P-51D Vs. P-38J

[Clay_Allison]

Which one would you rather fly if you had to fight against the other at high altitudes?

Assuming you could procure either, which would you prefer as the commanding general of an Air Force in the ETO or Pacific?

 

[Erich]

Clay please check the archiv's as this matter has already been discussed and went nowhere ...........

 

[Marshall_Stack]

In an one-on-one dogfight, I would rather have the P-51 since it is more agile and has better visibility below the aircraft.

In the PTO, I would rather have the P-38 for its advantage of two engine reliability over shark infested water.

In the the ETO, I would rather have the P-51 for if I was in the 8th Air Force since it is easier to maintain and less demanding of pilots. If I was in the 9th, I may prefer the P-38 for its ability to carry more bombs and rockets for interdiction and having two engines in case of flak damage.

Just my $0.02

 

[merlin540]

An old friend of mine flew the photo verions of both the P-38 and P-51 in the ETO during WWII, including over Normandy before, during and after D-day.Although he said they were both good planes, he liked the P-38 much better than the P-51.
He liked the two engines vs. the single, plus he said it just was a better, more refined aircraft.
Conversely, it also required quite a bit more maintenance than the P-51, and it was the main cause of its demise-much like the F-14 vs. the F-18 today.

 

[davebender]

The P-38 had two engines but they were not reliable. That was one of the main reasons it was replaced with the P-51.

 

[FLYBOYJ]

The P-38 had two engines but they were not reliable. That was one of the main reasons it was replaced with the P-51.

Not totally true - plenty reliable in the PTO, it was a matter of where and how they were operated.

 

[drgondog]

The P-38 had two engines but they were not reliable. That was one of the main reasons it was replaced with the P-51.

Dave - the 38's 'failures' were primarily high altitude escort in Fall/winter 1943 through February/March 1944 over ETO Continent at 55 below temps - way different from medium altitudes (or even same high altitude 25K+) over PTO where the temps were at least 40 degrees warmer.

Having said that, the ETO record clearly favors the 51. It is curious that P-38's weren't used for escort over Japan, based out of the Marianas or Iwo.. Logistics clearly favored the 51 as far as spares and fuel but I have always wondered 'why not'

 

[LWulf]

The P-38 J had a very nice weapon package and ok climb, but I find the P-51 D to be a more dynamic fighter. Also the P-38 was a bigger target in a turn, had poorer visibility, had that evil compressibility problem and until the L model with boosted ailerons it was rather slow in a roll. Overall I think the P-51 D comes out on top, despite some good points the P-38 has over the 51.

 

[Milosh]

Merlin powered Mustangs had there share of problems in the ETO.

 

[Clay_Allison]

The P-38 J had a very nice weapon package and ok climb, but I find the P-51 D to be a more dynamic fighter. Also the P-38 was a bigger target in a turn, had poorer visibility, had that evil compressibility problem and until the L model with boosted ailerons it was rather slow in a roll. Overall I think the P-51 D comes out on top, despite some good points the P-38 has over the 51.

Some Js had dive brakes installed to stop that compressibility problem. I think the J also fixed most of the high-altitude cold-weather issues with the move to the chin-intercooler and general improvements on the turbo.

I probably should have said P-38L since it was the most produced example and incorporated the design features that were introduced during the P-38J run.

 

[drgondog]

Merlin powered Mustangs had there share of problems in the ETO.

Yes.

Having said that there were only two fighters in the war that had the range and performance to fight German fighters on equal terms over the German capital. The problems were negligible (except to the pilots that exeprienced them) in contrast to the results achieved.

If one were to design into the Fw 190A or Me 109 the capability to have the same range and performance as the P51B/C/D/K and P-38J-25 and P-38-L, there would be 'greater' problems by far than those experienced by Mustangs.

The 'mission' often influences the problems. The longer a high performance fighter remains in the air on an operation, the higher the probability of a serious system or component failure.

 

[drgondog]

Some Js had dive brakes installed to stop that compressibility problem. I think the J also fixed most of the high-altitude cold-weather issues with the move to the chin-intercooler and general improvements on the turbo.

I probably should have said P-38L since it was the most produced example and incorporated the design features that were introduced during the P-38J run.

the -25 was first production version and kits were applied to earlier versions of the P-38J.. The P-38L never did fly with the 8th AF (I am pretty sure but Not 100% positive on this - if any made it they were in the 479th in September 1944).. so the performance of the Mustang is P-51A vs P-38F/G and P-51B/C against P-38H and J and P-51B/C/D versus P-38L

Compressibility problems were never resolved once the P-38 achieved ~ .72M in a dive.

What the mods achieved was enough drag to retard the acceleration enough to enable the pilot to prevent entering compressibility dive speed... however the 109/190 he was chasing was under no such limitations.

Prior to the dive flap, the 38 simply accelerated into compressibility after entering a steep dive, almost instantaneously ,at high altitudes - and he was stuck in the dive until long after his quarry had escaped.

 

[LWulf]

Some Js had dive brakes installed to stop that compressibility problem. I think the J also fixed most of the high-altitude cold-weather issues with the move to the chin-intercooler and general improvements on the turbo.

I probably should have said P-38L since it was the most produced example and incorporated the design features that were introduced during the P-38J run.

.
Yeah, I think you would've done better choosing the L for comparison. Still, my humble opinion is that dive brakes were a way to make the aircraft safer and didn't help with the compressibility issue itself, that's why I still treat it as a negative point. I see it as an inherent design problem.
Even with the P-38 L I think I'd choose the P-51 D. The L with boosted ailerons improves its attack and defense, but l'd still expect the P-51 D to have the edge in a multiple aircraft fight.
AFAIR at slower speeds the P-38 had more inertia in its maneuvers than the P-51, tho the P-51 had worse acceleration in the horizontal and slower climb, at least at low to medium altitude and at typical maneuvering combat speed. I think it's an interesting comparison, both aircraft have their own edge over the other, but as I've said I see the P-51 D coming out on top.

 

[Clay_Allison]

I guess the innate problem of compressibility is a tie breaker if nothing else.It's a shame that the great dive speed of the P-38 was wasted by being uncontrollable.

 

[FLYBOYJ]

I guess the innate problem of compressibility is a tie breaker if nothing else.It's a shame that the great dive speed of the P-38 was wasted by being uncontrollable.

The Mustang had a higher critical mach number and was "better" controlled at a terminal dive, but that didn't mean it could not destroy itself due to compressibility.

 

[Clay_Allison]

The Mustang had a higher critical mach number and was "better" controlled at a terminal dive, but that didn't mean it could not destroy itself due to compressibility.

anything could, but the distance between the P-38's front and the tail control surfaces had to really hurt things.

 

[drgondog]

anything could, but the distance between the P-38's front and the tail control surfaces had to really hurt things.

Clay the issue was aerodynamics. Early on it it's life it it was flow separation about the centerbody causing buffeting (which masked the compressibility issue) on the elevator. They fixed that but the 'frozen stick' terminal dive issue remained.

The 38 had a relatively thick chord wing and had a lower Critical mach number than say a 109 or 47 or 51 (or Spit). When the shock started forming at ~.72 M the center of Pressure moved aft creating a Moment Coefficient issue forcing the nose to try to 'tuck' (similar to Me 262).

The purpose of the dive flap was to enable the pilot to control the dive up to and around .68M, keeping it below Mcr.

 

[MikeGazdik]

Which one would you rather fly if you had to fight against the other at high altitudes?

Assuming you could procure either, which would you prefer as the commanding general of an Air Force in the ETO or Pacific?

In the first part of your question, I will have to say I would rather be the Lightning pilot. That is Mustang vs Lightning in a 1 on 1 duel. My guess as far performance against each other: the Lightning would have a slower roll rate, and would be restricted in a dive. Its absolute top speed would be less than the P-51 too. On its plus sides, I think the P-38 would out climb the Mustang. I think the sustained turn rates would be close ( though slightly in favor of the Mustang). I think the P-38 would be more rugged and more tolerant of damage. And I certainly would rather be in the P-38 during a head on pass!


The second question is impossible for me to anwer, because history has already taught us this lesson! I cetainly see the benefit of a twin engined fighter over the vast Pacific.