Best Heavy Fighter

[Brooke]

Some references talk about the P-51H having a lower g limit than the P-51D, which would imply less structural strength.  I don't know if the F-51H increased structure strength mentioned in the document means that it was then up to strength of the P-51D or more.  Being able to take 2000 lbs of bombs and rockets seems to indicate good strength, but better would be g limit.

[Widewing]

Some references talk about the P-51H having a lower g limit than the P-51D, which would imply less structural strength.  I don't know if the F-51H increased structure strength mentioned in the document means that it was then up to strength of the P-51D or more.  Being able to take 2000 lbs of bombs and rockets seems to indicate good strength, but better would be g limit.

There were other issues with the H model. They suffered so many failures of the tail wheel cylinder (tail wheel not coming down), that some ANG units removed the hydraulic cylinders and bolted the tail wheel down. The V-1650-9 had a significantly higher rate of failures than did the -7. Largely due to the high boost pressures. Some ANG units limited MAP to 75". The biggest issue was propagating cracks in the main wing spars of several well used P-51Hs. This was not a common problem, but it didn't take many incidences to convince the USAF not to use the H as a fighter bomber. Indeed, the 5th AF specifically asked NOT to be sent any H models.

There's a great deal written about the P-51s in Korea. A good place to start is with Mustangs Over Korea, by David McLaren (Schiffer). P-51s (F-51D) did excellent work in Korea, despite being terribly vulnerable to ground fire. 474 were lost in Korea, the vast majority to ground fire.

[J.A.W.]

 Yeah Ww, & as previously posted - we've actually already gone over why the `51H wasn't selected for service in Korea, so what have you got on `51H's USN counterpart, the F8F? & why the USN didn't want them for Korea either..

Its hardly a surprise 'bout flak being the major reason for fighter bomber losses, esp' in the absence of serious A2A opposition,[ jets suffered too].

But what can you reveal about the Corsair & its being 'terribly vulnerable' too..

What about the Corsair in Korea & its dreaded oil-cooler vulnerability..

& do those 474 Mustangs you list as lost include those flown by other UN air forces, such as the RAAF,SAAF & South Koreans?

[Widewing]

Yeah Ww, & as previously posted - we've actually already gone over why the `51H wasn't selected for service in Korea, so what have you got on `51H's USN counterpart, the F8F? & why the USN didn't want them for Korea either..

Its hardly a surprise 'bout flak being the major reason for fighter bomber losses, esp' in the absence of serious A2A opposition,[ jets suffered too].

But what can you reveal about the Corsair & its being 'terribly vulnerable' too..

What about the Corsair in Korea & its dreaded oil-cooler vulnerability..

& do those 474 Mustangs you list as lost include those flown by other UN air forces, such as the RAAF,SAAF & South Koreans?

F8Fs didn't serve in Korea because they were no longer deployed aboard carriers. They has been replaced by the F9F and the F2H. By the early 1950s, F8Fs were being transferred to reserve units and some were sold to other countries, with France receiving a significant number. The French used them very effectively as fighter bombers in Indochina.

And yes, the 474 include all P-51s lost by UN forces to all causes.

[J.A.W.]

Thanks for the reply, Ww,
& do you know if Marine units ever operated F8Fs, or if Marines flew Korean A2G missions from shore bases, like in WW2?

[Brooke]

There were other issues with the H model. They suffered so many failures of the tail wheel cylinder (tail wheel not coming down), that some ANG units removed the hydraulic cylinders and bolted the tail wheel down. The V-1650-9 had a significantly higher rate of failures than did the -7. Largely due to the high boost pressures. Some ANG units limited MAP to 75". The biggest issue was propagating cracks in the main wing spars of several well used P-51Hs. This was not a common problem, but it didn't take many incidences to convince the USAF not to use the H as a fighter bomber. Indeed, the 5th AF specifically asked NOT to be sent any H models.

There's a great deal written about the P-51s in Korea. A good place to start is with Mustangs Over Korea, by David McLaren (Schiffer). P-51s (F-51D) did excellent work in Korea, despite being terribly vulnerable to ground fire. 474 were lost in Korea, the vast majority to ground fire.

Thanks for the info.

Looking at the huge boost on the P-51H figures above (90" Hg!), I wondered if there would be problems there.  Did the -7 use 90" for WEP?

[J.A.W.]

No, since 90in required ADI & earlier Mustangs were not so equipped..

However, use of high-test 150 grade Av-gas[ from mid `44] by increasing TEL [lead] content did provide improved performance,via useful boost increases, & at some serviceability cost [ leaded plugs, shorter TBO intervals & etc] but the performance increase was more so on liquid cooled mills,
[ or at least 'til R-2800s began using ADI - or internal liquid cooling - in fact].

 But since radials also had to run extra rich gas mixture settings [as another internal cooling measure] - they would always remain gas-hogs in high out-put high speed fighter use, anyhow..

See here,

http://www.spitfireperformance.com/mustang/rae1501-fig8.jpg

[J.A.W.]

The P-51H seems like a performance monster on WEP (climb rate of 5500 fpm), but more like a typical Mustang without WEP:

(Image removed from quote.)

You can find Bearcat performance without WEP here:  http://www.wwiiaircraftperformance.org/F8F/F8F-2_Standard_Aircraft_Characteristics.pdf
The Bearcat without WEP is much a better climber than the P-51H without WEP, but what are they both with WEP?

For Bearcat climb rate with WEP, my best reference is this one (written by the test pilot's son, who has access to his dad's log book):

http://www.ww2aircraft.net/forum/aviation/goodyear-f2g-vs-grumman-f8f-bearcat-33022-5.html#post911193

This gives the Bearcat's WEP climb rate as about 5900 fpm and explains how the F8F might have had time to climb record yet still not be in FAI records (as FAI wasn't keeping such records until 1951).

Brooke,
 - FYI, in your post quoted above, where you have written
 "Bearcat performance without WEP"
 - in referring to the 'Standard Characteristics' - well, actually the USN term 'combat' power = WEP.

 Also it is noted that the F8F is using ADI - same as the `51H,
& see therein, '16 gallons of water is supplied for water injection'.

I wonder why F8F's were not used in the fighter-bomber role in Korea, since they are listed there as being cleared to tote 3.5klbs of bombs..

[J.A.W.]

Also of possible interest is, not only did Grumman pick up the Hawker-type blown bubble canopy for the F8F, & the 4 X 20mm Hispano cannon, but the Hawker patented aileron spring tabs too, which increased high speed roll rate [by reducing stick forces] significantly..

[Brooke]

Brooke,
 - FYI, in your post quoted above, where you have written
 "Bearcat performance without WEP"
 - in referring to the 'Standard Characteristics' - well, actually the USN term 'combat' power = WEP.

You could be right.  It's odd though -- manuals for the F4U and F6F (and P-51, P-38, and P-47N), for example, refer to it as "war emergency power" and not as "combat power".  Could combat power be just a particular setting of manifold pressure and RPM without pushing the throttle past its normal stops and without water injection being engaged?  The F8F reference (http://www.wwiiaircraftperformance.org/F8F/F8F-2_Standard_Aircraft_Characteristics.pdf) on page 3, it shows that combat power is only a little higher than takeoff and military power, and on the last page, it lists combat power as lasting at least 10 minutes, which seems long for WEP for a US plane.  But it does seem that combat power, listed as a higher power setting than military power, should be WEP, as you say.

I wonder why F8F's were not used in the fighter-bomber role in Korea, since they are listed there as being cleared to tote 3.5klbs of bombs..

Maybe not many of them around to press into service.

[Brooke]

Also of possible interest is, not only did Grumman pick up the Hawker-type blown bubble canopy for the F8F, & the 4 X 20mm Hispano cannon, but the Hawker patented aileron spring tabs too, which increased high speed roll rate [by reducing stick forces] significantly..

I don't think that Hawker invented the bubble canopy (see history of that Malcolm Hood and the Miles M.20), use of 4 guns as armament (in the realm of patent law, that would not surmount an obviousness rejection), or the spring tab (as it was one among many standard trimming and force-reduction mechanisms commonly known about -- but I don't know who invented it, so maybe it was Hawker).  Regardless, they did put all of those things to good use.

[J.A.W.]

Hawker were certainly 1st to prove those features in combat/heavy fighter..

The spring tab patent reference is findable,& I'll dig it up later..

& I should add H.U.D. [head up display] - when they adapted the reflector sight to dispense with its regular screen & project directly onto the integral armour glass front windscreen/shield..

The P-47, P-51, FW 190, Spitfire & others later all jumped on board the blown canopy band-wagon..
 
Yet, oddly the P-38 always stuck with its [vision obstructing] framed canopy..
& too bad it didn't tote the standard Brit heavy fighter 4 X 20mm Hispano set,
but at least it did get powered ailerons - in its late production series..

[MiloMorai]

[J.A.W.]

Thanks for posting those M.M., but obviously the poor old Miles was never gonna see production/combat, with that undercart..

& the FW 190 didn't get a blown bubble canopy 'til years later in the JABO & late Dora variants..

The earlier Typhoons [prior to adopting the Miles pioneered B.B. type] featured a canopy very like the He 112 - as well as P-39 like 'car' doors..

[Widewing]

Brooke,
 - FYI, in your post quoted above, where you have written
 "Bearcat performance without WEP"
 - in referring to the 'Standard Characteristics' - well, actually the USN term 'combat' power = WEP.

 Also it is noted that the F8F is using ADI - same as the `51H,
& see therein, '16 gallons of water is supplied for water injection'.

I wonder why F8F's were not used in the fighter-bomber role in Korea, since they are listed there as being cleared to tote 3.5klbs of bombs..

By 1944, virtually all R-2800 fighters were employing water injection. By the way, when the ADI was in use, it reduced the volume of fuel consumed. Not that this was a significant fuel savings.

The Allies were a bit late to the water injection solution in their water cooled engines, especially relative to Germany.