Unlikely Adversaries !

[JoeB]

409 mph is very fast for a F6F-5 (for the USN the F-5 with racks go to 330 knts and for FAA go to 392 mph (probably w/o racks))

USN official A/c characteristics booklet for F6F-5 dated November '45* gave top speed as 378mph at combat power=WEP at 18,000ft. However, AFAIK 409mph at 21,600ft (presumably at WEP) was a real number obtained by a production F6F-5 in trials v a captured Zero Model 52 and F4U-1D (which topped out at 413mph at 20,400, much closer to the F4U-1D's official max of 409 at 19.9k ft, per ACP dated Jan '45). As with some Japanese fighters, USN fighter official top speeds may have been considerably conservative in some cases. I suppose zero-length rocket rails or other pertuberances fitted or not also affected these numbers.

Tillman said in "Hellcat" that some units believed the -5 was both faster and climbed better than the -3, though according to official stats (comparing to F6F-3's ACP dated Oct '45), -5's best speed was only 6mph higher than -3's, and time to climb to both 10k and 20k ft definitely longer. Tillman himself quotes yet again different speed for the two versions, 388mph @ 25k ft for -3, 400mph @ 20k ft for -5, but gives no original source.

*by then the standard armament of F6F-5 was 4*.50 cal and 2*20mm but this weight and drag (of the barrels and fairings of 20mm) difference would not explain such a speed difference by itself.

Joe

 

[Vincenzo]

Oh, now i remember the TAIC report it's available on Williams site it's the only source give so high speed fo F6F-5, maybe that plane is a top Hellcat with superiour performance but hard to understand w/o also information.
The FAA data are congruent the Hellcat I had 371 mph speed with a 1650 hp engine, the Hellcat II had 392 mph speed with a 1975 hp engine (the cubic roots wirk fine taking in the count the difference in FTH)

 

[CORSNING]

Dag-nabit now guys, I got to go DJ now and can't get all the way into it. But the small difference in -3 and -5 speeds is because the -3 was retrofitted with water injection in the field and the -5 was slightly cleaner. And if you're going to pump out horse power figures for the Pratt and Whitney you better get them up to 2,000hp or better. And just one more thing, the early F4Us could eventually reach the 430mph. range. I just don't have any darn time to get into it now. But its great to see you all getting into this thread. I looking forward to reading all your views. Thanks Guys, see you later.

 

[CORSNING]

Before I start I must confess that I do not know enough about these two to do either of them justice. My main focus of study is on USSR, Japan and US aircraft of WW2. So I'm just going to post what I have found to date. I went around and around in my mind on the graphs on these two. I studied what others considered "standard operational" and "tested potential" performance of both. My main sources are wwiiaircraftperformance, Kurfurst and Dietmar Harmann's Ta 152. I chose to go with the potential of the aircraft reached in tests. So, here goes. Altitude is in meters and speed is in mph.

Height.Fw-190D-9...Bf.109K-4
----0.....386...........369
1,000.....398...........385
2,000.....406...........400
3,000.....414...........410
4,000.....423...........419
5,000.....432...........430
6,000.....433...........440
7,000.....426...........450
8,000.....417...........444
Max.....437/5,300...452/7,100
I could not find a good graph on the D-9's climb but from what I have read WEP climb was in the 4,100-4,400fpm (?) range at sea level. There was some loss of roll compared to the A-8 but still way better than most other fighters and it held this roll rate at faster speeds. The main difference was its rate of turn at higher speeds increased.
The 109K-4 could outclimb the D-9 at any altitude as far as my information and could outturn the D-9 at speeds lower than 330mph. Above that I do not know (and I'm not afraid to say it). I have not studied these two aircraft enough to make any more statements.
A few things should be noted: The D-9 figures represent use of 2.02ata boost or C3 fuel and the K-4 figures represent the thin blade propeller. These figures are not representative of the majority of these two fine aircraft in the field. OK, it's time for someone way more knowledgeable than me on German aircraft to step in and set us all straight.

 

[CORSNING]

Retire Grumman test pilot Corwin Meyer described in detail why the F6F was rated below its actual maximum speed in Flight Journal magazine. It boiled down to incorrect positioning of the airspeed pitot tube. Due to this, an error of about 5 up to about 20 mph (depending upon actual airspeed) was seen on the airspeed indicator. Aircraft instrumented with independent test equipment showed this discrepancy. Grumman asked the Navy to allow them to change the location. However, the Navy did not wish to delay manufacturing (the modification wasn't a simple one) over an unimportant issue that added nothing to performance. Request denied.

In December of 1944, the Royal Navy issued a document to be distributed to all Hellcat squadrons either in or headed to the Pacific. This document, titled Naval Air Tactical Note 106, included test results of the F6F-5 conducted by; the Naval Air Intelligence Center at NAS Patuxent, Maryland. Within the document, the maximum speed of the F6F-5 was reported as 409 mph @ 21,600 ft.

In AHT, Francis Dean says on page 560 the top speed is 410 mph.

 

[Vincenzo]

I kept looking in my files and found a document that I had forgotten about. It catagorises the different rolls the Hellcat performed and lists the performance expected in each: Combat, Long range fighter, bomber,...ect.
In the combat (interceptor/air superiority) column it list the F6F-5's performance as 358 mph/S.L., 409 mph/19,900 ft. and initial climb at 3,370 fpm.

The real suprise is in the foot notes: CLEAN CONDITION: Same as Combat Condition except pylons and Fuse drop tank rack removed: V-max/S.L. 366mph, V-max 417/20,000 (Combat Power).

This document is titled AIRPLANE CHARACTERISTICS PERFORMANCE, Bureau of Aeronautics. That's Navy Department Bureau of Aeronautics, Washington 25, D.C.

I almost forgot, horse power is listed: 2,250 hp/2,700 rpm/ S.L. and test weight is 12,175 lbs.

strange 366 (358) and 417 (409) mph are the same speed for the F4U-1 in the same condition, also same weight, in the own AIRPLANE CHARACTERISTICS PERFORMANCE. i think maybe there is a wrong somewhere

 

[CORSNING]

Nice catch Vincenzo. Although the copy sheet is marked F6F, it is not. I looked it over closer and found the R-2800-8W was the engine used. That is F4U territory. It must have gotten in my Grumman files because of the topic F6F. Once again, nice catch and thanks. I'm pulling it and puting in the Chance-Vought files where it belongs. (And I edited my previous post).

 

[Vincenzo]

an other explanation that the 409 mph at 21.6k it is not a true TAS (like some german report maybe not correct per compressibility). however 21.6k it's high altitude for FTH with WI

 

[Glider]

Hello

In early 1944, the 31st Fighter Group was converting from Spitfires to Mustangs. After some time for pilots to get familiar with the Mustang, an informal dogfight was conducted between the Spitfire Mk IX and the P-51B. The result- both pilots concluded that the Spitfire had won the fight. The IX could out climb, out accelerate and out maneuver the P-51. The Mustang could out dive and out run the Spit. Now, I would guess that the 2 pilots each were more familiar with the Spitfire than the Mustang, but at least in this case, the Spitfire won.

Eagledad

The above can be found in Flying American Combat Aircraft of WWII pg 315

I don't know if it was that book or another but I did read once about a USAAF upit that switched to the Mustang. For some reason the commander was away, before he returned most of the pilots had checked out in the Spit and all preferred the Spit IX. When the commander returned he took up the Mustang really rang it out, landed and said that he would take the P51 any time. When he left the pilots looked at each other and one said the obvious, he had to say that, hes in charge.

 

[CORSNING]

Hi guys,
I haven't forgotten this thread. It just takes time to do a workup on aircraft. I'm a little over 1/2 done on one. I was thinking that the IJA and IJN definitely had there differences. The only places the U.S. armed forces seem to have a problem with each other is on a sports playing field or in a bar. So, what if in very early 1942 things had gone picture perfect for the Japanese. Then their armed forces started clashing on how to split up the goodies. That would be pit the A6M2 model 21 against Ki.43-II. Give me a couple more days and round one begins. I have some knowledge on there capabilities, I'm just fine tuning the graphs at this time. The Zero's maximum speed values are what has been holding me up. If anyone is interested...?