P-38 Lightning vs P-51 Mustang: Which was the Better Fighter?

[kool kitty89]

A little off topic, but how do you think the P-39 would have stood up in comparison had the turbo not been deleted?

Though I don't think range would have been sufficient for escort inless they could have put under-wing racks and plumbing for drop-tanks...


The P-47 was decent as an escort too, it was just a bit fuel greedy though.

[ETO_RULES]

Some simple stats.

The number one scoring fighter group in the US army during WWII was the 354th fighter group. They had 701 air-to-air kills confirmed kills. That was more than the 56th fighter group. They were the first mustang outfit flying the Merlin powered mustang and started ops in Nov of 1943. The 354th group was assigned to the 9th air force in the ETO. The 56th was the highest scoring group in the 8TH AIR FORCE in the ETO (Excluding ground kills). The 56th group started flying missions in April of 1943 and had 600 air-to-air kills.

The mustang had the most army pilots to become aces flying a certain type. 275 pilots become aces flying the mustang. The Navy Hellcat is the number 1 ace maker in US history. Over 300 pilots become aces flying the Hellcat.

The following fighter groups started ops in the ETO in the same timeframe

354th(MUSTANG) NOV 43
20th(P-3 NOV 43
357th(MUSTANG) FEB 44
55th(P-3 FEB 44

By July of 1944 the 354/357 had obtained about 40 air-to-air aces. The 20th and 55th totaled 5! The P-38 outfits starting in August began checking out in mustangs. All 4 groups in the 8th air force flying p-38s (20th, 55th, 364th and 479th) would be flying the p-51 in the fall of 44.

The top ace of the 364th fighter group Lt/Col. George F. Ceuleers (10 kills) flew both the p-38(1 kill) and the p-51(9kills) preferred the mustang in dogfighting.


Kill totals do not lie. Short of a dog eating their homework I have seen every excuse for explaining the lack of success of the p-38 in the ETO. It wasn't cost or a conspiracy that caused the ETO to go with the P-51. It was RESULTS.


By the way didn’t someone win the Medal of honor flying the P-51 in the PTO. William Shomo scoring 7 kills in a single misson. The P-51 started late in the PTO but had a nice impact in just a few months of combat. Due to demands in the ETO and MTO the mustang was not available in numbers in the PTO till Apirl of 1945.

[eddie_brunette]

Ligtning for me.

[drgondog]

Originally Posted by ETO_RULES

Some simple stats.

The number one scoring fighter group in the US army during WWII was the 354th fighter group. They had 701 air-to-air kills confirmed kills. That was more than the 56th fighter group. They were the first mustang outfit flying the Merlin powered mustang and started ops in Nov of 1943. The 354th group was assigned to the 9th air force in the ETO. The 56th was the highest scoring group in the 8TH AIR FORCE in the ETO (Excluding ground kills). The 56th group started flying missions in April of 1943 and had 600 air-to-air kills.

Only a minor point but the 354th FG was attached to, and under operational control of, the 8th AF through early May when both the 363rd and 354th were returned to 9th AF

The mustang had the most army pilots to become aces flying a certain type. 275 pilots become aces flying the mustang. The Navy Hellcat is the number 1 ace maker in US history. Over 300 pilots become aces flying the Hellcat.

The following fighter groups started ops in the ETO in the same timeframe

354th(MUSTANG) NOV 43 I think 1 Dec was first mission, led by Blakeslee
20th(P-3 NOV 43
357th(MUSTANG) FEB 44
55th(P-3 FEB 44 (first ops 9/43, with 363th in March, 1944)

By July of 1944 the 354/357 had obtained about 40 air-to-air aces. The 20th and 55th totaled 5! The P-38 outfits starting in August began checking out in mustangs. All 4 groups in the 8th air force flying p-38s (20th, 55th, 364th and 479th) would be flying the p-51 in the fall of 44.

P-38 transitions - July for 20, 55, 364th and late September for 479th

The top ace of the 364th fighter group Lt/Col. George F. Ceuleers (10 kills) flew both the p-38(1 kill) and the p-51(9kills) preferred the mustang in dogfighting.

Interestingly enough the 479th, flying the P-38L from very beginning of ops had an astonishing air to air ratio - at the top of 8th AF before transition to 51. On the other hand it scored first in May, 1944 when the Luftwaffe experienced pilot roster had been severly diluted between October 1943 and May 1944, so hard to make the right judgements vs other P-38 outfits flyin F and J's

Kill totals do not lie. Short of a dog eating their homework I have seen every excuse for explaining the lack of success of the p-38 in the ETO. It wasn't cost or a conspiracy that caused the ETO to go with the P-51. It was RESULTS.

But hard to make phased judgements for the reason noted above.

By the way didn’t someone win the Medal of honor flying the P-51 in the PTO. William Shomo scoring 7 kills in a single misson. The P-51 started late in the PTO but had a nice impact in just a few months of combat. Due to demands in the ETO and MTO the mustang was not available in numbers in the PTO till Apirl of 1945.

But a lot of P-38 and F4U pilots in the PTO. Only one MoH winner in 51 in ETO (James Howard, 354th FG, attched to 8th AF when he got his)..

A lot of guys that DSCs in the ETO had feats as great or greater than theri counterparts in PTO - so go figure the process?

I say Mustang unequivocally for ETO/MTO post 1943, P-38 through 1943 all theatres and PTO for entire war... the 51 would have been even more important had we invaded Japan, but didn't have the same impact the 38 had for the entire war in the Pacific.

[renrich]

No way the P39 would have ever been a premier fighter in WW2. Turbo or not. Too small and if provisions for more internal fuel could have been made (doubtful) the performance would have been even worse. Besides there may not have been enough 5 foot 8 inch or less pilots to go around. To me one cannot really understand what WW2 and fighters is all about unless one gets his arms about the roles of the various air forces. Germany and Britain designed fighters ( in the beginning) to be used as interceptors and air superiority weapons. The idea of fighter bombers or escort fighters was not provided for in their thinking with the Hurricane, Spitfire , BF109 and even later the FW190. Plus those aircraft were designed when there were no engines available with the requisite HP to enable them to carry a lot of fuel and still have good performance. It was a tribute to their inherent design excellence that later they were able to accept engines with twice the HP of the original power plants. Nevertheless they were still range limited. The P39 was of a similar design. Get a lot of performance because of being small and light. The P40 went a little larger but was still range limited partly because of drag. The P38 got range, performance and bigness by using two engines. The P51 got range by being fairly large(so it could carry a lot of fuel) but also was very low drag and when it got the Merlin it could get high and really motor and still go a long way. The Corsair, Hellcat and to a lesser extent P47 got decent range, carrying a lot of fuel because they were big and had lots of HP(all having 2000 HP at first) I don't know if the AAF and USN necessarily had good crystal balls about having good range built into their premier fighters but that is the way it turned out. The P39 was like a 1933-34 European design with short range except it could not get high and still have good performance.

[renrich]

Not to take anything away from the Hellcat, it's pilots or records but the Hellcat came on scene when the highly skilled IJN pilots were beginning to be depleted. Plus if you look at the record many of it's kills were not against fighters but bombers and later kamikazes flown by fledglings. The many kills by Mustangs, P38s and Jugs were mostly against fighters although the skill of the LW pilots gradually eroded on average.

[syscom3]

Renrich, dont forget that the P38 was designed to be a bomber interceptor from the onset.

The fact that it could also be used as a decent fighter and fighter-bomber speaks volumes on its basic design.

[drgondog]

Originally Posted by syscom3

Renrich, dont forget that the P38 was designed to be a bomber interceptor from the onset.

The fact that it could also be used as a decent fighter and fighter-bomber speaks volumes on its basic design.

Syscom - I wonder how the remembrance of the P-38 in ETO would be different if the prototype had not crashed on the Army cross country stunt - and the Lockheed team had that lost year to sort out compressibiliy, engine, dive performance and boosted ailerons by 1943 instead of mid 1944?

I had a hard time getting either Olds or Landers to give a decisive edge to the P-51 as the 'clear' best fighter. They favored the Mustang as a high altitude fighter but felt the 38L could hold its own with anything at medium to low altitude. Having said that both agreed that if the 8th AF had to have just one fighter it would have been the Merlin equipped Mustang for their choice.

Landers flat out said the 38L would have been his choice for 'beginning to end' in ALL US theatres...if only one possible - because of PTO... but not for Europe in Bomber escort role

IIRC correctly he got 6 w/P-40 and 49th, 4 w/P-38 and 55th and 4.5 w/P-51 and 78th, including a 262. Nearly an ace in three different ships

[renrich]

Of course Sys, and when the P38 was designed in 1937 the Allison engine that was the only feasible engine to be used put out only about 1000 HP. Around 1600 Hp was needed in a single engine fighter, unless you went really small and light. Bell went that direction and Lockheed went the two engine path which resulted in an airplane with a lot of wing which gave it good high altitude handling and also a lot of load carrying capacity which meant a lot of fuel could be carried which meant a long range. I guess the long range the AC could manage was a by product of the need for more power and was a bit of an accident. Inspired design that resulted in the best twin engined fighter of the war.

[drgondog]

Originally Posted by renrich

Of course Sys, and when the P38 was designed in 1937 the Allison engine that was the only feasible engine to be used put out only about 1000 HP. Around 1600 Hp was needed in a single engine fighter, unless you went really small and light. Bell went that direction and Lockheed went the two engine path which resulted in an airplane with a lot of wing which gave it good high altitude handling and also a lot of load carrying capacity which meant a lot of fuel could be carried which meant a long range. I guess the long range the AC could manage was a by product of the need for more power and was a bit of an accident. Inspired design that resulted in the best twin engined fighter of the war.

And the big hog that became the L would out climb, out roll and out accelerate a 51D (and an F4U) in most altitudes and speed ranges...

[renrich]

I know I am prejudiced but all considered: performance, maintainability, survivability, versatility, cost effectiveness, length of time for pilot proficiency, short field take off and land capability, etc. I will take the Hog, the U-Bird, the Ensign Eliminator, it's big it's blue it's the F4U in it's various iterations for the one fighter concept. I believe Rex Barber who did some good in the P38 felt the same way about the Corsair.

[kool kitty89]

Just some notes on the P-39: the original P-39 had longer wings giving more wing ares and room for internal stores. (and easier to add external stores, plus higher wing area means more room for weight growth and better climb and turn rate) Had a larger canopy-- so more head room and better visibillity. Had a turbo (obviously). And had a shorter rear fusalage wich provided better stability. And of course the turbo...

The USAAF went crazy with streamling- the only positive thing to change was a larger tail fin for better control and stability. The longer fusalage causing COG problems, the new canopy having pooer vision and head room, wing area deopping etc.

Plus the P-39D-2, N, and Q (and a few others) wre not underpowered with a WEP of 1,320 to 1,480 hp.

The P-39 never received a Merlin like the P-40 did (albeit only 1,300 hp with a crit alt of ~19,000 ft for 1,120 hp) or the V-1710-81 of the P-40M and P-51A with 1,480 WEP at 10,400 ft and 1,120 ho at ~18,000 ft.

The XP-76 corected some of this (long wings with square tips and 236 ft2 area, and better engine-- 2-stage Allison with nearly 386 mph at 21,000 ft)

Though the P-63 was a more promising a/c with performance similar to the P-51 in range (with 3 drop tanks), climb slightly lower, speed similar and better at low altitude (P-63C had a WEP of 1,800 hp with water injection) and a critical altitude of ~23,000 ft (higher on some models). Armament was as good as the P-51A/B/C and better with a 20mm cannon with ~170 rounds. (the 37mm cannon being debatable while the 20mm was an alternate).




On the range of the P-40, it could range farther than the Mustang when wing tanks were used, though these were only avaiable for the P-40N iirc and mostly used for ferrying (max 3,100 mi at minimum cruise settings) ~1,400 miles was usual with a 141 gal drop tank. And it had the P-39 beat in range armament (by most standards) and climb (comparing the P-40M to the P-39N/Q).


The P-47D could range 2,100 mi at 206 mph with 780 US gallons total. (note this is with the 70 gal increased main tank, and not considdering the 200 gal conformal paper tank used only early when no wing plumbing was stansard, or the 215 gal steel belly tank, or the "big and ugly" 200 gal wing tanks used in the PTO)


And the P-38L could only out roll the P-47D (~86 degrees/sec at 250 mph) above 300 mph and late model F4Us (~100 degrees/sec at 250 mph) above 350 mph and the P-47N even later (108 degrees at 250 mph with less degredation at higher speeds than the D model or the F4U). The P-38L's roll kept increasing up to its redline speed and was faster than the P-51 at all speeds. It didn't exceed 80 degrees/sec until ~300 mph and did ~90 degrees at 400 mph iirc.

[drgondog]

Originally Posted by kool kitty89

And the P-38L could only out roll the P-47D (~86 degrees/sec at 250 mph) above 300 mph and late model F4Us (~100 degrees/sec at 250 mph) above 350 mph and the P-47N even later (108 degrees at 250 mph with less degredation at higher speeds than the D model or the F4U). The P-38L's roll kept increasing up to its redline speed and was faster than the P-51 at all speeds. It didn't exceed 80 degrees/sec until ~300 mph and did ~90 degrees at 400 mph iirc.

http://home.att.net/~ww2aviation/P-38-3

It would be hard to validate the roll statements against the P-51B/D and impossible against the P-51H. Interestingly enough if Lockheed's performance figures are correct the crossover point for the P-38L with boosted ailerons crossed over the 51 along with the Fw 190 at 350MPH.

The P-38J w/o boosted ailerons stayed below both the P-51B and Fw 190A at all speeds.

Having said that, I've often wondered about these charts as none of the aircraft models, including the P-38L, ever did 450mph in level flight.. Only the P-51H ever tested at that speed or above..so I would like to see something like these charts as a function of altitude as well as versions. It is also interesting that the climb performance charts and speed chart comparisons by Lockheed were carefully selected for the model of 51 (i.e P-51D vs P-38L for climb and dash speed instead of the B and H - both of which were faster and climbed as well or better).

Also interesting is that the redline dive speed for the P-38L was .68 Mach - which would imply stability and controllability but the 109G, Fw 190A and D, P-47D and P-51B/C/D/F all would excced that by .10 mach. I am assuming that is redline w/dive brakes -----> implying structural red line not aerodynamics.

[kool kitty89]

Anything greater than 442 mph for the P-38L would be in a dive. The P-38K probably could Best 450 mph (as long as it wasn't exceeding .68 mach) if it had been tested in WEP.

What I've wondered about the P-38K's propeller is why they didn't make kits for retrofitting new cowling and paddle props to P-38Ls in the field, as this wouldn't have caused any cease in production (the War Production board not even allowing the 2-3 weeks needed for retooling.

Or why not use a 4-bladed propeller like late-model P-39Qs did, the spinner and prop-diameter would be the same so there would be no need for new cowling and there would be more clearance for the props. (the paddle-props having a larger diameter as well) A 4-bladed prop would also be easier to fit in the field as no new cowling would be needed.

One big drawback that the P-38 never fully solved was high-speed dive capabillity, it could dive decently but even with the recovery flaps (allowed another 30-40 mph TAS to be aceived safely iirc) it was not much better than the P-51 in this category (depending on how much a pilot was willing to push the a/c), though at those speeds it would roll much better. Although it could dive about as well as 190's and 109's as well, nothing could out dive a P-47 (even a Me-262 would have trouble out accelerating a fully loaded P-47D in a dive) a late P-47D could safely dive to Mach .80 (~.82 critical) and even more with recovery flaps. The P-38's critical mach was increased to ~.75 with the dive-flaps, though the safe limit would be closer to .70.

In this respect the P-38 and P-47 were complete opposites, the P-47 easily escaping a P-38 in a dive (as long as it has decent altitude to work with) and the P-38 outclimbing the P-47 at almost any situation, except maby a P-47M or an N in clean configuration with empty wing tanks, though a P-38 with paddle props (or 4-blade) could beat this.


The 440+ mph figure for the P-38 was achieved with 100/150 fuel and high manifold pressures (either 65" Hg or 70" I can't rember) where WEP was boosted to just under (or possibly exceeding) 1,800 hp. On the same note the P-47D's R-2800-63 (or -59, wich was nearly identical) was cleared for 2,600 hp with 70" Hg (although it was limited to 2,535 hp with 65" for climb) with which it could achieve 444 mph at ~23,500 ft. (the critical altitude for 70" Hg)

The P-51 had been cleared for up to 90" Hg with 100/150 AvGas which it could exced 450 mph without wing racks, with racks (~10 mph drop in speed) it too could do ~444 mph. However the P-51 could not hold this power for long w/out having to open the radiator to full which dropped speed significantly, the P-47 and P-38 could maintain this power longer without overheating iirc due to their cooling systems and since the boost pressure was ~20" less. The P-47 could probably run the longest like this due to it's tough engine. (the R-2800-57C of the XP-47J, and P-47M/N was tested to 3,600 hp at extremly high boost pressures without failure, though there was much wear on the engines; the WEP of these engine was 2,800 hp at 2,800 rpm)

[drgondog]

Originally Posted by kool kitty89

Anything greater than 442 mph for the P-38L would be in a dive.

Actually - they were very close to critical Mach at 25,000 feet at 425mph in level flight - I'll have to check for STP. I don't believe any P-38 was rated to exceed .68 Mach. Without dive brakes they immediately went into compressibility between 430 and 440 mph at 25,000 feet. With Dive brakes they immediately hit .68 but it was controllable.

What I've wondered about the P-38K's propeller is why they didn't make kits for retrofitting new cowling and paddle props to P-38Ls in the field, as this wouldn't have caused any cease in production (the War Production board not even allowing the 2-3 weeks needed for retooling.

Or why not use a 4-bladed propeller like late-model P-39Qs did, the spinner and prop-diameter would be the same so there would be no need for new cowling and there would be more clearance for the props. (the paddle-props having a larger diameter as well) A 4-bladed prop would also be easier to fit in the field as no new cowling would be needed.

None of these changes would have helped the dive speed limit... but might have helped climb rate

One big drawback that the P-38 never fully solved was high-speed dive capabillity, it could dive decently but even with the recovery flaps (allowed another 30-40 mph TAS to be aceived safely iirc) it was not much better than the P-51 in this category (depending on how much a pilot was willing to push the a/c), though at those speeds it would roll much better.

Actually the P-38 was never close to a 51 or a 47 or F4U in a dive because of near immediately slip into compressibility if it started at high speed and altitude .. i.e 400mph at 25,000 feet when he pushes it over., or push it over and deply dive brakes. In the first case he want a long way before he could even pull out in denser air. In the second case he mainatins dive speed around .68 mach because of the drag of the brake.

The 51 would do .75 in a dive w/o power or prop. It was tested several times this way, being towed by P-61, then cut loose. The purpose of theses tests was to compare flight test treadings with experimental and calculated results from wind tunnel and analytical methods.

The dive limt of the 51 (manual) was 505 true, and IIRC about 280 IAS at 25,000 feet - but don't hold me to that. It has been way too long and I'm on the road. The manual recommended .75 but that was exceeded often in combat conditions.


Although it could dive about as well as 190's and 109's as well, nothing could out dive a P-47 (even a Me-262 would have trouble out accelerating a fully loaded P-47D in a dive) a late P-47D could safely dive to Mach .80 (~.82 critical) and even more with recovery flaps. The P-38's critical mach was increased to ~.75 with the dive-flaps, though the safe limit would be closer to .70.

KK - What is your source that the 38 could do .75 with the dive brake? It looked like the dive limit for the 38L as presented by the Lockheed thread was .68 for both the J and the L? Is that wrong in your opinion?

I do NOT know that it couldn't but it doesn't make a lot of sense that an airplane that can't match a 51 in level flight with nearly twice the Hp, also has a similar dive speed. The manual limit was .75 for the 51, the aero/drag limit was .80-.82 MAX

In this respect the P-38 and P-47 were complete opposites, the P-47 easily escaping a P-38 in a dive (as long as it has decent altitude to work with) and the P-38 outclimbing the P-47 at almost any situation, except maby a P-47M or an N in clean configuration with empty wing tanks, though a P-38 with paddle props (or 4-blade) could beat this.

I think all versions of the P-47D could also out roll the P-38 - even the P38L with boosted ailerons.. it certainly could through 400mph and I suspect at 425+ which is near max speed of P38L. If you have a comparison test or data point me in the right direction?


The 440+ mph figure for the P-38 was achieved with 100/150 fuel and high manifold pressures (either 65" Hg or 70" I can't rember) where WEP was boosted to just under (or possibly exceeding) 1,800 hp. On the same note the P-47D's R-2800-63 (or -59, wich was nearly identical) was cleared for 2,600 hp with 70" Hg (although it was limited to 2,535 hp with 65" for climb) with which it could achieve 444 mph at ~23,500 ft. (the critical altitude for 70" Hg)

The P-51 had been cleared for up to 90" Hg with 100/150 AvGas which it could exced 450 mph without wing racks, with racks (~10 mph drop in speed) it too could do ~444 mph. However the P-51 could not hold this power for long w/out having to open the radiator to full which dropped speed significantly, the P-47 and P-38 could maintain this power longer without overheating iirc due to their cooling systems and since the boost pressure was ~20" less. The P-47 could probably run the longest like this due to it's tough engine. (the R-2800-57C of the XP-47J, and P-47M/N was tested to 3,600 hp at extremly high boost pressures without failure, though there was much wear on the engines; the WEP of these engine was 2,800 hp at 2,800 rpm)

P-51 Mustang Performance
P-38 Performance Trials

441mph is a good number for P-51B at 75". It would help in the discussion if you referred to specific models and flight conditions so I knew what your were making comparisons against?

It is not a good number for the P-51H. The factory got 480+ w/o rack, but full combat load and wing tanks - only 25gal in fuse tank. at 9450 pounds

The NAA calculated performance had 487mph at 22K+ w/o racks in same condition at 9450 pounds

USAAF tested at Wright Pat with an a/c picked at random and got 451+ at 90inches at 21,600 at 9544 pounds (extra weight and drag for racks)..

If Mike's figures are right for the December 1945 test of the P-38L, it was 30mph slower than the P-51H at 26,000 feet and 60 mph slower at SL.

The climb of the H was 4680 with full combat load from SL through 4200 feet and got to 35,000 feet in 9.4 minutes, 16,000 in 4 minutes. W/O racks and the extra 100 pounds, the initial climb rate was 5,000fpm +..

The P-38L had some advantages over a P-51B, some over a D, few over an H.

Perhaps the bottom line is that in comparisons of P-38J and P-38L in air to air combat in ETO, the 51B and D had a huge edge in awards and air to air award to actual loss ratios. One can debate accuracy of awards but the process was same for 8th AF independent of the fighter.

I have no idea regarding either the MTO or PTO for similar comparisons - but the German opposition was in general far better than the Japanese.

Regards,

Bill