The P-38J and L in the European theater.

[Shortround6]

I would note that the article makes several mistakes that we have mentioned before.

1.
" Arrival of the newer P-38J to fill in behind the P-38H was supposed to help, but did not help enough. The J model's enlarged radiators were trouble-prone. Improperly blended British fuel exacerbated the problems: Anti-knock lead compounds literally seethed out and became separated in the Allison's induction system at extreme low temperatures. This could cause detonation and rapid engine failure, especially at the high power settings demanded for combat."

I have no idea if some of the fuel causing problems was blended in Britain or In British controlled refineries but at this point the US and the British were using a common fuel specification/s and had been for some sometime. This specification (for 100/130 fuel) had been changed 3 times (at least) and the changes were known to the parties (using air air forces and engine makers, in addition to the oil companies) involved. Allowable lead for instance had gone from 3.0cc per US gallon to 4.0cc per US gallon to 4.6 cc Per US gallon. This allowed for much higher production of 100/130 from base stocks without building additional refining capacity. The Problem the P-38s were having was NOT with the lead coming out of the fuel. Other changes in the fuel specification allowed for a higher use of aromatic compounds which do raise the knock limit, these are heavier than straight run gas and have different vapor points and freezing points. The effect of using these compounds (which are NOT lead) was suspected or known months before the P-38J showed up in Europe and Allison had been working on a new intake manifold to help combat the problems since the spring of 1943. It took until near the end of 1943 to get the Manifold in to service (and manifolds were shipped overseas for refitting to existing engines). I believe that Allison began fitting the new manifold to ALL Allison engines, not just P-38 engines shortly after.

2.
"In an article on ausairpower.net, Carlo Kopp noted that in their early days in the European theater, "Many of the P-38s assigned to escort missions were forced to abort and return to base. Most of the aborts were related to engines coming apart in flight….[due to] intercoolers that chilled the fuel/air mixture too much. Radiators that lowered engine temps below normal operating minimums. Oil coolers that could congeal the oil to sludge. These problems could have been fixed at the squadron level. Yet, they were not."

A partial fix was ready to hand, simply operate the P-38 according to Allison and Lockheed instructions. Instead the Army thought they knew better. They operated at a high cruise RPM and low boost. This kept the intake air cool or cold and really didn't work the engine very hard (part throttle at high rpm). Allison and Lockheed were recommending low rpm and high boost (greater use of the turbo when cruising) which would have heated the air more before it went through the intercooler and would have meant hotter air going though the engine supercharger and into the manifolds helping stop the the fuel separation and fuel puddling in the manifolds. Hotter air going in raises the temperature of the gases all the way through the engine, hotter combustion chamber temperature and hotter exhaust temperature. This may not have fixed the oil temp problem but it sure couldn't hurt. The Army gave in and began operating the P-38 the way Allison and Lockheed wanted but not until the late spring/summer of 1944. This was in conjunction with a visit by Tony Levier (Lockheed test pilot) to P-38 units in England.
Operating an aircraft against both the airframe and engine makers recommendations and then blaming the aircraft doesn't seem quite fair. The low RPM and high boost technique was hardly new or novel. The British had been doing it with non-turbo planes for several years before the P-38 showed up in late 1943.
It also helps with the turbo spool up problem as the turbo is operating at a higher speed when cruising than the high engine rpm/low boost method of cruising.
Yes you need for the engine and props to accelerate up to speed but the props should automatically adjust pitch to the power going to them. Trying to go from high cruise engine rpm to combat power with the turbo trying to go from just off idle to full boost is going to leave you with turbo lag (engine starving for air) while an engine at lower rpm but with full (or nearly full) boost from the turbo will actually make more power at the lower rpm and then build.

 

[FLYBOYJ]

"great difficulty in escaping it."

Please elaborate

The trick with the Mossie was keeping the speed high and lots of changes in course to prevent interception

Training, tactics, training, tactics, as with the P-38. BTW a common tactic by most if not ALL fighter pilots (except those very green) was to fly a zig-zag course, never fly straight and level and always keep your head on a swivel. The number of engines the fighter had made no difference.

 

[swampyankee]

The high rpm, low boost cruise may have increased the oil temperature, as the mechanical losses would have been greater and the fuel economy worse than with low rpm, high boost.

 

[BiffF15]

The high rpm, low boost cruise may have increased the oil temperature, as the mechanical losses would have been greater and the fuel economy worse than with low rpm, high boost.

Swampyankee,

I agree and thought the same thing. The upside is reliability and safety at the expense of maybe some range. However IIRC Lindbergh flying with the Lightning guys in SWP actually extended their range by quite a bit.

Cheers,
Biff

 

[eagledad]

Gentlemen

Tony LeVier (Lockheed P-38 test pilot) in a report written in May of 1944 after returning from visiting P-38 units in England recommended that for maximum engine efficiency/fuel economy pilots use 2300 rpm and 36" manifold pressure (MP) as the maximum for auto lean and cruise conditions. In reducing power (from 2300rpm and 36 MP), reduce MP from 1/2" to 1" for each decrease of 100 rpm. For increased power (from 2300rpm and 36"MP) , go to auto rich and increase MP 2" for each 100 rpm increase. He also stated that when he came to England, P-38 pilots were cruising between 2000 and 3000 rpm. One combination that he came across was 2800 rpm and 24 " MP.

The above is from Lockheed P-38 Lightning by Steve Pace, pages 74 and 76

Eagledad

 

[redcoat]

Please elaborate

The Mosquito didn't have a speed advantage over the Fw 190 or the Bf 109G, so if these fighters did manage a successful bounce the Mosquito had great difficulty in getting away.
This is why when the Mosquito bombers were first introduced in 1942 and used on long range penetration flights into Germany the loss rate was 16%, better tactics and modifications to increase it's speed reduced the loss after a while to around 8% before these long range daylight raids into Germany ended in mid 43 and they transitioned to night attacks.

 

[Barrett]

Boy, I think most of us have seen books with less info than this thread!

Just want to share an illuminating document that turned up when researching Forgotten Fifteenth:
Col. Obie Taylor rebuilt the 14th FG after the N Africa doledrums. He said that he never stopped learning about the 38, and that a newbie needed about 50% more transition time in a 38 than a s/e fighter, "but after that he could be nearly unbeatable."

The 15th's three P-38 groups did little escort after the Ploesti campaign (c. Aug 44) and most flew bombing-strafing missions til VE. Two of them (1st and 14th?) scored only about 4 kills in that time.

 

[FLYBOYJ]

Boy, I think most of us have seen books with less info than this thread!

Just want to share an illuminating document that turned up when researching Forgotten Fifteenth:
Col. Obie Taylor rebuilt the 14th FG after the N Africa doledrums. He said that he never stopped learning about the 38, and that a newbie needed about 50% more transition time in a 38 than a s/e fighter, "but after that he could be nearly unbeatable."

The 15th's three P-38 groups did little escort after the Ploesti campaign (c. Aug 44) and most flew bombing-strafing missions til VE. Two of them (1st and 14th?) scored only about 4 kills in that time.

I've been told by several veterans who flew P-38s and P-51s and they said the same. Usually 200 hours in a twin (B-25s and A-20s) made very proficient P-38 pilots

 

[FLYBOYJ]

The Mosquito didn't have a speed advantage over the Fw 190 or the Bf 109G, so if these fighters did manage a successful bounce the Mosquito had great difficulty in getting away.
This is why when the Mosquito bombers were first introduced in 1942 and used on long range penetration flights into Germany the loss rate was 16%, better tactics and modifications to increase it's speed reduced the loss after a while to around 8% before these long range daylight raids into Germany ended in mid 43 and they transitioned to night attacks.

And again, this shows that tactics and training was the key with regards to flying twin engine fighters - see above

 

[P-39 Expert]

Just a few words about the P-38:
1. More successful in PTO because it had a theoretical 70mph speed advantage and CLIMB ADVANTAGE at all altitudes over Zero and Oscar. In ETO P-38 had no speed advantage, no (or little) climb advantage and couldn't dive or turn as well as LW. Late J and L models addressed these issues, but the heavy lifting was done by the time they were operational.
2. One prime factor for 8th AF switching to P-51 was maintenance. Over twice the maintenance for each P-38 as there was for a Mustang.
3. P-38 was effective in the 8th AF escort role primarily because THEY WERE THERE. Presence of ANY escort fighter severely disrupted the LW's plan of attack. ANY escort fighter would have forced the withdrawal of twin engined interceptors and upgunned/rocket tube armed 109s and 190s. And the 109 and 190 had only enough fuel for about one pass at the bombers before they had to retire for more fuel.
4. P-38 was limited by not being able to use automatic boost control (until later models). Since the P-38's critical altitude was up to 30000' the engines could be over boosted at any altitude under that, which was basically the whole combat envelope. Virtually all the Allisons had auto boost except the P-38. Something about it fighting with the turbo regulator. Not much of a problem if critical altitude is 12000', hard to over boost above that. But with all the pilot workload on the twin engined P-38 the threat of over boosting at any altitude was an added headache.
5. Twice as expensive to produce, twice the maintenance, inferior dive/turn and a handful for ANY pilot much less a newby.
Probably not the best use of the AAF's limited resources IMO.

 

[tomo pauk]

Good post, but this:

...
Probably not the best use of the AAF's limited resources IMO.

AAF's resources were more than suitable to sustain production, use and maintenance of the P-38s.

 

[GrauGeist]

Good post...

I agree with Tomo, however, in point 3, I need to address this portion:

...ANY escort fighter would have forced the withdrawal of twin engined interceptors and upgunned/rocket tube armed 109s and 190s. And the 109 and 190 had only enough fuel for about one pass at the bombers before they had to retire for more fuel.

The Wfr.Gr.21 and R4M were not used as extensively as was the 30mm cannon.
It was much more typical to have the Bf109 flying top cover while the heavier armed types (Bf110, Me410, Fw190A-8, etc.) attacked the bombers. And the presence of Allied fighter escort didn't deter the Luftwaffe's attacks.
In regards to limited fuel, only the Me163 and Me262 had short fuel windows for engagement - particularly the Me163, which had roughly 7 minutes of fuel. The Me262 had roughly 80 minutes cruise or 30 minutes of combat.
The piston-engined types had a much better fuel window and often times, they were flying from very local fields that lay in the bomber's paths.

 

[P-39 Expert]

I agree with Tomo, however, in point 3, I need to address this portion:

The Wfr.Gr.21 and R4M were not used as extensively as was the 30mm cannon.
It was much more typical to have the Bf109 flying top cover while the heavier armed types (Bf110, Me410, Fw190A-8, etc.) attacked the bombers. And the presence of Allied fighter escort didn't deter the Luftwaffe's attacks.
In regards to limited fuel, only the Me163 and Me262 had short fuel windows for engagement - particularly the Me163, which had roughly 7 minutes of fuel. The Me262 had roughly 80 minutes cruise or 30 minutes of combat.
The piston-engined types had a much better fuel window and often times, they were flying from very local fields that lay in the bomber's paths.

All I'm saying is, those twins and rocket firing single engined planes were doing major damage.
ANY escort fighter will force their withdrawal since their performance is degraded.
Then the LW has to fight "fair", and intercept with interceptors not destroyers.
P-38s were valuable in the ETO, I'm just saying they were not twice as good since they were twice the price and suffered delayed combat introduction.

 

[Shortround6]

All I'm saying is, those twins and rocket firing single engined planes were doing major damage.
ANY escort fighter will force their withdrawal since their performance is degraded.
Then the LW has to fight "fair", and intercept with interceptors not destroyers.
P-38s were valuable in the ETO, I'm just saying they were not twice as good since they were twice the price and suffered delayed combat introduction.

They suffered delayed combat introduction in Europe because all available P-38s were going to the Med, Indo-China and Pacific. The 55th fighter group was the first fighter group to perform escort missions in NW Europe and that started in October of 1943, roughly 8 weeks before P-51s start flying escort missions. The actual planes are P-38H's.
I don't think anybody is saying they were twice as good.
In late 1943 the plane to compare to is the P-47 which equipped 7 fighter groups at the time the 55th became operational. P-47s had no paddle blade props and no water injection at this time (and wings were not plumbed for drop tanks). Things changed a lot in the next 4 months.

 

[P-39 Expert]

They suffered delayed combat introduction in Europe because all available P-38s were going to the Med, Indo-China and Pacific. The 55th fighter group was the first fighter group to perform escort missions in NW Europe and that started in October of 1943, roughly 8 weeks before P-51s start flying escort missions. The actual planes are P-38H's.
I don't think anybody is saying they were twice as good.
In late 1943 the plane to compare to is the P-47 which equipped 7 fighter groups at the time the 55th became operational. P-47s had no paddle blade props and no water injection at this time (and wings were not plumbed for drop tanks). Things changed a lot in the next 4 months.

My point about delayed combat introduction is that they didn't get into combat AT ALL until the end of '42.

 

[drgondog]

My point about delayed combat introduction is that they didn't get into combat AT ALL until the end of '42.

Not strictly true, even in context with fact that the AAF was just getting started in late 1942 in ETO and MTO. The 1st, 14th started combat ops in ETO August 1942 (1st) and October (14th) and 78th FG was on the way. Africa stripped the P-38 FG's from 8th AF and from that point until Blitz Week through Schweinfurt that 8th AF realized it was in deep trouble for un-escorted deep penetrations and Arnold approved emergency re-deployment of 55th FG and re-routed 20th and 364th to join the 55th.

P-38s were operational in May 1942 in the Aleutians and as Recon in Australia.

 

[swampyankee]

Good post, but this:


AAF's resources were more than suitable to sustain production, use and maintenance of the P-38s.

They were still finite. Removing the P-38 from production may permit increased production of equally effective, less expensive aircraft. It's not guaranteed, as Lockheed, for one, may not be able to produce Mustangs or Thunderbolts.

 

[GrauGeist]

All I'm saying is, those twins and rocket firing single engined planes were doing major damage.
ANY escort fighter will force their withdrawal since their performance is degraded.
Then the LW has to fight "fair", and intercept with interceptors not destroyers.
P-38s were valuable in the ETO, I'm just saying they were not twice as good since they were twice the price and suffered delayed combat introduction.

Warfare is not "fair" - each side will always escelate with new threat upgrades. The side that overpowers their enemy is the winner.
And like I mentioned earlier, the Wfr.Gr.21 was not used in large numbers, entered service from about mid-43 onward. The R4M entered service in '44 both with the goal of inflicting broader damage in a single salvo and to reduce the drag penalty from either gunpods or Grenate launch tubes. The R4M didn't see widespread service, either.

What was the primary destroyer of bombers, was the MG151/20 and both the Mk103 and Mk108. These were used aboard the dedicated interceptors, who had fighter protection of their own. The deadliest combination would be the late model Bf109s flying cover for the heavily armed and armored Fw190 Sturmbocks. The 109's drew off the fighter escort and the Sturmbocks moved in and tore the bombers apart with their 30mm minengeschoss rounds.

I cannot honestly think of any time that the Luftwaffe approached a bomber formation, saw Allied escorts and turned away. I CAN recall many instances when Luftwaffe elements engaged the escorted bombers without the benefit of top cover - the Me262 was one such type that would commit slashing attacks on the bombers while dodging the escorts and then used their speed to either climb up and away to prepare for another attack or leave the area, which was very frustrating to the Allied fighters.

 

[Shortround6]

They were still finite. Removing the P-38 from production may permit increased production of equally effective, less expensive aircraft. It's not guaranteed, as Lockheed, for one, may not be able to produce Mustangs or Thunderbolts.

Lockheed could probably build anything you wanted them to.
The Problem being that the P-38 was earlier in timing than the P-47 and the Merlin Mustang.

In March, April and May of 1942 Lockheed built 100 P-38s in each month. Republic built 1, 1 and 10 aircraft in each month and NA was building 52-86 Mustangs a month for the British with Allison engines.
At what point do you tell Lockheed to stop making P-38s and spend months swapping over the production lines?
In Dec of 1942 Lockheed built 160 P-38s, Republic built 142 P-47s and NA was building A-36s.
In 1943 Lockheed built 2497 P-38s, Republic built 4428 P-47s (660 in Dec) and NA had built 1710 P-51s (A-36s built in 1943 not counted).

Trying to get Lockheed to build P-51s in 1943 leads to the question of where do the engines come from?

From the Middle of 1942 to some point in 1944 every US Air Force Commander in Every Theater was screaming or begging for more P-38s.
When do you tell them to make do with P-39s and P-40s for months while Lockheed tools up for the P-47 and P-51?

Yes ,it was big and expensive but the US simply didn't have anything to replace it until the Spring of 1944 and in 1944 Lockheed built 4186 P-38s. (average 348 a month), perhaps Lockheed could have worked up to 4-500 P-51s per month, I don't know, but changing over in 1944 could have cost 600-1000 planes lost during the change over.

 

[FLYBOYJ]

Folks, do we forget that Lockheed never expected to build more than 100 P-38s or that the AAF never intended to buy more than 75?