The P-38J and L in the European theater. (1 Viewer)

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As to the other question.. this is what I stated

Each was equipped with P-38J-15 with leading edge fuel tanks when they started combat ops in April and early May, 1944. I haven't yet found out whether P-38L's were delivered but all the J's received the filed modifications for both the boosted ailerons and the Dive flaps by late June when all the ETO P-38s were upgraded to the P-38J-25


What I meant, and should have clarified, is that all the P-38J's were scheduled to be upgraded with Field kits to install the dive flaps and boosted ailerons and bring them to the J-25 capability.Retrofit capability to redesign the intercooler and install the leading edge fuel cells would have been impossible at Service centers in England. However, AFAIK it would not have been impossible to retrofit the earlier J-5 or -10 because I'm not as familiar with the internal design features of the P-38J blocks.

As to the sources - multiple conversations with both John Landers and Robin Olds, curiously on this subject of "what if". Landers was certain that he had both dive flaps and boosted ailerons on his June 25, 1944 fight with 109s and 190s near Paris. He was equally certain that he was flying the -15. The last of those conversations were in the mid 80's. In the only conversation with Olds on this subject, Zemke (and Loisel and Landers) were also in it... either 1984 0r 1986 AFA Reunion in Tuscon. Zemke, Olds and Loisel recall flying the 'modified' J-15 also in the summer of 1944. Neither Olds nor Zemke recall a P-38L-1 at 479th but the first P-38L-1's were rolling into USAAF inventories in June, 1944.

As an aside to frame the P-38L-1 combat arrival discussion - PTO aces Bong, McGuire and McDonald all scored in L-1s in October/November 1944. Two aces of the 474FG in ETO scored with J-25s in August (Kirkland - two 109s 8/25) and Milliken - 2-0-3 FW 190s on 9/12/44)

EDIT - 9/27 I haven't found the source(s) yet that cite Lockheed producing several hundred dive flap kits in late 1943 to March 1944 and dispatch them to ETO/PTO and MTO. A friendly fire incident took down a AAF transport carrying 200 en route to England in early March, 1944. It is in one of Ethell's and one of Bodie's books but I'm looking for a Ben Kelsey memo dated April 1943 citing his satisfaction with the dive flap mod on one of the very early -5's
 
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The latest sentence is dead on.
For the Griffo, we need also to add a substantial amount of exhaust thrust at such high altitudes, maybe equivalent of 20% of engine power? That woul make it about 1700 hp for military power at 27-30 kft?

I am not sure about the that much exhaust thrust. for 10,000ft difference in altitude you loose about 20% in air density (roughly) so you have 20% less exhaust mass. That gets balanced somewhat by the higher exhaust velocity because of the lower air pressure at the exhaust nozzles.
For the Merlin XX exhaust thrust (power) never exceeded 11.5% of brake hp. A two stage engine will show a higher percentage because you have the weight of the exhaust used to drive the supercharger but that is not a constant either, the Merlin XX needed 225hp to drive the supercharger at 20,000ft to give 12lb of boost. At 30,000ft the supercharger could only deliver a bit over 2lbs of boost . Charge flow(weight of air+fuel) had dropped from 144lb/min to 107.2lb/min and supercharger power requirement had dropped to 167hp.

I do have to apologize though, apparently I was looking at the wrong page in my book (and failed to check a second source) and a two stage Griffon will pretty much match at Late Turbo Allison at altitude (27-28,000ft).
 

I still believe the critical factor in the ETO, and to a degree in the MTO, for strategic incursions into Germany on bomber escort was simply that the LW fighter pilots were ordered to not engage escort - and the big freaking P-38 was easy to spot and avoid... and they did. But they had no such defense against the P-51.

The net - the P-38 escorted well and nobody came to the party. When they did engage, the 109 and 190 could both outdive and maintain control in the dive to easily escape many combat situations with the P-38. Until the dive flap and boosted ailerons, the P-38H and J were also at a maneuvering disadvantage except for a steep climbing turn to the right.. it was nowhere near as ideal as P-38 vs A6M, Ki 61, etc combat.
 

From my perspective this statement represents the 'average' concensus for the advocates of "The P-38 coulda done better in the ETO, if only.. - fill in the blanks -"

Here's the thing. For the Pre P-38J-15 which first started arriving in February 1944 to fill (maybe late January) operational squadrons in the ETO, there were two sets of issues, one group Objective, the other Intangible that hindered achievement of the Lightning versus the Bf 109 and FW 190. Thos two represented the primary adversaries with relatively equal performance at the altitudes in which the 8th AF bombers were escorted..

Mechanical/Aerodynamic - tangible and objective
* Intercooler issues resulting in mechanical engine failures
* Immediate entry into compressibility and uncontrollable dive when diving from high speed cruise.
* Lack of roll and turn maneuverability in comparison.

Intangibles
* Cockpit comfort due to frigid cockpit/lack of adequate heating resulting in increased fatigue
* Huge size and distinctive plan form making it uniquely identifiable from great distances
* Significant areas of rear and down aft visibility diminished by tail boom geometry
* Combination of twin engine operation and complicated control processes to move from cruise to combat state in short time.

In addition One Major Intangible representing External factors beyond Engineering solution
****** Luftwaffe High Command instructions to avoid bomber escort

So, on paper the entry of the 55th FG in October with the improved P-38H that still had all the above Tangible issues resulted in:
Operational issues reducing effective mission strength below that of comparable 8th AF P-47s (P-51s subject to this also as bugs were being fixed in first several months of operations).
* combat performance versus mainstream LW fighters well below P-47 when engaged.
* loss rate to mechanical problems and initially higher accident rate due to complexity and training required to operate twin engines versus single engine fighter.
* Twice as expensive to operate versus single engine fighters

Positive Factors - but intangible to the analyst wondering why the P-38 wasn't doing as well against the LW.
* The escort missions seemed successful because fewer attacks SEEMED to occur when P-38s were escorting specific bomber groups.. This is somewhat anecdotal but my own research of individual 8th AF Fighter Group Histories points to more Mission Summary Reports, Para H. Claims for A/c destroyed" cite the phrase 'NIL" far more than the P-51 and P-47 groups - even if in same general area and time as the other groups.

My conclusion is and has been for some time, that the avoidance of combat order by Goering was very easy to obey because the P-38 was mostly visible to the LW before the LW was visible to the P-38s. Secondly, until the dive flap was installed, avoidance of a P-38 even when engaged was relatively easy by simply pushing the 109 and 190 into a sharp roll and split S. If the P-38 even tried to follow, it would spend a long period of frustration until it reached sufficiently dense air to recover from the dive - due to the tuck issue following onset compressibility shock wave moving the CMac.

In the PTO, the Japanese fighters did not have either the speed or diving ability to escape from a P-38 and the combats were far more in middle altitudes where the .68M speeds were not often encountered even in a dive for some time or very steep dive angle. Nor were the Japanese inclined to avoid combat. Those are three factors for me which I think illustrates the relative effectiveness of the PTO P-38 versus the ETO/MTO long range escort utilization of the P-38 for attacks against Germany, Austria and Balkans.
 
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Combination of twin engine operation and complicated control processes to move from cruise to combat state in short time.

Excellent assessment Bill but I have issues with this one. I think it's obvious that a twin is more complicated to operate than a single engine fighter - two of everything. If you look at the placement of some of the controls on the P-38 and compare them to other twins of the day (and those developed after the P-38 ) some are in the same location and worked the same way. I think with training, a competent pilot could handle the work load and configure his aircraft to be combat ready in a required amount of time to defend himself, but this will go back to the complexity argument of operating a twin (let alone the time and cost to train pilots to handle the complexity of a twin). I never read much about PTO P-38 drivers complaining about the time it took to go from cruise to combat state. I think Rau's letter addressing this situation was a bit exaggerated, but funny that he talks about a new pilot with only 25 hours in the P-38, where AFAIK PTO P-38 drivers had a hell of a lot more time in type before they were cut loose to fly combat.
 

Hi Joe. I honestly do not know how much time the average replacement P-38 pilot had when a.) they got to England, and b.) how much time they got in the 496th FTG at Goxhill before moving into 8th and 9th AF P-38 groups. IMO the extra training and flight time translated to fewer mistakes making the multiple moves required to drop the tanks, run the RPM and throttle up, and go do sumtin' fast, but not significantly reduce the time.

But - it was definitely more steps than a 51 or a 47 with the attendant possibility of a mistake along the way.

At the Fighter Conference at Patuxent River in October 1944, the P-38L was ranked as the 'worst cockpit and control layout' and only 2 of the 28 ranked maneuverability as good, 10 'fair' and 16 'poor' when compared to the other fighters flown at the Conference. Note that this was the latest P-38, it was after the last one flew combat for the 8th AF and just then reaching combat units in the PTO.

At the end of the day your points make sense Joe - but begs the question "If I have to invest more time in training, more time to train maintenance procedures, more average time to maintain it on a daily basis, spend more money on fuel, drain the fuel storage 2x faster, fight with an opponent that is still more maneuverable, can still out dive me - when I have a single engine fighter (the Mustang B/D) that doesn't have those problems.. would I want the first one to fight with?"

I think Doolittle answered the question in January 1944 and would have answered it the same way even if he had more experience with the J before making the decision. Remember he came from 12th AF and 15th AF where the P-38 combat in the Africa and Med campaigns didn't expose the P-38F and H as much as European high altitude escort conditions..

At any rate, it is an interesting discussion.
 
Here's a good overview of the P-38 from a pilot who flew them: Capt. Robert DeHaven, 7th FS, 49th FG (14 victories: 10 w/P-40 - 4 w/P-38):
 

Yep, 20% of extra power should be a bit too much, somewhere around 15% should be available at 30000 ft?
Could you please elaborate a bit about the bolded part?
If I'm reading this chart right (for Jumo 213E), whenever the boost and RPM are at certain level, and the engine/plane is at ever higher altitude, the exhaust thrust is also increasing. That is despite the ever increasing power needed to drive a S/C.
Highest line is for the 'Sondernotleistung' (ie. use of MW-50; only available for lower 2 S/C gears), next one is for 'Notleistung', the bolded one is for 'Kampfleistung'.



The chart for the BMW-810D - despite greater need for the S/C, the exhaust thrust is cosiderably greater in second S/C gear, than in 1st:

 
Nothing about an engine change dramatically re-sets to table for the P-38 save reducing mechanical issues from the combination Intercooler/Turbosupercharger/engine issues. A Merlin 60 series IMO would do just fine as The alternate future 'what if' universe of possibilities, but

1. Doesn't change the 'whoops I shouldn't have pushed the nose down" issue
2. Doesn't make me roll (or transition into the Roll) appreciably faster - so the 190 and 109 cand still flick away as before.
3. Doesn't make my big fat planform shrink from a size 14 to a size 3
4. It Does reduces the range a bit as the Allizon was better on fuel conservation but yanking the intercooler and turbo out provides for more internal fuel or reduces weight for better climb and range.
5. Cockpit control procedures are the same
6. It is still 2x to fly and maintain but less so w/o Turbo to worry about
7. Reduced performance beyond 30,000 feet w/o turbo

But below 30K, say at 20-24K to FTH it is a wee bit faster - but also pushes it closer to the .68M limit for compressibility..

Now - change the wing to a 12% or less and a LOT of problems go away.
 
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Now - change the wing to a 12% or less and a LOT of problems go away.

Or use a laminar flow profile.

Now that we are changing the wings, would there be an advantage to trimming the wing span?

The P-38's wingspan was
  • 3' less than the XP-67 (which was heavier, with 6 x 37mm cannon!)
  • 2' 2" less than the Mosquito's (a bomber)
  • 2' greater than the Fw 187 (which was lighter at max take-off than the P-38 was empty!)
  • 7' greater than the Whirlwind (which was lighter at max take-off than the P-38 was empty!)
  • 7' greater than the Hornet (which was had a similar max take-off weight to the P-38)
  • 10' greater than the XF5F/XP-50 (which were much lighter)
  • 10' 5" greater than the Tairov Ta-3 series prototypes, which used two big fat radials and was still lighter at max take-off than the P-38 was empty
  • 12' greater than the proposed Supermarine Type 327 (which also would have been much lighter)

The XP-49 tidied up some of the details of the P-38 but used the same wing and dud engines (the IV-1430).
 
Pretty good response, Bill, and I bow to your research on the data. I have never had access to it and still don't. Good stuff.

What I CAN say is the P-38 has little trouble staying with the stock P-51 when flown as they are today. The guys I know who fly it are all amazed by the P-38. None have ever been attacked by anybody while doing it. No doubt they aren't using full power or, especially, WER. These are privately-owned aircraft, even ours (owned by the museum).

All the people who give talks on it praise the P-38's ability to spit ammunition out the front that ins't converging. All say it rolled very well if you were a strong armed guy, and our own P-38 has NO trouble rolling with our Mustangs and P-40 ... it just takes some muscle.

So, modern operational data collides with your war information. Plus, it WAS the mount of the two highest-scoring aces for the U.S.A.

I hope to GET some of your sources (Thanks for the thread on sources) but feel that verbal recollections from real WWII pilots trump modern revisionist books EVEY time. The pedestrian P-40 "woke up" when flown at 75" of MAP according to guys who DID it and that set of operations was responsible for a significant portion of the P-40's success. And that difference made the P-40 formidable when flown at WER power. I'm sure the P-38 guys had a similar experience as they have described it almost the same way on numerous occasions in live talks at the museum. Overboosting was common under certain circmstances, such as when you are about to die if you don't overboost.

Meanwhile, my opinions are in flux with your data shown ... and I can't verify them all at once ... so I'll refrain at this time.

I'm still a huge P-38 fan, but understand the data you posted. It speaks to me of ETO tactics versus PTO/MTO tactics. The latter were VERY effective. The former much less so, at least with the P-38. My jury is still deliberating ... but your data, if true, is somewhat telling.

Maybe you can tell me how the 60% of P-38's versus P-51's dropped 355% of the bomb tonnage if they were not on gound support missions?
 
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Note sure why people are even continuing this.

Griffons in a P-38, when the std engines in a late model meant max level speed was about 20mph off of the critical mach limit...
So it was aerodynamically limited.

Even if you could, then give it the gun ...and fall out of the air into an uncontrollable dive. That is what mach limits are..you lose total control of the aircraft....
You go into a dive you cant pull out off..lawn dart time.

Be in level flight...hit the limit and the nose goes down..and down. Your only hope is that, if it holds together that as you hit thicker air then the high mach limit mean you can start to regain control.

The only answer was to, which they did in the end, keep it to operations under 20,000ft, preferably 15,000ft, where the gap between the mach limit and the planes speed was much larger.

Totally flawed plane and you can't excuse Lockheed over this. Using the same data, at roughly the same time, Messerschmitt created the 109 with a 0.75-0.8 mach limit, Supermarine created the Spitfire with a 0.85 mach limit.

Lockheed were like Hawker, with the Hurricane having a 0.7'ish mach limit (and the Typhoon similar). Took them until the Tempest to get into the 0.8 region.

So, sadly Kelly Johnston (and Camm) cannot excuse their design mistakes, because others didn't.
 
A little harsh considering that the "boffins" at the RAE and the scientists/researchers Langley (NACA) didn't know there was problem with those airfoils in 1938-39-40. Neither company, in fact neither country had wind tunnels working at those speeds.

Building 400mph at sea level seaplanes may tell you that the thick airfoils may have more drag than the 'Boffins' are saying but it doesn't tell you about mach tuck either.

The P-38 had about all the engine power in 1944 that it could stand.

as for "Using the same data, at roughly the same time, Messerschmitt created the 109 with a 0.75-0.8 mach limit, Supermarine created the Spitfire with a 0.85 mach limit."

There was NO data, just guesses and some were better than others.
 
Or use a laminar flow profile.

Now that we are changing the wings, would there be an advantage to trimming the wing span?

A laminar flow airfoil should cut down the drag and move the Mcr from .68M to a higher value even at 16% T/C. Should also diminish the Mach Tuck issue by pushing the shock wave formation region farther aft of the aerodynamic center.

Reducing wing span would increase the Induced Drag but reduce Zero Lift Drag and reduce the available lift. Should increase top speed, reduce range potential, reduce climb performance - but those are gross generalizations as the introduction of the laminar flow airfoil should reduce zero lift drag even more than reducing wingspan which should tend to improve L/D and restore range potential..
 

What aircraft did you designed, so you have the credentials to throw mud on people that really designed aircraft?
 

Respectfully Kelly needs zero excuses and to label the 23016 airfoil a 'design mistake' is silly given the state of the aerodynamics 'art' of 1937-1938.

Once Kelly figured out the problem in 1942 he proposed the solution, but the War Production Board said 'no'.
 

The P38 in the MTO flew a lot of fighter bomber missions from the very beginning of the African campaign to the end of the war. The P-38/P-47 and P-51 flew some fighter bomber mission, about the same number, in the 8th AF but the prime mission was Escort. The 9th AF flew fighter bomber missions almost exclusively but following D-Day had one Mustang fighter Group (354) and one Recon Group (363) plus several recon P-38 and P-51 and Mosquito squadrons.

Pretty simple math when you contrast the 8th and 9th AF mission side by side, the look at the daily mission profile for 9th AF P-38s vs 8th AF P-51s
 
Excerpts concerning introduction of the Dive Flaps, the kits, and last a pice about Col CY Wilson killing a 109 from a dive with a recently modified P-51J-15 on JUNE 25, 1944.

Der Gabelschwanz Teufel - Assessing the Lockheed P-38 Lightning
The complaints were relayed to the Lockheed factory, and design changes were incorporated in the P-38L. Prior to the arrival of the "L's" at Wormingford, many modification kits were shipped to Langford Lodge, North Ireland, for field modifications of the "J" model Lightning then arriving in the theater. Unfortunately, an early shipment aboard a DC-4 was lost at sea when the Brits shot the cargo plane from the sky. It took several months to replace the lost modification kits. Early P-38J-5-LO's were modified at Langford Lodge by the addition of the replacement kits. The kits added dive recovery flaps under the wings, outboard of the engines, and a 3000psi hydraulically boosted aileron system. The P-38L's were now coming down the production line with the aileron boost and "speed boards" installed.

The P-38J resolved the intercooler efficiency problems of the earlier subtypes via the use of a core type intercooler in the forward nacelle chin. While prototypes were being tested in early 1943, P-38H production continued. The new nacelle chin provided increased oil cooling capacity, and automatic control of the intercooler vent, resulting in the full availability of the 1,600 HP War Emergency rating of the F-17 powerplant. Other design changes were introduced, including enlarged glycol radiators in the tail booms, in later build aircraft additional outboard leading edge tanks, and two major control system changes. These were hydraulically boosted ailerons which decreased control forces by a factor of six, and electrically actuated dive flaps under the wings which cured the dive compressibility problems. The latter were fitted standard from the P-38J-25-LO, sadly almost all retrofit kits intended for earlier P-38J subtypes were lost in a friendly fire incident in early 1944, thereby delaying the introduction of this important modification to theatre units by several months. Curiously, the modification entered production as a kit in late 1943, yet was not incorporated into production aircraft for another six months, until the P-38J-25-LO, although some P-38J-10/15-LO aircraft were retrofitted in the field.


P-38 Lightning Aces of the ETO/MTO - John Stanaway - Google Books this references a victory on June 25 by Col Cy Wilson with an upgraded P-38J-15 after installation of the Dive flaps Mod kit.

I'll have to dig up the references from the library - but the summary is that the second batch of kits arrived in late April and the installation process on the J-15's started in June, and proceeded all the way through September until the 479th converted 100% to Mustangs and the 479th P-38s went to 9th AF as replacements to 367, 370 and 474FG's. The J-25s arrived in September and the L's in October at various 9th AF Lightning Groups. Only the 474th finished ops with the P-38L's
 
Once Kelly figured out the problem in 1942 he proposed the solution, but the War Production Board said 'no'.

And something to consider here before too many people cast bricks/stones at the War Production Board.

They built almost 3 times the number of P-38s in 1942 than they did P-47s.
The P-47Bs were rather quickly relegated to use as trainers.
P-47C production didn't exceed P-38 production on a monthly basis until the spring of 1943 with any regularity.
Total number of P-47s produced doesn't pass total number of P-38s until about Oct/Nov of 1943. About the time P-51Bs first start showing up in Europe.
For a good part of 1942-43 is was P-38s or P-39/P-40s with very little else. Delays in P-38 production would have had serious consequences.

By Winter of 1943/44 The Mustang was passing BOTH the P-38 and P-47 by. Perhaps at this time the P-38 could have been "fixed" but then we come up against the cost factor. While a P-38 might NOT have been that much more expensive than a P-47, it certainly was much more expensive than a P-51.

Please remember not only factory lead times but transport times for US aircraft to war zones. It took weeks if not several months to get a fighter plane form the factory door to a combat theater so needs/wants had to be planned for several months in advance and hope there were no big surprises.
 

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