Which aircraft would you cancel?

[pbehn]

I would ditch the Battle in favour of any merlin engined single seat fighter that Fairey could produce either their own or Hurricane/Spitfire. I would not ditch the Typhoon jus make the spec for a griffon engine long range 4 cannon design. The defiant also could be ditched but if not ditched it should never have been used in combat within range of LW single engined fighters, it should have been kept in Northern England and Scotland freeing up Huricane spitfire squadrons for the real battle in the south.

 

[parsifal]

That's the point that's often overlooked...when a new weapon is introduced to the battlefield, there is always a response from the other side.

*IF* the Me262 developed sooner, and performed as hoped (and/or the He280, for that matter), it would have forced the accelerated development of the P-59, P-80, XP-83 and the FH Phantom from the U.S. alone. Britain had their own jet programs and would have also reacted the same, by accelerating their Meteor and Vampire programs.

I agree. If we are going to engage in this type of daydreaming and not degenerate into pointless fantasy scenarios, it should be on the basis of already available technologies and more importantly, historical types already in service. Choices already available and on the shelf, even if in prototype (but must be plausibly ready except final production approval).

Otherwise it degenerates very quickly

 

[kool kitty89]

Wasn't faster than the Spitfire IX at combat altitude, though, was it?

The point was comparison to the 190 and Typhoon, not Spitfire IX. And while the performance at military power for the Mustang I and IA may have been less, with WEP (or overboost prior to formal WEP rating) it's a different story below 10,000 ft. (especially below 6,000 ft) The Mustang II/P-51A was in the same boat comparing military to WEP, though with higher FTH, not as much power down low and critical altitude for level speed just above 10,000 ft.

Might have is guesswork, not history.

Bigger issue is the RAF simply disliked the P-39, they employed overboost plenty on P-40s, so it would have become relevant had they adopted the P-39 more heavily.

It didn't; the Merlin XX was as big an engine as it could take. The Hurricane was also a deathtrap for pilots, if the wing tanks were holed, since the cockpit's open framework drew the flames straight in, and onto them.

Weren't solutions for that already employed on later Hurricane models? (including firewalls)

And my comments regarding the Hurricane were also largely regarding its continued historical production for practical/volume reasons and possibly compromises to improve the design without totally shutting down production. Hawker also had Gloser, and if not just building more spitfires, Gloster's F.5/34 design had better drag characteristics than the Hurricane and high speed handling characteristics than the Spitfire plus better cockpit visibility. Hawker putting more resources into developing a Merlin powered derivative of that design may have supplanted Hurricane production. (A Taurus version would be bad in hindsight given that engine's problems and the weight of the Hercules might make it tougher to adapt than the Merlin, but perhaps worthwhile as well)

That of course, aside from twin-engine development, which is the only other practical option for heavier fighters with the Griffon not available sooner and the Saber unreliable.

How about the P-39's sudden and deadly flat-spin?
How about the Corsair's reputation for being fatal to new pilots?

Both of those were seriously problems that should have been caught earlier in testing and addressed sooner in the P-39's case, and seriously limited the Corsair's carrier suitability in general. Though, in both cases, I do wonder if wing slats (or even fixed slots) would have been worthwhile solutions. The P-39 may have had other solutions including nose ballast, but I believe tip-stall was still a bit harsh regardless of actually entering a spin. (and one of the issues complicating landing on both aircraft)

In the F4U's case, with the carrier landing requirement, wing slots ahead of the ailerons might have been enough to address the dangerous tip-stall and wing dropping tendencies. (take-off and turn performance may have improved as well, though at the expense of some added drag -at least in the case of fixed slots)

Other than that, the problems with the F4U as a useful carrier aircraft also should make it one of the more attractive potential export designs. (a land based Corsair in place of the Typhoon would have been extremely useful both as a counter to the 190 threat and especially adapted into the fighter-bomber role)

So we cancel the Typhoon and what shall we challenge the Fw190 with in a low-level fight? Surely not the Hurricane...

Again, Merlin XX powered spitfires. Less/no need for the cropped LF Mk.V as well. (putting those cropped merlins on Hurricane ground-attack aircraft may have been more useful)

And without the Typhoon, there would be no Tempest...

Unless development continued and only production was canceled. Including potential Griffon powered derivatives (possibly sooner) if the Sabre was canceled and Griffon expedited.

As above.
Given the problems that the Fw 190 encountered in early operations and development, should that have been cancelled too? Same for any number of WW2 types.

No, but using alternate engines certainly wouldn't have hurt, especially during the prototype stage. A DB-601N or E powered 190 prototype may have developed to totally supplant demand for that engine with the 109 once production could switch over in large enough volumes.

The landing/ground accident rate on the 109 was higher than the 190 as well as being more difficult to fly and having poorer cockpit visibility, and short of altering the 109, the 190 makes an attractive replacement for those reasons.

There doesn't seem to be a lot between the P51A and the Typhoon, but the P39 didn't come close to the Typhoon. I know of one test which gave the P51a a remarkable speed but that was factory fresh with specially sanded finish. With normal wear it seems to have a speed of approx. 370 at about 4 to 5000 ft. The Typhoon seems to have similar performance.

The Mustang I should be faster than the P-51 at low alt, but I haven't seen any formal reports actually USING WEP in tests as that rating came later. (akin to WEP on the P-40) The P-51A's figures do include WEP though, with critical altitude for 1,480 HP at 10,400 ft at which height it managed 415 MPH, and 380 mph at 1000 ft. (the earlier 8.8 supercharged Allison of the P-51, A-36, and Mustang I should have given significantly higher speed at that level under the same conditions up to around 5,000-6,000 ft -I'm not positive exactly where the power curves converge)

The A-36/P-51/Mustang I should also have been better at V-1 chasing than the P-51A or P-51B all using WEP/overboost.

First and foremost I do believe that the GA role is the issue for the Typhoon. It had limitations as a fighter but it was the RAF's main GA aircraft. Understandably A lot is made of the A36 as an attack aircraft but I always have one question in the back of my mind and that is, if it was as good as its cracked up to be, why didn't they carry on building them? presumably there was a reason.

Not as good for GA as the P-47 and merlin P-51s were more valuable as escorts.

 

[kool kitty89]

Get Vultee to produce that (non turbo P-38), instead of the Vengenace - per gjs' question re. Vengeance's future?

Still have the problem with Lockheed's own development and mass production tooling lagging for any model making that scenario more difficult.

If we really want a cannon-armed fighter powered by 1-stage Merlin, stick two cannons on the Spitfire as historically Four cannons on a single-stage Merlin means quite a big drag weight. Hurricane also have had thick wings (and of greater area than Daffy), maybe even thicker than Defiant. Thin wings were the key to Spitfire's performance, Spitfire was smaller, the Daffy was with wider fuselage because of the turret, so it would be hard pressed to emulate Spitfire's performance on same engine.

The idea is more to be a better Hurricane rather than a better Spitfire, and I haven't been able to find information on the actual airfoil section used on the Defiant. It's BIGGER than the Spitfire's for sure, but I'm not sure of the thickness.

The P-40's wing was also thicker than the spitfires, but had pretty good drag characteristics. (the P-40 itself may have been a better fighter/fighter-bomber option than the Hurricane as well, but that would likely mean setting up licensed P-36 production pre-war and adapting it to the Merlin and/or Hercules independently of the Americans)
I'm more or less just looking for the Defiant to be a British P-40 equivalent on the whole, cleaner than the hurricane, larger and sturdier than the spitfire, and longer ranged than either. Or ... perhaps if the British had retrofitted a Merlin to their import Hawks earlier on as they later did with their Merlin Mustang prototype there would have been a demand for shipping Curtis airframes overseas and fitting them with British engines. (still not very practical and didn't happen with the Mustang either -as much as the Merlin XX might have helped it)

A griffon powered Tornado/Typhoon may have managed all of that better, though.

Single seat Defiant is a recurring theme, I've even sqetched a long-range fighter based on it. However, once we recall how even the Spitfire was in performance disadvantage in a good part of 1941 and 1942 vs. LW, having yet another aircraft that has 10-20 mph disadvantage does not much good for the RAF and the Allies.

Until the engineering disparity the Mustang brings, long range aircraft are pretty much limited to being poorer performers than any single-engine counterparts and twin engine development was lacking. (and also had disadvantages)

The P-47 and Corsair might have been the earliest large, single engine exceptions, though. Getting drop tanks into service early enough would be a big factor though. (especially if Republic had invested in designing their own high capacity, pressurized belly tank early on) Lockheed seems to have been one of the few manufactuers to really put emphasis on an array of high capacity, streamlined drop tanks.

One designer making a "mistake" is one thing. Many designers being off by a large margin pretty much all at the same time (with a few years) on a variety of aircraft means something wrong with the basic drag assumptions they were working with.

Perhaps they were hearing what they wanted to hear as the thick wing/s were lighter than a thin wing AND offered high lift at low speed giving good short field performance (much prized by the Air Ministry) without resorting to the "trick' flaps.

There was also a ton of room for compromise. The 15% thickness ratio on the Whirlwind or the likes of the P-40 or P-39 or P-39 or P-47's, or BF-109, or Fw 190 wings all fit in between the very thick wings Hawker was using for its fighters. The F4U used a thick root section, but tapered down to a thinner airfoil profile fairly quickly outboard of that and Gloster's F.5/34 wing used a fairly thick root (NACA 2218 I believe) but tapered down far more than either the Hurricane or Typhoon.

And good short field performance would have been aided much sooner by use of variable pitch propellers ...

But if the Typhoon was cancelled early, would that necessarily mean the end of the Tempest? Certainly cancelling the Sabre would do that, but would Hawkers and Camm get on with the improved Typhoon if the Sabre was still going to be available?

With the Saber and Vulture canceled, the Typhoon potentially moves onto the Griffon which gets much more development priority than it did historically (ie Perigrine and Vulture canceled, Merlin and Griffon emphasized).

Beyond that, Gloster's Twin engine developments become a lot more attractive if you've only got the Hercules and Merlin in priority development. (say if everything else is canceled to streamline production)

And with the Griffon in service earlier, you have single stage Griffon spitfires to counter the 190 threat too.

Merlins for heavens sake - Merlins.

And Griffons.

The thing is, if we can engage the retrospectroscope and move forward development of the Me 262, then why can't we do the same for the P-51 and get fully escorted bombing underway earlier?
Just sayin'...

Except, unlike the Me 262, accelerated P-51 development and official USAAF support could have meant all the P-40's Merlins going to Mustangs instead, and no Allison P-51 at all, or a turbocharged Allison P-51.

 

[Shortround6]

The problem with most of these "improved" Defiant schemes seems to be the rather large number of modifications needed. AS in take off the engine and cowl from the firewall forward, detach the tail somewhere aft of the turret and unbolt the landing gear legs. Replace everything else and still call it a Defiant.

Defiant used the wing space just outboard of the landing for fuel. Right were you would put wing guns. Simply yanking the turret and sticking a big fuel tank back there doesn't work because it is well aft of the center of gravity. The fuel tank in the fuselage needs to go either were the pilots cockpit is or just under it. Move the pilot back several feet? New internal wing structure for gun bays? people what to use thinner airfoil for more speed, Ths means not only new ribs but possibly new spar caps or heavier wing skins or something to get the strength back up after the making the wing thinner.

A Defiant II was over 20mph slower than MK IIA Hurricane with both using the same engine. Getting rid of the turret is NOT going to turn it into a Spitfire.

The Fairey Battles most important contribution to the RAF and Commonwealth air forces was as a trainer. It doesn't matter how many more "single engine fighters" using Merlins you build if your bomber crews train by running about the airfield with arms outstretched yelling "vroom, vroom". Besides, just how many more fighters do you want powered by Merlin IIIs with two pitch props? Canceling Battles in 1938-39 does NOT get you Spitfire Vs or Hurricane IIs.

 

[GrauGeist]

Except, unlike the Me 262, accelerated P-51 development and official USAAF support could have meant all the P-40's Merlins going to Mustangs instead, and no Allison P-51 at all, or a turbocharged Allison P-51.

Well, that's news to me...I always understood the P-40 to use the Allison V-1710

 

[EKB]

Well, that's news to me...I always understood the P-40 to use the Allison V-1710

" P-40D AC40-360 was modified with a Rolls Royce built Merlin 28 and began flight testing on June 30, 1941. Production models of the Packard V-1650-1 were not available until January 1942. Interestingly, other than simply being a suitable airframe for the available Merlin's, one of the primary reasons given for the Production Board to insist on this installation was to free Allison V-1710's for use in the critically needed P-38's and Bell P-63's.
The Army Air Force felt that the Allison powered P-40N was superior to the Packard Merlin powered P-40, but because of the time necessary to convert Packard to all two-stage Merlin production, some 3,500 single-stage V-1650-1 engines would be available. In order to utilize these U.S. allocated Merlins, the Curtiss aircraft company was directed to produce the Merlin powered P-40F and P-40L aircraft."

See p.318
Daniel Whitney. Vee's For Victory: The Story of the Allison V-1710 Aircraft Engine 1929-1948
Schiffer Publishing, 1998

 

[GrauGeist]

Ahh yes, the Packard V-1650 "Merlin" (not RR Merlin) in the P-40F and some P-40L variants...

Otherwise all others had the Allison V-1710 series

By the way, we were discussing production, not a prototype...

 

[rochie]

Seems to me after reading this thread, the Typhoons biggest problem was the RAF roundels it wore !

 

[tomo pauk]

Still have the problem with Lockheed's own development and mass production tooling lagging for any model making that scenario more difficult.
...

Then there is something about multiple types of aircraft built by Lockheed (eg. Hudson, Ventura, Lightning all in the same time in Burbank, plus B-17s in the Vega factory), while the Vultee was not in great commitment for any 1st line aircraft. Get Vultee produce only non-turbo P-38 and that's it. The non-turbo Lightning are flying already in 1941, so there is very little of development needed there.

There was also a ton of room for compromise. The 15% thickness ratio on the Whirlwind or the likes of the P-40 or P-39 or P-39 or P-47's, or BF-109, or Fw 190 wings all fit in between the very thick wings Hawker was using for its fighters. The F4U used a thick root section, but tapered down to a thinner airfoil profile fairly quickly outboard of that and Gloster's F.5/34 wing used a fairly thick root (NACA 2218 I believe) but tapered down far more than either the Hurricane or Typhoon.

Hawker was using 19% thick (at root) wings for the Hurricane and Typhoon, that is more than 20% thicker than aircraft you mentioned; I'm not sure that wing profile series chosen for the two fighters was of the most modern type either. Another thing that held Hurricane down was the huge wing area for the power installed, while the Typhoon could've used a bit more area for a bit better altitude 'behavior' The wing of F4U did not tapper so fast, it was still 15% at the weapon bay?

Beyond that, Gloster's Twin engine developments become a lot more attractive if you've only got the Hercules and Merlin in priority development. (say if everything else is canceled to streamline production)

Maybe. Re. the Air Ministry not wanting to buy two-engined aircraft when 1-engines was around: they signed the contract for Whirlwind, Beaufighter (erstwhile as a day fighter?) and Lightning.

Except, unlike the Me 262, accelerated P-51 development and official USAAF support could have meant all the P-40's Merlins going to Mustangs instead, and no Allison P-51 at all, or a turbocharged Allison P-51.

That should've been one nifty aircraft for 1942/43, the Mustang with single stage Merlin.

 

[stona]

Maybe. Re. the Air Ministry not wanting to buy two-engined aircraft when 1-engines was around: they signed the contract for Whirlwind, Beaufighter (erstwhile as a day fighter?) and Lightning.

Whirlwind, relatively few (116) built amongst complaints that it used two engines to lift four cannon, the same as the 'Hawker fighter' which became the Typhoon would on one. That illustrates the original point.

Lightning, never saw service with the RAF. The order for 500 odd 'Lightning IIs' was cancelled.

Beaufighter is the exception, proving a versatile and useful aircraft, but hardly as a fighter and hardly comparable with a Spitfire, Typhoon or Tempest. It showed some of the advantages of a twin engine design in the roles in which it became competent.

Cheers

Steve

 

[tomo pauk]

The original point was, for the development of the Gloster twin-engined fighter: "Two engines, where one would do, never sat well with the Ministry." In the time the Gloster twin was flying, and also the Whirlwind, there was no single engine in production that could both lift 4 cannons and provide enough performance to match what was offered by lighter armed fighters of the time.
The Typhoon was promised as a 450 mph (460 mph? wuzak - help) fighter, why produce a fighter that can do 360 mph? Typhoon might have had one powerplant, but that is two power sections coupled, with common set of accessories, so saying it is 'one engine' might raise an eyebrow. The Vulture, another engine for the Hawker fighter, was sometimes called 'double Peregrine' (it was not really).

Lightning, never saw service with the RAF. The order for 500 odd 'Lightning IIs' was cancelled.

Lightning I and II was ordered by the AM. We can discuss pros and cons of the 'P-38 minus' and P-38, but it featured prominently in both British (both I and II) and French (only Mk.I) plans for purchase.

Beaufighter is the exception, proving a versatile and useful aircraft, but hardly as a fighter and hardly comparable with a Spitfire, Typhoon or Tempest. It showed some of the advantages of a twin engine design in the roles in which it became competent.

It was planned to produce Beaufighters in the factory (factories?) currently producing Spitfires - looks like the AM was sufficiently impressed by 4 cannons on-board, plus LMGs, plus the promise of 370 mph that was 40-50 mph too optimistic?
That is not to take away from Beaufighters capabilities for roles other than a day fighter, of course.

 

[kool kitty89]

The problem with most of these "improved" Defiant schemes seems to be the rather large number of modifications needed. AS in take off the engine and cowl from the firewall forward, detach the tail somewhere aft of the turret and unbolt the landing gear legs. Replace everything else and still call it a Defiant.

Regarding the suggestion as an alternative to the Firefly: wouldn't mounting hispanos in underwing pods avoid the issues with relocating the fuel tanks? (potentially with a smaller number of .303 brownings still able to fit elsewhere)

Given the turreted Defiant's performance was significantly better than the Fulmar's, it seems like there was a great deal of room for maintaining that edge without a drastic airframe redesign.

Then there is something about multiple types of aircraft built by Lockheed (eg. Hudson, Ventura, Lightning all in the same time in Burbank, plus B-17s in the Vega factory), while the Vultee was not in great commitment for any 1st line aircraft. Get Vultee produce only non-turbo P-38 and that's it. The non-turbo Lightning are flying already in 1941, so there is very little of development needed there.

Or cancel the P-38 and task Bell with developing the non-turbocharged P-38 derivative (given they'd be competing for the same engines anyway and development timelines were fairly similar for both aircraft at that point). The P-40 was ready for mass production significantly earlier than other American fighters, and pretty well irreplaceable early war. (with greater emphasis on the P-51, it could/should have displaced the P-40 sooner than historically and be better suited for the V-1650 than the P-38 was -no counter rotation, possibly additional modification to cowling and mounts, etc -and the P-38 being already designed for turbocharging as well, so better suited for the V-1710 in either configuration)

Hawker was using 19% thick (at root) wings for the Hurricane and Typhoon, that is more than 20% thicker than aircraft you mentioned; I'm not sure that wing profile series chosen for the two fighters was of the most modern type either. Another thing that held Hurricane down was the huge wing area for the power installed, while the Typhoon could've used a bit more area for a bit better altitude 'behavior'

Those wings are indeed very thick, that was my point. Supermarine used a very thin (for the time) 13% maximum thickness and reasonable compromises in thicker, stronger wings that were easier to build, and easier to fill with internal stores should have been very possible, practical and attractive. (and what the majority of other air forces had on their fighters wings)

I believe the Hurricane used a modified clark Y or clark YH airfoil. Not particularly efficient, but easier to build and part of the overall expediency in the Hurricane's design. It's also why I pointed to there being so much room for improvement on the Hurricane beyond the more modest redesigns seen with the Mk.II's wings. And with the wing root section more integral to the fuselage and landing gear, the overall airfoil section could still potentially be adjusted by adding leading and trailing edge extensions while more heavily altering the wing outboard of those points.

And, again, other than just building spitfires, the gloster single and twin engine ptototypes would have been major projects in Hawker's ownership to consider developing further and replacing the Hurricane in production.

The wing of F4U did not tapper so fast, it was still 15% at the weapon bay?

Thanks for that information, but that would still be significantly thinner than the Typhoon's case, wouldn't it?

Whirlwind, relatively few (116) built amongst complaints that it used two engines to lift four cannon, the same as the 'Hawker fighter' which became the Typhoon would on one. That illustrates the original point.

Engine power isn't what kept the Spitfire and Hurricane from mounting 2 or 4 cannons sooner, it was completely down to the reliability of the cannons themselves when mounted in those wings. Further development of both the wings, mounts, and cannons was necessary before that became really practical on the Spitfire V and Hurricane IIC.

The original point was, for the development of the Gloster twin-engined fighter: "Two engines, where one would do, never sat well with the Ministry." In the time the Gloster twin was flying, and also the Whirlwind, there was no single engine in production that could both lift 4 cannons and provide enough performance to match what was offered by lighter armed fighters of the time.
The Typhoon was promised as a 450 mph (460 mph? wuzak - help) fighter, why produce a fighter that can do 360 mph? Typhoon might have had one powerplant, but that is two power sections coupled, with common set of accessories, so saying it is 'one engine' might raise an eyebrow. The Vulture, another engine for the Hawker fighter, was sometimes called 'double Peregrine' (it was not really).

The bigger issue there is the Whirlwind gaining preference over the Gloster design (which did make its first flights later) and decision not to keep the competing designs in parallel development. It's guesswork here, but the Gloster design seems like it would have been more straightforward to continue development with than the Whirlwind, particularly given the overall size and wing design (more likely able to actually supplant the Beaufighter in many of its duties -and more of the duties anticipated before the real performance limits of the Beaufighter were seen) but the upward firing cannon arrangement would need to be modified and internal fuel capacity would been to be increased for long range use. (not that the existing fuel would make it worse than the Typhoon or even Whirlwind)

It should have been easier to adapt to merlins than the whirlwind was, and I believe Gloster's 'Reaper' twin merlin powered heavy fighter project was derived from the F.9/37 design.

Lightning I and II was ordered by the AM. We can discuss pros and cons of the 'P-38 minus' and P-38, but it featured prominently in both British (both I and II) and French (only Mk.I) plans for purchase.

American shift in policies regarding turbocharger export combined with shortages of P-38s in general pretty much nixed the potential there anyway. Even had the Lightning I been deemed satisfactory, unless P-38 production could have been ramped up dramatically sooner, it wouldn't have been viable for export.

My other point was that if the Sabre was outright cancelled early war, the Gloster twin engine designs become more attractive from Hawker's and Air Minstry's points of view, with accelerated development of the Griffon being the only real caveat for a Tornado/Typhoon derivative. (and possibly unattractive there in terms of performance with the existing wing -a Griffon powered Tempest might have been more appealing, but short of accelerated development of both engine and airframe that wouldn't be in service until mid/late 1943)

 

[stona]

The Lightning is a complete red herring. It never saw service in the RAF and the order was cancelled. The Air Ministry showed interest in a lot of different aircraft that were never manufactured or purchased...so what?

The Beaufighter got lucky, performing roles other than its original intended role rather well. It was not the only aircraft to do this.

Cheers

Steve

 

[Shortround6]

I am not sure where the fascination with single seat aircraft that need Spitfires to fly top cover for them comes from while the Spitfire seems to get little attention.
For all of 1942 and a good part of 1943 the turbo P-38 was the Best US fighter available in any numbers at all. It certainly had flaws but ripping out the turbo is like throwing the baby out with bath water. The reason the P-38F Gs had 1325hp engines is because they used 7:48 supercharger gears and depended on the turbo for altitude performance. Even if the inter-coolers left something to be desired. The later P-38s used 8:10 supercharger gears on their 1425hp engines.
Using 8:80 supercharger gears or 9:60 gears would have hurt take-off power and still not given the power wanted at even 15-20,000ft let alone higher.

BTW British canceled their order for Lighting IIs (with turbos) in Aug of 1942.

 

[tomo pauk]

I don't think that anybody is claiming that 'P-38 minus' will be equal to the P-38 for all the missions, nor that Lockheed should produce the 'minus'. Having a second source of production allows for a number of capable fighter-bombers to be produced, that would offer far better RoC, payload and combat radius than P-40 or P-39. It should be also a bit faster than those two. The take off power can be 1325 HP even with 1-stage V-1710 (8.80:1 S/C gearing) from mid 1942 on, as with P-40K.
Having a second source hopefully also means that Lockheed can have an easier time to introduce the modifications earlier.

 

[Shortround6]

The problem is that it won't equal the P-38 for most missions. It will strictly a low altitude machine. It also requires a lot of foresight, an awful lot of foresight. It could take Allison 2-3 years to get a version of the V-1710 from initial concept to production with a number of changes along the way. Engine used in the P-40K was first 'proposed' in 1938 but since the 100/130 fuel needed for the 1325hp take-off rating didn't exist (and wouldn't until some time in 1941) I don't know what the anticipated power ratings were. The F4 engine (-73) used generally beefed up components, gained 35lbs and used the pressurized water coolant system (30% Glycol as antifreeze) which allowed for much better heat transfer from the existing cooling system.
So when can Allison promise the -73 engine?
Lockheed built 207 P-38s in 1941, 128 of them in Nov and Dec. To get any real number of 'P-38 minus' aircraft in 1942 you need to sign contracts well back in 1941 if not late 1940. It could take around year from first production to the 500th with next 500 only taking a few months. This is one reason production lines were not shut down/changed over on whims. Vultee has been mentioned but even they had production problems. The Vengence dive bomber was mostly produced in the Stinson Factory in Nashville Tenn. and by Northrop as the Vultee main factory was busy building BT-13 trainers.
Now in the fall of 1940 or very early 1941 do you know when the -73 engines are going to start showing up? Do you know what the power ratings will be? Will they be running on 100 octane or 100/125 or 100/130?
First P-38E is delivered late Oct or early Nov of 1941, there were 2000 changes between the D and E. production of the D was 23 in July, 26 in Aug, 12 in Sept and only 3 P-38s were built in Oct as the switch is made, something like 1000 P-38s are on order. Lockeed manages 54 Es in Nov and 74 in Dec and 116 in Jan of 1942.
Which P-38 is the 'P-38 minus' based on?

 

[EKB]

The Lightning is a complete red herring. It never saw service in the RAF and the order was cancelled. The Air Ministry showed interest in a lot of different aircraft that were never manufactured or purchased...so what?

The Beaufighter got lucky, performing roles other than its original intended role rather well. It was not the only aircraft to do this.

In late 1942 the British again sought to purchase P-38 Lightnings after RAF Beaufighter squadrons suffered heavy losses during the anti-shipping war in the Bay of Biscay. By that time the USAAF had none to spare. From E. R. Hooton, Eagle in Flames, p.55:

" On 20 July Leutnant Stöffler claimed two Wellingtons, and by the end of August seven victories had been recorded (Coastal Command had lost a total of 26 aircraft in the Bay during this period), encouraging representations from Raeder which led Hitler to demand a Zerstörergruppe. A Stab V.(Z)/KG40 was formed under Hauptmann Korthals at the beginning of September, but two months elapsed before it reached establishment, and even by the end of the year there were only 27 aircraft (eight fell to enemy action). As a stop-gap the nimble Ar 196 floatplanes of 5./BdFlGr 196 were pressed into service, claiming eight victories to 6 September.

The British reacted by introducing two squadrons of Beaufighters, the heavyweights first clashing on 8 September when Leutnant von Hoensbroech claimed a victory, but the biggest threat to the Beaufighters came from the Fw 190s of 8./JG 2, which claimed most of the 17 Beaufighters which Coastal Command lost by December despite Fighter and Army Co-operation Command sweeps over JG 2's bases, leading Coastal Command to seek P-38 Lightnings."

 

[tomo pauk]

A quick look at the manual for the P-38D, E, F G shows that P-38D E were rated for 19000 lbs for take off (includes 2 x 300 gal drop tanks) in 1942, still with take off power of 2 x 1150 HP. Granted, 600 gals of external fuel is a bit pushing it on such take off power, but still. So the early 1941 'F' series of engines (1150 HP for take off) should do.
At 15000 ft, the P-38F was making 380 mph on 1325 HP (3000 rpm at 47 in Hg) and 350 mph on 1000 HP (2600 rpm and 38 in Hg). The 'P-38 minus', with ram effect and exhaust thrust calculated in, should be at some 1250 HP at 15000 ft - 370 mph? And a bit better with 'faster' supercharger that is available in second half of 1942.

 

[kool kitty89]

At 15000 ft, the P-38F was making 380 mph on 1325 HP (3000 rpm at 47 in Hg) and 350 mph on 1000 HP (2600 rpm and 38 in Hg). The 'P-38 minus', with ram effect and exhaust thrust calculated in, should be at some 1250 HP at 15000 ft - 370 mph? And a bit better with 'faster' supercharger that is available in second half of 1942.

Wouldn't omitting turbos and intercoolers also save on weight? (assuming P-38J style fuel tanks weren't added)