Author Topic: F4U vs. F6F (Read 14458 times)

Brooke · « **Reply #60 on:** March 23, 2006, 02:01:23 AM »

Quote

Originally posted by DamnedRen
Correct, oldman. But, it WAS started by Bob Prescott (original Flying Tiger) and even Pappy Boyinton worked for us when it first got going. We have annual reunions and Dick Rossi (original Flying Tiger) was always at em if yer interested in old tales of the real thing. I went to work for FTL in '81 and stayed with them until we were bought out by FedEx.

Here's the home page....http://www.flyingtigersavg.com/

That's pretty nifty! Sounds like a fun and good place to work.

Brooke · « **Reply #61 on:** March 23, 2006, 03:39:24 AM »

The book AMERICA'S HUNDRED THOUSAND, by Francis H. Dean has a huge amount of data, including comparative data, on the US WWII fighters. It is an awesome tome. At the end, it has lots of comparative data.

Speed: F4U-1D is 10-20 mph faster than F6F-5 (depending on alt)
Climb: F4U-1D climbs better than F6F-5 (1-1.5 minute faster to 10k)
Range, no drop tanks: F6F-5 300 miles longer than F4U-1D
Roll rate: F4U-1D better than F6F-5 (by a lot at higher speeds)
Turning performance: F6F-5 a lot better than F4U-1D (see below)
Dive acceleration: F4U-1D better than F6F-5
Limit dive speed: F6F-5 better than F4U-1D (only by 6 mph)

Turn radius (scaled units, as estimated by speed for 3g stall at gross wt.):
FM-2, 12.0
P-63A-9, 14.9
P-61B-1, 16.0
F6F-5, 16.5
P-51D-15, 21.5
P-38L, 24.6
P-47D-30, 24.7
F4U-1D, 25.4

Note, this is turn radius assuming each aircraft can sustain a 3 g turn, no better, no worse, and so does not properly include the effect of engine performance. Still, it's interesting that the F4U-1D comes out so poorly in this. The book estimates that this is because the F4U-1D had a "spoiler placed on the right wing of the Corsair to eliminate an unsymmetric stall problem" that is estimated to drop the overall lift coefficient by a lot ("in fact an NACA test report notes this was indeed the case").

In the end, I think it boils down to the fact that the F4U-1D is faster and rolls better than the F6F-5, was much worse in lower-speed turning, but in real-life combat, lower-speed turning was not as important as speed and roll rate.

(As an aside, many people are mistaken about the idea that bigger, heavier aircraft have poorer turning performance. This is not what determines low-speed turning performance. If a big, heavy plane has a large wing with good max. lift coefficient, it will turn well, like the P-61 Black Widow.)

F4UDOA · « **Reply #62 on:** March 23, 2006, 12:17:10 PM »

Brooke,

The Clmax listed in America's Hundred Thousand are mostly way off hence the turn calculations are way off.

SgtPappy · « **Reply #63 on:** March 23, 2006, 02:18:38 PM »

quote:

"In the end, I think it boils down to the fact that the F4U-1D is faster and rolls better than the F6F-5, was much worse in lower-speed turning, but in real-life combat, lower-speed turning was not as important as speed and roll rate." - Brooke
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lol i screwed up the auto-quoting but anyway...

that can be argued though, rite? cuz speed and roll rate are definitely very important, and as some pilots say, turning doesnt win fights... but the Hellcat's turning ability allowed it to dogfight with japanese planes (as widewing said) and THAT single ability made the japanese more fearful of the F6F.

F4UDOA · « **Reply #64 on:** March 23, 2006, 03:58:22 PM »

Quote

but the Hellcat's turning ability allowed it to dogfight with japanese planes (as widewing said) and THAT single ability made the japanese more fearful of the F6F.

That is pretty subjective, I prefer to stick with the facts.

In terms of history you can point to the fact that the F4U scored almost twice as many kills in 1943 than the F6F and that a great many F6F kills (over 1,000 in Oct 1944 alone) were scored against inferior pilots. In fact there were 4 20 kill aces in the F4U by January of 1944, Aldrich VMF 215 20kills, Hanson 25kills VMF 215 , Boyington VMF 214 22Kills, and Walsh 21Kills VMF121.

The F6F may have been the King of the Kills for 1944/45 but in 1943 it was the F4U. Also it was the F4U in the Solomon Island campaign during that time.

From March of 1944 to December 1944 in 10 months the F6F scored 2459 kills. During the same period of time the F4U scored a 71kills and if you eliminate December for the F4U it only had 16kills in 9 months of 1944!!

The rest of the war was more evenly distributed.

Saxman · « **Reply #65 on:** March 23, 2006, 05:11:59 PM »

FD: I'm pretty firmly in the F4U > F6F camp, but as a point of order, wasn't the F4U beginning to see combat as early as Feb/March, with the Fatcat's combat debut on 1 December? A better measure would probably to figure the average number of kills/month of service.

Interesting thing to point out is that of those roughly 1000 kills the F6F scored in October 1944, a HUGE chunk would have been recorded during the Turkey Shoot/Battle of the Phillippine Sea.

SgtPappy · « **Reply #66 on:** March 23, 2006, 06:06:56 PM »

true, but the Hellcat was shooting down more planes per month, at least early on. and the plane entered, like u sed, almost 1/2 a year after the F4U entered WWII, and still destroyed more planes with a better kill ratio. there were more, yes, but thats also something to consider. the hellcat was built to easy to produce, and in war, a huge lot of relatively ok overall performers is better than a tiny amount of great overall performers. so, because of its easier productivity, the hallcat can be considered pretty much just as great as the F4U.

... by the way.. its Philippines

Masherbrum · « **Reply #67 on:** March 23, 2006, 06:41:23 PM »

Quote

Originally posted by Jebus
What plane had the biggest impact in WW2.

Fw-190 series.

Karaya

SgtPappy · « **Reply #68 on:** March 23, 2006, 07:55:29 PM »

lol really now.. however.. i think we should get back to the F6F vs. F4U stuff =p

Widewing · « **Reply #69 on:** March 23, 2006, 08:34:03 PM »

Quote

Originally posted by F4UDOA
That is pretty subjective, I prefer to stick with the facts.

In terms of history you can point to the fact that the F4U scored almost twice as many kills in 1943 than the F6F and that a great many F6F kills (over 1,000 in Oct 1944 alone) were scored against inferior pilots. In fact there were 4 20 kill aces in the F4U by January of 1944, Aldrich VMF 215 20kills, Hanson 25kills VMF 215 , Boyington VMF 214 22Kills, and Walsh 21Kills VMF121.

The F6F may have been the King of the Kills for 1944/45 but in 1943 it was the F4U. Also it was the F4U in the Solomon Island campaign during that time.

From March of 1944 to December 1944 in 10 months the F6F scored 2459 kills. During the same period of time the F4U scored a 71kills and if you eliminate December for the F4U it only had 16kills in 9 months of 1944!!

The rest of the war was more evenly distributed.

What you neglect to mention is that the F6F didn't see combat until August 28, 1943 and then in limited numbers initially. Kinda skews the results a bit...

My regards,

Widewing

Brooke · « **Reply #70 on:** March 23, 2006, 08:34:36 PM »

Quote

Originally posted by F4UDOA
Brooke,

The Clmax listed in America's Hundred Thousand are mostly way off hence the turn calculations are way off.

The turn calculations are based on stall speed at 3 g's, which according to the text was measured in flight tests. If so, the turn calculations are spot on, given the provision of 3 g turns, of course, which was noted in what I posted.

Widewing · « **Reply #71 on:** March 23, 2006, 08:39:03 PM »

Quote

Originally posted by F4UDOA
Brooke,

The Clmax listed in America's Hundred Thousand are mostly way off hence the turn calculations are way off.

Dean used NACA report 829 for CLmax data on the F6F and F4U... Are you saying NACA was wrong?

Get it here.

Furthermore, you have stated that Dean's Drag Coefficient of .0267 for the F4U is also wrong. However, he obtained this from NACA Report WR-ACR-L5A30, A Summary of Drag Results From Recent Tests of Army and Navy Airplanes.

It seems to me that every data point cited by Dean that rains on the F4U love-fest is dismissed as an error. Yet, Dean obtained the data from NACA test reports. Therefore if you believe it's wrong, you'll need a more authoritative source than NACA, and I have some doubts that such a source exists.

My regards,

Widewing

F4UDOA · « **Reply #72 on:** March 23, 2006, 10:30:35 PM »

Widewing,

I agree with NACA. Did you actually read the document you referenced? As for my F4U lovefest you might notice the name of this thread is F4U Vrs F6F. The next P-38 lovefest you can do the fawning.

My information comes from when I was standing in Mr.Dean's study a few years ago before he passed and I asked him where he got those Clmax numbers. He got (at least some of them if not all of them) from the 1944 Joint Fighter Conferance test results of 3G stalls. Most of them make no sense what so ever when compared with real life Clmax numbers.

The only one that is accurate is the F4U at 1.48 which may have come from the NACA report burried somewhere but I doubt as it only makes reference to the F4U Clmax of 1.88 with full flaps or 1.17 or 1.26 on page 25 with no flap and no propellor. I know you didn't read the thing or you would have seen that.

America's Hundred Thousand list the F6F-5 Clmax as 2.27. NACA shows it on page 25 with no flap and no propellor as 1.40 approx and approx 1.9 with prop idling.

So no NACA is not wrong but it also has nothing to do with the Clamx numbers in AHT.

What is the Clmax of the F4U and F6F? That is easy on most A/C such as the F4U, P-51 etc. Except the pitot tube error is so bad on the F6F that the CAS chart still makes it subjective. The IAS stall is roughly 73Knots and the pitot error says add 4Knots so that puts the stall at roughly 90MPH at 12,000lbs.

Both from the Pilots Handbooks

12,000 * 391 / 90^2 * 334
4692000 / 2705400
Clmax = 1.73 Which I have to say is higher than I thought it would be.

The F4U-1

11,300lbs * 391 / 97^2 * 314
4418300 / 2954426
1.49 On the money

Now recalculate AHT performance index with the right Clmax. Also take a look at the 1944 JFC and notcie the Mr.Dean is the publisher of the minutes through Shiffer Books.

Now look at the real EM diagram for the F6F and F4U. Which one has the better turning ability?

F4UDOA · « **Reply #73 on:** March 23, 2006, 10:44:36 PM »

Widewing,

Here is a detailed drag analysis of the F4U-1 on page 13 of this Vought document.

Do you have the Army document you referenced? I would like to compare it.

Vought Internal Comparison

Brooke · « **Reply #74 on:** March 23, 2006, 11:22:29 PM »

F4UDOA, I see what you mean about the CLmax's.

You don't need CLmax to calculate turn radius (assuming a 3g steady-state turn). It is, using Newtonian mechanics and assuming I haven't made a calculation error, r = v^2 / a, where r = radius, v = velocity, and a = radial acceleration = g * sqrt(G^2 - 1), where g is acceleration due to gravity and G are the number of g's the pilot is experiencing. Thus, in a 3 g turn, r = v^2 / (2.83 * g).

In this case, if the F6F-5 has a 3 g stall speed of 139 mph = 62.1 m/s, r = 139 m.

If the F4U-1D has a 3 g stall speed of 172.5 mph = 77.1 m/s, r = 214 m.

If you scale things to "index units" so that 139 m is 12.0 index units, the radius for the F4U-1D comes out to 18.5 (not the 25.4 listed in the book).

So, the F4U-1D has a much larger turning radius than the F6F-5, but not as much larger as listed by the "index units" measurement in the book.

Thanks for pointing that out.

On a separate note, you got to meet Francis Dean, eh? That's very nifty! I love his book!