Why was the F4u faster than the F6f?

[joeblogs]

It depends entirely on the editions you are looking at. Wilkinson's coverage of Axis engines AFTER the war is pretty good. During the war it was sketchy.

-Blogs

Originally posted by pasoleati
Maybe, but the Jane´s AWA of the same period has much more reliable data and e.g. the sections on the Jumo 211J and DB 605A are in perfect agreement with the respective engine manuals while Wilkinson is pure speculation. ...

 

[Squire]

I have never seen any references giving the F6F-5 a 400mph top speed, for an operational example. 380 mph I have seen, with 20,000 ft being reached in 7 min.

Would be nice if references were given when making claims like that.

[Widewing]

Originally posted by Squire
I have never seen any references giving the F6F-5 a 400mph top speed, for an operational example. 380 mph I have seen, with 20,000 ft being reached in 7 min.

Would be nice if references were given when making claims like that.

That's not a claim, it's actually a fact. However, I will provide a reference you can verify.

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 feet.

The original TAIC document is currently in the National Archives.

A copy of the Royal Navy document was published by Historian Barrett Tillman in his book, "Hellcat: The F6F in World War II".

Retired 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.

Besides, the F8F-1 was entering production and was expected to completely replace the F6F-5. Indeed, the Navy didn't bother to issue a contract for the R-2800 C series powered F6F-6 because the F8F was deemed superior as a fleet defense fighter. Various sources quote speeds between 417 and 425 mph for the XF6F-6. However, Meyer has stated that when corrected for pitot tube error, actual max speed of the XF6F-6 was 435 mph @ 25,400 feet.

Head to head testing of the F4U-1A and F6F-5 showed virtually indentical max speeds at altitude. Down low, the F4U was faster as described in this thread.

My regards,

Widewing

[Squire]

Maybe the F6F needs some tweaking.

[stantond]

I think Widewing needs to take his argument up with the Navy: Naval historical archives

I will leave it to each person to decide if this is really the 'word' on historical peformance data, but it is documented.  And seeing how the Navy approved the document, there is probably some level of its validity.  I have to note that the F4U-4 climb rates present in this archive are ignored by the AH staff, for what that's worth.



Regards,

Malta

[Widewing]

Originally posted by stantond
I think Widewing needs to take his argument up with the Navy: Naval historical archives

Regards,

Malta

Been there, read that. Standard stuff, NOT signed on to by TAIC. The aircraft were not instrumented independently, but use the standard F6F static pitot system, so their data is flawed.

We have TAIC documents, there are Grumman documents available at CAM, and we have the testing performed by Vought (yes Vought was given a Hellcat to test, just like Grumman received an F4U). All agree that the F6F-5 was just about as fast as the F4U-1A at altitude. We have the writings of Bob Hall and Corwin Meyer, both of whom have addressed this issue. Any aviation historian who has researched the F6F will state, categorically mind you, that the F6F-5 was a genuine 400 mph+ fighter.  

My regards,

Widewing

[Rebel]

in one airshow, I've seen a P47, F6f-5, and an F4U-1D all together in a line.

The Hellcat's wing area is huge, and it has a surprisingly bulky body.   Funny thing is, it "tapers" at the end.  It looks like a big bellybutton tadpole. The wings were made big to give it better lift, I suppose.

The F4 is tall as hell, but is relatively far more streamlined then the other two.   Note that I saw it on the ground- that bent wing coupled with probably the biggest gear I ever saw on a WW2 fighter makes it stand out.  Like Uncle Sam in his dress blues on stilts.

But nothing comes to the sheer girth and bigness that is the P-47 Thunderbolt.  That plane is just mammoth.   From the first mooment you see her up close, she looks like a bomber, she's so big.  No fancy streamlined lines, no sex appeal whatsoever.  Brutal and lethal function is all that comes to mind when looking at her.