Aces High Bulletin Board
General Forums => Aircraft and Vehicles => Topic started by: SgtPappy on November 14, 2007, 03:55:22 PM
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I'm in a conversation with a few people at WWII Aircraft Forums (http://www2ww2aircraft.net); some of whom argue that the F4U cannot outturn a Spitfire XIV (regardless of flap position) and that the Fw 190 flaps were more efficient at increasing the 190's turn rate than the F4U's flaps.
(i.e. not necessarily that the 190 outturned the F4U, but that the 190's flaps increased the turn rate by a higher percentage that the F4U's flaps did).
With all the tests already done on proving that the F4U's flap performance is credible and theoretically correct, I'd like to know if there are any sites that will give me the numbers I need to plug the Spitfire XIV and 190-A5/D9 into the equation at this site: The Math Behind Turning (http://www.electraforge.com/brooke/flightsims/aces_high/stallSpeedMath/turningMath.html)
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ow that made my head hurt:huh
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Haha, yea, I'm still trying to understand the site fully as well, but for now, I just need to prove the WWII Aircraft Forum members that, mathematically, a Corsair WILL outturn a Spit 14 and a 190 with flaps.
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Somewhere around here someone posted the report of an actual "aggressor" test between the 190, F4U and F6F, and the F4U generally pwned the 190.
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Ah, thanks again Sax. I'll be looking for that then.
Though still have to plug in the co-efficients for the Spit14. I've looked it up and since I'm a bit slow, I'd still like to know what the prop reduction gear ratio has to do with calculating turning ability.
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Originally posted by Saxman
Somewhere around here someone posted the report of an actual "aggressor" test between the 190, F4U and F6F, and the F4U generally pwned the 190.
You can find this report here. (http://www.wwiiaircraftperformance.org/fw190/ptr-1107.pdf)
My regards,
Widewing
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RofL. It's like magic. Mention "someone has flight test data" and *poof* Widewing appears with a link. :D
It's too bad they didn't list the BuNo for the F4U involved in the test. Would have been interesting to know if this was a birdcage, or a 1A with the improved engine. I noticed at the end the test specified the F4U was fit with the original factory-installed toothpick prop, not the paddle prop aircraft in the field were being equipped with. I'd say the improvement in acceleration and climb that would provide should only up the pwnage the F4U has over the 190.
Downside is, if Pappy tries to use this document to prove his point he's bound to get nay-sayers complaining because it was a test run by Allied pilots so MUST be slanted for propaganda!
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hey Saxman, check these sites too:
http://www.uberfw190spwntsorryarsef4uslikenobodysbusiness.com
If that link doesn't work try this one:
http://www.suxmangroupsallalliestogetheraslikemindedlol.com
or this one:
http://www.ifyoudontbelievethissitethenyouareanaysayer.com
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With my magic powers I sense a upcoming...
(http://img206.imageshack.us/img206/7531/futurebe3.jpg)
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Originally posted by Saxman
RofL. It's like magic. Mention "someone has flight test data" and *poof* Widewing appears with a link. :D
It's too bad they didn't list the BuNo for the F4U involved in the test. Would have been interesting to know if this was a birdcage, or a 1A with the improved engine. I noticed at the end the test specified the F4U was fit with the original factory-installed toothpick prop, not the paddle prop aircraft in the field were being equipped with. I'd say the improvement in acceleration and climb that would provide should only up the pwnage the F4U has over the 190.
Downside is, if Pappy tries to use this document to prove his point he's bound to get nay-sayers complaining because it was a test run by Allied pilots so MUST be slanted for propaganda!
Did you happen to notice that this test recorded a maximum speed of 391 mph TAS for the F6F-3? Meanwhile, our more powerful, cleaner F6F-5 does only 386 mph TAS... Time to fix that, I think.
My regards,
Widewing
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Originally posted by Widewing
Did you happen to notice that this test recorded a maximum speed of 391 mph TAS for the F6F-3? Meanwhile, our more powerful, cleaner F6F-5 does only 386 mph TAS... Time to fix that, I think.
My regards,
Widewing
Is there any way to fix it accurately, though? If what I've read here and eslwhere is correct, the pitot tube on the F6 did not measure its speed correctly. Can we go by heresay evidence that it was able to keep up with the F4u when they flew together? I hope there is a quantifyable way to prove it. Otherwise I doubt we get a faster F6F-5.
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That's WW for ya.
yes, it's Allied work, Sax but those guys are using German documents to support their flap theories as well.
It's likely HTC does have the ability to fix the Hellcat, but theyve gotta be busy for now... working on the perk ord system most likely. I have heard that one day, all the AH:I planes will be upgraded to AH:II standards.
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Originally posted by schlowy2
hey Saxman, check these sites too:
http://www.uberfw190spwntsorryarsef4uslikenobodysbusiness.com
If that link doesn't work try this one:
http://www.suxmangroupsallalliestogetheraslikemindedlol.com
or this one:
http://www.ifyoudontbelievethissitethenyouareanaysayer.com
Dweeb and Spammer.
Skuzzy, get your big 'ol PNG stick out, please!
Regards,
Subway
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So they responded with this:
http://allyoucanupload.webshots.com/v/2000409169664360027 (http://allyoucanupload.webshots.com/v/2000409169664360027)
I argued that this only works for a constant airfoil, while the F4U's airfoil in combo with its thrust features allow it to turn better.
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Originally posted by Stang
Is there any way to fix it accurately, though? If what I've read here and eslwhere is correct, the pitot tube on the F6 did not measure its speed correctly. Can we go by heresay evidence that it was able to keep up with the F4u when they flew together? I hope there is a quantifyable way to prove it. Otherwise I doubt we get a faster F6F-5.
There's plenty of flight test data, done with a data tube independent of the airplane's pitot tube to substantiate speed. There's several Navy tests that show the F6F-5 doing 391 mph in MIL power. Another TAIC test shows (Report #17) shows a max speed of 409 mph in WEP with water injection. Grumman tests also show speeds in excess of 400 mph. HTC has seen these and more.
As to the pitot tube issue; the air speed indicator showed a slower than actual speed. However, if that were modeled, E6B should show true air speed being different than the indicator. It doesn't.
You can read these reports online, courtesy of Mike Williams and Neil Sterling.
Here's a few links.
TAIC Report No. 17 (http://www.wwiiaircraftperformance.org/japan/ptr-1111.pdf)
Navy Test (http://www.wwiiaircraftperformance.org/f6f/f6f-5-72731.pdf)
Another Navy test (http://www.wwiiaircraftperformance.org/f6f/f6f-5-58310.pdf)
My regards,
Widewing
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(http://img.photobucket.com/albums/v99/dichotomy/skuzzysignal.gif)
Someone is about as fanatical as kurfy, but not one tenth as intelligent.
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Originally posted by Widewing
There's plenty of flight test data, done with a data tube independent of the airplane's pitot tube to substantiate speed. There's several Navy tests that show the F6F-5 doing 391 mph in MIL power. Another TAIC test shows (Report #17) shows a max speed of 409 mph in WEP with water injection. Grumman tests also show speeds in excess of 400 mph. HTC has seen these and more.
As to the pitot tube issue; the air speed indicator showed a slower than actual speed. However, if that were modeled, E6B should show true air speed being different than the indicator. It doesn't.
You can read these reports online, courtesy of Mike Williams and Neil Sterling.
Here's a few links.
TAIC Report No. 17 (http://www.wwiiaircraftperformance.org/japan/ptr-1111.pdf)
Navy Test (http://www.wwiiaircraftperformance.org/f6f/f6f-5-72731.pdf)
Another Navy test (http://www.wwiiaircraftperformance.org/f6f/f6f-5-58310.pdf)
My regards,
Widewing
Maybe when the rest of the navy ac are updated they will address this.
Widewing did you also mention at one time, something about the FM2's low alt performance being off?
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Pappy,
You could always post the page of the F4U flight manual that gives the stall speeds under clean and full flap conditions. Compare the reduction in stall speed with that of the 190 at full flaps vs clean.
IIRC, no one here really solved the question of WHY the F4U's flaps are so darned effective, just all the calculations and the flight manual supported it.
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Anyone know what airfoil shape the FW190 used? I know the Corsair's and the Spitfire's.
EDIT: Looked it up. Spitfire used the NACA 2213 (root) and 2209.4 (tip), Corsair and FW190 used the NACA 23015 (root) and 23009 tip.
I don't know that these guys would be swayed by your mathmatical "proof" if they buy into annecdotal information so easily.
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Kind of surprised to see that both the F4U and 190 used the same airfoil. I'm guessing this refers to cross-section? What these guys don't seem to understand is that while the F4U's odd wing configuration may have been solely intended to length the landing gear without sacrificing strength, it STILL had any number of odd side-effects on flight performance (such as decreasing drag, poor elevator authority when all three wheels were on the ground, etc).
Also, the flight manuals were written by the guys who designed and built the things and knew their operational tolerances. If the dweebs on that board are so dense they refuse to believe documentation written specifically with pilot safety in mind (meaning the estimates may be somewhat conservative and the actual stall speeds might have been somewhat lower than indicated) that ALREADY shows a significant increase in lift with flaps deployed, they're not worth arguing with.
Either that, or maybe we should just sic WW on 'em from the start. ;)
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Originally posted by SgtPappy
So they responded with this:
http://allyoucanupload.webshots.com/v/2000409169664360027 (http://allyoucanupload.webshots.com/v/2000409169664360027)
I argued that this only works for a constant airfoil, while the F4U's airfoil in combo with its thrust features allow it to turn better.
Merely arguing that since the NACA report shows a higher Clmax with a split flap than a plain flap shows that these guys do not know what they're talking about. There are so many other factors in play--its a prime example of folks knowing just enough to be dangerous.
For example, combining a tapered wing planform with a tapered chord thickness ensures the wing tip stalls before the root, which explains why almost all aircraft in AH will roll over on their back in a flash when stalled. Reynolds number (a fluid dynamics term that describes flow characteristics) has a huge impact on wing section performance. Aspect ratio can have a huge impact on induced drag differences, which become extremely important in high lift conditions as induced drag skyrockets. The airspeeds at which flaps can be used is also important. Gross weight, wing area, wing loading, Clmax at different reynolds numbers, all of these things impact turn performance during different conditions of flight. Even altitude plays a huge part, as lower dynamic pressure (typically at higher altitudes) impacts performance.
The answer to your question is extremely complicated and its difficult sometimes to find out some of the values you need for those equations as some WWII aircraft possess voluminous amounts of recorded and maintained documentation and some do not. Even some flight test data is questionable as alluded to above, and not nearly enough of it from different sources is consistent.
Are there situations where a Corsair can outturn a Spit 14--absolutely, even without flaps. Could we find a flight condition where 190 flaps are more "effective" than a Corsairs flaps--perhaps though I doubt it.
If you really want to get into some research, I can recommend some of the books I've been reading lately. Regardless though, I think you're efforts may be wasted on those that want to cling to anecdotal evidence.
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Originally posted by Saxman
Kind of surprised to see that both the F4U and 190 used the same airfoil. I'm guessing this refers to cross-section?
The NACA 23000 series of airfoil sections was extremely popular at the time due to NACA proclaiming it as a sort of wonder-airfoil. Relatively low drag, good lift/drag ratio, low pitching moments, etc. It was used on more WWII aircraft than any other single airfoil section. Its also used on Dale's RV-8 and other modern aircraft.
But, as I stated above, there are so many more factors in play that affect the wing's characteristics than simply the airfoil.
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Thanks once again all.
I recently picked up a book on aircraft piston engines spanning from the 1920s to the 1950's, so I'm getting there.
Which book was it that you would recommend, Stoney?
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Originally posted by SgtPappy
Thanks once again all.
I recently picked up a book on aircraft piston engines spanning from the 1920s to the 1950's, so I'm getting there.
Which book was it that you would recommend, Stoney?
For simply an aerodynamics primer, I'd recommend "Aerodynamics for Naval Aviators". I'm sure there are other opinions about this book...perhaps there are other recommendations from the rest of the forum readers here.
To learn about airfoils and how they work, how flaps affect them, the single source book is "Theory of Wing Sections" by Abbott and Von Doenhoff. This is basically an edited version of NACA report 824, and simply regurges all the info that NACA came up with. A nice complement to "Theory of Wing Sections" is GA Airfoils by Harry Riblett.
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i'll be sure to check those out, if i can find them.
the museum i volunteer at hopefully has them. thanks again!
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lol, all gamers, the whole lot of you.
Soren
The difference between Crumpp and the people at the Aces High II Forum is that Crumpp has actual real life experience and expert knowledge on the subject. Crumpp unlike the guys at AHII works with these a/c daily, currently he works on a an actual FW-190 (White 1), you can visit here: Focke-Wulf FW 190 - White 1 (http://www.white1foundation.org/)
Games are hardly relevant. They are mass market media attempting to make a profit. IMHO, the games should be left where they belong, in the toybox.
All the best,
Crumpp
Don't you know that:
Soren
Fw-190 Dora-9, the best piston engined fighter to be produced in quantity during WW2. It possessed better maneuverability in all aspects of flight compared to virtually every late war Allied fighter except for the Spitfire Mk.XIV.
http://www.ww2aircraft.net/forum/aviation/best-fighter-iii-614-71.html
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Maybe we should get Bodhi to have a nice talk with Mr. Crumpp.
Or maybe Widewing can ejumacate Soren on all the aspects where the F4U-4 pwns the Dora.
:rolleyes:
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Yep, Bodhi was one of the first people that sprang to mind. Though there are a number of others.
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Although I do have to say that Pappy may have taken the wrong approach. I think he focused too much on how performance was in the game, rather than the data HTC actually USED to determine performance in the game.
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The "expert" has spoken,
...full flaps will not improve any aircraft's turning performance.
http://www.ww2aircraft.net/forum/aviation/best-fighter-iii-614-73.html#post292941
:huh
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Originally posted by Murdr
The "expert" has spoken, :huh
There are good reasons why he was PNGed.
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Sax, I think you're right.
The only problem is, I'm not sure exactly where the information that HTC uses is found. Also, they continue to disprove the 'math behind turning' page.
They state that the extra drag is so huge, you need an equal amount of extra thrust to compensate. Makes sense, but I cannot seem to find any errors in here (http://www.electraforge.com/brooke/flightsims/aces_high/stallSpeedMath/turningMath.html)
If you want to find a quick link to the most recent page of our discussion, it's here (http://www.ww2aircraft.net/forum/aviation/best-fighter-iii-614-73.html#post292963)
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Here (http://forums.hitechcreations.com/forums/showthread.php?s=&threadid=148978&highlight=crumpp) is a thread you might find very interesting pappy (you might want to work from the most recent pages backwards).
You have to understand that if this is the same guy, he has a habit of selectively ignoring data that disagree with his position, mis-representing data that does, and generally trying to attribute the weight of documentation to what is really his own statements.
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Thanks, Murdr.
That may very well be the same guy.
But if it IS the same guy, he's smarter now as he posted actual proven data in the ww2 a/c forums this time.
The only thing is that his data conflicts with DTango's mathematical equations, and it also conflict with the website link. Too bad he's not able to read all those posts regarding the turn rate of the Corsair in the other forums.
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There was a long long debate in the past about flaps several of us had with Crumpp many moons ago here. From glancing at his posts in the thread you've pointed out he still has not changed his thinking on the topic :). I've and others tried to help him understand the concepts in the past to no avail. I doubt seriously that you'll get further than others have tried here.
BTW His mode of operation is that he'll throw out charts, diagrams, and references which seems to impress some folks. I don't take him too seriously though.
He was PNG'd here for some reason. Don't know the details but if you look at his past posts in here you might get an impression as to why.
Tango, XO
412th FS Braunco Mustangs
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Maybe someone should start tossing up some links to these conversations. Maybe it won't prove him wrong, but at the very least may humiliate and ostracize him from his new friends. ;)
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Yea, I've seen a few of his posts. Though I'm more inclined to believe you guys and your very impressive links, I feel that I should at least take his posts into some consideration.
To me, this debate is kinda like religion... and many issues for that matter. I have to view all sides and then conclude for my own what I feel is correct.
So far, all the mathematically-proven sites dtango has displayed (in addition to other links others have shown), I'm leaning towards you guys lol.
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Brooke calculated his data from the calibrated stall speeds, and then compared them to the scale test data. The scale test data was a different flap configuration as he pointed out, and also said "I'll use the values from [F4U], though, as those are for the real, flying, full-scale F4U-1".
Regarding bank angle, don't forget that when you lower flaps, you also lower the speed thresholds for stall conditions. Hence, a higher bank angle can be maintained at lower speeds with flaps deployed in comparison to clean configuration.
It is a given that you will have a higher total drag with flaps deployed in comparison to clean. The question is, at what point do total drag and available thrust reach equalibrium, because that AoA and speed can be maintained without deterioation? Then, how does that comapre with the best sustained rate of turn under clean configuration?
Oh, and actually in the game, while the full flap f4U-4 does have a smaller turn radius than the spit16, the spit16 clean maintains an advantage in turn rate regardless of what the F4U-4 does.
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Yes, very impressive that the F4U and F6F managed in a 1944 test to beat a 1941 model Fw190A-4 with a rough-running engine. And not even a fighter version, but a JaBo version of the 190A-4 (which presumably makes it a 190G originally). I wonder how those US Navy planes would have done against a 190A-6 or A-7 in that early 1944 test.
What I think is impressive is that the three year old 190 managed to out climb both Ami planes and was considered equal in a dive.
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I'm loathe to go posting on another website to get into another debate with crumpp. I can only take so much of trying to patiently reason with someone who it's so nearly impossible to reason with. Reading the posts he's still his same old self as arrogant as ever claiming some higher knowledge than others, spouting out a wall of text with some aerodynamic info yet misapplying what he's saying. He hasn't stated anything most of us aero-geeks don't already know.
For starters thrust also varies with airspeed and increases as airspeed decreases, one of several factors that make assessing sustained turn rate tricky so we can't just make a blanket statement about what increased drag would do in a turn because thrust also increases as airspeeds reduce.
Pappy, my advice is to use this as motivation to study up on aerodynamics :) . Spend some time learning and you'll start to see where crumpp could improve on his formal education.
Tango, XO
412th FS Braunco Mustangs
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Thanks, Dtango and all.
I've always been pretty interested in the sector of aerodynamics. I recently borrowed a book on the characteristics of air around wings and the factors contributing to lift co-efficients of airfoils (aerodynamics book in general).
When I find time, I'll be sure to read up on this stuff so as to formulate some of my own reasoning... I'm just not smart enough yet.
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Originally posted by Murdr
Hence, a higher bank angle can be maintained at lower speeds with flaps deployed in comparison to clean configuration.
You sure about this? I thought the critical AoA was lowered when flaps were deployed? I thought the increased camber and wing area were the reasons for the increased Clmax at the same or less than AoA?
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Bank angle, angle of roll from wings level. It was mentioned on the other board in regards to level turning.
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Ooops. Sorry, didn't see bank angle--was thinking angle of attack. That's what I get for trying to be Mr. Smarty Pants...