P38 at high altitude

[bob44]

Let's talk P38's for a bit.
Why did the P38 have so many problems flying bomber escort in Western Europe in late 1943, early 1944? Blown engines and such.
I have read about the cold temps at 30000ft. causing issues with the early models.
I have not read that other aircraft where having so many problems at high altitudes.

 

[Shortround6]

There were a number of contributing factors. There is a 6-8 page article in an issue ( vol 1 no 2) of the "Torque Meter Journal" at the AEHS website.

Basically, it comes down to a change in fuel specification, bad piloting technique, an intake manifold problem, improper turbo control adjustment/rigging and a few other minor factors.

One P-38 squadron on the Indian border blew up at least a dozen engines, almost all of them on one side of the airplane. Turbo controls were not exactly the same on the left and right engines.

Pilots were being taught to fly (cruise) at high rpm and low boost which was against both Allison's and Lockheed's recommendations. It was bad for fuel economy (range), engine life, pilot survival, and hleped blow up the engines.

 

[GregP]

I work at a shop that does nothing but Allison V-1710 engines. We have engines in all the P-38's in the world except for the Red Bull unit, which doesn't fly much or often due to engine problems caused by another builder. We have a LOT of Allisons out there in P-38's, P-39's, P-40's, various Yaks and some Spitfire replicas. More than 12 have 850 - 1,250 hours on them with no trouble other than normal maintenance. Properly run, the Allison runs and operates just fine. All ours are built to stock Allison specifications except for teh engines for the Yak-3's. Most Yak-3 pwners added a carb intake right over the top of the carb, and they get a LOT or ram air, so the carbuuretors have to be jetted very ruich in the mid-range or the engine lean out due to ram air. All other installations run normally.

The Allison early-on had issues with the intakes. The intake piping was such that the airflow would impinge on a certain curve and cause a couple of cylinders to run rich with another couple running lean. It toook Allison about 6 - 8 month to clear that up. The solution was a turbuilator in the intake piping. All the engine we build and selll have the turbulator and the mixture disperses evenly.

A second problems was the European fuels. 100+ Octane fuel in the U.S.A. had 2% aromatics in it. European fuels had up to 20% aromatics, so the carburetors were jetted wrong right from the factory, but ran just fine on US fuel. Once the fuel issue and intake issue had been corrected, the P-38's ran just fine. By that time the P-51 was arriving and there was simply no need for two top fighters in the ETO with two logistics chains and two sets of mechanics, etc. The P-38's were mostly transferred to the Pacific where they ran just fine ON AMERICAN FUEL. Our two top aces, Bong and McGuire, both flew P-38's.

A third issue not frequently brought up was the lack of an adequate cockpit heater in the P-38. Pilots were freezing during European escort duties and were quite happy in the PTO to remain lower than 30,000+ feet whenever possible.

The forth issue was caused by hitting the critical Mach number in a dive from altitude, and the dive flaps fixed that one enough to prevent loss of aircraft and pilot. The REAL solution was a different wing profile and perhaps a slight chang in the vertical position of the horizontal stabilizer ... but they never did do it since the war was essentially won by the end of 1943 / early 1944 and the handwriting was on the wall.

The P-38 had a couple of early issues and the low critical Mach number stayed with it, but it was a formidable fighter until the end of the war.

 

[alejandro_]

Greg, the fuel composition detail is interesting. Was there any problem with other types (P-39/47/51)? Airacobra served in the RAF and arrived to Europe with USAAF at the same time frame.

I have saved some discussions on the P-38 performance in Europe over the years. These reports point out at some of the problems. I would also like to emphasize that Luftwaffe was a stronger enemy in 1943/early 1944 than later on i.e. when P-51B/C/D arrived. Also, some of the P-38 advantages when compared to P-47/51 are not the case when compared to German models (climb rate).

Hubert "Hub" Zemke, P-38, P-47, and P-51 pilot and fighter group commander

I was fortunate enough to have flown the P-51, P-47, and P-38 in combat and have led fighter groups with all three.

P-38 - Though this aircraft had virtues, for me it was the poorest of the three US Army fighters in the European Theater. The fact that the extreme cold at altitude affected it's performance hardly endears the machine. The turbosuperchargers were controlled by an oil regulator. At altitude the oil had a tendency to congeal, which caused serious problems. On two occasions I recall, when entering combat with enemy single seaters it was a case of life and death to get away and survive, though I had started with the advantage.

On both occasions the engines either cut out completely or overran rpm limitations as throttles were cut or advanced. It was enough just to regulate the engines and control the aircraft without entering combat.

The second serious limiting factor that detracted from the P-38's combat capability was its steep diving restriction -- estimated at about 375 mph. A common tactic of the Luftwaffe single seaters was to split-S for the clouds or the deck. Ofentimes their head-on attacks on the bomber formations saw them roll over and dive for the deck to confuse and outdistance the flexible machine gunners. P-38s had little chance to pursue. When on defensive, it can be easily understood that a dive to safety was the best maneuver for longevity.

Another factor to degrade the P-38's combat capability was its identification factor. The eyes of a pilot often picked up the specks in the distance that could not be immediately identified as friend or foe. These were reported as "bogies." Appropriate tactical maneuvers were taken to prevent bogies from having an advantage of a subsequent attack. In the case of the P-38, the twin booms and slab elevator gave this aircraft's identity away -- as far as the eye could see.

It was also necessary for the P-38 pilot to do much more weaving to look down over the two engines that lay on each side of the cockpit. A better cockpit heating system could have been provided as my feet always froze at altitude.

Taken alone, the above statements would conclude that the P-38 had no oustanding features... it did! As a gun platform it was steady as a shooting stand. With two engines, there was no torque. With a little trim for buildup of speed (in a dive), a pilot could ride directly into a target.

As to the armament installation, I have seen no better. Four machine guns and one cannon in a tight pocket directly in front of the pilot. This armament being so closely aligned to the sight of plane of the gunsight required no convergence of fire as necessitated in fighters having their guns placed in the wings.

Though the P-38 had a wheel instead of the proverbial stick, this was no handicap -- control were light and reponse was excellent.

Relative to load carrying capacity, the aircraft could take off with just about anything. I've taken off with a thousand pound bomb under each wing and cruised with ease. On fusel consumption, the P-38 enabled us to cruise out to combat areas deep in Germany without the anguish of not having enough "petrol" to return home.

A tricycle landing gear made it much easier for a junior pilot to "spike the kite" on the runway and chalk up another landing. This was also an advantage in taxiing -- a large engine and cowling did not deter from forward vision.

Edward B. Giller, P-38 pilot, 55th Fighter Group

Returning to England with considerable undercast always presented a severe problem of location. We had only four channels of VHF which were always crowded. Once over England we could only let down straight ahead until you could see the ground. The other P-38 groups were operating with the same problem as the 55th. But one thing we liked about the P-38 was its instrument flying ability.

Flying around 30,000 feet resulted in extreme fouling of the plugs in the Allison engine as well as a great number of thrown rods and swallowed valves. Needless to say, a P-38 on a single engine was in an unenviable condition. Our record during this period was very poor, about 1.5 Germans shot down to each American lost to all causes.

This was the world's coldest airplane and we tried every combination of suit, glove and heater imaginable, including some that would short out and give you a hot foot. We were so cold sometimes, we did not even want to fight.

The twin tails provided positive recognition for the Germans at distances greater than we could see them. Therefore, our initial engagements were always at a disadvantage. We were forced to go to very high altitudes, 30,000 feet to 35,000 feet. Even so, the Germans flew way above us. The Germans would escape by a split-S maneuver from these altitudes and the P-38 could not follow due to compressibility.

The maintenance on the P-38 was something to behold. The engines were extremely closely-cowled with much piping and no space. The mechanics did a magnificent job with extremly long hours of trying tediously to fix coolant leaks, rough engines, etc. It was truly a crew chief's nightmare. The plane employed oleo socks on all three landing gear struts. These had a habit of leaking as soon as it got cold and required considerable maintenance to reinflate. The turbo supercharger regulator had a delightful habit of freezing at high altitude, resulting in only two throttle settings... 10 inches of mercury, which would not sustain flight, or 80 inches which would blow up a supercharger. I recall one very cold day over the Ruhr Valley [in Germany] where both the pilots and the regulators were so frozen that, in spite of heavy flak in that vicinity, we let down to 3,000 feet to warm up both us and the airplanes.

 

[alejandro_]

20th Fighter Group Headquarters
APO 637 U.S. Army
(E-2)

3 June 1944

Subject: P-38 Airplane in Combat.

To: Commanding General, VIII Fighter Command, APO 637, U.S. Army.

1. The following observations are being put in writing by the undersigned at the request of the Commanding General, VII FC. They are intended purely as constructive criticism and are intended in any way to "low rate" our present equipment.

2. After flying the P-38 for a little over one hundred hours on combat missions it is my belief that the airplane, as it stands now, is too complicated for the 'average' pilot. I want to put strong emphasis on the word 'average, taking full consideration just how little combat training our pilots have before going on as operational status.

3. As a typical case to demonstrate my point, let us assume that we have a pilot fresh out of flying school with about a total of twenty-five hours in a P-38, starting out on a combat mission. He is on a deep ramrod, penetration and target support to maximum endurance. He is cruising along with his power set at maximum economy. He is pulling 31" Hg and 2100 RPM. He is auto lean and running on external tanks. His gun heater is off to relieve the load on his generator, which frequently gives out (under sustained heavy load). His sight is off to save burning out the bulb. His combat switch may or may not be on. Flying along in this condition, he suddenly gets "bounced", what to do flashes through his mind. He must turn, he must increase power and get rid of those external tanks and get on his main. So, he reaches down and turns two stiff, difficult gas switches {valves} to main - turns on his drop tank switches, presses his release button, puts the mixture to auto rich (two separate and clumsy operations), increases his RPM, increases his manifold pressure, turns on his gun heater switch (which he must feel for and cannot possibly see), turns on his combat switch and he is ready to fight. At this point, he has probably been shot down or he has done one of several things wrong. Most common error is to push the throttles wide open before increasing RPM. This causes detonation and subsequent engine failure. Or, he forgets to switch back to auto rich, and gets excessive cylinder head temperature with subsequent engine failure.

4. In my limited experience with a P-38 group, we have lost as least four (4) pilots, who when bounced, took no immediate evasive action. The logical assumption is that they were so busy in the cockpit, trying to get organized that they were shot down before they could get going.

5. The question that arises is, what are you going to do about it? It is standard procedure for the group leader to call, five minutes before R/V and tell all the pilots to "prepare for trouble". This is the signal for everyone to get into auto rich, turn drop tank switches on, gun heaters on, combat and sight switches on and to increase RPM and manifold pressure to maximum cruise. This procedure, however, does not help the pilot who is bounced on the way in and who is trying to conserve his gasoline and equipment for the escort job ahead.

6. What is the answer to these difficulties? During the past several weeks we have been visited at this station time and time again by Lockheed representatives, Allison representatives and high ranking Army personnel connected with these two companies. They all ask about our troubles and then proceed to tell us about the marvelous mechanisms that they have devised to overcome these troubles that the Air Force has turned down as "unnecessary". Chief among these is a unit power control, incorporating an automatic manifold pressure regulator, which will control power, RPM and mixture by use of a single lever. It is obvious that there is a crying need for a device like that in combat.

7. It is easy to understand why test pilots, who have never been in combat, cannot readily appreciate what each split second means when a "bounce" occurs. Every last motion when you get bounced is just another nail in your coffin. Any device which would eliminate any of the enumerated above, are obviously very necessary to make the P-38 a really effective combat airplane.

8. It is also felt that that much could done to simplify the gas switching system in this airplane. The switches {valve selector handles} are all in awkward positions and extremely hard to turn. The toggle switches for outboard tanks are almost impossible to operate with gloves on.

9. My personal feeling about this airplane is that it is a fine piece of equipment, and if properly handled, takes a back seat for nothing that the enemy can produce. But it does need simplifying to bring it within the capabilities of the 'average' pilot. I believe that pilots like Colonel Ben Kelsey and Colonel Cass Huff are among the finest pilots in the world today. But I also believe that it is difficult for men like them to place their thinking and ability on the level of a youngster with a bare 25 hours in the airplane, going into his first combat. That is the sort of thinking that will have to be done, in my opinion, to make the P-38 a first-class all around fighting airplane.

HAROLD J. RAU
Colonel, Air Corps,
Commanding.

 

[Balljoint]

It's my understanding that the mach problem with the P-38 originated with the original "interceptor" design spec that required a very high RoC. To meet this spec the wing was designed to be rather thick. This led to a transonic aero phenomenon as the slipstream accelerated over the thick wing. Specifically, the CoP moved back on the wing causing the aircraft to pitch on its back resulting in breakup. Two or three test pilots were killed before the plane was released to service uncorrected.

The "dive brakes" fix actually functioned to shift the CoP forward into a stable position. After a tough teething period the P-38 matured into a rather good if expensive plane.

 

[drgondog]

It's my understanding that the mach problem with the P-38 originated with the original "interceptor" design spec that required a very high RoC. To meet this spec the wing was designed to be rather thick. This led to a transonic aero phenomenon as the slipstream accelerated over the thick wing. Specifically, the CoP moved back on the wing causing the aircraft to pitch on its back resulting in breakup. Two or three test pilots were killed before the plane was released to service uncorrected.

True on movement of CoP, but it had the effect of causing a Nose down CMac - another callenge when trying to pull stck back to get the nose up and pull out.

The "dive brakes" fix actually functioned to shift the CoP forward into a stable position. After a tough teething period the P-38 matured into a rather good if expensive plane.

The Dive Brake primarily kept the P-38 from immediately entering into drag Divergence regime leading to transonix Mcr - (which had the effect of moving CoP aft as the shock wave formed at 25% chord and moved aft.. in other words it didn't move anything, it kept 'anything' from moving aft.

 

[Balljoint]

The Dive Brake primarily kept the P-38 from immediately entering into drag Divergence regime leading to transonix Mcr - (which had the effect of moving CoP aft as the shock wave formed at 25% chord and moved aft.. in other words it didn't move anything, it kept 'anything' from moving aft.

Put much better than my attempt. The pitch was indeed forward and the CoP was stabilized so it didn't wander.

 

[drgondog]

I have saved some discussions on the P-38 performance in Europe over the years. These reports point out at some of the problems. I would also like to emphasize that Luftwaffe was a stronger enemy in 1943/early 1944 than later on i.e. when P-51B/C/D arrived. Also, some of the P-38 advantages when compared to P-47/51 are not the case when compared to German models (climb rate).

The 'later on' was the P-51B which arrived in ETO combat in Sep 1943, then added 2 more in Feb 1944, then 1 more in March, then more in April and May. The two P-51B Groups (354 and 357FG) destroyed far more German aircraft during Big Week and nearly as many as the 10 operational P-47 FG's during Big Week (Feb 20-25, 1944).

ETO (8th/9th AF FC Victory Credits during Big Week) - The P-38s (10), P-47s (78 ) P-51 (64.5), From start of Big Week to end of March, 1944
P-38 (35). P-47 (316), P-51B (318.5) where most of the P-51 credits were against LuftFlotte Reich which had been steadily building up with veteran Gruppe's transferring into Germany November 1943 - February 1944. In other words the Reich composition was not 'rookies' -

 

[tomo pauk]

Let's talk P38's for a bit.
Why did the P38 have so many problems flying bomber escort in Western Europe in late 1943, early 1944? Blown engines and such.
I have read about the cold temps at 30000ft. causing issues with the early models.
I have not read that other aircraft where having so many problems at high altitudes.

Shortround6 and GregP covered most of the questions, I'll attempt to answer the bolded one.
The issues early models had in high alt (and not only there) were mostly connected with insufficient capacity of the intercoolers, so the engine had problems developing the power it was supposed to do. EG. the P-38H was restricted to 1425 HP per engine (with B-33 turbo), while the P-38J was managing 1600 HP, with same engine. The pre-J models have had the intercoolers tailored for 1100-1200 HP engines, and were hard pressed to do their job with growing engine power, while the intercoolers in the J and later models were able to support 2000 HP per engine (maybe more?). The Mike Williams' site has some fine data about the late P-38's V-1710s tested with more than 1600 HP.
Sure enough, the cold pilot compartment was the issue also with early models.

 

[bob44]

Good reading here. Some of this I have seen before, some is new to me.
A couple of things come to mind.
First, the frozen turbo regulators. How is it the B17 engines with turbos did not seem to have these problems? Perhaps a different setup than the P38?
Second, the P38's flying in the Aleutians did not seem to have these cold temp problems. Must have been just as cold or colder. What were they doing different from the European P38's?

 

[Aaron Brooks Wolters]

I found this video on YouTube. Lt. A.F. Shaw is narorrating. He explains to some degree how the got more mileage out of the P-38, if you listen you will hear him mention Lindberg's name. Charles Lindberg spent time in the Pacific as a civilian observer, I did not know this until about a month ago. Looking for that video at the moment. But CB explained and showed them that they could run longer and farther on the same amount of fuel running different settings. I know not enough about this to explain it so I won't try but if I can find the video I will post it. I just thought you guys might like this.
Here's the link:
View: https://www.youtube.com/watch?v=Mjlp5rmGM-Y

 

[Hop]

A second problems was the European fuels.

By the time the P-38 arrived in Europe almost all the aviation fuel was being supplied by the US.

100+ Octane fuel in the U.S.A. had 2% aromatics in it. European fuels had up to 20% aromatics, so the carburetors were jetted wrong right from the factory, but ran just fine on US fuel.

Early US "100 octane" fuel did have very low aromatics. As a result it had very low rich mixture response, typically rated 100/102.

When the UK adopted "100 octane" the specification called for a much higher rich mixture performance, typically 100/125 or 100/130. This was achieved with much higher aromatics.

In 1941 the US adopted a similar specification to the UK, 100/130. This fuel too had an aromatic content of around 20%. It was this fuel that was supplied to Europe.

If the Allison truly had a problem with the aromatics, which is unlikely, it was a problem with the new, higher performance fuel the US had standardised on, and was producing in vast quantities. The only thing "European" about the fuel is that it was similar to the "100 octane" the RAF had adopted in order to get more power. The US adopted it for the same reason. 100/102 fuel didn't allow enough power to be produced.

Far more likely is that the P-38 ran in to problems when the US increased the tetra ethyl lead content of 100/130 fuel in 1943. This was done in order to increase production. A letter from the British Air Ministry, after being informed of the change in the US specification:

As you may know, the U.S. authorities recently decided without further reference to us, that all supplies of 130 grade would, as from August 10th, be leaded up to 5.5 cc. per Imperial gallon as compared with 4.8 cc. previously. So rapidly has this decision been implemented that there are at present two cargoes of the new base material (to be leaded in this country) on the high seas and a further three loadings for this country are anticipated very shortly.
It now transpires that the increase in lead content is likely to cause serious disturbances on a variety of American engines fitted to British machines, or American machines taken over by R.A.F. This is particularly true of heavy engines used by Costal Command and Allison engines for Fighter Command. The details are given on the attached minute by M.A.P. which was considered at a meeting today of all concerned, including the Americans.
It was assumed by the meeting that the American decision cannot have left out of account the difficulties now feared in the U.K. and that therefore the results of tests are available in U.S.A. which will point the way to the steps to be taken to overcome these obstacles. M.A.P. and Colonel Johnson are immediately telegraphing to Washington to renew requests for such information, and it has been agreed that we will defer asking the U.S. authorities to discontinue shipping the new material, until the results in particular of Colonel Johnson's telegram are received. It has been necessary to protect his position to some extent as he was a strong protagonist of the new fuel during his visit to Washington and, indeed, largely helped to push the decision through on the basis that the British agreed and that the increase in potential production was indispensable.
As regards the two cargoes which will arrive very shortly in the U.K. with the new material, it has been decided that Petroleum Board should

(a) as far as possible segregate the material

or

(b) will blend it in with old specification material I.
subject to the stipulation that the resulting lead content will not exceed 5 cc.

The carrying through of the above decision may, I fear, result in the delaying of one or other of the two tankers as they may need to be moved to a different port of discharge. It is the prime purpose of this minute to advise you of this, and I am also sending a copy to Mr. Wackcrill at Ministry of War Transport so that he should be fully informed.
The troubles are feared as much or more in the Overseas
Commands such as the ME and North Africa.

1. All British engines are cleared for this fuel;
The following table summarises the petition with American engine types :-

Wright and P W:
British Plugs - Probably OK
US Ceramic Plugs - No definite information
US Mica - No information

Allison:
British plugs - Severe fouling after 20 hours
US Ceramic - No information
US Mica - Not approved for combat ratings on 4.8

It cannot yet be said that British plugs will make all Wright Pratt Whitney engines satisfactory on 5.5 co fuel although the evidence obtained to date is encouraging. Tests are continuing,

We have no evidence to show suitability of America ceramic type plugs on 5.5 cc fuel. Tests are in progress on Double Cyclones and Double Wasps, If these tests are satisfactory, it will be assumed those plugs arc equally suitable for Cyclones and Twin Wasps,

British plugs have failed in the Allison engine in Mustang aircraft; no information is available as to the suitability of American ceramic plugs on this engine except that on 4,8 cc fuel the British plugs were not inferior to American plugs.

The position regarding the utilisation of 5,5 cc fuel by the RAF, is therefore,

a. British engines O.K.
b. Allison engines cannot use it and tests so far conducted indicate that the engine itself cannot digest 5.5 cc fuel. Considerable further test data is therefore required both on engine and plugs,
c. Wright and Pratt Whitney engines - no decision can be taken until flight tests under 3 and 4 above are completed. In view of the encouraging preliminary results on British plugs, adequate production of these types should be provided.

 

[Shortround6]

Thank you for this information.

To date a really comprehensive history of aviation fuel in the 2nd World War has yet to be written. And I have a copy of "Development of Aviation fuels" by S. D. Heron. While it contains much information it doesn't usually give exact dates on when certain changes occurred. It was also written in 1949 and may not represent the Axis side very well. While the Author was well acquainted with the Allied side of things he relied on war time reports and probably a hasty post war analysis of the German developments.

There was not only a problem with the lead content but certain compounds were allowed to be used to stretch the supply of 100/130 fuel. Not only does adding lead cause plug and other problems but the lead usually works on a declining scale. Adding 1 cc of lead can give a pretty good improvement. going from 1cc to 2cc's shows a good improvement, going from 5cc to 6cc shows an improvement that can be measured but is a much smaller improvement than the 1st or 2nd cc. Some of these compounds brought problems of their own and you cannot lead dope most fuel stocks with enough lead to reach 150PN. You may not be able to lead dope some base stocks to reach 130PN.
Some of these compounds were "heavy" compounds that had higher weight and lower volatility than the bulk of the compounds used in fuel. They tended to separate out or cause the fuel blend to vaporize less readily than early fuel batches. Not a problem in North Africa but over Europe in the winter at 30,000ft?

The Aleutian Islands are actually not that cold. There is only about a 10-20 degree variation from summer to winter and the average temperature is a few degrees above freezing.

Back to the poor piloting technique, Low boost and high rpm vs high boost and low rpm. The friction goes up with the square of the speed so the engine is using a lot of power ( relatively speaking) in friction turning the higher rpm while cruising this way. The low boost means the air wasn't heated much in the turbo by compression and then it still went through the inter-cooler leading to cool or cold air in the intake manifold even after the engine supercharger. It also means the engine is running relatively cool and trying to go to full throttle is that much more difficult. Using fewer rpm but more boost means less friction, warmer air in the intake manifold for better vaporization, the turbo spun up a bit more and not lagging if higher power is called for in a hurry, and the engine intake manifolds are bit warmer and a large quantity of fuel air mixture as the engine is "opened up" is less likely to separate out and have raw fuel puddling on the bottom of the manifold.

Allison was aware of the fuel problem and was working on a new intake manifold before the first P-38H ever got to Europe. New Manifolds were being fitted to production engines (ALL engines?) in Nov or Dec of 1943 and manifolds were sent out into the field for refit.

Bombers do not fly like fighters, they may be using a higher percentage of their normal power in cruising flight than the P-38. They change altitude much more slowly allowing time for the "frozen" turbo control to catch up. The radials have shorter intake manifolds/runners than the V-12 giving the fuel less opportunity to "puddle". They have a flight engineer to monitor the engines while the pilot flies the plane.

Slight changes in component location or linkage runs can also affect performance. Why did that P-38 Squadron in the CBI theater blow up 10-12 engines on one side of the P-38 for every one blown up on the other side?
They found the problem by flying with parts of the cowl removed and a factory representative crammed in the space behind the pilot observing the operation of the linkage.

As I said earlier this was a problem with many contributing factors.

 

[FLYBOYJ]

Charles Lindberg spent time in the Pacific as a civilian observer, I did not know this until about a month ago.

 

[GregP]

Hi Hop,

It is not "unlikely" the P-38 had issues with aromatics, it is a fact. One of the best people in the world on carbureted engines of the WWII variety is Pete Law. He is local and a good friend of the shop and the planes of Fame Museum. . According to Pete, if you jet for the low aromatic gasoline and then run with the high aromatic gasoline, you will be considerably mis-jetted. Since the later American gas was aromatic adjusted up, the factory carburation settings were ALSO adjusted and they left the factory with correctly-jetted carbs. The P-38 had pretty good ram air flow. It was much better than the P-39, P-40, P-63 flow and the P-38 tended to lean out and mid-range morethan those aircraft did. Still holds true today and the carbs have to jetted correctly.

Today, we jet for the fuel available today, and our Allisons run JUST FINE, ask any owner of a Yancey's Allison.

Rod Lewis is running 5 of our engines (4 for his P-38 Glacier Girl ... two at a time, and one for his P-39, Brooklyn Bum). He is a happy camper. So is Tom Friedken, the Planes of Fame, Graham Frew in New Zealand, Bob DeFord with a Spitfire replica, Steven Gray in the UK, and probably another dozen P-40's and assorted tractors and thunderboats. As I stated, our engines are in all the flying P-38's in the world except for the red Bull aircraft in Switzerland. They run engines from another builder. We have a a very healthy backlog right now, too, and demand is good.

 

[alejandro_]

P-38 (35). P-47 (316), P-51B (318.5) where most of the P-51 credits were against LuftFlotte Reich which had been steadily building up with veteran Gruppe's transferring into Germany November 1943 - February 1944. In other words the Reich composition was not 'rookies' -

By 1943 Luftwaffe losses had risen to alarming levels, see graph below.

By the time the Big Week was launched the Luftwaffe had already been weakened, and Allied tactics were much more effective. This led to massive losses (funeral of the Luftwaffe according to some).

 

[Hop]

It is not "unlikely" the P-38 had issues with aromatics, it is a fact.

According to Pete, if you jet for the low aromatic gasoline and then run with the high aromatic gasoline, you will be considerably mis-jetted. Since the later American gas was aromatic adjusted up, the factory carburation settings were ALSO adjusted and they left the factory with correctly-jetted carbs.

That's the point I was trying to make. It's unlikely the aromatic content was a problem for the P-38 in Europe because by the time they started operations they would have been using 100/130 fuel to the standard US specification. The US adopted 100/130 high aromatic fuel in 1941.

What did change suddenly in 1943 was the lead content of US supplied fuel, and as we have seen from the British tests, it caused major problems for the Allison engine.

 

[drgondog]

By 1943 Luftwaffe losses had risen to alarming levels, see graph below.

By the time the Big Week was launched the Luftwaffe had already been weakened, and Allied tactics were much more effective. This led to massive losses (funeral of the Luftwaffe according to some).

I'm not sure which conclusions are self evident? First what is the source? Second - where is the breakout between MTO/ETO and East? Third - there is no doubt the ETO became more dangerous for Luftflotte 3 pre-Schweinfurt as well as Mitt through October. Another point that the chart displays is that LW losses went down after October 1943 (when 8th AF quit going deep to recover from Aug/Oct Schweinfurt losses)until Feb 1944 when the really big shift to reinforce Reich defenses took place.

To illustrate your point you might just extrtact Reich/West from all the other losses and display them separately through May 1944.

 

[GregP]

Sorry Hop,

The P-38 did have problems with European gasoline. We have far too many former P-38 pilots come to the Planes of Fame Museum and our shop telling us it was so for it to be dismissed so easily. One of Joe Yancey's best freinds was Lefty Gardner who flew the P-38 White Lightning for so many years in airshows and at Reno. His son is still a good friend. Lefty was there in Europe when the issue was happening. Mostly he was flying bombers at the time, but got the occasional P-38 flight in himself. He spoke with very many of the P-38 escort pilots and his story of the P-38 was acquired first-hand.

If people chose to not believe it, that's their choice, but the facts are out there if one cares to dig for them. Since we build the Allison V-1710, we get a lot of war memories via stories from former operational pilots who come visit from time to time. Of course, they are getting fewer these days. They love hearing the engines and it brings back vivid memories for most.

We definitely have to rejet from stock carb specs to get the engines to run well on modern fuel, but it can be done ... at least WE do it and our engines run very well. Ask any owner of one.