Turbo prop P-38 for Vietnam?

A friend was telling me that he read in a book on the P-38 that it was such a good design that there was a proposal in the '60s to put it back
in production with turbo props & a redesigned wing, for ground attack. I've never seen anything along those lines, but that doesn't mean anything. I asked if he was confusing the P-38 with the P-51, but he said 'no way', because the P-38 is his fav WWII fighter & that story impressed him. Anybody else ever see this tale?
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Convair proposed a counterinsurgency fighter that looked like a turboprop P-38, but this design lost the competition to the Rockwell OV-10 Bronco. I'm not sure that Lockheed themselves tried to bring the Lightning back into production, but back then they had a lot on their plates with the F-104, U-2, SR-71 and C-141 all in the works.
Stephen "FPilot" Bierce/IPMS #35922 {Sig Quotes Removed on Request}
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I don't know about the Convair Charger I'm assuming. It looks like the OV-10, which means that the OV-10 would look a lot like a P-38. I don't think there's anything to it, but you never know.
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Stephen Bierce wrote:

Unfortunately, the 38 was designed in the mid to late 30s, and had a lot of problems aerodynamically that limited its performance. Fixing these would have required such a major redesign I don't wonder that they went to a newer design.
There was also a turbo-prop Mustang. The 51 was a later design. Only by a few years- but those were years that saw big advances, such as airfoils with a higher critical mach number. Even the 51 had to be fixed for the later versions, but the fixes were not as radical as what would have been required for the 38.
A contemporary of the 38 was the 39, again a plane that started with good goals, but the results showed limitations of the state of the art. Biggest problem of course was the installation of the Allison with the single stage blower instead of the turbo originally intended, but even if they had put in the better engine its design was so critical and optimized that every change they made in the thing made it worse :-(
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frank wrote:

FWIW The part of the P-38 story that I would like to see investigated is why there was no attempt to fit the P-38 with the Merlin 60 series in place of the Allison/Westinghouse supercharger/inter cooler combination. Two 60 series Merlins with their internal supercharger would have resulted in a weight saving and more space for gas. It was never attempted, and as far as I know was never investigated by Lockheed. Why?     The more research I do on the P-38 the more I believe that there was a decided bias against the Lockheed product in the top echelons of the U.S.A.A.F. All the other main U.S.A.A.F. types had two production sources and a few had three. It wasn't until late 1944 when a second line was opened for the P-38. Kenny in 5th Air Force was crying for more 38's, he got unwanted 47's. A plant in Texas was tied up building a couple of thousand of those lousy Vultee Vengeance dive bombers that no one wanted instead of building something needed like the 38.     The Lightning's problems in Europe were never properly investigated but that was due more to the command failures in the 8th Air Force than anything else. Lockheed test pilot Tony LeVier has stated that he felt that the engine/intercooler fires and explosions were due to the different gasoline chemistry of the gas available in England as opposed to the Pacific where the problem never arose.     I have been told that the main reason the Allison wasn't replaced was because the head of the war production board was a former CEO of Allison's parent company, GM I believe, and he was all ready p.o. about Allison losing out to Packard's Merlin in the Mustang program and wasn't about to see GM lose more business. Incidentally, for those old enough to remember the comic strip "Lil Abner", this guy was the inspiration for the character of General Bullmoose. Remember him? "What's good for Bullmoose Motors is good for America".
                        Bill Shuey
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I am sure that there were profit motives involved in which fighter got produced, but I think the thing that hurt the P-38 more than anything was it's own cost, and a Merlin engined P-38 would be even more expensive than a regular version.
Keith Walker
: frank wrote: : > : > A friend was telling me that he read in a book on the P-38 that it was : > such a good design that there was a proposal in the '60s to put it back : > in production with turbo props & a redesigned wing, for ground attack. : > I've never seen anything along those lines, but that doesn't mean : > anything. I asked if he was confusing the P-38 with the P-51, but he : > said 'no way', because the P-38 is his fav WWII fighter & that story : > impressed him. Anybody else ever see this tale? : : : FWIW The part of the P-38 story that I would like to see investigated : is why there was no attempt to fit the P-38 with the Merlin 60 series in : place of the Allison/Westinghouse supercharger/inter cooler combination. : Two 60 series Merlins with their internal supercharger would have : resulted in a weight saving and more space for gas. It was never : attempted, and as far as I know was never investigated by Lockheed. Why? : The more research I do on the P-38 the more I believe that there was a : decided bias against the Lockheed product in the top echelons of the : U.S.A.A.F. All the other main U.S.A.A.F. types had two production : sources and a few had three. It wasn't until late 1944 when a second : line was opened for the P-38. Kenny in 5th Air Force was crying for more : 38's, he got unwanted 47's. A plant in Texas was tied up building a : couple of thousand of those lousy Vultee Vengeance dive bombers that no : one wanted instead of building something needed like the 38. : The Lightning's problems in Europe were never properly investigated but : that was due more to the command failures in the 8th Air Force than : anything else. Lockheed test pilot Tony LeVier has stated that he felt : that the engine/intercooler fires and explosions were due to the : different gasoline chemistry of the gas available in England as opposed : to the Pacific where the problem never arose. : I have been told that the main reason the Allison wasn't replaced was : because the head of the war production board was a former CEO of : Allison's parent company, GM I believe, and he was all ready p.o. about : Allison losing out to Packard's Merlin in the Mustang program and wasn't : about to see GM lose more business. Incidentally, for those old enough : to remember the comic strip "Lil Abner", this guy was the inspiration : for the character of General Bullmoose. Remember him? "What's good for : Bullmoose Motors is good for America". : : Bill Shuey
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Wasn't there a Merlin engined prototype, the XP-49 or something?
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On 9/15/05 6:33 , in article snipped-for-privacy@g47g2000cwa.googlegroups.com, "frank" wrote:

The P-49 was a twin boomed outgrowth of the P-38 with a proposed P&W X-1800 engines, but these proved to ambitious in the planning stages and the Continental XIV-1430-1 was used instead.
The single example first flew in November 1942, crashed and was repaired in early 1943, and finally scrapped with the advent of the Mustangs' ability to reach Berlin with drop tanks.
The other somewhat similar plane was the P-58 Chain Lightning using Allison V-3420-11 turbocharged engines, but only in designation of 'convoy fighter' and having twin booms. Nothing was similar in dimension, performance, or components.
The one example flew on D-Day and scrapped in 1947. A second uncompleted frame was abandoned as a relic sometime thereafter.
--



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Lockheed probably served up inferior hookers to the USAAF officials. Dunno about the Merlins, but it seems they could have at least... ahem, pursued... the P-38K
http://home.att.net/~C.C.Jordan/P-38K.html
What I want to know is did the bulk of the production of P-40Ns, 5000 built from 1943 onward, go to the Soviets? Because... that's about the only reason I could ever figure why they kept cranking out those obsolete crates along with their obsolete Allisons at such a late date. Does it cost that much more to manufacture a Merlin/Packard over an Allison?
WmB
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Because the priorities for Merlin production at Packard were headed up by shipments for British-built and Canadian-built aircraft, meaning Mosquitoes, Lancasters, Halifaxes and Mark XVI Spitfires. The heavy bombers probably went through the engines faster than the Mustangs did, I'd imagine. Besides, as far as the P-40 airframe was concerned, the Merlin engine wasn't all that much of an improvement.
The Allison V-1710 finally caught up to the Merlin in power (by the time it was installed in the P-82 Twin Mustang), but of course by then RR had moved on to the Griffon. A Griffon Warhawk?--Would that have been worth building in 1944? Curtiss knew that the P-40 was obsolete and by then were building P-47 Thunderbolts.
Stephen "FPilot" Bierce/IPMS #35922 {Sig Quotes Removed on Request}
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wrote:

My bad, I was unclear - I wasn't suggesting they install Merlins in P-40s. They tried that and it was hardly worth the effort. I was criticizing the P-40 and the Allison independently from one another, or at least that was my intention. Why keep the P-40 in production when better aircraft were available? If the explanation lies with Merlin engine shortages, well that begs the question of why maintain high outputs of Allison production at the expense of Merlins.
Said the oversight official to the procurement agent:
Oversight: "Why in God's name do we have so many P-40s on order"
Procurement: "What would we ever do with all those Allisons we have on order"
Oversight: "Good point. Better double the order"
Another way to look at it, if the US Navy operated along those lines of thinking they would never have given the greenlight to F8Fs & F7Fs, with Corsairs and Hellcats devouring R-2800 capacity, not to mention P-47 consumption among others. Many people suspect the USAAF's rationale behind maintaining P-40 production had more to do with the long standing relationship between the Army and Curtiss and little else. After all, we all know that martinis and hookers have scuttled more than their fair share of low-man or best-man-got-the-job deals. Or it could have been something entirely plausible, as was the need for keeping Wildcats in production for service aboard the small escort carriers. Just hard to see it from here.
WmB
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WmB wrote:

1. Allisons were easier to maintain and build than Merlins
not a bad thing for a Lend Lease item.
2. Had better sub 15,000 foot performance
Most combat over the Russian Front fit this
3. Cost less.
the P-40 in 1943 cost just under $10k less than a P-51 per aiframe
4. Allison and Curtiss already had production lines going for them
Now had there been no LL to the Soviets, the P-40 would have probably been killed sooner, along with P-63 production
** mike **
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Ah-ha, details - now we're getting to it. #1-3 kind of bucks up where my thinking was on the advantages of extending the service life of the P-40. It's easier to see why the unique P-39 had legs with its heavy hitting 37mm cannon, the P-40 is a little tougher to see. Any details on what it was about the Merlin that made it more costly over the Allison? On the surface you'd think they'd both would have comparables outlays with respect to casting, forging and machining costs? The only thing I can imagine is they might have made heavier use of forgings? Don't tell me R-R gouged us on the licensing.
On an aside I read a tech article a few years ago concerning the difficulties P&W had with a shaft vibration problem during R-2800 development. While I don't recall the eventual cure (nor the problem) off the top of my head, I recall being impressed with the realization that solutions we take for granted today as SOP were ground breaking and pioneering as recently as WWII. Probably a good idea to keep that sort of frame of mind when balancing these things out. The fog is lifting a little - I think they designed a thrust bearing that is common equipment today and for many years since. That had to add to the overall cost.
And on yet another aside I caught something the other day on the latest generation of GM's Corvette Z06 that gave me a chuckle. In addition to its weight saving use of an aluminum frame, they chose to replace fiberglass with a lightweight composite mat'l. I'm thinking it was the floor pans. In this case the mat'l they selected was sandwiched balsawood - as many know a feature notably present in the design of the F-86 Sabre.
What is old is new again. Which sort of brings us full circle to the original message about turboprop extended life P-38s. ;-)
WmB
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Alright then my question is the P-39. Why in the heck did they decide to not include the turbocharger. It seems to have really crippled it. Why not add it back in when they realized the problem? I would have thought it would have been easy enough, it was designed with it.
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Gray Ghost wrote:

When it was designed the -39 didn't have all the equipment included that it would need to survive combat. Adding the turbocharger back would have made the aircraft too heavy and would probably have rendered the addition useless. As it was it did a very good job low down and since most combat over the Eastern Front happened at low altitiudes there was no incentive to return the turbo. Just my educated guess.
Bill Banaszak, MFE
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The eventual cure for the vibration in the R2800 was the use of dampeners in the crank web counter weights, spring dampeners in the accessories drives and many more.
There were iterations of the solution, the book R2800 - Pratt & Whitney's Dependable Masterpiece, has a table that is 20 (!) pages long detailing the crankshaft studies in relation to vibration.
There is a mini history here: http://www.enginehistory.org/engines.htm (pdf's here) http://www.enginehistory.org/r-2800.htm http://www.nomeking.com/cbal.htm (nice radial animations)
Keith Walker
: On an aside I read a tech article a few years ago concerning the : difficulties P&W had with a shaft vibration problem during R-2800 : development. While I don't recall the eventual cure (nor the problem) off : the top of my head, I recall being impressed with the realization that : solutions we take for granted today as SOP were ground breaking and : pioneering as recently as WWII. Probably a good idea to keep that sort of : frame of mind when balancing these things out. The fog is lifting a little - : I think they designed a thrust bearing that is common equipment today and : for many years since. That had to add to the overall cost. : : What is old is new again. Which sort of brings us full circle to the : original message about turboprop extended life P-38s. ;-) : : WmB : :
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I'm guessing it has to do with the cooling arrangements. The P-38 was essentially a flying radiator. It might have been more difficult to cool a pair of Merlins than a pair of Allisons? Just guessing.
(kim)
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Engine Availability -
Packard's merlin production was sucked up by North American for the Mustang and also for Canadian built Lancasters and Mosquitos, as well as Aussie produced Mosquitos. Packard built Merlins were also used in Spitfires and Hurricanes.
Why not just stop production of Allisons and convert to Merlins? Time and production numbers. The turn around time for retooling to build merlins, then redesign the aircraft using allisons (or retool the aircraft plants to produce aircraft that used the merlin) would have taken too much time and slowed production numbers too much. By 1942 every theater was screaming for replacement aircraft or new squadrons that they simply cound't slow the production to change over.
kim wrote:

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38 that it

'60s to put

wing, for

lines, but that

38 with the

WWII fighter

tale?
with the

Merlins with

weight saving and

I know was

The P-38 was

difficult to

guessing.
Um you do know that the early Mustang was Allsion powered and that the Brits did a quickie conversion to the Merlin which made the Mustang the legend it was. Doesn't seem that hard to switch engines. Mosquitos and Lancs were actually designed to accept "Power Packs" - interchangeable engines.
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Swapping a singlestage blower equipped Merlin in a P-40F showed little improvement over the singlestage Allison.

It wasn't internal to the engineblock, but coupled.The disadvantage of the Allison was it had an Integral blower, which made it difficult to add an extra gearbox onto it, but no effect on adding Turbos. This wasn't changed on Allisons till late in the war. More on this later.

Turbochargers could be lighter than a gear driven multistage, multispeed blower, but take up more volume for ducting. This advantage is lessened if the supercharged Merlin was fitted with an Aftercooler, that cooled the compressed air before it got to the intake manifold
Allisons could be Intercooled, the airtemp reduced between turbo and internal blower, but not aftercooled easily.

For a given HP output, an engine will make similar amount of waste heat, needing cooling from oil and glycol to prevent the engine from melting down. The two engines had similar displacements and compression ratios, and so for the same power levels, would make similar amounts of BTUs to be cooled
All forms of Boost takes HP to run the compressor. A Merlin might need 150HP off the crankshaft to get to 1500HP, while the Allison gets that from the free exhaust to get to 1500HP.
The gear setup needs to make 850HP worth of max boost, while the Turbo only 700 to get to 1500HP total, given that both engines made about 7-800HP at Sealevel without any extra boost/water injection/etc
At 30,000 feet, either engine would make about 1/3rds its base sealevel
HP output, about 300HP. It was easier for the Turbo to make up the extra boost needed to keep power levels up in very thin air, the Supercharger is starting to eat a large percentage of the engines output,just to run the supercharger, let alone provide boost to increase the power level
This is why the USAAF Bombers and P-38 and P-47 had Turbos, V.high altitude performance.
Postwar, the 'Twin Mustang' used Allison power, but with a two stage blower, and was similar to the Merlin in HP output at Altitude.
Also postwar, hydroplane racing showed the Allison did well vs Merlin powered boats.
The engines were really pretty similar. Its just the Merlin had a two stage blower, vs the Allison single stage, that gave the Merlin its advantage.
The 'Ultimate Allison' near 3000HP using Turbocompounding, was cut short by tubojets.
** mike **
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