8th Dec 1941, USAAF: you are in charge

Get drop the proper drop tanks for the P-47 into the ETO as soon as possible. It could have been done much earlier.
A simple inexpensive way to cut bomber losses dramatically.
Spaatz had told Arnold in April 1942 that "auxiliary (expendable) tanks offer the only immediate solution for extending the range of fighters.."
Despite efforts with virtually useless unpressurised tanks and then slightly better 75 gallon tanks in July 1943,the required 108 gallon tanks did not see operational service until September 1943,seventeen months later. That's also six months after the P-47 became operational in the ETO.
Cheers
Steve

Could have not agree more, hence the proper drop tank installation is only one modification on my list, about the P-47. We can note that in Brisbane, Australia, the drop tank (not a ferry tank, 'cow udder') of 200 gals was being produced for the 5th AF Thunderbolts, from Aug 1942 on.

tomo pauk said:

Really big bomber: at least 3 prototypes, one with R-2800, other with R-3350, yet another with V-3420; construction must allow for this. Initial deployment n Australia, vs. Sumatran oil fields.
B-17/-24: do as they were, a more powerful R-1830 or R-2000 for B-24 when available.
B-25: go for stronger HMG weaponry.
B-26: install proper flaps, along with bigger wing ASAP. Keep the number of defensive guns at moderate quantity. Or go for speed: a pair of defensive HMGs, stay at small wing.
A-20: install additional fuel tanks, plus wing drop tank facility (akin to P-38). Maybe try it out with turbo V-1710, should get better mileage vs. R-2600, but will provide less TO power. Better speed above 15000 ft, too.
A-26: more attention funding into this one, produce it with 2-stage R-2800, or turbo. Or, go for (X)B-28, Douglas building the A-20 with uprated R-2600s and more fuel instead.
As an alternative for existing twins, a twin engined pusher a-la Mixmaster.
Forget about A-24, A-25 and like.

P-38: get the second source of those, so the number supplied can be a decent one by early 1943, in all theaters, plus the Allies can get it. It will allow for modifications (dive flaps, better inter coolers, ADI, better propellers, generators on both engines, cabin heaters) to be introduced earlier without damaging the production too much.
to-be-P-51: try and get V-1650-1 installed. Field it in 1943. Dallas factory will need to build those, too.
P-47: drop tanks. Get Curtiss to do their job about the P-47G.
P-39: delete the wing MGs, maybe install some fuel instead.
P-40: as is, the Packard Merlin models built in small numbers only. Maybe do the 'A-40', dive bombing version.
P-63: Bell builds P-51 with 2-stage V-1710 instead?
Night fighters: A-20 with turbo V-1710, or P-38 with new central gondola, maybe the to-be-P-51 twin.

Radars: essential force multiplier, as much of those (both static, movable and airborne) need to be produced used.

Engines:
Allison: go for fuel injection (should solve the backfiring other fuel related issues), two stage engine is the way. ADI (anti-detonant injection), for turbo models too. The V-3420 might get installed into a really big bomber.
P&W: ADI.
Wright: the R-2600 need to go grow in power earlier, ADI for all models.
US Merlin: try to get another producer, or another line in Packard.

Armament: neck-up the .50 BMG into 18-20 mm cannon. Let Colt, Browning or other competent firm do the belt fed Hispano.

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I really concur with both Dave and Tomo approaches. Some alternate considerations incude:

I would immediately negotiate a Merlin License with Rolls and direct Lockheed and North American to 'bolt' the Merlin series into the P-51 and P-38. The P-51 gets a single stage version initially while the P-38 maintains the supercharger capability. As the improved 61 and 65 series evolves the Superchargers and plumbing are eliminated

To simplify - concentrate planning around three fighters that were in production, or about to be, for mass deployment early 1943. Given that you can't 'impact' the USN supply chain, I would still negotiate a licensing agreement to produce F4U-1 for USAAF - probably with Bell with intent to break off the late P-39 and all P-63 production in favor of the 'light' F4U-1. I would kill the P-39 and P-63 production around the time the first 100 F4U-1's were operational in late 1942 ~ 6mo after USN).

The P-40 continues with notion to convert to Merlin early. Packard and Allison to re-tool from V-1710 to Merlin series in close collaboration with Rolls Immediately, with shift to Merlins while maintaining enough capacity for P-39 and P-40 earlier series. P-40 becomes export CAS fighter until enough F4U's are built to supply USAAF Tactical Commands as well as Soviets and the Commonwealth. Although the F4U would be superb in medium high altitude escort, this would be the workhorse of the USAAF for tactical escort medium bombers and CAS. As the supercharged versions of the R-2800 become available the Corsair role expands.

I would kill the P-47 in 1943 as the F4U production ramps up. Not sure what I would do with design and production assets but I would both pick up additional F4U production as well as focus on CAS version to include armor and dive brakes along lines of Skyraider. In the early stages of 1942 I would have Republic re-tool the Evansville plant for the P-38.

I would make changes in P-38 airfoil, dive flaps and boosted ailerons in anticipation of solving compressibility issues with fat wing as well as mandate the Merlin retrofit for the Allison 1710, design changes to start immediately in December 1941. Production break when the Packard Merlin 1650-1 avalable in quantity. I would immediately start on the P-51 Lightweight design (P-51H) for introduction in 1944.

I'm torn on 20mm versus .60 cal/15mm. The latter can, and was developed for USAF in 1949-1950 but not quite superior enough to replace .50 cal or 20mm. It did however have a Browning platform which would have made production of the gun very easy with few changes over the M2. However, whichever is adopted, it goes into all fighters with mixture of HE and API depending on the mission. I would seriously consider .60 cal as base for all USAAF fighters and bombers and base defense.

What changes?
First, the P-40 holds its position as mainstream fighter in North Africa and Aleutians and PTO/CBI. The P-39s as they existed from the 1941 to late 1942 production prior to the F4U break, is directed to augment PTO and USSR... thereafter the USSR and Commonwealth receives P-40s until enough F4Us and P-51s arrive to replace them but VVS does not get anything but P-40 after mid 1943.

The A-36 is never built because all Mustangs after the Mk I and early II's are the last of the Allison P-51s. Instead of starting in July 1942, Rolls immediately starts feasibility study in December 1941 - NAA also starts in December, 1941 - cutting 8 months off the delivery of the first Packard/Allison Merlin P-51. P-51 arrives in ETO in April-May 1943.

The P-38F (now P-38J six months early) is first production version with Packard/Allison Merlin w/superchargers and new wing and is operational in July-August 1942 with deployments first to PTO, then to ETO in February 1943. It will have less range than the Allison version but much better high altitude reliability and start the long range escort process at least to Brunswick and Stuttgart from England. The 8th FC never flys a P-47. The P-38 never goes to North Africa as the F4U will replace the P-38 role there and continue to serve in medium altitude escort and CAS roles.

Packard and Allison collaborate on 'griffon' equivalent two stage supercharged engine with design goal of adapting to P-38 and P-51 airframe. Engine variations to be considered for B-29/B-36 airframes.

The 12/15th AF will convert entirely from historical P-40, P-38, P-39 and Spitfire mix to F4U and P-51. Most P-38s will go to PTO because of twin engine safety over long stretches of water while the P-51 and F4U fill the entire volume of missions from CAS to very long range escort.

The Mossie becomes the primary Recce/Scout/Night Fighter/Night Intruder for USAAF. NAA, Lockheed and Northrup collaborate in 1942 to design and produce an extremely long range escort and night fighter with the Merlin engine as powerplant.

The F4U-1 starts to equip 9th AF, then all TAC squadrons world wide beginning in November 1942. In early to mid 1943 the F4U is operational in North Africa, MTO, PTO and CBI. In late 1943 the Commonwealth in ETO, MTO and PTO start receiving them.

Frank Whittle is welcomed with open arms and GE and Allison and Pratt are instructed to further develop the engine as highest priority while Lockheed and NAA design teams work in collaboration to develop US jet fighter in early 1942. Early German wind tunnel test data on swept wing stolen. Axial and Centrifugal engine designs run in parallel.

Bomber and Transport thoughts next.

A competent General can accomplish a lot during two months. An inept General cannot get things right even with several years to prepare.

For tactical, close air support aircraft, Iam going with the P47 and A26. For a medium bomber, the B25. Stop development and production of others.

As of Dec 8 1941, the US will develop and mass produce for the USAAF,
P51B,D with merlin 2 stage for air superiority fighter.
B29 for strategic bomber.
P47 without turbo and A26 for tactical close air support.
B25 for medium bomber.
Continue development of P38 for an intercepter and recon role.
Develop jet engine aircraft.
Use B17 for strategic bombing until B29 available.
Existing commercial and GA type aircraft used as transport, liaison.

You need the P-38, P-39 and P-40 to "hold the line" during 1942 and early 1943. Their main use after that time is as trainers and lend lease supply to the Russians and other allies.

Almost 2000 P-47s are already on order on Dec 8th 1941. Granted it takes less time to switch a factory over than to build a brand new factory but switching factories over from one type to another can result in several hundred planes lost production during the change over. US production doesn't really hit it's stride until 1944. For the years 1940 through 1944 45.9% of combat aircraft and large transports were delivered in 1944 alone, measured in pounds of airframe 50.6% of combat aircraft and large transports were delivered in 1944. Mucking about very much in 1942 with the existing programs is just going to screw things up. By 1944 you can afford it. In 1942 you may not be able to afford mucking things up much.

Allison was making about 1100-1300 engines per month in 1942 and reached a bit over 2000 engines a month in 1943, Allison made 14,900 engines in 1942 compared to Packard making 7,256 engines in 1942 (and 2/3 of them were for the British by contract). In 1943 Allison made just over 21,000 engines, Packard built just over 15,000 engines of which about 2800 were two stage engines. By 1944 the Allison engines were becoming redundant and Packard did out produce Allison. You might say that this shows that Allison should have produced Merlins but the question is when should the change over occur? and the unknown is how many engines you would loose in the change over, a few hundred, a thousand, two thousand?

AS far as "new" planes go. ANYTHING not on the drawing board Dec 7th, the day BEFORE you take over will NOT see service until the beginning of 1944 at BEST. The F6F was noted as being a pretty rapid program for WW II and took just about 2 years from Request/prototype ordered to first service squadrons being used over seas.

AS far as "NEW" big bombers go, The B-29 and B-32 first prototypes were ordered on Sept 6th 1940. "...... On May 17, 1941, the Army announced that an order would be placed for 250 B-29s to be built in a new government-owned facility at Wichita, Kansas that would be leased by Boeing for B-29 production." A lot of swapping back and forth was done as to what factories would do what but by Dec 1941 numerous engine and air-frame factories were already either well under construction or already starting to deliver products. Work having been started in 1940/early 1941.

Buick takes until March 1942 to start delivering R-1830 engines but delivers 440 in the first month of production. They build just under 8400 R-1830s in 1942 and go on to 24,624 in 1943.
Chevrolet takes until April to deliver it's first 4 R-1830 engines but delivers 4058 by the end of the year and 23,414 in 1943.
Ford delivers 264 R-2800s in 1941 after starting work in Sept 1940. they deliver 6400 engines in 1942 and 13,337 in 1943. None are two stage engines.
Studebaker was supposed to build R-2600s but was switched to R-1820s because the government thought they were more flexible than Wright. They delivered 4 engines in Feb 1942, 7 in March, 35 in April, 168 in May and by August were over 1,000 a month. 1943 sees 23,066 engines delivered.
Both P&W and Wright are doing massive expansions to their own factories and building/leasing satellite factories.

Putting a big push on drop tanks is a lot easier than changing plane types. Fixing the American 20mm guns would have take about 10 minutes. Just authorize a manufacturing change that sees the chamber reamer not run into the back of the barrel quite as far/deep, later reamers could be cut shorter.
Changing tactics and targeting requires no change in production of aircraft.

Decide what you really want and push for those things and leave the rest alone. Allison doesn't have the engineering staff to develop better single stage superchargers, two stage superchargers, fuel injection and the V-3420 engine AND expand the factory ( or change engine types). Pick just a few.

Wright had to develop a new method of cylinder construction and switch from cast heads to forged heads to get the R-2600 from 1700hp to 1900hp. It needs new manufacturing equipment in the factory to make these engines. you cannot modify a 1700hp engine to the 1900hp standard. You cannot make the 1900hp cylinders and heads without new machinery for some operations.

bob44 said:

For tactical, close air support aircraft, Iam going with the P47 and A26. For a medium bomber, the B25. Stop development and production of others.

As of Dec 8 1941, the US will develop and mass produce for the USAAF,
P51B,D with merlin 2 stage for air superiority fighter.
B29 for strategic bomber.
P47 without turbo and A26 for tactical close air support.
B25 for medium bomber.
Continue development of P38 for an intercepter and recon role.
Develop jet engine aircraft.
Use B17 for strategic bombing until B29 available.
Existing commercial and GA type aircraft used as transport, liaison.

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as for the P-51 in DEC 1941.

First production Merlin 61, 2 March 1942. That is the British engine. Packard delivers a total of 5 two stage engines in 1942. I am not saying that things could not have been speed up some but dumping the P-39 and P-40 in in 1942 leaves you with darn few fighters of any type until you can get the the P-51s lines up and running and in DEC of 1941 the Merlin Mustang is at best an idea that is starting to be put on paper.
B-29 is a complicated aircraft with a lot of troubles, it won't see service until the summer of 1944 despite being one of the largest programs of WW II.

A P-47 without a turbo is a whole new plane, or at least a new fuselage. A-26, even with the best of intentions/implimentaion won't show up until late 1943 and that is a year earlier than historically.

OK, let's get real here. As a few others have indicated, the Merlin/Packard P-51 wasn't even thought of on 8 Dec 41, so drop that idea. The A-36/P-51 Mk1 wasn't a stellar performer in Dec 41, so it may never bloom into the air superiority fighter it became. So how do we win the air war without the P-51?

Of the aircraft in the 'pipeline," I agree we need to prioritize production immediately and focus near term development on our best prospects.

Continue/and expand the P-40 line. It will be our backbone fighter initially. Cancel or divert P-39 (to P-40) production. There will be no P-63. If Bell is to produce fighters, they'll be P-38's or P-40s.
Maximize production and development of the P-38, which is our most promising prospect for air superiority at the time of Pearl Harbor. The P-38 will also solve the long range fighter escort problem.

Continue to ramp up P-47 development and production as an alternative to the P-38.

Cancel the Martin B-26, and concentrate medium bomber production on the B-25 and light bomber (and night fighter) production on the A-20, but continue development on the Douglas A-26.

Cancel the B-24, and concentrate on B-17 production.

Accelerate development of the B-29, but only envision it as a stopgap until a more capable "global" bomber is developed, and that would be either the B-35 or B-36.

muskeg13 said:

OK, let's get real here. As a few others have indicated, the Merlin/Packard P-51 wasn't even thought of on 8 Dec 41, so drop that idea. The A-36/P-51 Mk1 wasn't a stellar performer in Dec 41, so it may never bloom into the air superiority fighter it became. So how do we win the air war without the P-51?

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The P-51 was a better performer than the P-40 with the same engine, though. The Merlin engine was not unknown to the USAAF, and had been used as a comparison for performance of the V-1710.

The problem with the P-51 is numbers. It will take time to get production up to the required level. So, instead of using Bell to make P-40s and P-38s use them to make P-51s. This will also help Allison as they will be making one less variant of the V-1710 (ie the E-series).

Merlin production is happening at Packard, albeit the V-1650-1 (20 series Merlin). Can certainly try that out before the -3 (60 series) engines are coming off the line. Maybe even use it as a stick to get Allison to develop a 2 speed single stage V-1710.

I think the P-38 is problematic for a fast build up of fighter numbers - simply because it has two engines, meaning an increase in P-38 production has to be matched by twice that increase in V-1710 production. Sticking with single engine fighters would be better, for the most part.

I suppose we are blessed for having hindsight. The USAAF powers-that-be didn't believe long range escorts were necessary for bombing missions in mid 1943, let alone late 1941. If that was known earlier I am sure the procurement mix would have ended up being different.

muskeg13 said:

Cancel the Martin B-26, and concentrate medium bomber production on the B-25 and light bomber (and night fighter) production on the A-20, but continue development on the Douglas A-26.

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I would not cancel the B-26. I would give it later R-2800s, significantly increasing the power. Also, continue developing the Martin XB-27 and North American XB-28 for high altitude, high speed bombing.

muskeg13 said:

Cancel the B-24, and concentrate on B-17 production.

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Originally Consolidated were tasked with building B-17s, but they reckoned they could do it better - and came up with the B-24.

The B-24 did have some advantages over the B-17 - range being one. I suggest that the B-24 be put into production, but not built in as big numbers. Use the B-24 for maritime patrol - fit extra tanks in the bomb bay to enable them to cover the mid-atlantic.

Task Consolidated with developing an improved B-24, using R-2600s or R-2800s. This could be used as an interim until the B-29 is available.

muskeg13 said:

Accelerate development of the B-29, but only envision it as a stopgap until a more capable "global" bomber is developed, and that would be either the B-35 or B-36.

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Boeing's development couldn't have gone much faster. Unless we get them to build a simplified B-29A - maybe lose the remote controlled turrets, maintain the rear turret only. The B-29B development can follow on after the B-29A is in series production.

Source an alternative engine supply to the R-3350. The best bet is the V-3420.

Drop all development of the IV-1430 - it's going nowhere. Give production of V-3420s to Continental.

Another alternative would be the Lycoming H-2470. But we wouldn't hold out hope for speedy delivery of those. R-4360 is still to be started by P&W, so is a non starter. Consider 6 x R-2800 as an alternative.

Both too conservative and too ambitious;

When the Army ordered the first 5 hundred and some odd P-40s back in the Spring of 1939 they knew it was an interim fighter. They were right, and with 6883 built by the end of 1942 it was "our backbone fighter initially". Total production of the P-38,P-39, P-47 and P-51 total 5863 at this point. Depending on it to be our back bone fighter very far into 1943 would be a mistake, it is, by far, the oldest air frame. Unfortunately the P-39 is the 2nd most produced Us fighter aircraft at this time, with 2871 produced by the end of 1942. 1932 of them in 1942. Shutting down the line/s and converting it to P-40s would result in several hundred fewer fighters in 1942, minimum.

2nd sourcing the P-38 is a good idea but you need engines.
P-47 was being developed about as fast as it could. Both the Evansville plant and the Curtiss contract are signed in Jan 1942, initial talks started when?
Development needs better engines and propellers, ie, water injection and paddle blades. An early P-47 (clean) needs several hundred feet more runway than a P-40E with drop tank. Drop tanks should be developed much earlier but expecting early P-47s (late 42. early 43) versions to act like 1944 versions wasn't going to happen without many other things happening at the same time.

Canceling the B-26?

seems to be a popular Idea. Trouble is that 1131 of them were on order as of Sept 28th 1940. Production starts to roll (5th produced) in the spring of 1941, over 200 are finished by Oct of 1941 and the 500th shows up in summer of 1942. Martin is rolling now and completes another 500 in around 4-5 months, before the end of 1942.

Perhaps they should have been canceled in in late 1943 or 44 but canceling the B-26 in Dec 1941 or in the spring of of 1942 leaves you short hundreds of twin engine bombers in 1942/43 until the B-25 production can be expanded. You also have to juggle engine production. B-26s used R-2800s and B-25s used R-2600s and they are not interchangeable.

The B-24 "program" was already in high gear.

From Joe Baugher's web site.

"In order to meet the projected demand for the B-24, in early 1941 the government established the Liberator Production Pool Program. Under this program, Consolidated would set up a new plant in Fort Worth, Texas to supplement the Liberator production in its main San Diego plant and Douglas would open up a similar plant for Liberator production in Tulsa, Oklahoma. The initial plan was for the Douglas/Tulsa plant to put together complete Liberators from sub-assemblies and components provided to it by Consolidated until it acquired enough experience to build complete aircraft on its own.

Shortly thereafter, the Ford Motor Company joined the Liberator Production Pool Program as a third member. Ford planned to build Liberators at an entirely new plant at Willow Run near Detroit. Initially, Ford was assigned the task of providing components for final assembly by Consolidated/Fort Worth and Douglas/Tulsa, but in October of 1941 Ford received permission to assemble complete Liberators on its own.

In January of 1942, following Pearl Harbor, North American Aviation was given a contract for the manufacture of B-24s at its Dallas, Texas plant. This brought the total number of plants involved in Liberator production to five."

Yeah, you could switch the plants over to B-17s but again, how long would it take? how much would it cost? how much lost production would it entail?
You also have to switch the Buick and Chevrolet plants from R-1830 production to R-1820 production or come up with a B-17 powered by R-1830s. Perhaps not that a big a deal?

The B-29 was "Accelerated" about as much as it could be and perhaps a bit too much already, first versions in combat had a lot of faults, and planes were being moved from production lines to "modification centers" where up to 800 modifications were done on new planes to bring them up to standard rather than disrupt the production lines.

Dec 1941 is too late to really affect production of aircraft until the sometime in 1943. Our "in charge" guy is inheriting programs that date back 1 to 2 years are are just about to pay off (start producing).

Too much mucking about with the programs already in place will result in fewer planes in 1942, possibly fewer in 1943, and only show a real advantage in 1944.

It is NOT too late to change "ideas" about unescorted bombers (include drop tanks) , tactics, strategy on how to use the aircraft( bombing campaigns). Some armament details and the like.

We can note that USA was also the Arsenal of Democracy - ie. it builds the weapons for other Allied forces. The P-39/-40 in hands of Allied pilot in 1942 is worth maybe two such planes in 1943. Or it's of better worth than 2 P-51s in 1944, by then the outcome of war is decided long time ago.
In short, churn out the P-38s/-39s and P-40s in 1942 in the existing production lines , while the P-47/-51, along with increased quantities of P-38s are needed from early 1943 on. Almost as historically was done, with changes (single stage V-1650 in P-51, drop tanks earlier for P-47, greater quantities of P-38). The reduced need for P-39/-40 should allow for more engines for P-38.

Send a one question memo to the top brass. The question, "Can strategic bombers self-defend?". Fire all that answer in the affirmative.

muskeg13 said:

OK, let's get real here. As a few others have indicated, the Merlin/Packard P-51 wasn't even thought of on 8 Dec 41, so drop that idea. The A-36/P-51 Mk1 wasn't a stellar performer in Dec 41, so it may never bloom into the air superiority fighter it became. So how do we win the air war without the P-51?

According to Ed horkley the Spitfire and Merlin was indeed in the back of Edgar Schmeud's mind during the pre-design stage in 1940. The A-36 contract, with subsequent design team application, was a result of the bone Arnold threw to keep the NAA/P-51 alive and intact. The contract was signed in June/July 1942. 40,000+ engineering hours were devoted that, had the order been given Dec 8, 1941 (with foreknowledge per this thread) could have been devoted to a.) acquiring the licenses, b.) acquiring four Merlins, c.) lining up manufacturing capacity, and d.) applying that engineering talent before the end of 1941.

During the tests at Wright Pat in July/August 1942 the P-51 got rave reviews from the test pilots and these reports were funneled to Arnold.

Had the orders been given to prioritze the Development of the P-51B, the Dallas facility could have been started (planning) in December 1941 plus any other plants to meet the projected fighter needs for 1943 that were currently being filled by the P-39 and P-40. That would have by itself accelerated the delivery of production P-51B's by the end of 1942, assuming the first version was the single stage Packard/Merlin. The Dallas Plant would perhaps be the first to produce the B while the NAA Plant continued building the Mustang I/P-51A until changeover in 1943.

Of the aircraft in the 'pipeline," I agree we need to prioritize production immediately and focus near term development on our best prospects.



.

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The key to the focus on the P-51B/D development is the parallel priority of First getting the physical engines immediately - perhaps 6 Merlin XX/Packard Merlin 1650-1's (two to Allison, two to another potential engine manufacturer) and direct Allison and Packard to collaborate with the Brits on forthcoming designs but tool for the 1650-1 and subsequent releases and plan for production of combined 5000 per month at new facilities geared for that level of production by the mid 1943. The first Packard Merlin XX/1650-1 was delivered to RAF in September 1940.

The two going to NAA for re-design and integration of the Merlin in one of the first Mk I's rolling off production lines in December 1941. Second, in parallel, negotiate license and technical support from Rolls for Allison - and Allison payments funded by USAAF for design and tooling data from Packard, concluded by end of December 1941. Third, Prioritize in-line engine engineering resources across the US and allocate to Allison and Packard. Fourth, secure percentage of early Merlin XX, delivered in March 1942, to NAA for low scale production as the flight tests of XP-51B should be possible in April (assuming the 40,000 hours are prioritized at NAA - which will in some cases be taken from B-25 and prototype XB-28 teams to augment P-51B team).

Net - the gestation cycle that hindered introduction of the P-51B into production in April 1943, can be shortened by as much as 8-10 months because NAA starts the integration of the Merlin into the P-51A in December 1941 rather than order the Merlin equipped Mustangs in July 1942, the engineering and tooling plans could have started 8 months earlier. The XP-51 flight testing would have resulted in the aileron mods. wing pylons, and other design features prior to completion of Design for the P-51B say, in late April 1942. Tooling at NAA for the separate fuselage and wing mods would have resulted in a branch in the Plant to take the New block and be ready for first production in July 1942. In the interim, NAA would not have been delayed for engine tests and discoveries which delayed flight test for the two completed airframs - for three months.

Net, the XP-51B could have been in flight test for three months from April through July to prepare for July Production.

Also, as a gesture of "reverse Lend Lease' the P-51B production could have been planned for UK and Australia production for all Mustang III versions and been ready by December 1942 for production in parallel with Dallas and Inglewood.

As Shortround noted, the engine manufacturing would have been the key choke point - but given a December 1941 to allocate more resources to the Production of the Merlin 61 in parallel with Packard's start in 1941, I believe it could be handled.

As for the P-38. With the benefit of hindsight it was the single platform with enough range for all the USAAF needs for Recon, intermediate to long range high level escort and performance potential to fight anything on equal or better terms - if the wing and engines had been fixed at the beginning. The XP-38K, with foresight, could have been designed with a broader chord wing with less thickness ratio but same internal capacity and higher critical mach and same boosted ailerons and manuever flaps, kill the Allison, install the 1650-1 with Supercharger. The contract to design the P-38K (new) would be let on December 8, while the P-38E was being produced. Four P-38E's would be the platform for the XP-38K . The back up design would be the 1650-1 with Turbo, but the primary design is the 1650-3 two stage Merlin 65. It would probably take four or five months to design and install the engines with GE support on the Merlin Turbo design. (Big Guess) while the rest of the airframe mods and tooling were designed. Speculatively the P-38K would be ready for flight test by April 1942 and production start by September 1942 based on the results of Packard 1650-1/Turbo results or the release of the Packard 1650-3. While the turbo integration is taking place, the 1650-1 version is complete and into flight test by April 1942.

By the August 1942 timeframe both the P-51B and P-38K could have been ready for North Africa invasion as well as long range escort for 8th AF.

Subcontract casting and forging suppliers experienced in the aircraft engine special metallurgy are also in short supply - the entire manufacturing infrastructure will be greatly facilitated by cutting the aircraft types by 30 to 50%.

In 1941 - Cargo - I would concentrate on the C-47 and C-54 and C-46.
Heavy bombers - I would allocate the B-17 to the ETO and the B-24 to PTO to simplify logistics and optimize mission.
Very Heavy Bombers - No change B-29 and 3350 engine
Medium Bombers - B-26 and B-25 initially and Mosquito with Preliminary design of metal based airframe for weight estimates.
Light Bombers - A-20 with fuel mods and engine upgrades - to be replaced with Mosquito in 1943. Douglas to concentrate on Skyraider development starting with R-2800 in 1942.
Trainers - PT 19, BT-13, AT-6
Night Fighter/Anti shipping/Night Intruder/long range Recon - Mosquito

Fighters 1942; First 9 months P-38, P-39, P-40, A-36 (if hours can be obtained without harming P-51B) Allison based fleet.
Fighters 1942; Last three months P-38, P-38K, P-40, A-36, P-51B (mix of Packard Merlin and Allison)
Fighters 1943; First 9 months P-39, P-40, P-38, P-38K, A-36, P-51B. Last 3 months P-38 (PTO), P-38K, A-36, P-51B, F4U - with all P-40's and P-39s deployed to Commonwealth and USSR with parallel production while Curtis and Bell shift production capacity to F4U and P-38K. XP-80 flight test
Fighters 1944; P-38K, P-51B, F4U, maybe A-36 while the USAAF F4-U is deployed. P-51H and P-38N (w/1650-9), P-80A in last three months of 1944.
Fighters 1945; P-38K, P-51H, F4U-5 and P-80

The key changes - Reduce the airframes and engine variations, reduce the diversity of engineering team focus for airframe design, manufacturing engineering, engine and airframe production line variations and methods, reduce the variations in steel/forgings/castings specs.

Significantly reduce the supply chain requirements for Maintenance by 1943.

Introduce Long Range escort capability into ETO by late 1942, early 1943 by the time the 8th is ready to bomb German targets. Introduce faster, more manueverable F4-U to USAAF specs for low to medium high level multi mission capability in PTO in 1943 and MTO/ETO by 1944. All P-40s and P-39s replaced at squadron level by early 1944 with F4U's.

The Lend Lease P-51B/H would have replaced the Spitfires in PTO and perhaps MTO.

The US Mossies would have replaced the A-20 and B-26 in 1943 and eliminated, the P-61 and the A-26. The draw on the R-2800 design and production teams could be more focused on the two stage supercharger version of the R-2800 and the development of the 4360

Shortround6 said:

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Decide what you really want and push for those things and leave the rest alone. Allison doesn't have the engineering staff to develop better single stage superchargers, two stage superchargers, fuel injection and the V-3420 engine AND expand the factory ( or change engine types). Pick just a few.

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The better single stage superchargers (ie. those with 9.6:1 SC drive ratio) were no brainers, and should go as scheduled (late 1942). The two stage SC, with availability of (single stage) Merlin Mustang, longer ranged P-47s and more P-38s, is not such a necessity, so can be produced as historically it was. V-3420 can use a more affirmative stance for the USAF. Three 24 cyls were shipped prior 1942, having them in production by late 1943 does not seem like a stretch. Phasing out the P-40 in 1944 will make possible the V-3420 production to hit the stride.
The Allison was managing to do anything from your list (bar fuel injection). USAF can 'delete' the Chrysler V-16, Continental inverted Vee, Wright Tornado and Lycoming H engine, so more manpower resources can be used to improve other engines, like to design a fuel injection version of V-1710.

Wright had to develop a new method of cylinder construction and switch from cast heads to forged heads to get the R-2600 from 1700hp to 1900hp. It needs new manufacturing equipment in the factory to make these engines. you cannot modify a 1700hp engine to the 1900hp standard. You cannot make the 1900hp cylinders and heads without new machinery for some operations.

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Indeed you're right, it would be 1944 for the 1900HP R-2600 to be produced, as historically. With ADI (that was not included in historically), that would mean easy 2100 HP, down low.

[QUOTEas for the P-51 in DEC 1941.

First production Merlin 61, 2 March 1942. That is the British engine. Packard delivers a total of 5 two stage engines in 1942. I am not saying that things could not have been speed up some but dumping the P-39 and P-40 in in 1942 leaves you with darn few fighters of any type until you can get the the P-51s lines up and running and in DEC of 1941 the Merlin Mustang is at best an idea that is starting to be put on paper.
B-29 is a complicated aircraft with a lot of troubles, it won't see service until the summer of 1944 despite being one of the largest programs of WW II.

A P-47 without a turbo is a whole new plane, or at least a new fuselage. A-26, even with the best of intentions/implimentaion won't show up until late 1943 and that is a year earlier than historically. ][/QUOTE]

Yes, we are looking at 2 years or longer to get the P51, A26 and B29 into service.
My list is assuming what we know now, after the war.
Using existing aircraft in 42 and 43 to fight the war, but put development into the P51, P47, A26, B25, B29.

The early introduction of P-51 (but with V-1650-1, in late 1942) and drop tank installation for P-47 (early 1943) would've made the second source for the P-38 a redundant thing, so maybe better that source produces P-51s from 1943? Vultee, maybe?

Maybe you could iron out the issues with the P53 Lancer and use that to hold the line until Merlin P51 arrives in numbers?

vinnye said:

Maybe you could iron out the issues with the P53 Lancer and use that to hold the line until Merlin P51 arrives in numbers?

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Think they tried that and ended up with the P-47