Aces High Bulletin Board
General Forums => Aces High General Discussion => Topic started by: hitech on June 05, 2000, 04:42:00 PM
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F4u-1C/D:
3G stall speed: 150 knts IAS (176 mph CAS, +3 knts)
Turn radius: 224m (70 degree bank)
Tested in AH: 30s @ 130 mph = 278m
3G radius corrected to 130mph/1.64G/52 degree bank = 266m
Error = 5%
P-51D:
3G stall speed: 159 mph IAS (162 mph CAS)
Turn radius: 190m (70 degree bank)
Tested in AH (75% fuel, no fuse tank):
27s @ 150 mph = 288m
3G radius corrected for 150mph/2.57G/67 bank = 194m
Error = 48%
P-38L:
3G stall speed: 170 mph IAS (175 mph CAS)
Turn radius: 221m (70 degree bank)
Tested in AH: 26s @ 160 mph = 296m
3G radius corrected for 160 mph/2.51G/66 bank = 226m
Error = 31%
Off the 3g stall numbers on a P51 did a quick Max LCO calc on the stang.
With a weight of 9600 Lb's and an area of 234 sqr feet I come up with a max lco of 1.9 This dosn't sound like a clean configuration.
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HiTech
For Bribes (http://www.internetwines.com/pa95154.html)
[This message has been edited by hitech (edited 06-05-2000).]
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sorry for those as me that dont know what's that...that means that the turning radius of the P51 is bigger than it should be?...
Damn it, I am letting the Fw190 for the P51 again (http://bbs.hitechcreations.com/smf/Smileys/default/biggrin.gif)
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Yah... Any of you nerds wanna translate that for us? (http://bbs.hitechcreations.com/smf/Smileys/default/smile.gif)
edit---
er.. Not meaning HTC. If youve participated in the Turn Rate Is Hosed thread, you qualify.
[This message has been edited by Nash (edited 06-05-2000).]
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Yes Bazil, but what does it all mean?
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International fan of misery
Yeager
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Lift coefficient is a good measure of the amount of lift generated per unit area by the wing. For an ideal, infinite span airfoil, the maximum slope of the Cl/alpha curve is 2*Pi/alpha in radians or about .11 per degree. HT saying that the maximum lift coefficient of the P51 is about 1.9 means that the mustang turns BETTER than it should. I dont know the specifics of the pony wing, but it likely stalls somewhere around 16 degrees AOA. It has camber, so its angle of zero lift is probably around -3 or 4 degrees AOA. And, for class i had to do an analysis of a wing planform not too unlike the pony (though not exactly the same) at about .078 per degree, which would give the pony a max LC of 1.56. IE the mustang turns too well (http://bbs.hitechcreations.com/smf/Smileys/default/smile.gif)
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Originally posted by Zigrat:
HT saying that the maximum lift coefficient of the P51 is about 1.9 means that the mustang turns BETTER than it should.
Ahem...who was the one saying that Fw190 turns like a P51?
(http://bbs.hitechcreations.com/smf/Smileys/default/biggrin.gif) (http://bbs.hitechcreations.com/smf/Smileys/default/biggrin.gif) (http://bbs.hitechcreations.com/smf/Smileys/default/biggrin.gif) (http://bbs.hitechcreations.com/smf/Smileys/default/biggrin.gif) (http://bbs.hitechcreations.com/smf/Smileys/default/biggrin.gif)
hhihihihihihi
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Ummm... who actually turns a Pony anyways (http://bbs.hitechcreations.com/smf/Smileys/default/wink.gif) ?
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Vermillion
**MOL**, Men of Leisure
"Real Men fly Radials, Nancy Boys fly Spitfires"
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Spitfire too spitfire too!
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"Stupids are like flies. they are everywere, but are easy to kill"
RAM
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The P-38 has an error of 31%, does that mean it turns too good also?
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Mino
The Wrecking Crew
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btw anyone know the naca code of the airfoil used in the p51 wing? I know they attemped to delay boundry layer transition(to turbulent flow), but im not sure what method they used. My guess is they pushed the position of max thickness/chord rear to reduce the adverse pressure gradient over the majority of the airfoil. This would probably also mean that camber was slight and angle of zero lift would be more like - 2 degrees than -4. So that numberI gave earlier might even be a bit high, but effects such as lift generated by the fuselage might cancel it out.
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Would somebody please pay attention to me on this subject. The max lift coefficient of the P-51 is seen as aircraft A in this NACA document. http://naca.larc.nasa.gov/reports/1945/naca-report-829/index.cgi?page09.gif (http://naca.larc.nasa.gov/reports/1945/naca-report-829/index.cgi?page09.gif)
It is in fact approximately 1.50 no flaps.
Full flaps it is 1.89 the F4U is 1.88(reduced from 2.33 and also 1.48 with no flaps with the addition of the wing spoiler). You can see this clearly in the full document.
Thanks
F4UDOA
I am the Rodney Dangerfield of Aces High
[This message has been edited by F4UDOA (edited 06-05-2000).]
[This message has been edited by F4UDOA (edited 06-05-2000).]
[This message has been edited by F4UDOA (edited 06-05-2000).]
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Gents: i'm not talking about our stang having wrong numbers. The 3g stall wells is talking about was some test that were done.
From this testI calculated a max lift co.
Like anything numbers in isolation ,i.e 3g stall,with out the other items don't realy give you much information.
My guess is that they did a 3g stall test with flaps down and hence wells descrepency between us and them.
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HiTech
For Bribes (http://www.internetwines.com/pa95154.html)
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ah cc hitech i just figured it out and the numbers in the aces high test correctate pretty well with a max CL of around 1.5, which is what should be expected for the p51, nice to see that theory actually works in some cases (http://bbs.hitechcreations.com/smf/Smileys/default/smile.gif)
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"Ummm... who actually turns a Pony anyways?"
LOL... I do. (http://bbs.hitechcreations.com/smf/Smileys/default/cool.gif)
Hang
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I got a couple of former NASA guys at work I might be able to run this stuff by, I know I got an Aerospace engineer that can look at it.
I don't know any former North American types or test pilots to ask.
HT I wish you would have used the <> in your %'s so we would know if they were greater or lesser %'s
RAM,
According to the numbers above, you shouldn't be turning a pony at all. I got burned by Hogs making S turns a couple times, this will make it worse!
Zig what are you Aerospace, Aeronautical Engineering, or just read too damn much?
F4UDOA, you Gif didn't come out right.
I know I can find the NACA for the P-36 and P-40 airfoils, but like I said I am bereft of North American Stuff.
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(http://www.tir.com/~lkbrown1/dtahcard.gif)
"Downtown" Lincoln Brown.
lkbrown1@tir.com
http://www.tir.com/~lkbrown1 (http://www.tir.com/~lkbrown1)
Wrecking Crews "Drag and Die Guy"
Hals und beinbruch!
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Don't forget that more than just the wing determines the lift of the aircraft.
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Please Funked!!! Let's not start with fuselage lift in the equation. (http://bbs.hitechcreations.com/smf/Smileys/default/wink.gif) I just got pass prop theory by the skin of my tooth at FIT. (http://bbs.hitechcreations.com/smf/Smileys/default/smile.gif)
Ozark
BTW: The toothbrush was invented in the Ozarks....If it was invented anywhere else, it whould have been called the teethbrush. (http://bbs.hitechcreations.com/smf/Smileys/default/smile.gif)
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Don't forget that little wing back on the tail either... (http://bbs.hitechcreations.com/smf/Smileys/default/wink.gif)
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Hey,
The image of the graph showing the max lift coefficient for the P-51 would not display so I posted the link. HiTech I agree with you that the max lift coefficient in Wells calculation is to high and the difference was caused by the use of full flaps. In AHT it list lift coefficients without flaps but the coresponding numbers are to high for any of the A/C envolved. Wells pointed this out to me in an earlier post. In fact the number listed for the P-51 is 1.89 which would approximate your findings. I believe that the same is true for the P-38. My question is what lift coefficients are you using for your FM's?
F4UDOA
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Right Funked, that 1.9 is the Clmax of the entire airframe, but HT is right, it is too high for a clean configuration and without considering the effect of propwash because the pitot tube is usually way out on the wing somewhere.
Hitech, consider this...
The pilot sees 160 mph on the gauge. What's the thrust at 160 mph? What's the propwash velocity over the inner portion of the wing and fuselage at that IAS? What effect does that have on the overall effective airspeed? Then, what's the 'real' CLmax? Example:
Thrust ~ 2600 lbs (75% efficiency, 1490 hp)
Propwash velocity ~ 55 mph over 30% surface area (based on the 2600 lbs thrust)
Effective airspeed ~ (55 * 0.3) + 160 = 176.5 mph
CLmax = 1.54 <--- this is reasonable
Are you really factoring in propwash???
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I just finished junior year as an undergrad in aerospace engineering, only 1 more year till degree baby (http://bbs.hitechcreations.com/smf/Smileys/default/smile.gif)
Yeah that graph you posted looks like it should, with stall around 19 degrees aoa and alpha 0L around -1 degree (little higher than i guessed because the wing is cambered even less than id thought).
If you guys wanna calculate the cl for the wings of any other ww2 planes i wrote a program that does it in matlab for class so it wouldnt be hard if you have the wing planform to figure out the theoretical performance of the wing, but its only usually accurate up to like 16 degrees aoa, where seperation messes all the invisid calculations up. But then again, its probably just better to look at naca test data though i *do* kinda like finding answers then finding they match real world data (http://bbs.hitechcreations.com/smf/Smileys/default/smile.gif)
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<----timidly raises hand, "2+2=4".
"Hope that helps in the AoA thingie...ah..ah.....I used to own a slide-rule."
<quietly leaves room with head down,thinks to self----man,I hope the P-51 turns better, not worse.>
(http://bbs.hitechcreations.com/smf/Smileys/default/confused.gif)
[This message has been edited by 1776 (edited 06-06-2000).]
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ROFL...1776!!
That's why I became a firefighter!! It's EZ...Just put the wet stuff on the red stuff. (http://bbs.hitechcreations.com/smf/Smileys/default/wink.gif)
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Damn it, I am letting the Fw190 for the P51 again
Welcome back RAM! We really missed you while you were away about one day after quitting!
(http://bbs.hitechcreations.com/smf/Smileys/default/wink.gif)
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jochen Jagdflieger JG 2 'Richthofen' Aces High
jochen Geschwaderkommodore (on leave) Jagdgeschwader 2 'Richthofen' (http://personal.inet.fi/cool/jan.nousiainen/JG2) Warbirds
Thanks for the Fw 190A-5 HTC!
Ladysmith wants you forthwith to come to her relief
Burn your briefs you leave for France tonight
Carefully cut the straps of the booby-traps and set the captives free
But don't shoot 'til you see her big blue eyes
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I have the airfoil data, CLmax, Cdo, and alot of the other data for most of the american fighters at home. I will try to find it when I go home from work tonight.
I found it in several downloadable documents on the NACA server (pre-NASA agency), so if any of you guys have time you can track it down on there.
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Vermillion
**MOL**, Men of Leisure
"Real Men fly Radials, Nancy Boys fly Spitfires"
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Verm, don't tease, put the link up.
I know that in the early NACA Days the P-36, P-37, and P-40 Airframes were heavily tested by NACA.
I WANT THAT DATA!
Regardless, send me any P-40 Stuff you got.
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(http://www.tir.com/~lkbrown1/dtahcard.gif)
"Downtown" Lincoln Brown.
lkbrown1@tir.com
http://www.tir.com/~lkbrown1 (http://www.tir.com/~lkbrown1)
Wrecking Crews "Drag and Die Guy"
Hals und beinbruch!
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Downtown, here is the best I can do till I get home and find out where I put it, and where the electronic version is on the web.
Here is where I found them originally.
http://techreports.larc.nasa.gov/cgi-bin/NTRS (http://techreports.larc.nasa.gov/cgi-bin/NTRS)
Nice search engine, with most of the stuff we are interested in, located on one of the two NACA servers.
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Vermillion
**MOL**, Men of Leisure
"Real Men fly Radials, Nancy Boys fly Spitfires"
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Downtown,
Here is your link http://naca.larc.nasa.gov/reports/1945/naca-report-829/ (http://naca.larc.nasa.gov/reports/1945/naca-report-829/)
If you do a search on lift coefficients you will find it also but it is a bit buried.
Verm,
Do you have any info on the P-38 other that AHT? I'am having a hard time with that one. Also looking for info on undated drag numbers for the F4U. The drag numbers in this document are for early model F4U-1. I know modifications were made to the -1A and D IE bubble canopy, cowl flaps sealed in front of pilot, wings surfaces faired and sealed.
Oh and by the way if you come back to Phila area on June 17 or 18 there will be a F4U at Willow Grove NAS for an Airshow. Let me know.
Later
F4UDOA
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F4u,
E-mail me, I can probably help you with some of that info...
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The NACA Report # 829, that F4UDOA posted the link too, is the one I had printed out at home and was thinking of. It has alot of data on the P-51B, P-39 (P-63?), F6F, F4U, Helldiver, Brewster Buffalo, F4F (FM2?), Dauntless, Catalina, and a couple of others.
Also if you use that search engine I posted the link too, and use "Flight Characterisitics" as search keys, you will find ALOT more reports, but most of them you will have too order.
Good Luck!
F4UDOA, On Memorial Day I came up to Lancaster (first time since last time I told you about it) and helped my girlfriend to move down to live with me, so I probably won't be up in that area, unless I come to Philly for work (which happens occaisonally). If I do, we can arange to meet for dinner and a beer. I would have tried on Memorial day weekend, but there wasn't any spare time, and it was a nightmare moving her 450 miles.
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Vermillion
**MOL**, Men of Leisure
"Real Men fly Radials, Nancy Boys fly Spitfires"
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After spending a few minutes trying to figure out what you guys are talking about, I think that I finally have a clue how my first grade students must feel while they are learning to read.
eskimo
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in a book, i found a typical polare for a laminar wing. According to the book the advantage of low drag disappears complety in a situation of high AoA. Is this right?
(http://www.stud.mw.tum.de/~sl1/flugmechanik/laminar.gif)
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Yep Niklas, that would be true. Because a laminar flow wing has it's thickest point further back along the chord length, it also has a steeper angle to the trailing edge, which causes separation (drag) sooner (lower angle of attack) than on a more conventional wing. Usually, when separation starts at the trailing edge, the separation point creeps forward as angle of attack is increased. When the separation point is ahead of the thickest part of the wing, the wing stalls completely. This also happens quicker with a laminar flow wing because the thickest part is closer to the trailing edge. This is why laminar flow wings don't give much stall warning and any changes in angle of attack should be made slowly and smoothly (flying technique).
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yes thats what they are showing there, the Cw(x axis) they have listed is the section drag coefficient of the airfoil, and the Ca(Y axis) is the lift coefficient. Its easier to picture the graph if you flip it 90 degreees to the left IMHO. Then you see that at low AOA (positive or negative) the section drag is much lower but by the time you get to typical values of +- .4 values for the lift coefficient the benefit disappears and the wing actually produces more drag. So what does it mean? Basically, you should keep the mustang fast and not pull back on the stick much, because its wing is designed for cruise at high speeds with low wing loadings (http://bbs.hitechcreations.com/smf/Smileys/default/smile.gif)
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This thread scares me. (http://bbs.hitechcreations.com/smf/Smileys/default/wink.gif)
I hate it when you put a whole bunch of really smart people together and they communicate in an challenging, yet open and non threatening manner.
I was getting used to the insecure types who love to maintain the status quo and can't see anything except the inside walls of their respective boxes.
I just hope when you're all done, someone will put it into layman's terms for us country boys. (http://bbs.hitechcreations.com/smf/Smileys/default/smile.gif)
<Salute> to all of you.......
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I just hope when you're all done, someone will put it into layman's terms for us country boys
Plane go fast and fly? (http://bbs.hitechcreations.com/smf/Smileys/default/biggrin.gif)
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Vermillion
**MOL**, Men of Leisure
"Real Men fly Radials, Nancy Boys fly Spitfires"
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All I know in RL is how to fly em....get out of the classroom and take a spin at your nearest cessna dealer (http://bbs.hitechcreations.com/smf/Smileys/default/smile.gif) You might enjoy it (http://bbs.hitechcreations.com/smf/Smileys/default/smile.gif)
Rude Out!
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All I know in RL is how to fly em....get out of the classroom and take a spin at your nearest cessna dealer, you might enjoy it (http://bbs.hitechcreations.com/smf/Smileys/default/smile.gif)
Rude Out!
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So how much too slow, on average, are the turn rates in AH?
lazs
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I would guess about as much as WB turn rates are too fast.
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jochen Jagdflieger JG 2 'Richthofen' Aces High
jochen Geschwaderkommodore (on leave) Jagdgeschwader 2 'Richthofen' (http://personal.inet.fi/cool/jan.nousiainen/JG2) Warbirds
Thanks for the Fw 190A-5 HTC!
Ladysmith wants you forthwith to come to her relief
Burn your briefs you leave for France tonight
Carefully cut the straps of the booby-traps and set the captives free
But don't shoot 'til you see her big blue eyes
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so joc... 20% on average? Except of course the LW planes which are actually a little fast in AH and the Hog which is about 30% slow?
lazs
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Prove it Lazs...
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funked, u spent a lot of time convincing me that WB was right... Now AH is right... You showed yourself that AH's fastest turners are off by 10% or more from VVS stuff and you show WB 10-30% below that. I know you know that a Corsair should turn 30% better than an A (LOL) 8 so that one is way off. All together.... AH is 30-50% slower than WB.
Hey, no big deal if they get comparitive (make everyone off the same %) rates right except that a slower turn rate makes for a slower game and less acm... It gets boring quicker and attracts fewer new players. I like allmost every other aspect of AH's flight model better tho. The endless "hartman stomps" are out.... The very frustrating Warp rolls are all but eliminated. Fix the comparitive turn rates and it would be a step in the right direction tho.
lazs
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lazs
Wasn´t it a A5 that was outturned in a flight test by a f4u, where the f4u gained one in 3 turns? And didn´t you mentioned that the P51 was only a bit worse in the circle time compared to the f4u?
Now:
The P51 has a laminar wing. It has a lot of drag in a situation of high AoA. The laminar wing doesn´t allow as high maximum AoA like a usual fighter airfoil (naca230, fw190). max AoA of a laminar wing is highly dependent on the quality surface of a wing. You can read in the naca829 report that the surface of wing of the P51 was changed, improved.
consider high drag in a high AoA situation and less max. possible AoA and you know why the P51 could NOT easily outturn a fw190. And if your test report tells you something different, well than i think something was wrong with the FW. And NEVER believe in tests which compares aircrafts. Find a number for the minimum circle time of a Fu4. That would be interesting!
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Lazs, I never did any analysis of turn rates or radius in WB. I have no idea what you are talking about.
". I know you know that a Corsair should turn 30% better than an A (LOL) 8 so that one is way off."
Don't know that at all.
[This message has been edited by funked (edited 06-09-2000).]
[This message has been edited by funked (edited 06-10-2000).]
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niklas... The A5 should turn much better than the pig of an A8. In the tests the Corsair gained 1 turn in three on it and turned slightly better than the 51B. That would give the P51 a huge edge against the 190 still and that matches all the anecdotal stuff out there. Corsair and P51 pilots knew that the Hog would turn inside a 51b,c or d. Hellcat pilots knew they could squeak by a Hog in the turn.
The A5 is coming soon... Do you say that it should turn 30% worse than both the Hog and the current A8? Do you see the problem? As new planes are added the problem is compounded.
lazs
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Doh Beaver No he said that her bobs are big!
Sorry guys I was having a hard time understand this one hehe but finally Butthead explain it to me.
Bash
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Lazs,
Nothing is known about the conditions in which the F4u could gain 1 in 3 turns on the 190. Was the 190 cruising along while the F4u *bounced* him at greater speed? There is no other explanation other than a cautious 190 pilot. Sure, an F4u could turn inside a 190, but gain 1 in 3 turns? Not from co-E states!!! You must have that report that says the 190 can out-turn a 38F above 140 mph??? These fly-offs make me laugh, even more so, now that I've seen the results from the Fighter Conference!
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"That would give the P51 a huge edge against the 190 still and that matches all the anecdotal stuff out there."
Nope, sorry.
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Originally posted by funked:
"That would give the P51 a huge edge against the 190 still and that matches all the anecdotal stuff out there."
Nope, sorry.
LOL
I don't turn. I set my controls up so I CAN'T turn. I fly the Mustang like it's a Mustang. It kills 190's dead. You stick to your Luftwaffe stuff. (http://bbs.hitechcreations.com/smf/Smileys/default/wink.gif)
(http://www.geocities.com/tas13th/vosssig.jpg)
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I have been wondering if some of the modeled AC over-accelerate in a dive at lower altitude (thicker air) compared to the real AC figures which I don't know. There is supposed to be lot of technical stuff on WW2 plane performance in the national archives if somebody can figure out how to access the data.
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wells... that data was from a test with a captured 190A5 against both a Hellcat and a Corsair and done by the TAIS.
"the hellcat and Corsair were far superior to the FW 190 in turning circles and characteristics. The Corsair and Hellcat could follow the 190 in turns with ease at any speed, but the 190 could not follow either of the other two airplanes(8690lb/197sq ft/44.1; Hellcat 12406 lb/334 sqft/37.1 lbs/sqft; Corsair 11988 lb/314 sqft/38.1 lb/sqft)" " From a head on meeting with the FW 190 both the Corsair and Hellcat could come directly behind it in one turn. From a position directly behind it it was possible to turn inside the FW 190 and be directly behind it again in about 3 turns."
These test were with an A5 and . Other comparitive tests with a P51B are revealing as to Corsair and Hellcat turn ability. Hey. they may not have climbed that great but at least give em their turn ability. Bet they would be used more.... And not for the cannon.
lazs
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USN test says F4U-1A out-turns P-51B.
AFDU test says Mustang Mk III "had no difficulty in out-turning" Me 109G-6.
Therefore the F4U-1A should have no trouble out-turning Me 109G-6. (http://bbs.hitechcreations.com/smf/Smileys/default/biggrin.gif)
Something that may be important is the spoiler they put on the F4U to stop it dropping a wing at stall - what effect did it have on turn performance? Did those trial planes have it fitted or not?
[This message has been edited by juzz (edited 06-11-2000).]
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I'm a sim pilot Jim, not a areospace engineer!
Well the way I read it, the corrected data is tighter that the not corrected data.
So when is this new Pony coming out?
Mr.ED
327th A.C.G.
[This message has been edited by Mr.ED (edited 06-11-2000).]
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AFDU said turn fighting the 190 in the P-51A was "not altogether recommended". P-51B/C/D are much heavier than the A. You think they turned better?
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Probably the US pilot driving the 190A5 on that test had 0 hours experience with that plane, probably that pilot was not taking the best from that A5. Anyway, as far as I know, F4U was anything but an agile aircraft.
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From the original document:
Prior to the comparitive tests the Fw 190 was stripped and painted with standard smooth finish camoflage finish, and the pilots were familiarised with the airplane.
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U.S. pilots new that a Corsair could turn inside a 51 or 47 with ease. Even in the "soccer" war of '69 those pilots all knew a Corsair could outturn a 51 and the 51 was no match for a Corsair under about 18K..... This is a carrier plane guys with a low wingloading and boosted ailerons and manouver flaps.... It don't climb spectacular but at least give it it's rightfull turn and acceleration performance. Wouldn't it be nice to have another useful plane that was also realistic?
Again... If our A (LOL) 8 turns this well... How will they model the more nimble A4.... You know, the one that a Corsair so easily outurned?
lazs
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It don't climb spectacular but at least give it it's rightfull turn and acceleration performance.
You know, acceleration and climb are very dependent on eachothers? Poor climb = Poor acceleration (in level flight)
Again... If our A (LOL) 8 turns this well... How will they model the more nimble A4.... You know, the one that a Corsair so easily outurned?
Our A-8? Does this mean that you somehow feel like being part of AH community already?
I bet I can arrange test here in AH where A-8 will gain 1 turn during 3 turns against F4U-1... Just don't ask me accurate details how I did it since you don't provide them either about real life test with opposite result.
On more serious note, I don't think that USN test is very conclusive... As test document says, pilots were familiarized with A-5 and off they went to the blue yonder. I bet they didn't have skil to fly A-5 to it's limits like they did have with F6F and F4U. That will skew the results against A-5.
How about looking scientific data? I think F4U does not have 33% lighter wingloading or 33% better lift...
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jochen Jagdflieger JG 2 'Richthofen' Aces High
jochen Geschwaderkommodore (on leave) Jagdgeschwader 2 'Richthofen' (http://personal.inet.fi/cool/jan.nousiainen/JG2) Warbirds
Thanks for the Fw 190A-5 HTC!
Ladysmith wants you forthwith to come to her relief
Burn your briefs you leave for France tonight
Carefully cut the straps of the booby-traps and set the captives free
But don't shoot 'til you see her big blue eyes
[This message has been edited by Jochen (edited 06-12-2000).]
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Jochen,
I don't really think the issue is how well the A-8 performes in the game currently. Remember this is a game based on real A/C. The A-5 does not currently exist in AH yet so we don't know how it will perform. What we do know however is that in 1944 the Navy Tested these A/C against one another in preperation for the invation of Europe and a possible encounter between these A/C. All pilots involved were veteren combat test pilots doing a tactical evaluation. Thier findings are very conclusive based on the fact that the Max speeds for the Fw-190 as well as rated horsepower and boost as well as the weighted condition were all in accordance to the captured manual they were using. In fact the F4U had engine problems during the test which may have slowed it down. For anyone on this message board to second guess their report would be a bit silly don't you think?
As far as the physics of the situation it is relatively simple. The wingloading of the Fw-190A-5 is simply to high to perform tight turns or loops. It is also stated in the report that the F4U accellerates better than A-5 up until higher altitudes. The F4U was known to have excellent accelleration during wartime and carrier waveoffs and I can quote several sources on this. The reason for this is also very simple and it relates to the climb of the Fw-190 as well. The propeller of the FW190 is a paddle blade propeller meaning that it is extremely efficient at low speed improving climb performance dramatically. This is also the case in the P-47D-25. When the Prop was changed to a paddle blade the climb improved almost 1,000fpm(using combat power) with no increase in engine horsepower. The F4U has a similer benifit because it used the largest prop on any WW2 fighter the 13'4" Hamilton standard. A larger prop generates more thrust IE greater acceration and climb. The AH FM while it is mostly accurate does not account for prop efficiency. In fact most people on this message board calculating the numbers do not account for it either . It is easier to rate them all at 80% efficiency at all speeds when in fact this is far from the truth. That is why actual flight test data is the one truth in flight testing. It is why you play the Super Bowl instead of reading the stats and calculating a score. Just because some very bright people have written a compute simulation does not make it so. My one true facination is with WW2 fighter A/C. Simulators just make it possible to express that feeling. If you modify the truth to fit your hobby then you are just "Gaming the Game" You can't change history.
F4UDOA
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[sarcasm]But we have to remember that all German tests are 100% accurate, while Aliied tests are always biased against German kites.[/sarcasm]
Sisu
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F4U,
So what do you make of one person(s) who say the stall speed of an A4/A5 is 110 mph, while Eric Brown says it's 127 mph?? That's quite a difference! You have the Fighter Conference Report, don't you think those numbers are WAY too scattered to be considered accurate? Also, don't assume all the pilots involved are combat pilots. I have a report of a flyoff between a P-47D and a captured 190. The qualifications of the pilots were this...
The pilot of the P-47 had nearly 200 hours in P-40 type airplanes, with seventeen months of combat experience and had flown the test airplane five hours. The pilot of the Fw-190 had 300 hours in twin-engine aircraft and 500 hours in single engine airplanes, but had no combat experience. He also had five hours in the test airplane. Thus the pilots were about evenly matched
NOT!!! No amount of flying experience can make up for a lack of combat experience!
Also, check this out
The FW 190 was very heavy in fore and aft control, vibrated excessively and tended to blackout the pilot
That's what no combat experience does for ya. Oh yeah, the P-47 easily out-turned the 190 in that flyoff too! Is there any wonder why??
Sorry, but these type of flyoff reports are absolutely useless and provide no additional information that can't be determined from the physical attributes of the plane and a good physics model. It's up to the pilot, be in real life or simulation to get the most out of it!
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Geez Wells,
A little cranky today? Did you break your favorite calculator or something? The point is Wells that any physics model including yours doesn't mean anything until someone goes out and proves it. In this case we are talking about pilots. Fighter pilots to be specific. Not a bunch of engineers or application developers. I can e-mail you or fax you the Grumman physics model of the F6F-3 before it flew. Those engineers thought they designed the F8F Bearcat except for the fact that they were off by a mile. Has physics changed that much since 1943? I don't think so. The reason you have such a variance in test data is simple. It is also the reason engineers are often wrong and test pilots often die. Because airplanes don't fly in a vacuum. They fly in air with weather and wind and everything else that people forget when designing an aircraft. Do you think that the pilots that flew these test flights lied about their results to impress their superior officers. Marion Carl, Chuck Yeager, Ken Walsh to name a few Americans test pilots. These were tactical evaluations that their friends would rely on in combat against A/C they may or may not be familier with. The fact is that the top speed, stall speed and turning ability may vary from sortie to sortie but they do not vary relative to the A/C sharing the same airspace with it flying side by side. During the test between that FW190A-5 and the F4U-1D their is no doubt that one A/C could out turn the other. Would that vary with different pilots in different conditions, Yes. But not to a degree were you can either reverse the findings or disregard the test. The results were very definitive. And Wells, if my life depended on the result of weather a pilot or an engineer said an airplane could fly. Guess what, if my bellybutton is in the plane I'm listening to the pilot. These test are the single most accurate piece of history you have because the two A/C are in the same area at the same time. Anything else is just speculation.
You are an engineer Wells, explain why the P-47D could climb at less than 3000fpm and the the P-47D25 could climb at almost 3500fpm at the same rated power. Also explain why the Vought engineers went to the trouble of designing an airplane with bent wings and special landing gear just to fit an extra large propeller on it if there was to be no gain in performance? And how does that performance vary with alt. and speed? Is this modeled in the game? Do you have the Max lift coefficient of a Fw-190? What do you think the results should be?
F4UDOA
[This message has been edited by F4UDOA (edited 06-12-2000).]
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F4UDOA:
are u arguing or doing the agw-breast-thumbing-thingy.
danish
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F4UDOA if you are thinking that today's engineers can't predict aircraft performance better than 1940's engineers, you got another think comin'!
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Do you think that the pilots that flew these test
flights lied about their results to impress their superior officers.
Not at all! But I do think that any variance in the results is due to some *reason* that is up to the engineers to find and is irrelevant in a simulation. These reasons for lack of climb rate or differences in reported stall speeds or whatever, are not given in flight test reports for the most part and unless the person analyzing the report can fill in the holes, it's of little value in designing a simulation which is entirely based on numbers that have to make sense all of the time.
I can e-mail you or fax you the Grumman physics
model of the F6F-3 before it flew.
Please do! I would be interested in seeing that.
Also explain why the Vought engineers went to the trouble of
designing an airplane with bent wings and special landing gear just to fit an
extra large propeller on it if there was to be no gain in performance?
Well, to be honest, there was no performance advantage to building it with 'bent wings'. The P-47 didn't need bent wings nor did the Bearcat or Hellcat. The wings had to bend that way anyway for carrier ops and forward visibility was slightly improved (they needed all the help in that area they could get). The wing had 3% more surface area (drag) than it really needed, compared to if it were a straight wing. In the NACA report, they state that the gaps created between the wing panels had an adverse effect on the max lift coefficient as compared to the Hellcat.
A little cranky today? Did you break your favorite calculator or something?
Sorry I may have sounded that way, but really was not attacking you personally, only trying to provide a counterpoint in a hurry! (http://bbs.hitechcreations.com/smf/Smileys/default/smile.gif)
I'm pretty happy, I got my DVDrom working smoothly, so now I can watch my Roaring Glory Warbirds videos!!
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Wells,
I'm glad to hear your not flaming me too. Got enough people to deal with on these boards. You are always a voice of reason.
I guess the point of my post is to show things that would not be considered in a game design. For instance the F4U and F6F have the same engine and roughly the same drag (.0267 to .0272) but the F4U is significantly faster especially at sea level. Some 30plus knots faster. But there would be no way for a game designer using the AH method to factor that difference in the game using the current physics model. But the reason in fact is a more efficient low blower stage of the F4U engine. The air intakes are placed to inject air more directly into the engine. It also swings a slightly larger prop. But there is no way to model this without taking the word of people who flew and designed these A/C. I think this is a good example because everyone knows an F4U is faster than a Hellcat. So again when the Hellcat comes to AH will it be just as fast as the F4U or modeled to a historicly slower speed? And if so why??
Also what I meant about the bent wings wasn't that they were an advantage. The large propeller was the advantage and they built the entire A/C around it. The question then is why do it. What is the benifit of the largest propeller available and is this benifit reflected in the flight model? I really think that props in AH are all represented with an 80% efficiency at all speeds and conditions.
I will email you the Grumman report. I just need to scan it. Or I could fax it if you send me your fax #.
Later
F4UDOA
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All pilots involved were veteren combat test pilots doing a tactical evaluation. Thier findings are very conclusive based on the fact that the Max speeds for the Fw-190 as well as rated horsepower and boost as well as the weighted condition were all in accordance to the captured manual they were using. In fact the F4U had engine problems during the test which may have slowed it down.
I have news for you... 190 that was tested in RAE test had "rough running" engine which was caused by bad spark plugs. So it's nothing new to have plane performing below itäs par.
For anyone on this message board to second guess their report would be a bit silly don't you think?
It's not silly at all! RAE's report which compared captured 190 against Spit V and Spit IX is guestioned no end!
As far as the physics of the situation it is relatively simple. The wingloading of the Fw-190A-5 is simply to high to perform tight turns or loops.
Oh yeah? How do you explain P-38 turning so well when it does have much higher wingloading than even 190? There are many more factors affecting turn ability than wingloading alone.
The AH FM while it is mostly accurate does not account for prop efficiency.
Ummm... I'm not sure about that one.
That is why actual flight test data is the one truth in flight testing. It is why you play the Super Bowl instead of reading the stats and calculating a score. Just because some very bright people have written a compute simulation does not make it so.
My one true facination is with WW2 fighter A/C. Simulators just make it possible to express that feeling. If you modify the truth to fit your hobby then you are just "Gaming the Game" You can't change history.
Yep, I like WW2 fighters too. But if you blindly look historical evicence which is 60 years old without ANY critical attitude and scientific reaosning you will not get accurate results.
If you modify the truth to fit your hobby then you are just "Gaming the Game" You can't change history.
Yeah, but you can't change or forgot laws of nature or just forget parameters that surely will affect outcome of tests. Combat veteran of Lufwaffe did fly 190 to it's limits unlike some test pilot that have few hours of experience in 190 and NO combat experience.
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jochen Jagdflieger JG 2 'Richthofen' Aces High
jochen Geschwaderkommodore (on leave) Jagdgeschwader 2 'Richthofen' (http://personal.inet.fi/cool/jan.nousiainen/JG2) Warbirds
Thanks for the Fw 190A-5 HTC!
Ladysmith wants you forthwith to come to her relief
Burn your briefs you leave for France tonight
Carefully cut the straps of the booby-traps and set the captives free
But don't shoot 'til you see her big blue eyes
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gotta side with F4U on this one. I will pick a comparisson test over single tests any day and I don't have much faith in engineers predicting the performance of these planes.
Take one test of 190's in Germany in 1942 using a third year combat vet in wintertime running balls out to get to 5k as fast as he can.... Take a 200 hr U.S pilot in the Mojave desert in summer trying to get best climb to 20k and then say "the FW 190 climbs at xxxxfpm at 5k and the p51 climbs at xxxxfpm at 5k" No, I like comparisson tests where the planes are flown on the same day by the same pilots side by side.
In the 190 test the results were very conclusive... ALL the pilots said they could follow the 190 with ease.... All the pilots said the 190 was very simple to fly but had a vicious stall... If they didn't fly it hard how did they know it had a vicious stall? the vast weight of anecdotal combat reports and all the comparisson tests all point to the fact that a 190 is easily outturned by a 51 and that a Corsair outurns a 51... If you read "Soviet Fighters" you will LOL at the "engineers" predictions for soviet planes and their actual performance. Certainly our modern engineers can do more than they could in '44 but I don't think they can do it with the data they have available for these WWII planes. How do we know how each prop performed exactly for instance? It seems here that people want to believe that a 190 will turn with a Corsair or a p51.
joc... I pay my fee just like any one else. Or does pointing out the emperors lack of clothing make you not one of the community?
Oh... every test I've seen of a 190 said that it ran rough at low speeds, most say that it cleared out at high speed. The Brits blamed it on bad plugs, My guess is that the automatic controls cause this problem and that it is common and not a big deal..
lazs
[This message has been edited by -lazs- (edited 06-13-2000).]
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Jochen,
I am not making a statement about anyone A/C performance as I am asking an open question. I would like to know if the current FM design characteristics take into account things like propeller performance and historic differences that cannot be accounted for with any of the basic criteria for flight performance. I will give two examples.
A. The F4U and F6F. Both had the same rated HP. 2,000HP. Both had approximately the same drag coefficient. F4U=.0267 F6F=.0272 Both had approximately the same wing span, area and Propeller. Then why was there such a disparity in performance and how would this be factored into AH using the current FM design points?
B. The P-47 is on it's way. Well if you get a P-47D5 you will find out that the max rate of climb is aprox. 2700fpm using combat power. If you get a P-47D25 you will get an A/C that climbs at nearly 3400FPM combat power. Why the differance? Because of the change of propeller. Is this accounted for in AH? I have no clue?? Do you Jochen, Funked? Please don't tell me you think so if you don't know for sure. The F4U is faster than the F6F because of a more efficient means of intaking the air into the engine and the turbo but this seemingly cannot be accounted for in the current format. If we are to have a P-47, F6F and F4U in the same simm then we should have three different FM's. It is not as simple as a BF-109F4, G2, G6 and G10 where you have a significant increase in HP to represent the performance increase. The differences are clear but not as easily defined.
By the way Jochen, the P-38 couldn't turn worth a crap. That's why the Fowler flap installation was installed. It increased the wing area over 30% drastically increasing lift coefficient. That was good enough to turn with German iron but it wasn't anymore effective at dogfighting with Jap A/C as any other Army mount. That is a good example of an easily defined performance feature.
Later
F4UDOA
[This message has been edited by F4UDOA (edited 06-13-2000).]
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No turbo on F4U or F6F. I haven't noticed any large disparities between tested top speeds and climb rates for the aircraft in the game, except for the Me 109G-10, which seems to be an Me 109K-4.
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Funked,
Ommit the word "turbo" and insert "Low Blower". The PW-R2800 was a Mech two speed two stage 18cylinder engine. It used compressed air in both blower stages to feed the engine.
In any case you didn't answer my question. Why the difference in performance in the F4U/F6F and P-47D5/P-47D25? and are these factors modeled in AH?
F4UDOA
[This message has been edited by F4UDOA (edited 06-13-2000).]
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DOA: I'm sure those differences can be explained by variations in powerplant installation, propeller characteristics, and airframe drag. You'll have to ask Pyro and Hitech to answer your second question though.
Lazs: since that USN Fw 190A-5 test was such a good one, you're saying the AH A-5 should be faster than the F4U-1D above 15,000 feet?
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except for the Me 109G-10, which seems to be an Me 109K-4
What should the difference be between a G10 and a K4?
The reason I ask is because the G10 was produced at the same time as a K4. The G10's were just upgrades of G6's to meet K4 performance specs including (for the most part)the new engine in the K4.
The only difference I can think of without referring to my notes is that the K4 had a smoothed out cowling and some changes in the oil cooling system (or a larger oil capacity - can't remember off hand).
The performance difference should be neglegable, shouldn't it?
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Funked,
Your right it is the power plant installation. But how is that modeled in AH.
The same for the P-47d models. How is that to be represented in AH. After the HOG the Thunderbolt and F6F are my favorite mounts you know.
Also the test between the A-5 and F4U did not reach top speed. The speeds were taken after short speed runs. Although the performance advantage over the F6F is notable especially below 10k.
Funked, I did some testing last night with Troxel after our Ladder duel(after he used me like a cheap potato)in a F4U-1C and a
Bf-109G-10. I found that with flaps and WEP in both A/C that in a purely flat turn I could stay on his tail no problem and he could not follow me. However if he used his virtical ability he could make high side runs on me all day and I would have no place to go. The F4U in AH is a complete dog in accelleration at low speed. Due to the fact that the F4U had to qualify for carrier waveoff landings it seems odd. In fact the F4U has lower power loading according to AHT at sea level than a P-38L which has excellent accelleration in AH. In fact the only american A/C that are better are the
FM-2=7487lbs 1260HP HP/LBS=5.94
F6F-3=12213lbs 2000HP HP/LBS=6.11
F4U-1D=12289lbs 2000HP HP/LBS=6.14
P-38L=17699 2850HP HP/LBS=6.21
Not surprisingly the Carrier fighter have a better ratio for carrier takeoff and landing. The F4U and F6F ratio changes with loading but I listed them as they appear in AHT. So I also cannot understand why the F4U accellerates so poorly in AH considering it has better power to weight, an enormous propeller and a lower drag coefficient than the P-38L?? I realize that the G-10 has a large advantage in power loading over the F4U but the difference between the F4U and P-38L seems a bit off. I will do some testing I give you numbers on it. I am starting to believe it is the acceleration and not the turn ability of the F4U that is affecting flight performance.
Thanx F4UDOA
[This message has been edited by F4UDOA (edited 06-13-2000).]
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Kats, based on flight test data, the difference should be about 30 mph. But here the G-10 is good for 450 plus. (http://bbs.hitechcreations.com/smf/Smileys/default/smile.gif)
DOA, try some acceleration tests at different altitudes. I already did a bunch of stuff for P-38 and P-51 here: http://bbs.hitechcreations.com/smf/Smileys/default/Forum9/HTML/000516.html (http://bbs.hitechcreations.com/smf/Smileys/default/Forum9/HTML/000516.html)
The way I did these was to put the plane on autolevel a couple hundred feet above the target altitude, then idle the throttle. The airplane would sink and the TAS would drop below my start speed right as the altitude hit the target altitude. Then I would firewall the throttle and engage WEP. The plane would hold altitude, then as the speed increases to my start speed I hit the stopwatch.
[This message has been edited by funked (edited 06-13-2000).]
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A. The F4U and F6F. Both had the same rated HP. 2,000HP. Both had
approximately the same drag coefficient. F4U=.0267 F6F=.0272 Both had
approximately the same wing span, area and Propeller. Then why was there
such a disparity in performance and how would this be factored into AH
using the current FM design points?
I think you are being too general in your observations. The wing areas are not as approximately the same as you might think when it comes to performance, nor are the drag coefficients. That's why they are measured to 3 significant figures. Example:
F4u = 0.0267 * 314 = 8.38 < drag index (note typo in AHT)
F6f = 0.0272 * 334 = 9.08 < drag index
So it can be estimated that the F6f is about 8% draggier or 4% slower than the F4u. If an F4u can hit 360 mph on the deck, then we should expect 346 mph from the Hellcat. That is pretty much true going by AHT. It looks like the Hellcat is even a tad better than that at 350 mph.
Or, looking at it in reverse, you could say that the F4u should be capable of 365 mph. If one factors in the 3% extra wing surface area on the F4u due to it's gull wing design, one could say that it accounts for about 1.5% loss in speed, which happens to almost exactly make up for the missing 5 mph.
[This message has been edited by wells (edited 06-13-2000).]
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Wells,
The F6F-5 was supposed to be able to do 350 on the deck. But if you look at the Navy's speed performance you will see that it only does about 330Mph at sea level. Another source that gives the same result would be the Fw-190, F4U, F6F test were again the F6F can only achieve 334MpH at sea level and the F4U reaches 363Mph. Also the F4U in AHT records a top speed of some 20Mph faster at altitudes above 20K. Even if Grumman's numbers are right the disparity at higher altitude still remains.
Do you know how to calculate thrust output from different propellers? With a 2000HP engine what would be the diffeence in thrust from say a 12'2" 4 blade prop vrs a 13'1" prop. I am looking for pitch and chord info on them but I'm curious about the thrust differential.
Thanks F4UDOA
Scanning those Grumman docs for you.
[This message has been edited by F4UDOA (edited 06-13-2000).]
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There was a 20 knts instrument error in early F6f's (found by flying with a Corsair in formation), that was later corrected, after the -3 model, I believe...and maybe retrofitted to some earlier planes. The Hellcat is a 400 mph airplane.
As for propellers, it is ideal to use an airfoil that has a good Lift/Drag ratio as well as high aspect ratio for the blades without having such a narrow chord that the low Rn (Reynolds number) adversely affects drag. Any drag equates to torque, requiring more power to turn the same RPM. The power required to turn a 12'2" prop at the same RPM as a 13'1" prop varies to the 5th exponent.
(12'2" / 13'1")^5 = 70% power required
Propeller efficiency is a function of disc area vs power. The larger the disc area for the power, the more efficient (ie, helicopter).
If 2000 hp is turning the 13'1" prop, then about 1400 hp would turn the 12'2" prop.
Maximum efficiencies at say 200 mph are 93.7% for the large prop/engine combo vs 94.9% for the smaller prop/engine. If 2000 hp is turning the smaller prop, efficiency drops to 92.8%. Real world efficiencies are about 85% of these values due to rotational and tip losses. I should point out that there is a larger difference in thrust efficiencies at lower speeds. At 100 mph, for example, maximum efficiencies are 65.2% vs 61.7% for the 13' and 12' props respectively.
Likewise, the number of blades affects the power and diameter requirements. Less blades is more efficient up to a point. Tip speeds need to be kept reasonable.
Going from 3 blades to 4 would require a reduction in diameter to 94.4% that of an equivalent 3-bladed prop (3/4)^1/5.
Where paddle blade props are concerned, more blade area is concentrated out towards the tips, where the majority of thrust comes from. Also, with a constant speed prop, the tips are almost always operating at an optimum angle of attack throughout the speed range, while the roots may stall at lower airspeeds, so it's beneficial to have more blade area towards the tip under those conditions.
[This message has been edited by wells (edited 06-13-2000).]
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Wells,
I read that to about the Hellcat pitot tube config. The Grumman engineers were screaming for years about it. It depends on who you listen too. Even after the mistake was corrected in the F6F-6 which was the comtemporary of the F4U-4 with again the same engine and prop it was still 25mph slower that the F4U-4. That is a conversation for another day.
Anyway I think I follow you on the efficiency's but how does that translate into thrust? Why not use a smaller prop if there is no advantage to using a larger one.
Another engineer friend of mine told me that a larger prop delivers more thrust. Is that a true statement?
Later
F4UDOA
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Anyway I think I follow you on the efficiency's but how does that translate
into thrust? Why not use a smaller prop if there is no advantage to using a
larger one.
Another engineer friend of mine told me that a larger prop delivers more
thrust. Is that a true statement?
Yes, a larger prop is more efficient.
The difference in thrust will depend on airspeed, so at 100 mph, there might be a difference of 300 lbs between the 2 props.
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funked the Hog had the wrong prop and was running lean and used wep for only 3min.... Under those conditions..... Yes I believe the 190 should be faster at 15K.
lazs
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Wells,
I am reading "The Illustrated Guide To Aerodynamics" and it discusses optimizing propeller efficiency ranges to suit the needs of an aircraft IE if an A/C needs to cruise at 200mph then the prop would be optimized for 200mph max efficiency. And If you need an A/C to climb steeply you would optimize it's range at 150mph. By following this logic I am looking at the P-51 and P-38 which were purpose built for long range cruising as well as their best climb speed being around 200mph. I am also assuming that their best prop efficiency is in the 200mph range. By contrast you can say that the F4U and F6F which have a best cruise at 170mph and 150mph respectively and also have a best climb speed of approximately 140mph would have propellers that were at max efficiency at 150mph. Due to the purpose build of a carrier fighter having a need to take of in a short distance and have the ability to wave off of landing with extreme low speed acceleration I think it is a reasonable assumption. In that case the standard power loading tables would have to be re-evaluated. See if you agree with my concept. My numbers are not accurate since I am not sure of the calculation for prop efficiency.
All numbers for sea level max fighter weights
P-38L combat Max horsepower 100%effic. 3200
150mph max brake horse power 75%effic. 2400
Power loading 100% effic.17699lbs/3200hp=5.53
Power Loading 75% effic.17699lbs/2400bhp=7.37
F4U-1D Combat Max Horsepower 100% effic. 2135
150Mph Max Brake Horsepower 90% effic. 1921
Power Loading 100%effic. 12289lbs/2135hp=5.75
Power Loading 90%effic. 12289lbs/1921bhp=6.39
This would mean that the F4U would accellerate at a higher rate at low speed relative to those aircraft that are purpose built for a high speed cruising condition. I think what is taking place in the current FM is that all prop efficiency's are modelled at 80% throughout the speed range causing certain aircraft to loose characteristics that they were reputed to have. This would also effect such A/C such as the N1KI and the FW-190A8 as well as the F4U and any future modeling of the F6F or P-47D-25.
Wells if I snatch the pebble from your hand may I leave the temple??
Later
Grasshopper
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A propeller's design (twist) is optimized for a certain advance ratio (ratio of forward speed to RPM) to give optimum angle of attack at all points on the blade. For the most part, designing for speed is also designing for cruise. Example: 300 mph @ 3000 rpm is the same as 200 mph @ 2000 rpm. That's one area of performance that I have yet to do much research with WW2 planes, not having very good access to them. I would like to measure the twist of the propellers used on these planes!
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How would you measure it Wells? I'll be in Dayton visiting my grandparents soon...
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I dunno funk,
Some kind of incidence meter placed at various intervals along the blade, say 0.25r, 0.5r, 0.75r and 1.0r (the tip). I'd imagine that it would be very clumsy to try and measure it while it's on the plane (if they'd even let you?). Maybe they have the specs for the propeller hidden away somewhere in some kind of manual?
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Too bad I don't work for Ham. Std. any more. (http://bbs.hitechcreations.com/smf/Smileys/default/smile.gif)