at the footnote, it´s from an NACA report and you can even download it. It has 76 pages, too much for my modem connect (http://bbs.hitechcreations.com/smf/Smileys/default/smile.gif), but you can find it here
http://naca.larc.nasa.gov/reports/1947/naca-report-868/ (http://naca.larc.nasa.gov/reports/1947/naca-report-868/)
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look at the dramatic decrease in roll rate on the typhoon past 260mph
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Holy toejame, that link is very important and useful!
I thought P-47 would roll better, almost like Fw 190 but seems like that is not the case.
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jochen Gefectsverband Kuhlmey I/SG 5
Sieg oder bolsevismus!
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oops, wrong line (http://bbs.hitechcreations.com/smf/Smileys/default/smile.gif) hehehe
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-Rebel
"You Rebel Scum"
[This message has been edited by Rebel (edited 01-03-2001).]
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Interesting!
(Graf: look for page 42 Acrobat Reader - other than that: too many numbers.Wells, Funked, others: help!heh).
danish
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Whole report is only 6.6 megs, all 76 pages. I'm gonna e-mail the link to Pyro or HT and see what they can do with it.
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Flakbait
Delta 6's Flight School (http://www.worldaccessnet.com/~delta6)
"With all due respect Chaplian, I don't think God wants to hear from me right now.
I'm gonna go out there and remove one of His creations from this universe.
And when I get back I'm gonna drink a bottle of Scotch like it was Chiggy von Richthofen's blood and celebrate his death."
Col. McQueen, Space: Above and Beyond
(http://www.worldaccessnet.com/~delta6/htbin/custom1.jpg)
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Originally posted by Citabria:
look at the dramatic decrease in roll rate on the typhoon past 260mph
Most curves have a special point where the curve begins to decrease. Note, all curves are for 50 pound stickforce. That means left from this point, at slower speeds, the rollrate is for maximum deflection of the aillerons. The stickforce which is necessary for full deflection is lower than 50pounds. At this special point the stick forces reaches 50pounds. And for higher speeds, 50 pounds don´t allow anymore full deflection, and roll rate dereases.
That´s my interpretation
niklas
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Hey, people who think that the Spit shouldn't roll at high speeds, heres an update for ya: we don't have a Spit I or II that had FABRIC ailerons. We have Spitfires of higher Marks that had METAL ailerons, which was fitted to Spitfires in late '40, which drastically increased reponse in the roll axis at high speeds.
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Nath_____
9./JG 54 "Grünherz"
(http://www.angelfire.com/nt/regoch/sig.gif)
"It felt as if an angel was pushing..."
-Reponse of Gen. Adolf Galland after flying the fourth prototype Me 262 in May 1943.
[This message has been edited by Nath-BDP (edited 01-03-2001).]
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Niklas your interpretation is correct.
Nath I'm pretty sure the clipped wing planes all had metal ailerons. Not sure if the "normal wing" data is for metal or cloth ailerons. I'd guess the latter.
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Just had a look at the full text of the report. It's got transient data woohoo! (http://bbs.hitechcreations.com/smf/Smileys/default/smile.gif)
It's also got information on wing twist (Pg 131) and aileron skin deformation (Pg 174).
Cool stuff.
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Fw190, goes upside down in a second.. whee.
Must be an experience..
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Being carefull not to read all the stuff with numbers and the funny signs it seems to me that the figure 47 (the above Figure 10.1) is drawn up of a hat, without any context to the math.
Quote: "Data have been collected on the rolling performance characteristics of a number of fighter airplanes of American and foreign manufacture." and then reference to fig 46 and 47 + tabel VI ect...page 39-40 Adobe.Sorry copy/paste dosnt seem to work.
There isnt any references as to these collected data, and a brief visual serch on the "Reference" section dosnt show anything.
Is the Holy Gral out there?Is there a number of Flight Tests waiting to be discovered still?
danish
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Is there anything in there that indicates 50 pounds might be the max stick force you can achieve in any particular plane.
I'm thinking that if you could get 60 or pounds, the rollrates would change?
Still, really nice info there. Hope Pyro has it or is checking it out.
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Toad see the peaks on each curve? The data on the left side of the peak is for full aileron deflection - adding more force won't help. But on the right side of the peak the aileron deflection is limited by the stick force. If you add stick force, the roll rates to the right of the peak would increase until full aileron deflection was achieved.
[This message has been edited by funked (edited 01-03-2001).]
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Yeah, Funk, I saw that.
The question is can you get more stick force in some/all the cockpits?
IIRC, some (like the 109) were limited by the room available for stick movement.
I'm sure a scared, adrenline charged guy could generate more than 50lbs. (http://bbs.hitechcreations.com/smf/Smileys/default/wink.gif)
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Thanks for the link niklas. The Info will come in useful for a project I'm working on. (http://bbs.hitechcreations.com/smf/Smileys/default/wink.gif)
Whilst you're mentioning clipped wing Spits:
(http://www.internet-today.co.uk/myweb/bradburger/images/LFIXe2.jpg)
LFIXe
(http://www.internet-today.co.uk/myweb/bradburger/images/LFIXe5.jpg)
Nath is correct.The fabric covered ailerons on the early MkI's used to balloon at high speeds making them unpleasent and very hard to move. If my memory serves me correctly they were replaced by the metal ones were during November 1940.
However they never really cured the problem and even the metal covered ones became heavy at high speeds. In fact i can think of a few modern day pilots that have flown the MkIX were suprised how heavy the ailerons were.
On the subject of stick forces, I remeber a long time back reading an article about flying the Hispano Buchon (Spanish built 109 - can't remeber who by but it was after the filming of Memphis Belle i think) and it mentioned that during medium-high speed flight a stick force of 80lb or more would be required for for the ailerons. Coupled with almost as heavy elevators and no rudder trim, one can see how demanding the 109 must have to fly been during combat.
Cheers
Paul
Bradburgers SDOE Projects (http://www.internet-today.co.uk/myweb/bradburger/projects.htm)
[This message has been edited by Bradburger (edited 01-03-2001).]
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Bradburger
>>The fabric covered ailerons on the early MkI's used to balloon at high speeds making them unpleasent and very hard to move.<<
What does 'balloon' mean? Is the problem due to some characteristic of fabric covered ailerons...or is this a mechanical advantage issue dependent on airspeed?
Andy
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Andy: The pressure differential between static air inside the aileron and the moving air outside would cause the skin to swell outwards or be sucked inwards.
Bradburger: The reason the aileron change didn't completely fix the high speed roll problem on the Spitfires was wing twist. If you read that NACA paper they mention that the Brits found that wing twist accounted for 60% of the roll rate loss at some speeds!
All: I sure would love to see a Spitfire LF Mk. XVI in AH someday. I know a certain squad that flew them. (http://bbs.hitechcreations.com/smf/Smileys/default/smile.gif)
(http://www.raf303.org/308/photos/spitxvi.jpg)
[This message has been edited by funked (edited 01-03-2001).]
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Basically, I'm wondering why they chose to run the test to 50lbs.
Physiological reason?
The max you could get in one particular plane so that became the baseline?
Obviously, you could get more than 50# in some planes and the roll rate would then show improvement at the right of the graph.
So why 50?
Just a question. Any ideas?
[This message has been edited by Toad (edited 01-03-2001).]
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Funked
OK...that makes sense.
Now, did that bind the ailerons when they were moved, or was the problem in a reduced aerodynamic efficiency of the aileron airfoil?
Andy
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The 50 lbs was a design requirement for the airforce. That is, plane X had to have a roll rate of Y at such and such a speed with force not exceeding 50 lbs. The Navy's force requirements were lower, 30 lbs. You can get an idea of what the forces were like by checking out the peak airspeeds. A lower peak means higher forces for any given speed. It wasn't practical to design with lower forces anyway. The F4u was limited to max aileron deflection at 300 knts, even though the pilot could get full deflection at higher speeds, it put too much strain either on the aileron itself or on the wing as a whole. 50 lbs was plenty. Where planes had hydraulic aileron boost, pilots complained of having no feel. Even the F-86's roll rate almost came to a stop at higher speeds, due to wing twisting, even though stick forces were comfortable.
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Thanks, Wells.
Appreciate the info.
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danish, i know from some NACA WARTIME REPORTS, each written for an individual aircraft. But they´re not published in the net afaik.
i.e. Flight Measurements of the flying qualities of an f6f-3 airplane I- Longitudinal stability and control
Rollrate is here a bit better for the F6F:
79deg/sec to the right and 73deg/sec to the left.
or: Measurement of individual aileron hinge Moments and aileron control characteristics of a P40F airplane.
91deg/sec to the left and 85deg/sec to the right, maximum stick forces which occur for speeds up to 300mph 43pounds to the right and 36pounds to the left. So it doesn´t matter whether you apply 50, 60, or 100lb, over 43lb your rollrate is limited by the wing design.
i also saw many reports for the P39 and P63.
Or check this NACA report for the P47D-30: http://naca.larc.nasa.gov/reports/1952/naca-tn-2675/ (http://naca.larc.nasa.gov/reports/1952/naca-tn-2675/)
Here they test the P47D-30 (yes, our P47) with only 30pounds stickforce. Maximum rollrate only 60deg/sec (page 57 acr.rdr.)
Conclusion (pg. 10) : the general characterics of the aileron controls were good but the effectiveness of the ailerons were below the army requirements....
I never believed that such big fighter with large wingspans like a P47 can roll with a 190 at normal speeds. 85deg/sec, that means 4,2 sec for a full circle. Good to know that this was considered to be an excellent rollrate. How long does it take for the AH P47?? 3 seconds or even less ...
And now imagine how good the P38 rolled with a wingspan of more than 45feet...
wells, can you tell me how do i get the maximul rollrate when i only have a chart with Pb/2V-values??
niklas
[This message has been edited by niklas (edited 01-04-2001).]
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For the sake of discussion, these roll rates when compared to a modern fighter are just unbelievably slow!
Even today's advanced trainer, the T-38, can easily generate roll rates in excess of 360dps...and without using full stick throw.
Whenever I fly these WW2 sims, I'm continually amazed at how poorly the aircraft roll. But, is roll rate all that important?
Absolutely! The whole point to effective BFM is orientation of the lift vector...and that breaks down into two considerations: (1) the magnitude of that lift vector (radial G), and (2) how quickly the pilot can get the lift vector pointed in the direction he wants.
No question...roll rate is significant!
Andy
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Niklas,
Pb/2V is the helix angle at the wingtip in radians. In the case of the P-47, this angle was 0.074 * 180 / PI = 4.24 degrees
Then roll rate will vary in direct proportion to wingspan and forward velocity.
In the P-47's case, with a 41' wingspan, the tip must travel a distance of PI * 41' = 128.8' in one roll.
tan(4.24) * forward velocity = roll velocity
for 200 mph (293.3 ft/sec)
roll velcity = 21.75 ft/sec
time to roll = 128.8 ft / 21.75 ft/sec = 5.92s
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Wow,
That FW190 was a rolling monster.
Wells, could you explain that little equation, especially the part about Pb/2V being the helix angle of .074.
Also why is the 190 so superior in roll. Is it the aspect ratio or just the wing span? Should engine torque effect that ability?
Just as a reference. Here are some results conducted on four A/C by test pilots in 1989 for those who haven't read the report.
230MPH
-------------Roll left---------Roll Right
P-47D-40-----5.9sec61dps-------4.9sec 74dps
F4U-1D-------4.9sec73dps-------4.5sec 81dps
F6F-5--------5.9sec61dps-------4.6sec 78dps
P-51D--------5.1sec71dps-------4.8sec 75dps
Stick force measured
pounds per G
F4U-1D 5.0 lbs per G
P-47D-40 7.5 lbs per G
F6F-5 12.5 lbs per G
P-51D 20.0 LBS per G
Quite a differance when you are pulling heavy sustained G's in a prolonged dogfight.
[This message has been edited by F4UDOA (edited 01-04-2001).]
[This message has been edited by F4UDOA (edited 01-04-2001).]
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F4u- 190 was so superior because it's short fueselage and thick stubby wings made it extremely unstable in the rolling vector. IE think of what resists a roll: Inertia, since the 190 had no high inertia to overcome to start rolling it spun fast! Also it's short wings had almost no wing twist/torsion, it had a full metal skin as well.
Better question (and harder to explain) how does the F4U have such a great roll when it has almost none of these characteristics? (err, short of the metal skin). I am not sure how they made the F4U so unstable- it has always made me curious if the Gullwing helped.
(BTW "unstable" is a term that does not imply poorness- the more unstabe a plane is a vector the less force it needs to change it's state.)
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Sorrow,
My guess would be the aspect ratio of the F4U being very low made the wing more rigid and less prone to twist. Modern fighters all have a very low aspect wing as well although I'm not sure of the cause of the benefit. The gull design probably had something to do with it as well. It seems when looking at an F4U in flight that it is riding on the air as a duel hull racing boat would ride above the water. I have a pretty good book on aerodynamics I refer too when I have a question but eventually I just ask Wells to explain it to me.
Wells???
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F4U, do you have a source for those stick forces?. (Not that I doubt them, I just want to get my dirty little hands on them)
Daff
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CO, 56th Fighter Group
"This is Yardstick. Follow me"
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Daff,
No prob.
In 1989 a group of military test pilots known as the the "Society of Experimental test pilots" tested the F4U-1D, F6F-5, P47D-40 and P-51D all loaded to combat weight and using modern evaluation tactics for the purpose of determining the best WW2 fighter. They published the report in the 1989 Symposium and is entitled "End of the arguement". I contacted them on there web site and they sent out me a copy (no charge). The report is a book containing test data on the Harrier, F15, B-58 Hustler and others. Very serious guy's. In the end their conclusion was it "It depends on the mission" .
But just as a tease I will leave you with their conclusion on the F4U.
Quote
In a turning fight the FG-1D emerged with a slight advantage over it's rivals. Light and comfortable stick forces, good performance, adequate stall warning and docile behavior at the stall made it the "weapon of choice" among those tested
So much for those who say the F4U can't maneuver.
[This message has been edited by F4UDOA (edited 01-05-2001).]
[This message has been edited by F4UDOA (edited 01-05-2001).]
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Almost forgot
http://www.netport.com/setp/ (http://www.netport.com/setp/)
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F4UDOA;
Links dosnt seem to work.Thx anyways :=)
danish
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I must say I'm surprised that no-one has yet has done any kind of comparison of AH rollrates with those in the NACA report.
So I did it instead (http://bbs.hitechcreations.com/smf/Smileys/default/wink.gif)
(http://www.users.bigpond.net.au/phoenix/images/rollrates.jpg)
I haven't tested all the aircraft as yet, and there are bound to be discrepancies between the NACA data and AH test results, e.g.
We don't know what model of Fw190 was tested,
We don't know what Spitfire (normal wing) was tested,
The report lists the F6F-3, while we have the F6F-5.
My testing was done in the following manner. Load aircraft with full internal fuel and no stores. Climb to 10,000 feet AGL. Perform 5 rolls to left, and 5 rolls to right at the indicated airspeed. Time each 360 degree roll with stopwatch and take average rollrate from the 10 rolls at each airspeed.
Results? Interesting to say the least. Based on the NACA data, each AH aircraft rolls too fast, except for the 190 (now why isn't THAT a surprise). The 190 actually seems to be up to 40 degrees per second too slow at some airspeeds, while it appears to roll too fast at high speed.
Each other AH aircraft tested rolled too fast. The Typhoon was as much as 40 deg/sec too fast at some airspeeds, the Spit IX some 35 deg/sec too fast at high speed and the F6F was a modest 15 deg/sec too fast at some airspeeds.
I'll be testing the P51-D and P47 varients next. Now, if only we had NACA data on the CHog and N1K2 (http://bbs.hitechcreations.com/smf/Smileys/default/frown.gif)
Pyro, can the 190's have their 40 deg/sec back please? (http://bbs.hitechcreations.com/smf/Smileys/default/wink.gif)
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=357th Pony Express=
Aces High Training Corps
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conspiracy ! (http://bbs.hitechcreations.com/smf/Smileys/default/wink.gif)
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Update: P51 tested and chart updated. Pretty close to the NACA results, averaged only 7 deg/sec too fast across the speed range.
Testing continues (http://bbs.hitechcreations.com/smf/Smileys/default/wink.gif)
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=357th Pony Express=
Aces High Training Corps
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Appreciate it Jekyll ;=)
It may be possible to discuss details, but the overall pattern seems convincing.
danish
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Yup, the testing revealed some obvious anomolies.
You can see that the AH Spitfire IX has a faster roll rate across the entire speed range than the F6F-5.
Does ANYONE believe that?
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=357th Pony Express=
Aces High Training Corps
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those tests will silent some guys that were yelling stupid things about warprolling Fw190s...when it should be rolling 33% faster than it does now (http://bbs.hitechcreations.com/smf/Smileys/default/biggrin.gif)
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YES and end to squeaking with out facts!!!!!!!! YES, YES! Real data! Now we can talk and not just hear babble and opinion posture. Like you said we don't know all of the particulars about each plane but we're much much closer. No more of this uneducated "The F4U couldn't do this or that" crap! Now we have a very good idea how some of these planes compare to the game with hard facts! Thanks for posting it. It will start a whole new round squeaking but at least it will be backed with hard facts! Sorry I'm yelling (http://bbs.hitechcreations.com/smf/Smileys/default/smile.gif). I just got so tiered of people hacking the game without data like this. You hear so many people blah blah blah about this plane and that plane. As I said in a different posting, I'm a mechanical engineer (I see there are a lot of engineering types on hear) and I can't just say AH has it all wrong. Come on! With out this kind of data all you have to go on is the spec listed in some books. Not that it's all bad but that tells so little about how they really flew. You can assume that the average (given that the books very a little on stats) top speed, rate of climb, etc better be close on the sim or something is wrong. I don't have any complaints about the flight model as it is on AH but I would be disappointed if they didn't incorporate these facts into the flight model in the future.
PS Don't you just love reading this old stuff. This is real old fashioned engineering. These guys used their calculus! I have a slide rule I keep to remind me that people didn't always dump the problem into a computer. It is what these people did that gives us the computer programs we relay on today. I worked for an irrigation district and did some consulting for another. I loved looking back through these old documents that went back over 100 years. I got to see how engineering changed from the 1870's to the present. I have a great respect for what the people from the pre computer age did with the tools they had. The engineers I've meant that went to school and worked pre computer and moved into the computer area have a very good understanding of numbers and what they are really telling you. They don't just take for granted that the computer said it was so. Anyway I wax poetic (http://bbs.hitechcreations.com/smf/Smileys/default/smile.gif) Thanks again for the posting.
[This message has been edited by Jimdandy (edited 01-06-2001).]
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thx Jekyll, great work.
The really interesting result of you test is that the trend of many aircrafts, like the AH-190 and P51, are equal.
I mean where did pyro know from that he has to model a peak for the 190 at exactly 250mph, which is the same like in the Naca report? Where did he know from that the trend of the p51-rollrate is completly different?
I really would like to bet that this report, or some individual reports where this report is based on, is not new for Pyro (http://bbs.hitechcreations.com/smf/Smileys/default/wink.gif)
Of course there remains the question why he models the 190 worse and other fighter better... honit soît...
And concerning the F4U: 4.5 sec@250mph, just look in the naca-chart where you are with this rollrate. you also can estimate where you are at 200mph or at 350mph when you don´t exceed the stick force limit or structural limit of the wings / ailerons (deformation)
niklas
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I believe the roll rate for the P-51D vs P-51B is pretty much on, when the D model was introduced they added a canvas panal connecting the leading edge of the aileron and the trailing edge of the wing to correct the bleed over with the B models that was said to improve roll rate marginally through about 350 mph
Whether it improved that much, I dunno.
It would make sense that all planes might have proportionally decreased roll rates for lag reasons but, them actually being higher is rather strange.
Does say alot about the work HTC put into their data, even with suposed errors it's very close.
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The top row of the chart looks like it says 180 but if you check the scale, you'll see that it's really 160.
Also, not all NACA or other evaluation reports corraborate each others data. So it's not possible to be in agreement with all the good data out there.
Different models can yield different results due to changes such as on the F6F with and without the spring tab ailerons so you have to make sure you're dealing with an apples to apples comparison. Sometimes you have two very differing sets of data for two variants that should be very similar if not identical because of a lack of any changes that would have an effect there. That certainly murks the waters a lot.
Roll rate also varies with the direction of your roll. Some charts plot both left and right hand roll rates while some leave it ambiguous.
The Typhoon sure jumps out at me because it was known for being a poor roller and I can't recall of the top of my head where I got the information I used on it. I'm actually surprised that it rolls that well in AH. I'll have to take a look at that when I get a chance.
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Doug "Pyro" Balmos
HiTech Creations
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Looking at Jekyll's data a little closer I'm thinking the NACA data was taken in the direction of torque. The average of both (for example the 190) is flatter. Maybe if Jekyll preformed the test again this time only in the direction of torque it my be closer. As Pyro and Jekyll stated we don't know all the particulars of each plane and exactly how the data was collected. But AH is very close considering those things.
I forgot to add this. To F4UDOA's question on the ability of the F4U to roll I would guess that it was the gull wing. A good example of this is the F-104. The wings on the F-104 were angled down to decrease stability and increase roll response. The F4 Phantom had a similar wing arrangement. Think of the wings as being a peace of Hotwheels car track and the center of gravity of the plane as a car on the track. Bend the track down at both ends and try to balance the car at the top of the arc. Then bend the track up a try to balance the car in the trough at the bottom. Obviously balancing the car at the top of an arc is harder than letting it set in the trough. The angle of the wings to the hull places the force vector in such a way as to stabilize the plane with lift or destabilize it. I hope this makes since and if your already way past me on this forgive the simplicity. (http://bbs.hitechcreations.com/smf/Smileys/default/smile.gif)
[This message has been edited by Jimdandy (edited 01-06-2001).]
[This message has been edited by Jimdandy (edited 01-06-2001).]
[This message has been edited by Jimdandy (edited 01-06-2001).]
[This message has been edited by Jimdandy (edited 01-06-2001).]
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I dont remember where I read that anhedral angled wings improve rollrat and dihedral angled wings worsens it.
F4U has both anhedral and dihedral wing parts, so I dont know why does that mean that the plane rolls that good. (I'm not saying that it rolls too good, I only say that I dont understand the inverted gull wing as an explanation)
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Hey, dont shoot me! I'm on the light side!!
(http://smilecwm.tripod.com/owen/luke3.gif)
(http://www.navegalia.com/hosting/000e0/illumm/huggers.gif)
[This message has been edited by Luke Skywalker (edited 01-06-2001).]
[This message has been edited by Luke Skywalker (edited 01-06-2001).]
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Actually I'm just guessing. Maybe in some way gull wing helped. Other wise I see no explanation other than the roll in the direction of torque was real good. If I remember right the F4U had one of the largest props on any fighter (Thus the gull wing btw. They had no idea that the gull wing would give it the benefits it turned out to do. They just needed ground clearance for the prop.) With a large prop and high torque engine the roll in the direction of torque might be the answer. Or as someone said the wings may have been very ridged. I also remember something about the F4U having some very advanced control surfaces. I can't remember the features. If anyone knows please tell me. Tell me I'm wrong if I am. I've been there before (http://bbs.hitechcreations.com/smf/Smileys/default/smile.gif)
[This message has been edited by Jimdandy (edited 01-06-2001).]
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Gents,
I am surprised that there isn't more info on the rolling ability of the F4U. It was supposed to be very good compared to other American mounts. As for the gull wings helping it roll I am just guessing like everyone else.
However I am always doing research. My latest venture is with the Vought company itself. I have contacted someone in Dallas at the old Vought plant who has access to there micro-phish(SP). He has promised to look through some of the old files for me. Specifically anything involving the rolling performance.
As a side note he did mention if I was in Dallas that I would be welcome to help him poke around. So if HT, Pyro or anyone else in the area is interested let me know and I will try to hook it up.
The truth is out there.
Later
F4UDOA
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The Corsair rolls so well because it has a well designed aileron system that uses balance tabs to reduce stick force. If you look at the ailerons of the F4U, you'll see the trim tab in the center of the left aileron but you'll also see another tab on both ailerons at the most inboard position. Those are the balance tabs. They work on the same principle as trim tabs but they automatically move opposite to the direction that the ailerons are moving. This imparts a force on the aileron to help it move or hold in that direction. The downside to this system is that it can get overbalanced at high speed. Because of this F4U was placarded against using full aileron deflection above 300 knots.
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Doug "Pyro" Balmos
HiTech Creations
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OK, added data for the Mitsubishi Zero and P47. Also added data for the AH N1K2-J for comparison purposes.
Corrected the error regarding Fw190 roll rate at 250mph.
Anyone out there have roll data for the Hog or other AH planes across this speed range?
(http://www.users.bigpond.net.au/phoenix/images/rollrates.jpg)
Summary so far?
The F6F-5 averages 14 deg/sec too fast
The Fw190 averages 6 deg/sec too slow (1)
The Typhoon averages 37 degrees too fast
The Spitfire averages 11 degrees too fast (2)
The Mustang averages 7 degrees too fast
The Zero averages 19 degrees too fast
The P47 averages 15 degrees too fast
(1)The Fw190 averages 16 deg/sec too slow below 300mph, and 9 deg/sec too fast over 300mph
(2) The Spitfire averages 11 deg/sec too slow below 225mph, and 15 deg/sec too fast above 225mph
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=357th Pony Express=
Aces High Training Corps
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Thx Pyro thats what I was trying to remember.
Originally posted by Pyro:
The Corsair rolls so well because it has a well designed aileron system that uses balance tabs to reduce stick force. If you look at the ailerons of the F4U, you'll see the trim tab in the center of the left aileron but you'll also see another tab on both ailerons at the most inboard position. Those are the balance tabs. They work on the same principle as trim tabs but they automatically move opposite to the direction that the ailerons are moving. This imparts a force on the aileron to help it move or hold in that direction. The downside to this system is that it can get overbalanced at high speed. Because of this F4U was placarded against using full aileron deflection above 300 knots.
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Great info, Pyro. I also wondered why did the Corsair had historically such a good rollrate. Now I know (http://bbs.hitechcreations.com/smf/Smileys/default/smile.gif)
The tiffie's rollrate doesnt surprise me. I already thought it was a bit too fast, not as much as it seems it is,but indeed faster than what I expected.
What strikes me is the Zeke. I knew that at high speeds it was hard to roll...but didnt had a clue on it having such bad low speed roll performance.
[This message has been edited by RAM (edited 01-06-2001).]
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Sounds like fun! Good hunting.
Originally posted by F4UDOA:
Gents,
I am surprised that there isn't more info on the rolling ability of the F4U. It was supposed to be very good compared to other American mounts. As for the gull wings helping it roll I am just guessing like everyone else.
However I am always doing research. My latest venture is with the Vought company itself. I have contacted someone in Dallas at the old Vought plant who has access to there micro-phish(SP). He has promised to look through some of the old files for me. Specifically anything involving the rolling performance.
As a side note he did mention if I was in Dallas that I would be welcome to help him poke around. So if HT, Pyro or anyone else in the area is interested let me know and I will try to hook it up.
The truth is out there.
Later
F4UDOA
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Because of this F4U was placarded against using full aileron deflection above 300 knots.
Something else for 1.06 Pyro? (http://bbs.hitechcreations.com/smf/Smileys/default/wink.gif)
Maybe 1.07
BTW 230MPH
-------------Roll left---------Roll Right
P-47D-40-----5.9sec61dps-------4.9sec 74dps
F4U-1D-------4.9sec73dps-------4.5sec 81dps
F6F-5--------5.9sec61dps-------4.6sec 78dps
P-51D--------5.1sec71dps-------4.8sec 75dps
AH F4U1-D results
230 mph, 10,000 feet.
Roll left 3.72 sec, 96.77 deg/sec
Roll Right 3.91 sec, 92.07 deg/sec
Interesting that the AH Hog rolls left faster than it rolls to the right, completely at odds with above test results.
Would not engine torque provide an advantage when rolling to the right?
AH's missing torque strikes again?
[This message has been edited by Jekyll (edited 01-06-2001).]
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Pyro do you mean the F4U had a Flettner Rudder??
If so why has the G10 the same aileron characteristic like the other 109? It was also equipped with a Flettner Rudder.
Flettner Rudder was just one possibility to decrease stickforces. Frise type ailerons had the same effect, but worked different.
I´m wondering myself at the moment why the 190 reaches 50lb stickforce already at 250mph. All sources i read so far about the 190 said it had very light aileron controls up to high speeds. Sure, they became harder at very high speeds, but 50lb at 250mph??? Strange.
niklas
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The f4u didn't get spring tabs on the elevator or rudder until the F4u-5.
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That's interesting Jekyll but not for the reason you think. The F4U in that case is the only one showing a stronger roll in the direction of torque which if you threw out everything else would indicate stronger torque, not weaker. I'll have to try it out and see what's going on. It's most likely something in the way that trim is modeled.
Niklas, I was just pointing out the Corsair had mechanically assisted ailerons. There's other factors that affect the rollrate but that one seemed obvious and overlooked.
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Doug "Pyro" Balmos
HiTech Creations
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hi
it seems that with the exception of the fw-190 almost all aircraft roll too quickly?
especially looking at the high speed comparison of 190 v spitfire for esxampe, the real naca difference between 190 and spit is double the aces high difference
the 109 is not listed on this chart, but i have long believed the 109 rolls too well at 400 mph, if it was included on this chart i think it would also be rolling too quickly compared to naca findings
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also this da supports alot of anecdotal stuff you read about
it would make the typhoon unsuited to a2a combat (moreso than it is now) because of poor rollrate. This would make sense since it was typically used as a ground attack fighter, i believe the tempest would have better rollrate? (not sure)
spitfire would roll worse at high speed, but performs correctly at low speeds
zeke would roll worse
anyways if anyone can find some other info on other airplanes or corroberating info would be great! especially any 109 data? i heard it only managed 15 degrees/second at 400 knots.
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Yup you're right Pyro. For some strange reason I was thinking that the props rotated counter clockwise from the POV of the cockpit.
I must have been flying too many Yaks in H2H recently (http://bbs.hitechcreations.com/smf/Smileys/default/smile.gif)
Any other thoughts on the above charts though? (http://bbs.hitechcreations.com/smf/Smileys/default/smile.gif)
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Hey good job guys!
Some thoughts:
1. Jekyll are you timing 5 individual rolls and averaging the times, or are you timing 5 consecutive rolls and computing average roll rate from (total degrees / total time)? The latter method will be more accurate if you can hold the airspeed constant (not a trivial task). However I doubt it will change the curves much.
2. We don't know that AH has a 50 lb force limit. A different force limit will change high speed roll performance greatly.
3. Pyro made an important comment about different data sets. He may have other data for these planes. This NACA chart is great but it's not Gospel. (http://bbs.hitechcreations.com/smf/Smileys/default/smile.gif)
4. I'd love to see the high speed roll deficiencies of the Spitfires. This would seperate the men from the boys among Spit pilots. And it would also create a reason to have the cropped wing versions.
(http://www.raf303.org/308/photos/spitxvi.jpg)
5. America's Hundred Thousand has an F4U-1D roll rate chart which shows roll rate between 225 and 300 mph. It ranges linearly from about 72 degrees per second to about 90 degrees per second.
[This message has been edited by funked (edited 01-12-2001).]
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Zigrat,
I think you missed this:
Originally posted by Jekyll:
(2) The Spitfire averages 11 deg/sec too slow below 225mph, and 15 deg/sec too fast above 225mph
The Spitfire appears to roll too slow at low speed and too fast at high speed not, as you claimed, correctly at low speed and too fast at high speed.
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We few, we happy few, we band of brothers;
For he to-day that sheds his blood with me
Shall be my brother
Sisu
-Karnak
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RAM said:
> What strikes me is the Zeke. I knew that at high speeds it was hard to roll...but didnt
> had a clue on it having such bad low speed roll performance.
Yep, the Type 0 sucked at roll rate. The A.V.G. knew it. See what Eric Shilling said at :
http://www.johnco.cc.ks.us/~droberts/p40/p40a.html (http://www.johnco.cc.ks.us/~droberts/p40/p40a.html)
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M.C.202
Dino in Reno
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Under 200mph however, the Zero had a very high roll rate.
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Funked, I'm performing 10 individual rolls (5 to the left and 5 to the right) and timing each roll, then taking the average.
Trying to axial roll an AH aircraft 5 times in a row leads to the a/c burying its nose. You end up finishing the 5 rolls 50 mph faster than you began them, which introduces errors of its own.
Pyro made an important comment about different data sets. He may have other data for these planes. This NACA chart is great but it's not Gospel.
I can understand minor inconsistencies between data sets, BUT
take a look at the Typhoon data. 37 degrees per second too fast on average? I find it hard to accept that ANY real data set for the Tiffie would support AH rollrates. The Zero, 19 degrees, F6F-5 at 14 degrees.
I can understand trying to narrow the rollrate gap for playability reasons, but why can't they just tell us that? (if that is indeed the reason)
Don't expect any of this changed any time soon. Funny thing is, the 190 back in 0.36 or so was closer to the NACA rollrate than it is at present. In the early days of AH I did a heap of flight testing of AH aircraft, which included rollrates. The 190A8 used to roll at about 150 degrees/sec at 250mph.
But no longer.
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Jekyll,
He also said that something was off on the Tiffie and that he'd look into it.
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We few, we happy few, we band of brothers;
For he to-day that sheds his blood with me
Shall be my brother
Sisu
-Karnak
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Jigster said:
> Under 200mph however, the Zero had a very high roll rate.
At all times and speeds less than any model P-40. I think the reason for the type 0's record
was more poor Alied pilot training early in the war than anything else. A.V.G. did well
against IJN and IJA aircraft with the P-40B. Yes I know, but their Hawk was closer to a P-40B than anything else.
Anyone have any Italian aircraft roll rates?
M.C.200/202/205, Re2000/2001/2002/2005, FIAT 32/42/50/55, etc.
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M.C.202
Dino in Reno
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S! all
What everyone seems to be missing is the roll rates of the P-51b and P-47 at very high speeds. At IAS over 360mph the P-51b is BETTER than the 190. At IAS over 400, the P-47 is BETTER than the 190. Which goes to show, these two aircraft, when flown correctly (high speed, low g) should be more than capable of outmaneuvering anything.
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Originally posted by M.C.202:
Jigster said:
> Under 200mph however, the Zero had a very high roll rate.
At all times and speeds less than any model P-40. I think the reason for the type 0's record
was more poor Alied pilot training early in the war than anything else. A.V.G. did well
against IJN and IJA aircraft with the P-40B. Yes I know, but their Hawk was closer to a P-40B than anything else.
Anyone have any Italian aircraft roll rates?
M.C.200/202/205, Re2000/2001/2002/2005, FIAT 32/42/50/55, etc.
Posting a response under a new thread. I believe this might be why the NACA report and the AH Zero are different...the NACA Zero was probably A6M2 (and probably Koga's) which had alieron lock-up over 200 mph. The A6M5 fixed some of these problems, along with dive speed.
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I acknowledge what you're saying Karnak, but my reply was directed more towards funked's comment that Pyro may have 'other data for these planes'. Hard to imagine ANY data which provided the model for the AH Typhoon rollrate.
Oh wait, what do I see here on the back of this breakfast cereal box?
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190 rolls too slow
Anti LW conpsiracy, once again (http://bbs.hitechcreations.com/smf/Smileys/default/biggrin.gif)
All because we're superior pilots
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StSanta
9./JG 54 "Grünherz"
(http://www.geocities.com/nirfurian/stSanta.jpg)
"I am the light at the end of your sorry little tunnel." - A. Eldricht
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No apparent change to aircraft rollrates in 1.05 Rev 5.
Must be more important to have vodka bottles in the La5 cockpit than have the aircraft perform correctly (http://bbs.hitechcreations.com/smf/Smileys/default/wink.gif)
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Originally posted by Jekyll:
take a look at the Typhoon data. 37 degrees per second too fast on average? I find it hard to accept that ANY real data set for the Tiffie would support AH rollrates. The Zero, 19 degrees, F6F-5 at 14 degrees.
The original chart posted was for roll rates at stick forces of 50lbs]
I'd expect data like that to shed more light on how heavy the controls of a particular aircraft were than its maximum roll-rate. For the latter you really wont rolll-rate at full (or as full as hunmanly possible) stick deflection....
I'm not trying to say the Typhoon roll-rate isn't too high, just that you have to make sure you understand the data you're reading...
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Graywolfe <tim@flibble.org>
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I'm aware of that gray, but any way you look at it, there is something definitely wrong with the AH rollrates it seems.
I could understand it if ALL aircraft rolled too fast, or too slow, but of course the 190 is the exception (http://bbs.hitechcreations.com/smf/Smileys/default/wink.gif)
Parity would be nice, wouldn't it?
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Jekyll asked:
"Anyone out there have roll data for the Hog or other AH planes across this speed range?"
Yeah, for boosted and unboosted P-38 go to: http://home.att.net/~ww2aviation/RollChart.html (http://home.att.net/~ww2aviation/RollChart.html)
My regards,
Widewing
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(http://home.att.net/~ww2aviation/P-38rollchart.JPG)
great info
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Hmm, the P38L also seems to suffer from the 'Allied Rollrate Disease' in AH.
And yes, I noticed the info was for 'True Airspeed'. At 5k though, the difference is marginal.
(http://www.users.bigpond.net.au/phoenix/images/p38roll.jpg)
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I find it promising that this thread has not degenerated into a flamewar (http://bbs.hitechcreations.com/smf/Smileys/default/smile.gif)
Also, didn't the P-51D have a slightly higher rollrate than the P-51B because of re-worked ailerons? That might explain part of the reason the AH one rolls somewhat better.
J_A_B
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You could be right J A B. Hopefully someone can come up with data to solve the question.
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quote]The Typhoon sure jumps out at me because it was known for being a poor roller and I can't recall of the top of my head where I got the information I used on it. I'm actually surprised that it rolls that well in AH. I'll have to take a look at that when I get a chance.[/quote]
That would be great! The error seems to be quite large so maybe there is something wrong.
I would also think that Spitfire could be looked upon, I find it to roll too well in high speeds for plane that did have very thin wing (flexes during roll).
Great thread alltogether!
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jochen Gefechtsverband Kuhlmey I/SG 5
Sieg oder bolsevismus!
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quote]The Typhoon sure jumps out at me because it was known for being a poor roller and I can't recall of the top of my head where I got the information I used on it. I'm actually surprised that it rolls that well in AH. I'll have to take a look at that when I get a chance.[/quote]
That would be great! The error seems to be quite large so maybe there is something wrong.
I would also think that Spitfire could be looked upon, I find it to roll too well in high speeds for plane that did have very thin wing (flexes during roll).
Great thread alltogether!
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jochen Gefechtsverband Kuhlmey I/SG 5
Sieg oder bolsevismus!
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Hm, the documents I've seen here on this board do not indicate such a vast drop off in roll rate for the FW.
Migh have interpreted them wrong, but they dinnae mention this, which they ought to if it was so dramatic
Maybe they dinnae dare to take her up past 300 mph (http://bbs.hitechcreations.com/smf/Smileys/default/biggrin.gif)
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Baron Claus "StSanta" Von Ribbentroppen
9./JG 54 "Grünherz"
(http://us.st5.yimg.com/store4.yimg.com/I/demotivators_1619_4916770)
"We are the light at the end of your sorry little tunnel." - A. Eldritch
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Jekyll, I posted the P-51D mod further up in the thread. I know the canvas link did improve rollrate but I'm not sure to what extent. I believe most gains were from 250mph and lower.
I did some looking into the Zeros the US captured and tested, there were only a handfull due Zero's light construction that made it very hard to ship or capture intact.
The evaluation on Koga's Zero stated that the ailerons locked over 200mph (A6M2) and rolling was practically impossible with the exception torque reaction. (Which is probably and exaggeration, but...) This chart doesn't appear to be a A6M2, the roll performence looks to be either the A6M5 with the missing tips(along with a few other mods for testing) that allowed slightly extended preformence past 250 MPH while keeping the same roll performence (and perhaps slightly better) below 200 MPH and degrading turning ability slightly.
The US also added counterweights to the ailerons for testing, and I believe this might be the one used for this chart.
(http://bigdweeb.homestead.com/files/A6M5.jpg)
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How about this quote?
"I was sure I could easily bag the opposing fighter leader, so I left my wingmen behind and followed the Zeke down. He violently twisted and turned as we screamed down from the heavens. It was dogma that the Zeke's ailerons got unusually stiff at high speeds, but I saw no evidence of that as the nimble fighter kept a step or two away from my gunsight pipper. To the contrary, at my own high speed, my ailerons overbalanced and I needed a light but firm touch to avoid going into an uncontrollable wing roll."
Now this was November 1943, and the writer was Tom Blackburn, Commander of VF-17.
So the questions arise: Might these have been the clipped tip Zeke 32's?
And when is 'uncontrollable wing roll' being modelled in AH for Corsairs over 300 mph (http://bbs.hitechcreations.com/smf/Smileys/default/smile.gif)
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=357th Pony Express=
Aces High Training Corps