Bob Johnson's Johnson

[F4UDOA]

WW,

The F4U-1D was faster than the P-47D even with less HP at sea level. Also check the document on my website for Cdo listings of many American Fighter types of 1944. The F4U-1D is .020 and the P-47D is .022. There is a detailed breakdown of the F4U-1D drag including rocket rails, bomb racks etc.

Having said that I don't see why 470MPH would not be attainable at 32,000FT if an F4U-3 could do 480MPH at 64" MAP at the same alt?

[HoHun]

Hi Widewing,

>When Johnson said during my interview [...]

I hadn't realized it had been you doing the interview :-) Great job!

>I thought a speed just above 450 mph was reasonable, and I still think that it is.

I think we're not far apart here as my estimate arrives at a similar speed, too. The problem I see is only altitude - if we agree that Johnson's engine couldn't pull 72" Hg at 32000 ft, this means that at whatever the critical altitude for 72" Hg might be, the P-47D would be even faster there. If we take the 470 mph at 32000 ft literally, we might have a 480+ mph top speed P-47D.

I'd agree that just above 450 mph would be a reasonable speed for a 72" Hg P-47D, but at a lower altitude than 32000 ft.

>And believe me, there was nothing that Johnson was going to encounter in December of 1943 that could get within 60 mph of his Jug at altitude anyway.

Just for the trivia value, the Me 109G-1/R2 (GM-1 equipped) did achieve 410 mph @ 39400 ft. I figure it might do around 420 mph @ 32000 ft, which would be about the same as a standard P-47D.

>When I examine the power curve for the P-47M-1-RE, I see that it could reach 475 mph at 32,600 feet, pulling 72" Hg.

This partly explains the P-47M analogy - the P-47M reaches its top speed due to the ability to sustain high boost pressure at very high altitude. At equal altitude below critical altitude, the P-47M speed gain was mainly due to the "cleaning up" done to the aerodynamics.

(For the F4U-3 comparison, the full 72" Hg seem to be available only up to around 28500 ft from the R-2800-C, by the way.)

>Now about comparing drag between the P-47D/N and F4U-3. In terms of drag coefficient, the P-47D-25 thru M is lower than the the F4U-1D.

The F4U-4 comparison reports lists the F4U-3 as capable of 486 mph @ 30000 ft on 2800 HP, while the standard P-47D achieves only 425 mph on 2200 HP. That would give the standard P-47D a top speed of 461 mph, indicating a higher total drag for the P-47 than for the F4U-3. (I'm not sure the data for the F4U-3 is real flight test data, though.)

The second reference P-47 might be closer, though at 32000 ft estimates are a bit difficult due to the increased compressiblity drag.

Regards,

Henning (HoHun)

[HoHun]

Hi Nomak,

>Its a good thing Bob Johnson never saw hennings charts......He would have never got a kill  in his inferior US aircraft  

Which charts? Where did I call the P-47 an "inferior US aircraft"?

If you want to see what the P-47 is really worth, just superimpose the speed and climb graphs of the standard P-47D I'm using for comparison, and those of the Fw 190A-8.

The P-47D is slightly faster below 20000 ft than the boosted Fw 190A-8 (with erhöhtem Ladedruck), and much faster above that altitude. While the Fw 190A-8 has a slight climb rate advantage at low altitude, both types are equal at around 25000 ft, and above that the P-47D gains an advantage.

At 27700 ft, the P-47D is almost 70 mph faster than the Fw 190A-8 - I'd certainly not call that "inferior" :-)

Even the Me 109K-4, though it would easily outclimb the P-47D at any altitude and outrun it just fine at low and medium altitude, couldn't compete with the P-47D's speed above 25000 ft.

As the strategic air war in the ETO raged between 20000 - 30000 ft, the P-47D was certainly better suited for it performance-wise than the Fw 190, and was good enough to take on even the highest-performance Me 109 ever built.

If I'd to pick a WW2 fighter that the P-47 is "inferior" to, I'd select the P-51, not a Luftwaffe fighter.

(I'll leave it as an excercise for the reader to figure out what I think the best WW2 piston fighter was.)

Regards,

Henning (HoHun)

[-ammo-]

I would guess at a bearcat, but that depends on what you mean by "WWII AC".

My money would be on the P-47D as the allied fighter AC that that had the most impact on the air war over europe

[Widewing]

Originally posted by HoHun
Hi Widewing,

The F4U-4 comparison reports lists the F4U-3 as capable of 486 mph @ 30000 ft on 2800 HP, while the standard P-47D achieves only 425 mph on 2200 HP. That would give the standard P-47D a top speed of 461 mph, indicating a higher total drag for the P-47 than for the F4U-3. (I'm not sure the data for the F4U-3 is real flight test data, though.)

The second reference P-47 might be closer, though at 32000 ft estimates are a bit difficult due to the increased compressiblity drag.

Regards,

Henning (HoHun)

What hasn't been mentioned is that the F4U-3 was really the XF4U-3. Three prototypes were built and tested. Like all prototypes, these were carefully built aircraft. What I would like to see is flight data on this bird from the Navy, Vought was considered one of the worst when it came to padding performance. Grumman test pilot Corwin Meyer (Corky) thought so little of Vought's claims for the XF2G-1, that he challenged them to race it against the XF8F-1 Bearcat. Vought was reluctant, but finally agreed to the race. With both fighters doing run-ups on the end of the runway at NAS Pautuxtent River, Vought's Chief Engineer quietly asked the Navy to prevent the race, which they did by calling both back to the service ramp. Meyer was convinced that the 460 mph XF8F-1 would have won easily..  Why was the XF8F-1 so fast? Because, it was powered by an engine purposely built for maximum possible power. That's what prototypes were all about, and gundecking the specs to impress the Navy was SOP.

So, if we're going to compare prototypes, let us include the mighty XP-47J. It was powered by a P&W R-2800-57 "C" series engine with the latest and more efficient G.E. CH-5 turbo. The engine was rated for 2,800 hp at 32,600 ft @ 72" Hg. It was built from a modified P-47D-20 airframe. Changes were significant, as the fuselage was shortened by some 3 feet due to a revised engine installation.

Performance was staggering, to say the least. Maximum level speed was 507 mph @ 34,300 ft.

Climb was equally impressive, Climb from sea level was 4,930 fpm, and it was still climbing at 4,000 fpm as it passed 20,000 feet. Empty weight was just 9,663 pounds. Designed as an interceptor, the XP-47J was an awesome monster. However, it was a much massaged prototype, and such lofty performance could not be expected in production aircraft. As it was, the XP-47J program was cancelled in favor of the XP-72. Designed for altitudes between 20,000 and 30,000 ft., it made 490 mph @ 25,000 feet during preliminary testing with an engine still early in its development (R-4360).

Note: XP-47J performance numbers are from factory data sheets.

Of all the American fighters that reached production during WWII, none can come close to matching the P-47M for speed at high altitude. Not even the P-51H could come close to the big M above 27,000 feet.

My regards,

Widewing

[HoHun]

Hi Widewing,

>What I would like to see is flight data on this bird from the Navy, Vought was considered one of the worst when it came to padding performance.

Well, that would actually reinforce my point about the F4U-3 speed not being realistical for a front-line P-47D, wouldn't it? :-)

Regards,

Henning (HoHun)

[F4UDOA]

Widwing,

Some facts about the F4U-3 series.

The Navy accepted these aircraft from Goodyear not Vought so they actually had a FG-3 designation not XF4U-3. There were 26 aircraft delivered to the Navy at Johnsonville between July 3 and 7th 1945. They remained in service until 31 July 1949. Two of them were assigned to Patuxant for electronics testing. BuNos 92382 and 92383. Vought actually built the first two XF4U-3's in 1942.

Also the NAVAIR reports as well as the Royal Navy confirm all of the Vought claims for speed for the rest of the F4U series.

And Goodyear made the F2G too not Vought.

Remember these three items.

1. Only four aircraft types have ever won at the Reno unlimited air races. A F4U-1 with a R-4360 is one of them in 1985 setting the course record at the time.

2. The F2G's dominated when pitted against P-51's, P-63's, P-38 and P-39 running at 80" MAP with the best fuels the AAF could provide in the Cleveland air races and set speed records that lasted 30 years.

3. Corkey Meyer tested the F4U-4 and found it to be faster than listed speed at sea level. 380+MPH

WW,

Have you ever interviewed Boone Guyton when he was alive?

[Drunky]

I must admit that I am terrible impressed by everyone's maturity and reserve in discussing differing perpsectives on the "facts".

I have found this thread a wonderfull read and have enjoyed all the points presented.

Would that other threads maintain this high level of integrity and respect.   to all.

[bj229r]

Aye, Drunky, havent seen any 'mother' insults or anythin here...(almost miss them;) Widewing, do you have a link to some of these articles? Sounds like good reading