Why was the F4u faster than the F6f?

[joeblogs]

I know a million threads have been devoted to this, and there are a lot of reasons.

But I am just reading Graham White's new book R2800 and I heard a new facet - RAM air at low to medium altitudes.

Here he discusses how the supercharger on the Hellcat worked:

"The main stage was driven at all times and had a single speed. The auxilarry stage could operate in three modes: neutral, i.e. the blower impeller was not driven; low speed; and high speed. For low altitudes, those under 12,000 feet, the engine was aspirated through the single speed main stage. ...  Therefore, at all altitudes below 12,000 feet the R2800-10 operated soley on the main stage. Rather surprisingly, ram air was not supplied to the main stage blower, only to the auxillary stage. This anomally explains why a Corsair handily outperforms a Hellcat at lower altitudes. The Corsair's main stage was fed ram air and thus gained a significant amount of power. At higher altitude, with the auxillary stage engaged, there was little to choose between the Hellcat and an F4u-1." (p. 503)

-blogs

[Spongebob]

I know also that the F6F was a deceptively big plane. It looks stubby taken by itself and maybe it's resemblance to the F4F plays into that too.

Another item of note - the gull wings of the Hog, specifically where they attached at 90 degrees to the tangent of the fuselage, allowed for a nice little decrease in drag. Some kind of airflow thing. The gull wings were originally put on the Hog to allow for shorter landing gear struts yet still have the huge prop clear. I don't know if the drag thing was a happy discovery or something that was anticipated as a secondary benefit.

One thing I've always wondered about is why the vertical stabilizer is slid forward on the fuselage several feet. what's that all about, strength?
 
Magoo

[agent 009]

I've wondered that too. About the stabilizer. looks ugly.

[Delirium]

there was little to choose between the Hellcat and an F4u-1

I'm not real familiar with Navy aircraft, but from what I know, the Hellcat came out much later than the F4U. Add that to the fact they are comparing the Hellcat to the F4u-1 and the comparison seems a little 'stacked' in the Hellcat's favor.

It is akin to comparing the FW190A5 to the 109E when the 190 was introduced in combat.

[Flayed1]

the Hellcat came out much later than the F4U.

  Not so this all depends on what F6F and what F4U you are compairing.
 The F6F-3 first entered combat in August 1943 and the F4U enterd operational service in February 1943. The F6F-5 entered service April 1944  but was actually about 10mph slower than the F6F-3.
   
   Take this as you will Got the dates from a book here so if there are any arguements, argue with the author not me

[Widewing]

Originally posted by Flayed1
Not so this all depends on what F6F and what F4U you are compairing.
 The F6F-3 first entered combat in August 1943 and the F4U enterd operational service in February 1943. The F6F-5 entered service April 1944  but was actually about 10mph slower than the F6F-3.
   
   Take this as you will Got the dates from a book here so if there are any arguements, argue with the author not me

No need to argue, talk to one of the Grumman test pilots. According to him and supporting data from various agencies, the F6F-5 was a genuine 400+ mph fighter (typically 406-412 mph depending upon the test) and about 10-12 mph FASTER than the F6F-3.

My regards,

Widewing

[joeblogs]

This may all be true.

White is pointing out a performance disadvantage for the F6f at altitudes below 12k.

Both planes hit their maximum true airspeed at much higher altitude, where both are pushing RAM air through the supercharger.

-Blogs

Originally posted by Widewing
No need to argue, talk to one of the Grumman test pilots. According to him and supporting data from various agencies, the F6F-5 was a genuine 400+ mph fighter (typically 406-412 mph depending upon the test) and about 10-12 mph FASTER than the F6F-3.

My regards,

Widewing

[stantond]

My understanding of the F4U vs F6F speed difference was from design considerations.  The F4U was designed in the late thirties with specifications requiring speed, more speed, and above all ... speed.  The F6F was optimized to kill the japanese zero (which was a slow plane) and its design was an extension of the F4F Northrop Grumman design.  The F4U was designed and optimized (even before WW2) to have minimum drag for the engine configuration used.  I have read many reports on the XF4U-1 from the NACA Langley wind tunnels on drag reduction.  The F6F was also tested, but not as thoroughly (due to the urgency of the war).  Also, as noted before due to the landing gear strength concerns, the F4U wing root makes a 90 deg angle with the airframe which minimizes drag.

The F4U was raced successfully after WW2, but I don't think the F6F was ever raced.  If so, I never read about it.  While the F6F was a great design, and held a higer kill/death ratio than the F4U, the F4U was designed to make it a faster plane.  Along with the wing root drag reduction, the F6F was designed as a lower wing loaded plane with about the same weight as the F4U.  That requires the F6F to have more wing surface than the F4U which generates more drag.  The F6F could turn better than the F4U because of the lower wing loading, but that lower wing loading also made it slower.   That's oK if you are still faster than your opponent, which in this case was the zero.  


Regards,

Malta

[Krusty]

Not to quibble, but the F6F was designed from scratch, taking into consideration everything pilots wanted, needed, and were most likely to use to kill the enemy. They externally made it resemble the F4F, as it was a direct descendent. However it's not an extension of the F4F design. It was totally new.

[Shane]

the f6f is *as* big as a p-47...  and the f4u is surprisingly smaller than one would imagine.

[Bodhi]

Originally posted by Shane
the f6f is *as* big as a p-47...  and the f4u is surprisingly smaller than one would imagine.

Have u ever "seen" a 47, F4u, and a Hellcat together?

[stantond]

My impression of the F4U size was that similar to the Spitfire 7.  Of course that is not having them side by side, but rather after looking at the Spitfire 7 in the Smithsonian Institue and the F4U(D) in the Hampton Air and Space Center.  As a note, the 109G was a smaller aircraft than the Spit 7.  The P&W R2800 engine is not that big either, per the Smithsonian.  What I did find impressively huge was a F4E Phantom II in the Hampton Air and Space.  That's a big aircraft!

I have never seen a P47 or F6F (any model).  Although I did assemble a model of the F6F as a kid.  I have been in the full scale wind tunnel at Langely AFB where most of the (US) WW2 aircraft were tested by the NACA.  It's a continuous flow fan driven tunnel currently operated by Old Dominon University.  


Regards,

Malta

[Shane]

Originally posted by Bodhi
Have u ever "seen" a 47, F4u, and a Hellcat together?

yes. reading, pa... 2001 i think, not sure if the cat was there, but jug and hog were.

as well as scale models.


just like the 109, while small, the FW is also surprisingly smallish.

[OOZ662]

Originally posted by Bodhi
Have u ever "seen" a 47, F4u, and a Hellcat together?

Using my "Giant Book of Aircraft of Doom" from all-knowing Jane...

F4U-5N had a wingspan of 41 ft and was 33 ft 6 in long.
F6F-5 had a wingspan of 42 ft 10 in and was 33 ft 6 5/8 in long.
P-47D had a 40 ft 9 1/4 in wingspan and was 36 ft 1 1/4 in long.

It only listed the data for one of the models in each series, but I'm guessing they didn't change much.

[AmRaaM]

Seen the f6f in flight, right over my head and low and loud, its a big bulky bird and damn cool sounding. seen the f4u but it was higher but seems to me it was smaller than the f6f or maybe its because the f6f is so fat looking.