Effectiveness of the P-38 (1 Viewer)

[Shortround6]

In 2002 Danial Whitney wrote an 11 page article about the "Allison Time Bomb" in the "Torque Meter" magazine. He is the man that wrote "Vees for Victory" about the Allison engine and this article extended his research into the problems with new information that was not included in the book.
He also includes sections on problems in the C-B-I and SWPA theaters.
There was not just a single problem but rather a number of problems that combined or overlapped.

As shown by Mr. Sinclair there were only a few (comparatively) P-38Fs built or in service in most theaters and the problems started (mostly) with the P-38G & H and the early Js really had problems. It took until the spring/summer of 1944 to solve most of them.

 

[Jugman]

1) Fuel issue: The British fuels had 20% aromatics and the US fuels, for whicj the ALlison carbs were jettedm used 2% aromatics. Once they figured this out (9 months) it was corrected. They could never duplicate the issue on the test stand until someone sent home a somple of British fuel! Duhhhhhh .....

The minimum aromatic content of any mass production cracking method is 4%. From late 1942 onwards US and UK fuel specs were identical. Typical aromatic content was around 8% but could be as high as 20%. however values above 14% was very uncommon.

 

[GregP]

Not this myth again.

Not a myth. Was true. Was never an issue again after it was solved and we went to one formulation.

I didn't say it was a long-lasting issue, I said it was an early issue. Took about 8 months to solve and only got solved when a sample of British fuel was acquired and run in the test cell, replicating the problem for the first time. After that, the solution was pretty rapid.

 

[drgondog]

Not a myth. Was true. Was never an issue again after it was solved and we went to one formulation.

I didn't say it was a long-lasting issue, I said it was an early issue. Took about 8 months to solve and only got solved when a sample of British fuel was acquired and run in the test cell, replicating the problem for the first time. After that, the solution was pretty rapid.

Greg, are you referring to model 322/P-38D issues allegedly encountered, or P-38F issues as they went operational in late summer/fall 1942? I agree Geoffrey that POL for US/RAF was to conform to same standard/same specs/same storage locations as early as planning for Bolero.

The Mustang I with same engine and boost was operational as Bolero was in planning stage. The operational fuel did not come from storage in UK marked for 'US engines only'.

 

[Shortround6]

According to "Vees for Victory", and there maybe typo's/misprints, the Allison engines used in the P-38 and the fuel used for early testing/certificating were

YP-38, P-38, P-38D, P-38E...............V-1710-27/29..........................92 octane.
P-38F........................................................V-1710-49/53..........................100/125
P-38G.......................................................V-1710-51/55..........................100/125
P-38H, P-38J..........................................V-1710-89/91..........................100/130
P-38L........................................................V-1710-111/113.....................100/130

Manuals for the P-38D/E, F and G show just 100 octane??
100/125 fuel was pretty short lived as a standard. Not sure if it ever was shipped overseas. The US did not enough of the materials to make a lot of 100/125 in 1941/early 1942 and stayed with 100 PN fuel until supplies of raw materials could be straighten out. Actual 100 fuel varied from 100/104 to 100/120 depending on batch.
The Americans and British had to agree to 'standards' pretty much before any production started so problems could take a while (months) to show up. They also needed to arrange for the transportation of the raw materials to the desired refineries. Cat cracked gasoline and the higher lead component allowed for much increased production, but some base stocks need more or less alkylate and sometimes it was better to just have a refinery make lower grade fuel than use up a lot of alkylate trying to upgrade lower level base stocks and ship the alkylate to other refineries with higher grade base stock supplies.

I have no real idea of why the early P-38s engines were rated using 92 octane (or even if they truly were) as the P-40 long noses were rated with 100 octane as were the engines in the P-40E. P-40Ks using the -73 engines were rated on 100/125 and the -81 engines used in the P-40Ms and early N were rated on 100/130 fuel.

92 octane was very quickly regulated to training or for transports. Standardizing on one type of fuel for combat aircraft may have made good sense.
Books on fuel claim that the British and Americans had issued their 3rd joint specification for 100/130 fuel in very late 1942 or very early 1943 and they were guessing that if might cause problems with the heaver aromatics allowed. Fuel to the new standard was shipped to engine makers for testing as soon as possible. This new standard also had the higher permissible lead content and they also needed to see if there were going to be lead fouling problems.
When they OKed the increase from 3cc of lead to 4cc lead per US gallon that allowed for a 25% increase in production and that was in September 1941.
There was a lot of juggling of fuel supplies and raw materials in 1940-41 as all supplies came under the government control.

The 100/125 standard was very quickly replaced by the 100/130 standards.

 

[GregP]

Greg, are you referring to model 322/P-38D issues allegedly encountered, or P-38F issues as they went operational in late summer/fall 1942? I agree Geoffrey that POL for US/RAF was to conform to same standard/same specs/same storage locations as early as planning for Bolero.

The Mustang I with same engine and boost was operational as Bolero was in planning stage. The operational fuel did not come from storage in UK marked for 'US engines only'.

Hi Bill,

Never said it came from the UK makrked "for US engines only." I said the aromatics were different between US and UK duel in late 1942, and I have seen letters that say that dated at the time, from the USAAF and Allison. It took a shipment of that fuel back to Allison in Indiana to replicate the issue in the test cells which, prior to running the British fuel, never replicated the issue.

Joe Yancey had the letters indicating that, dated in early 1943. He has closed his shop and he sold his stock to Jose Flores at Vintage V-12s, and is still going to build engines, but not Allisons. Mostly Chevys and perhaps Harley Davidsons since he used to race them. I think he still retains 4 or 5 Allisons, including a left-turning engine on a trialer-stand for personal running, and he is moving to Arkansas from Chino. Basically he is now out of the airplane Allison business. He has ONE more Allison to deliver. It goes in a P-51A being restored now.

When Joe was in the business, all the aero Allisons he built had 100-series internals, with 12-counterweight crankshafts and late wrist pins, lifters, etc. All late hardware, manifolds, etc. The early hardware was saved for boat engines or drag racers / vintage cars / boat applications ... non-flying engines.

The letters I saw stated that the fuel issue was replicated in the test cells only when the sample of British fuel was run. The "one formulation" for fuel happened in 1943, but started when that issue was uncovered in the test cells (it had been reported but not confirmed in test cells prior to that), to the best of my recollection, and was never an issue again after that time. So, it wasn't a continuing thing after being solved. It was right about when the intakes also had turbulators installed to keep the mixture from separating at altitude in cold temps. Seems like the issue was solved by late spring 1943. After that the "Allison Time Bomb" stories sort of dried up and went away. It was never an issue in the Pacific with warmer temps anyway. Later-model P-38s than the early F/G units went to the Pacific, anyway. The early units weren't really combat-ready and were still having teething troubles.

Here's our P-38J-20 flying with the Horsemen in 2012. New left engine, no issue with 100LL fuel.


View: https://youtu.be/Yc94Tj7SP8o

 

[wuzak]

What other American aircraft suffered from this "British fuel" issue?

 

[Reluctant Poster]

The P-38 problems were not resolved in the spring of 1943. They occurred in the first few months of 1944. I made an extensive post on this in the past.
XP-39 and the Claims

The following are excerpts from that post:
"A good discussion of Britain's avgas supplies is presented in "Britain War Machine" by David Edgerton. There is a chapter that discusses Britain's sources of supply in some detail. As he notes "By the middle of the war nearly all of the aviation spirit, indeed nearly all the petroleum products, were to come from the USA""

Another good source is the Army Air Forces Historical Studies No 65 "Aviation Gasoline Production and Control which states:
"In addition, the British were asked to alter their fuel specifications to meet those of the U.S. Air Corps and Navy." (Dec 1941)

"As noted in "Army Air Forces in World War II" by Craven and Cates Volume 2

"Virtually all of the gasoline used in the United Kingdom from 1942 to 1945 came from American sources. The British were responsible for gasoline supply to the Middle East and China –Burma –India theaters.""

"In any event the basic premise of Bad British Fuel as the cause of the Allison failures is bogus. The Allison's problems were NOT limited to the ETO. This part of the myth was debunked by Daniel Whitney (author of Vees for Victory, the very comprehensive book on the V-1710) in the in his article "The Allison Time Bomb" in Volume 1 Number 2 of the "Torque Meter"
"Not long after the introduction of the P-38J pilots in all theaters began experiencing unexpected and sudden failures of their engines.""

"The entire topic is further complicated because of the common impression that the failures occurred only in the ETO, so the problem "must have been poor quality British fuel" or the "low temperature at the high operating altitudes over the Continent."

He goes on to describe in some detail the problems experienced in the CBI."

"The mode of failure was consistent. The outer most cylinders (1 and 6) received too rich a mixture, while the inner two (3 and 4) received too lean a mixture. The result was a failure of number 3 and 4 cylinders. This is can only be attributed to a flaw in the design. Looking at the intake manifold it is easy to see why. The air/fuel mixture has a straight shot into the number one cylinder while it has to make an abrupt 180 degree turn to reach the number 3 cylinder. The heavier than air fuel will tend to keep going in a straight line thus robbing the inner cylinders of enough fuel to avoid catastrophic consequences."

 

[drgondog]

Hi Bill,

Never said it came from the UK makrked "for US engines only." I said the aromatics were different between US and UK duel in late 1942, and I have seen letters that say that dated at the time, from the USAAF and Allison. It took a shipment of that fuel back to Allison in Indiana to replicate the issue in the test cells which, prior to running the British fuel, never replicated the issue.

I guess my question surrounds the fundamental question of a period of time when a sample of fuel could be identified as British Fuel, separate from US fuel - and stored separately?

Joe Yancey had the letters indicating that, dated in early 1943. He has closed his shop and he sold his stock to Jose Flores at Vintage V-12s, and is still going to build engines, but not Allisons. Mostly Chevys and perhaps Harley Davidsons since he used to race them. I think he still retains 4 or 5 Allisons, including a left-turning engine on a trialer-stand for personal running, and he is moving to Arkansas from Chino. Basically he is now out of the airplane Allison business. He has ONE more Allison to deliver. It goes in a P-51A being restored now.

Letters from whom (organization) to whom? Logically (for ETO in 1942/43) it would originate in Air Service Command, specifically VIII ATS and from there to Materiel Command, Wright Field, Powerplant Div and Engineering Div. What did Yancey say?

When Joe was in the business, all the aero Allisons he built had 100-series internals, with 12-counterweight crankshafts and late wrist pins, lifters, etc. All late hardware, manifolds, etc. The early hardware was saved for boat engines or drag racers / vintage cars / boat applications ... non-flying engines.

The letters I saw stated that the fuel issue was replicated in the test cells only when the sample of British fuel was run. The "one formulation" for fuel happened in 1943, but started when that issue was uncovered in the test cells (it had been reported but not confirmed in test cells prior to that), to the best of my recollection, and was never an issue again after that time. So, it wasn't a contionuing thing after being solved. It was right about when the intakes also had turbulators installed to keep the mixture from separating at altitude in cold temps. Seems like the issue was solved by late spring 1943. After that the "Allison Time Bomb" stories sort of dried up and went away. It was never an issue in the Pacific with warmer temps anyway. Later-model P-38s than the early F/G units went to the Pacific, anyway. The early units weren't really combat-ready and were still having teething troubles.

All of the P-38Js went to ETO initially under direct order from Arnold in July-Dec 1943 timeframe. That would be 20, 55, 364 and 479 FGs for 8th, 367, 370 and 474 Fgs for 9th. No new P-38 FGs went to MTO after departure of 1, 14 and 82nd in fall 1942.

The 475th was sent May 1943 to SWP before the Arnold order and the 21st FG was dispatched to the Hawaii in April 1944 but converted to Mustangs for combat ops in 1945. IIRC the 21st was the last P-38 FG composed as a P-38 FG during WWII. What did happen is that several Pacific based squadrons/FGs were converted from P-39 and P-40 to P-38. The 8th, 18th and 347th come to mind.

Allison 'time bomb' had at least three primary (and unique to P-38) high altitude engine related mechanical failures in the P-38:

Overspooling turbosupercharger when the combat practice was to cruise at low boost/low turbine rpm, causing a catastrophic failure when throttle was increased suddenly. IIRC the root cause was lubrication at below critical temps at high altitude.

Inefficient intercooling from turbo to engine resulting in detonation due to overheated fuel-air charge.

Overcooling the oil with the new J intake, alternatively causing catastrophic failure of the engine or sever increase in oil consumption

Additionally, poor fuel metering was identified as a secondary (and persistent) cause of detonation.

There is zero notice in VIII ATS files that I have seen either at NARA, USAFHRC highlighting a fuel blending issue leading to my question above.

 

[Shortround6]

There is some confusion in between the "United States of America" and "the Americas"
The Jersey refinery in Aruba was considered part of the Unites States manufacturing area after Dec 1941.

While the refinery in Aruba was owned by Standard Oil of New Jersey the import and tariff laws of the time considered this Venezuelan oil and products as imports into the US. because of this and for export to other countries Standard oil built one of the largest refineries in the world in Aruba. Before WW II only the Royal Dutch Shell refinery in Curaçao was larger.
American production of 100 octane fuel went from 650,000 gallons per day in June 1940 to about 2,000,000 gallons a day by using cat cracked gas, 4cc of lead and incorporating the
Aruba supplies into US production totals. I am not sure who got the count the Shell refinery in their production totals.

By 1943 production was pretty much established and areas of distribution/supply established as Reluctant Poster as said.

 

[Shortround6]

There could have been bad batches of fuel that arrived in England, but this is different from "British" fuel when all fuel in England was sourced from the "Americas".
Different batches of fuel could use different types and amounts of aromatics depending on the base gasoline stock to reach the fuel performance specification.
The under 2% aromatic US Military fuel went away in 1940-41 because you can't make 100+ octane fuel without aromatics cheaply/easily in quantity.
The under 2% aromatic fuel was never going to come back due to production requirements.

British fuel from the Dutch East Indies could contain up to 40% aromatics and this stuff caused considerable trouble in the Pacific and Asia right after Pearl Harbor. However with the loss of the Dutch East Indies to the Japanese this aromatic rich fuel disappeared from allied stocks.

One of the problems the P-38s suffered from (poor fuel distribution) had been anticipated when the 3rd 100/130 fuel specification was adopted. This was just theory at the time but they tried to manufacture test batches of fuel and send them to the engine makers to get them looking for problems before general issue of the new fuel. The US radials had little or no problems with new fuel (short intake ducts/manifolds). This was the start of the Allison "Madam Queen" intake manifold which wound up on all Allison engines regardless of type of supercharger or intercooling although none of the P-39/P-40s or Allison P-51/A-36s reported any problems (or not enough to make it into history). The new fuel allowed for heavier aromatic compounds and lower volatility fuel. This was not a response to "British" fuel but a response to the joint specification fuel and ALL manufactures had to test and find problems and solve them if problems were found.

You can get into trouble using captured fuel. Italians loved to mix a fair quantity of Benzine into their fuel. Benzol is an aromatic and has wonderful anti-knock qualities (160) when running rich. It is also heavy (7.34lbs per gallon), doesn't have as much energy (17,300btus per lb) and freezes at 42 degrees F.
But with better chemical industries you can get better products. For every 1000 gals of Benzol you can make most refineries could make 1200 gal of cumene (isopropyl benzene) which did not have the freezing problem and responded to lead better but had a higher a higher boiling point and less volatility.
There were about 12 compounds known as aromatics and many came in the crude oil and some needed more than just simple refining or distilling to make them.
Toluene is a decent aromatic additive for high performance fuel but now you are deciding between high performance fuel and HE shell filling.

It was hard getting the USN and the US Army to agree to a common fuel speciation or to certain additives let alone come up with a specification that would also be agreeable to the British.

 

[tomo pauk]

This was the start of the Allison "Madam Queen" intake manifold which wound up on all Allison engines regardless of type of supercharger or intercooling although none of the P-39/P-40s or Allison P-51/A-36s reported any problems (or not enough to make it into history).

Perhaps that had a lot to do with these aircraft flying mostly at the lower altitudes, so the air-fuel mixture was always well-heated? Going on a limb here.

 

[Barrett]

I'm late to this thread but especially appreciate the details from Greg and Geoffrey.

I'll quote from a letter I accessed researching the 15th AF book. Undated postwar from Col. Obie Taylor who rebuilt the 14th FG after North Africa. He said that a P-38 pilot needed 50 percent more training to reach the level of a s/e fighter pilot "but thereafter he should be nearly unbeatable."

Taylor made ace but was rotated out with polio.

 

[GregP]

What other American aircraft suffered from this "British fuel" issue?

None, Wayne. The P-38 was the only Allison-engined, turbocharged aircraft in the ETO, and the issue reared it's head at altitude when the temps got cold. The P-39s and P-40s, also with Allisons, didn't have turbos and almost never flew in the 25,000 foot and above range, so they didn't seem to have the issue. It was a high-altitude problem, and the P-38 was the only Allison-engined aircraft that regularly operated up there.

Good question, and one I'm pretty sure was asked by a lot of people at the time. Since the P-39s and P-40s were not having the issue, what was wrong with the P-38? I bet there was some head scratching.

Again, it took a lot of test cell time to replicate. After it was found, the "fix" wasn't difficult but, like all wartime changes to infrastructure supplies like standard USAAF fuel, took a bit of time. Once it was no longer an issue, the problem dried up. Of more concern was the air-fuel separation problem. It was easily solvable for new engines with an intake change. But, that didn't fix the entire inventory that was operating in the ETO / MTO at the time. So, either the crew chiefs had to replace the intake manifolds with new ones or they had to send new P-38s over with the fix built in.

I do not know the breakout of what really happened to "fix" the air-fuel separation issue or exatcly when it was completed, but later P-38s didn't have the air-fuel separation problem, so it was then or before then. I do not have the luxury of asking Joe Yancey to see his files any longer, either.

So, likely from the V-1710-89 / -91 and onward for the P-38Js. That's a guess, admittedly, but the issue disappeared with the P-38Js and forward, so it's not too far off in any case. Late-war Allison V-1710Fs were well-sorted engines with few issues. The G-series came out and introduced a new set of problems, but that's another discussion.

Cheers.

 

[Tiger11]

Ya' know, I can't think of many posts from outright fans of the Lightning. Spitfire v. Mustang v. Wurger v. Bf 109 v. Typhoon..... yeah. Does the P-38 have fans, other than aficionados of its Art Deco look?
I'm a bomber guy, myself.

As a fighter pilot in the greatest fighter plane of all time, the F-86 Sabre, both in looks and performance, I'm a wee bit biased. For the Cold War generation it was tops. Times change, though, and it can't hold a candle to the planes in today's air wars. Same thing goes for the P-38. It was designed in the mid- thirties as an interceptor and by the time it got to the hot war, things had changed as pointed out above. But the war went on, the aircraft was modified in the light of the conditions in which it had to fight. and by the end of the war it was pretty damn good all-around aircraft..

An interesting sidelight -Lockheed had service reps on site at most bases in all theatres. They listened to pilot complaints, tried out fixes, wrote out reports to the factory where the fixes were tried out on the YP-38s at Burbank, and if justified were added to the production line. Lockheed published a tech bulletin, I believe monthly, sent to all the tech reps to be shared with pilots and mechanics, with all the fixes and upgrades. I used to have a complete file of all these bulletins and it made fascinating reading when I was flying the Thirty-Eight as a civilian. It got lost in one of my many moves, sad to say.

 

[Shortround6]

P-38 was sometimes cursed by the USAAC/USAAF refusal to follow the recommendations in the Lockheed technical bulletins (or some of the Allison service bulletins).

 

[SaparotRob]

P-38 was sometimes cursed by the USAAC/USAAF refusal to follow the recommendations in the Lockheed technical bulletins (or some of the Allison service bulletins).

Wasn't Lindbergh one of those tech advisors?

 

[Shortround6]

I don't think he was an official tech adviser.
Both Lockheed and Allison had tech advisors in theaters that were long term (months or years) employees of the respective companies.
In the CBI theater the Lockheed Tech Rep was Wayne Sneddon and the Allison Tech Rep was Bill Aycock.
On the early P-38s with the hydraulic turbo control it was found that just a few turns on a control rod could fix one of the problems. On the P-38Js with the newer electronic turbo control it required both input and output links and a wiring change.
Wayne Sneddon flew in a P-38 sitting on the pilot's right knee and observing the linkage motion in the nacelle through the space where a panel had been removed. Once the local fix had been fabricated and tested information was sent back to Lockheed and the CBI workshops fabricated 300 kits that were sent to the South Pacific with another tech rep to be installed on the P-38Js in theater.

 

[Tiger11]

I don't think he was an official tech adviser.
Both Lockheed and Allison had tech advisors in theaters that were long term (months or years) employees of the respective companies.
In the CBI theater the Lockheed Tech Rep was Wayne Sneddon and the Allison Tech Rep was Bill Aycock.
On the early P-38s with the hydraulic turbo control it was found that just a few turns on a control rod could fix one of the problems. On the P-38Js with the newer electronic turbo control it required both input and output links and a wiring change.
Wayne Sneddon flew in a P-38 sitting on the pilot's right knee and observing the linkage motion in the nacelle through the space where a panel had been removed. Once the local fix had been fabricated and tested information was sent back to Lockheed and the CBI workshops fabricated 300 kits that were sent to the South Pacific with another tech rep to be installed on the P-38Js in theater.

That's the way it worked. Those tech reps weren't paid enough for the hardships and dangers they endured as civilians in war zones.

 

[BiffF15]

That's the way it worked. Those tech reps weren't paid enough for the hardships and dangers they endured as civilians in war zones.

My guess is they were paid more than the guys fighting in the war.