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

[tomo pauk]

That belief would Not be correct.

The AAF test pilot that first flew the Mustang I/XP-51 wrote a hatchet job, five liner on behalf of Material Command evaluation that stated 'crappy airplane" at Echols orders. Echols tried to force NAA to disengage from Mustang production, scrap tooling and convert Inglewood production to B-25. Echols despised NAA for disobeying his wishes to shut up and build P-40s

Kelsey was an unabashed supporter of Lockheed and the P-38 and NEVER got behind the Mustang. It was only after the CAS side of AAF got the Mustang evaluation away from Material Command/Wright Field to Eglin Field for evaluation, that AAF recognized what a good airplane the Mustang was in comparison with P-40, P-39, P-38 and P-47

Echols and Kelsey tried to re-write history post WWII, but nobody at NAA bought in. Col. Ben Bradley was a key facilitator in mid 1943 for AAF Mat'l Command and he had to be very careful to point out (when necessary) to his boss MG Echols that even the XP-75 which Echols championed - was a dangerous Turkey.

Bill - I must nudge you to have that book ready for print...

 

[Shortround6]

I Believe (but Bill can certainly correct me) that the A-36 order was placed for a number of reasons, in part to get some sort of Mustangs in operation in the US forces, in part to help NA finance plant expansion for later models of the Mustang, in part to keep the existing production line open and not be converted to something else (like the B-25 mentioned above) and in part to keep the workers who were trained/practiced at Mustang assembly from being dispersed to other plants/jobs making it that much harder to restart production.
There may be other reasons (like the existing Army dive bombers didn't suit the Armies needs? A-25 in 1942 anyone?) and how much weight is given to any one reason is certainly open to question/debate. I am just listing possible reasons, I have no idea how much actual weight any of them had, if any.

 

[tomo pauk]

...

Replacing P-38s with MustangXX Production means serious changes in events, like no Yamamoto shoot down? No flying fighters across the atlantic in 1942. No flying fighters from England to North Africa for operation Torch. Supporting the invasion of Sicily from bases in North Africa?

people seem to think that the MustangXX is some sort of P-51B lite. At just over 23,000ft the Merlin XX engine is down to around 940-950hp with no RAM compared to the 1330hp of the Merlin V-1650-3. Having about 72% of the power at that altitude really makes the plane a bit lite as while it will be lighter than the P-51B it sure won't be only 72% of the weight of the P-51B.

I myself think of the 'Mustang XX' as of the 'better P-51A', and earlier.
About the production of P-38 - more need to be produced, not less, and again earlier. Preferably by another source?
Kill the Vengeance, A-24, even B-26 need-be.

 

[pinehilljoe]

That belief would Not be correct.

The AAF test pilot that first flew the Mustang I/XP-51 wrote a hatchet job, five liner on behalf of Material Command evaluation that stated 'crappy airplane" at Echols orders. Echols tried to force NAA to disengage from Mustang production, scrap tooling and convert Inglewood production to B-25. Echols despised NAA for disobeying his wishes to shut up and build P-40s

Kelsey was an unabashed supporter of Lockheed and the P-38 and NEVER got behind the Mustang. It was only after the CAS side of AAF got the Mustang evaluation away from Material Command/Wright Field to Eglin Field for evaluation, that AAF recognized what a good airplane the Mustang was in comparison with P-40, P-39, P-38 and P-47

Echols and Kelsey tried to re-write history post WWII, but nobody at NAA bought in. Col. Ben Bradley was a key facilitator in mid 1943 for AAF Mat'l Command and he had to be very careful to point out (when necessary) to his boss MG Echols that even the XP-75 which Echols championed - was a dangerous Turkey.

The fiscal year constraint came from the article Wings/Airpower did on the A-36.

An online sources states the same
North American A-36 Apache
The Gathering of P-51 Mustangs and Legends, Sept 27-30, 2007, Columbus, Ohio, Rickenbacker Field

 

[wuzak]

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.

Equally, the Bf 109 and Fw 190 didn't have a great speed advantage over the Mosquito, which made their task of catching up difficult.

At certain height bands the Mosquito did, in fact, boast a slight speed advantage, or was equal. One of those was at or near sea level.

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.

If you have 6 aircraft and 1 is lost, that is a loss rate of 16%. And that was the usual situation in 1942.

If you send 12 you'd probably still only lose 1. That is a loss rate of 8.5%.

I use the comparison of the 8th AF to illustrate this. In the middle of 1943 the Luftwaffe would shoot down around 60 B-17s from a 300 aircraft raid. That is a 20% loss rate.
In early 1944, despite the presence of escort fighters, the Luftwaffe could still shoot down around 60 B-17s. The difference was that the raids had over 1,000 aircraft by then, giving loss rates of ~6%.
The escort fighters did take a toll on the Luftwaffe, such that in the following months the capacity of the Luftwaffe to shoot down B-17s was much reduced.

 

[wuzak]

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.

The turbo provided the function of automatic boost control for the P-38.

It basically compensated for altitude, the engine feeling like it was at sea level.

The engine superchargers on P-38s ran at lower rpm (gear ratio) than on P-39s and P-40s, which meant they had a lower pressure ratio. So less scope for overboosting the engine.

While a P-39 or P-40's engine had a critical altitude of maybe 12,000ft, the P-38's engines, ignoring the turbos, had a critical altitude of a couple of thousand feet, or less.

The turbo regulator worked to deliver air to the engine at sea level pressure. It did not provide overboosting capacity (though if the regulator failed it could, but that would likely lead to turbo failure before engine failure).

 

[wuzak]

The LW 109s and 190s had very little fuel to work with. The 190 held 140 gallons internal. It burned about 160gph at climb/combat setting giving it a theoretical 52 minutes of operation. Deduct 20 minutes to climb to 26000' and deduct 20 minutes reserve for landing and there are 12 minutes of fuel left for combat. Maybe one pass at the bombers, maybe two if there was no interference from escort fighters. The 109 was even more challenged with only 88 gallons internal.

Before the longer range escorts, the bombers would have to endure hours of attacks from the Luftwaffe on ingress and egress. Pausing around the time they got to target, which was also usually where they met intense flak.

The speed of massed B-17 formation attacks was such that the Luftwaffe fighters would have time to attack on the bombers' ingress, refuel and rearm and have another go as the bombers made their way out.

 

[drgondog]

The fiscal year constraint came from the article Wings/Airpower did on the A-36.

An online sources states the same
North American A-36 Apache
The Gathering of P-51 Mustangs and Legends, Sept 27-30, 2007, Columbus, Ohio, Rickenbacker Field

The requirement to keep NAA Mustang production line was solved when the CAS 'mafia' made their case that the Army needed a low-mid level fighter, not a slow attack bomber/dive bomber and drove the procurement that enabled NAA to bid on the 'dive bomber program funding'. It was ONLY this drive within the US Army Aviation cadre which removed Procurement of the Mustang from Material Command authority - and Oliver Echols.

There were no 1942 funds at that time for another Fighter, so the Director of Military Requirements, MG Muir Fairchild directed the procurement of the dive/attack bomber version of A-36 to be acquired under CTI-538. Mat'l Command was bypassed vis Chief of Air Staff General Milford Harmon in April 1942 and NA-97 was executed 4-16-1942.

Paul Ludwig did an excellent job of documenting the politics between AAF Mat'l Cmd, Army War Plans, NAA and Arnold.

 

[drgondog]

I Believe (but Bill can certainly correct me) that the A-36 order was placed for a number of reasons, in part to get some sort of Mustangs in operation in the US forces, in part to help NA finance plant expansion for later models of the Mustang, in part to keep the existing production line open and not be converted to something else (like the B-25 mentioned above) and in part to keep the workers who were trained/practiced at Mustang assembly from being dispersed to other plants/jobs making it that much harder to restart production.
There may be other reasons (like the existing Army dive bombers didn't suit the Armies needs? A-25 in 1942 anyone?) and how much weight is given to any one reason is certainly open to question/debate. I am just listing possible reasons, I have no idea how much actual weight any of them had, if any.

Steve - all of the above, but IMO, the last one was critical. The experiences of the RAF in Africa were becoming visible to War Plans and it was acutely conservative that airfield supremacy or at least equality was a requirement for CAS. The Mustang was embroiled in perhaps the nastiest political turmoil in USAAF during WWII.

 

[FLYBOYJ]

Lockheed dragged their feet for 10 precoius months - time between the contract for YP-38s until start of manufacturing of those. All together, they squandered the timing advanatge held vs. P-47 and P-51.

Actually that's inaccurate - nothing wasn't done for 10 months for a number of reasons - Lockheed was being contracted to mass produce aircraft that were originally built by hand and the AAF knew this. At the same time Lockheed was expanding their plant to support other government contract which at the time had priority. Adding to the situation was the compressibility issue which up to that time was an unknown factor. All this happening at a time where the US was trying to remain neutral and stay out of the European war.

 

[tomo pauk]

Actually that's inaccurate - nothing wasn't done for 10 months for a number of reasons - Lockheed was being contracted to mass produce aircraft that were originally built by hand and the AAF knew this. At the same time Lockheed was expanding their plant to support other government contract which at the time had priority. Adding to the situation was the compressibility issue which up to that time was an unknown factor. All this happening at a time where the US was trying to remain neutral and stay out of the European war.

Joe - USA trying to stay away from the Europen war have had any bearing to the time lost on the (Y)P-38s, US companies were more than happy to sell aircraft to anyone US goverment allowed, and was with money. Compressibility issue emerged after the YP-38 was flight tested, not in the design phase.
Granted, Lockheed was contracted to make other A/C, but design shop was more or less a separate entity within the company, doing it's specific job? It took Republic, a small company compared with Lockheed, less time to roll out the XP-47B after the contract, despite there nothing was the same on the XP-47B what was on the V-1710-powered mock-up of the XP-47A. The YP-38 used plenty of major items from XP-38 (wings, booms, pod, engine layout was the same).

 

[P-39 Expert]

The turbo provided the function of automatic boost control for the P-38.

It basically compensated for altitude, the engine feeling like it was at sea level.

The engine superchargers on P-38s ran at lower rpm (gear ratio) than on P-39s and P-40s, which meant they had a lower pressure ratio. So less scope for overboosting the engine.

While a P-39 or P-40's engine had a critical altitude of maybe 12,000ft, the P-38's engines, ignoring the turbos, had a critical altitude of a couple of thousand feet, or less.

The turbo regulator worked to deliver air to the engine at sea level pressure. It did not provide overboosting capacity (though if the regulator failed it could, but that would likely lead to turbo failure before engine failure).

So the turbo kept the engine from overboosting at altitude?

 

[FLYBOYJ]

Joe - USA trying to stay away from the Europen war have had any bearing to the time lost on the (Y)P-38s, US companies were more than happy to sell aircraft to anyone US goverment allowed, and was with money. Compressibility issue emerged after the YP-38 was flight tested, not in the design phase.
Granted, Lockheed was contracted to make other A/C, but design shop was more or less a separate entity within the company, doing it's specific job?

The fact that the US was trying to stay out of the war had a great bearing on all this - the DoD was not quickly releasing contracts or more importantly MONEY to support these programs. US defense spending was increased but the purse strings were still being watched. Answering your bolded question - NO, at that time the R&D engineering department was part of the production group and need funding both internally and externally to keep operating. Lockheed was only going to put out so much of its own capital for R&D work and wasn't going to work "at risk" unless they were guaranteed something in return, basically the way most if not all manufacturers work today. When the XP-80 came along, the R&D section of Lockheed was split from the rest of the company, given its own VP and set up it's own infrastructure. That eventually because the Skunk Works.

It took Republic, a small company compared with Lockheed, less time to roll out the XP-47B after the contract, despite there nothing was the same on the XP-47B what was on the V-1710-powered mock-up of the XP-47A. The YP-38 used plenty of major items from XP-38 (wings, booms, pod, engine layout was the same).

Republic (formally Seversky) was NOT a small company and had the resources and infrastructure in place to build and develop combat aircraft. Even though the P-47 was a monster of an aircraft it was still easier to build than a P-38.

I worked aircraft production for over 20 years - no manufacturer ever "drags it's feet" when they receive funding unless there are continual design changes or other production or funding issues. Back then and even more true today, aircraft manufacturers are hit with fines and penalties when schedules aren't met and stock holders don't like that.

 

[tomo pauk]

The fact that the US was trying to stay out of the war had a great bearing on all this - the DoD was not quickly releasing contracts or more importantly MONEY to support these programs. US defense spending was increased but the purse strings were still being watched. Answering your bolded question - NO, at that time the R&D engineering department was part of the production group and need funding both internally and externally to keep operating. Lockheed was only going to put out so much of its own capital for R&D work and wasn't going to work "at risk" unless they were guaranteed something in return, basically the way most if not all manufacturers work today.
...

The money was allocated for 13 YP-38s - 2180725 US$, contract signed at February 11th 1939. At August 10th, 66 production A/C were ordered by the Government/AAF. Lockheed starts making the 1st YP-38 at February of 1940, a full year after they got the contract.
the 1st YP-38 gets airborne for the 1st time at September 16th 1940. That is 19 moths after the contract was signed and money allocated.
It took Republic 8 months to make a 1st flight of the XP-47B after they got the contract.
For what it's worth.

 

[wuzak]

So the turbo kept the engine from overboosting at altitude?

If the regulator was working correctly, the MAP in the engine, at a given rpm and throttle setting, would not change with altitude up to critical altitude.

Beyond critical altitude the turbo was not capable of maintaining air pressure to the engine, as at critical altitude it was at its design limit. Going beyond that limit risked turbo failure. Overboosting above critical altitude was, therefore, impossible, and MAP fell away quickly.

Obviously there was some scope for overboosting, because WEP was added during the evolution of the P-38. But not nearly to the same extent as with automatic boost controlled altitude rated engines. These used much higher pressure ratios, which required throttling below rated altitude to maintain MAP in the safe range.

 

[Shortround6]

The turbo provided the function of automatic boost control for the P-38.

It basically compensated for altitude, the engine feeling like it was at sea level.

The engine superchargers on P-38s ran at lower rpm (gear ratio) than on P-39s and P-40s, which meant they had a lower pressure ratio. So less scope for overboosting the engine.

While a P-39 or P-40's engine had a critical altitude of maybe 12,000ft, the P-38's engines, ignoring the turbos, had a critical altitude of a couple of thousand feet, or less.

The turbo regulator worked to deliver air to the engine at sea level pressure. It did not provide overboosting capacity (though if the regulator failed it could, but that would likely lead to turbo failure before engine failure).

The P-38 engines had the most changes of planes powered by Allisons. The P-38s up to and including the E used 6.44 supercharger gears (and B-2 turbos) the F used 7.48 gears and the B-2 turbo, the G used 7.48 gears and the B-13 turbo, the H,J and L used 8.10 gears and the B-33 turbo.
Now throw in the turbo regulator changes and the intercoolers and blanket statements about the P-38 power plants are very difficult to make.

Wuzak is correct that the turbo regulator acted like a an automatic boost control. Later ones were better than early ones. On Late Js and Ls it was completely automatic. The regulator would hold whatever pressure the throttle setting called for. This is different than the actual throttle plate position in the carburetor. The regulator control also controlled the throttle plate in addition to the turbo wastegate to keep everything working together .

Some early aircraft had automatic boost control according to the pilots notes but they don't say which ones. They do say that when performing the mag check to quickly note the RPM drop before the automatic boost control kicks in and tries to compensate for the drop in RPM.

 

[FLYBOYJ]

The money was allocated for 13 YP-38s - 2180725 US$, contract signed at February 11th 1939. At August 10th, 66 production A/C were ordered by the Government/AAF. Lockheed starts making the 1st YP-38 at February of 1940, a full year after they got the contract.
the 1st YP-38 gets airborne for the 1st time at September 16th 1940. That is 19 moths after the contract was signed and money allocated.
It took Republic 8 months to make a 1st flight of the XP-47B after they got the contract.
For what it's worth.

And each contractor didn't get all that money at once, it was stretched out in progress payments. Additionally you have to look at the schedule that was agreed upon when the aircraft was signed. Lastly one has to consider the Government Furnished Equipment (engines, turbocharges, radios, etc.) and when they were scheduled for delivery. Bottom line, there was no intensional foot dragging by Lockheed in the development of the P-38, the prototype schedule was a product of the state of affairs at the time.

 

[GregP]

Well said, FlyboyJ.

There were a LOT of decisions made in WWII that were the result of the state of affairs at the time, including almost every aspect of the decision processes for weapons systems, all along the way. It crept into the decision process for almost everything, and still does today.

 

[P-39 Expert]

If the regulator was working correctly, the MAP in the engine, at a given rpm and throttle setting, would not change with altitude up to critical altitude.

Beyond critical altitude the turbo was not capable of maintaining air pressure to the engine, as at critical altitude it was at its design limit. Going beyond that limit risked turbo failure. Overboosting above critical altitude was, therefore, impossible, and MAP fell away quickly.

Obviously there was some scope for overboosting, because WEP was added during the evolution of the P-38. But not nearly to the same extent as with automatic boost controlled altitude rated engines. These used much higher pressure ratios, which required throttling below rated altitude to maintain MAP in the safe range.

So, if that P-38 was below critical altitude, it could not be overboosted because of the turbo regulation? Just asking.

 

[jmcalli2]

When the problems were finally fixed for the P-38, it was too late since the Mustang was already proving dominance. So my question is; how did/would the P-38J-25 and P-38L-5-LO preform against German fighters in the European theater if some of the USAAF still used the P-38 up until the end of the war.

Thanks
DSR_T-888

http://www.456fis.org/THE P-38/P-38speedchart.JPG
http://www.456fis.org/THE P-38/P-38climb.JPG
http://www.456fis.org/THE P-38/P-38rollchart.JPG

http://www.wwiiaircraftperformance.org/p-38/p-38-tactical-chart.jpg

This may give some idea; http://www.wwiiaircraftperformance.org/mustang/Performance_Data_on_Fighter_Aircraft.pdf
Seems the P-38 could our roll, out turn, and our climb the P-51 and P-47.