1943: USAAF's ideal fighter?

You know the drill - by using the 'ingredients' available for the USAAF, how do you picture the ideal fighter for the force? High fight performance capability (speed, climb, dive, combat range, roll, turn...), decent punch, sufficient ammo protection, not to much expensive (but not too cheap, with reduced capabilities) to own operate, capable to be steadily upgraded as the new stuff is produced...
The production starting Jan 1943, so it can be used in decent numbers in 1943. Single engined plane. It will be used beyond 1943, too, in the upgraded variant(s).

People are encouraged to think beyond what was really produced (as a complete plane; the disclaimer about historically available ingredients remains), either in 1943 or in some other period of the ww2

The USAAF Primary Mission was the deployment and success of the Strategic Bombing initiative - the single most imortant airplane on the production line was the B-29.

All fighter priorities start with support of that mission as well as establishing air superiority to enable the Strategic mission to succeed.

If you give a blank check to NAA, they already had the contract for 5 XP-51F's in January 1943. The P-51B production tooling was complete in Feb 1943 in California, the P-51C plant was complete in October 1942. The Dallas facility could have proceeded apace with design and development of the P-51C while reserving plant floor space for the future P-51H.

If the USAAF accepted the high risk of the lightweigtht Mustang development, it is conceivable that the XP-51F may have reached flight status in May/June 1943 and production tooling complete for limited production in the same general timeframe. There were no serious long lead time GFE or airframe forging/castings to worry about. The primary tooling and jigs would have to keep pace with the lines drawings to get the cowlling type contoured parts ready to stage production - while detail drawings of airframe structure and stress analysis proceeded in parallel. The various Merlins could have been dropped in for incremental performance boosts as separate dash numbers as performance changed from 1650-3 through -7 and -9.

Full scale production on an accelerated production plan accepting risks of show stoppers, (there really weren't any particular design faults resulting in months of delays) it again is conceivable that the P-51G or H could have been in production by January - February 1944 when the P-51C production could be allowed to wind down.

The result would have been fewer P-51 (B/C) airframes produced by approximately 25% through February. The P-51D production would have kept pace, but the K would be replaced entirely by the P-51G/H. The net is that the P-47N may never have been built, and the P-51H production would have been (IMO) mostly diverted to PTO to support B-29 sorties by August 1944 timeframe. In ETO/MTO fewer fighter groups would have converted to P-51D, more P-38s woul have been diverted if necessary to MTO to backfill the 'missing' P-51K, the 9th AF would have not received P-38, the 354th FG would have remained in P-47s post November. The 8th would have retained all of the planned conversions from P-38, but the MTO probably stays on P-38 for longer range escort - with some gaps in target cover.

So what? Daylight sorties over japan could have been lowered in altitude to 20K to improve bombing accuracy, all the requisite long range capability to Formosa would be retained by P-51G/H - not much strategic or tactical capability lost in PTO that couldn't be covered by P-47D replacement of P-39/P-40. Allies get fewere Mustangs and More P-47s.

tomo pauk said:

You know the drill - by using the 'ingredients' available for the USAAF, how do you picture the ideal fighter for the force? High fight performance capability (speed, climb, dive, combat range, roll, turn...), decent punch, sufficient ammo protection, not to much expensive (but not too cheap, with reduced capabilities) to own operate, capable to be steadily upgraded as the new stuff is produced...
The production starting Jan 1943, so it can be used in decent numbers in 1943. Single engined plane. It will be used beyond 1943, too, in the upgraded variant(s).

People are encouraged to think beyond what was really produced (as a complete plane; the disclaimer about historically available ingredients remains), either in 1943 or in some other period of the ww2

Click to expand...

You aren't going to do much better than what was produced. The US probably had the greatest diversity of engines and airframes already. Both in production and prototypes. The only thing that might have improved the P-51, aside from Dragondog's suggestions, would have been a reliable 20mm gun. Re-engining the airframe to an other available engine (non Merlin) would have delayed production by months if not more than a year and any improvement is highly debatable. There is no alternative engine for the P-47, F4U and F6F. The P-40 is little more than an advanced trainer in 1943 and the P-39 is pretty much for lend-lease. Leaves pretty much the P-38 which, fine as it was, rather fails at the "not to much expensive (but not too cheap, with reduced capabilities) to own operate" part of your requirement.
Trying to stuff turboed Allisons into an exiting airframe without major work wasn't going to happen.

America's major short coming was fouling up the Hispano cannon.

By 1942 the U.S. Army was already committed to certain aircraft, engines and the .50cal machinegun. You cannot change much without a huge disruption to production.

Start planning during 1940 and it's a different story. You could have the Mustang airframe powered by a Ford built Merlin engine and armed with a decent copy of the Hs.404 cannon by 1943.

It's proven that late war US birds were with fine war planes, but I was thinking about a clean-sheet-of-paper 'design' that could represent itself as an ideal one? P-38 is out of this thread - it was produced, plus - single engined jobs need to apply

V-3420 powered XP-54?

Ditch the 37mm cannon and the articulating nose for 20mm Hispanos and/or 0.50" Brownings.

Several possible thoughts. Rush the Merlin P-51, as was already said. Or, Turbo the Allison P-51. Don't yell at me for that one. With enough ingenuity I'm sure it could have been done. Turbo the P-39 and give it a little more fuel. Find a way. For instance, reduce armament to one 20mm Hispano and two .50's in the nose, and redo the wing a little for additional fuel. I know I'm going to catch flak for that one.... Other than that, I like the P-40Q. And really, I think they did a slap-bang job with what they had, as far as it goes, and the P-38, though expensive, was very effective in 1943, especially in the hands of well-trained pilots who were allowed to use good tactics. Merlin in a P-39, and maybe extend the wings a couple feet. Don't tell me it couldn't be done. Look at all the tricks that WERE accomplished during the war. Any time someone tells me something couldn't have been done, like swapping out a different type of engine, I point to the Ki-100 and say, "explain that."

tomo pauk said:

It's proven that late war US birds were with fine war planes, but I was thinking about a clean-sheet-of-paper 'design' that could represent itself as an ideal one? P-38 is out of this thread - it was produced, plus - single engined jobs need to apply

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Clean sheet for 1943 needs to have started in 1941. Clean sheet start in 1943 means plane shows up in 1945.

And even with ALL the different types the US had NO ONE aircraft was ideal for ALL missions. Especially in 1943. The P-47 R-2800s didn't have water injection until about Nov, the paddle blade props show up in Dec (on the production line combat is another story) Power is pretty much 2000hp. And so on.

Oreo said:

Or, Turbo the Allison P-51. Don't yell at me for that one. With enough ingenuity I'm sure it could have been done.Turbo the P-39 and give it a little more fuel. Find a way. For instance, reduce armament to one 20mm Hispano and two .50's in the nose, and redo the wing a little for additional fuel. I know I'm going to catch flak for that one.... Other than that, I like the P-40Q. And really, I think they did a slap-bang job with what they had, as far as it goes, and the P-38, though expensive, was very effective in 1943, especially in the hands of well-trained pilots who were allowed to use good tactics. Merlin in a P-39, and maybe extend the wings a couple feet. Don't tell me it couldn't be done. Look at all the tricks that WERE accomplished during the war. Any time someone tells me something couldn't have been done, like swapping out a different type of engine, I point to the Ki-100 and say, "explain that."

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>"I point to the Ki-100 and say, "explain that."<

easy, just because something could be done doesn't mean it should be done. Replacing an 1100hp engine with a 1500hp one usually helps. It also helps if the engines you are swapping are somewhat similar in weight (including cooling systems). The Kinsei engine mayactually have been lighter than the V-12 that came out. Swapping an R-2600 or R-2800 for an Allison or Merlin is not the same thing.

AS for the turbo Allison P-51, it could have been done, you just need about 12-15 cubic ft of space to stuff everything in. You also have to put up with the 20-30mph (minimum) loss of speed at low altitude because of the extra drag.

Same with the P-39. Bell tried two different external turbo set ups in mock up. They tried a two stage supercharger (like used in the XP-40Q)on the XP-39E (P-76) which turned into the P-63. Longer fuselage, bigger wing and still didn't get an inter cooler that worked or enough fuel. Fitting it all into the smaller P-39 wasn't going to happen unless you can get two objects to occupy the same space at the same time. You probably could swap the wing guns for fuel but you are getting into diminishing returns. The Fuel 'system' on a P-38 weighed about 290lbs (tanks and piping) for 120 gallons. the further out the wing you go the more surface area to volume your tanks are going to have (the wing is thinner) and the heavier per gallon of capacity the tanks are going to be.

As it was, I don't think they could have done a whole lot better than they did. If they could have sped up the P-63 development and had it available by mid '43 it might have been ok. But that probably wasn't feasible either. As it was the P-51B went into combat in Dec. '43 and from then on it was pretty much a matter of getting as much production into Mustangs as possible. The P-47 and P-38 still had their applications, and so they were retained as well. What else could they have done? Just sped up the Merlin Mustang, maybe. To start with a whole new system would have been unnecessary. A Merlin powered P-39 or P-63 would have been interesting.

I agree with Oreo. I really would like to see a P-39/63 with a Merlin or any other engine with a sufficient turbocharger

Hard to imagine a more perfect AAF fighter than the P-51. Cheap, easy to manufacture, relatively easy to fly, arguably the cleanest propeller driven fighter, defined high speed performance at high and low altitude, defined long range performance, and at fighter weights it had excellent climb and good maneuverability. Do everything drgondog and SR6 said. Identify up-engine and extended range efforts early to support escort much earlier in 1943 than it did. Also, develop a water injection Merlin (the -9?) to be ready by end of '43.

Question. Why wasn't water injection developed for the -7 Merlin? Was it a ruggedness issue?

NiceShotAustin said:

I agree with Oreo. I really would like to see a P-39/63 with a Merlin or any other engine with a sufficient turbocharger

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The problem isn't so much the supercharger as the intercooler needed to let the bigger, better supercharger work.
Perhaps you could have stuck a Merlin XX or 45 in a P-39. Performace would be bit better better but not a lot. Sticking in the Merlin 60 series (Packard _3 or _7) is a bit harder. A few extra inches of length and about 200lbs more weight. rather far from the center of gravity. Look at a P-63, the entire fuselage was not only longer but moved forward on the wing. And just because you have the supercharger on the back of the engine doesn't mean you have the inter/after cooler radiator in the plane yet. That "thing" that caused the Spit 9s radiator ducts/boxes to grow a fair amount in size. Take ONE of the under wing radiators from a Spit 9, shrink it slightly and then figure where to put it on the P-39?

Without the intercooler you cannot use anywhere near the full boost of the 2 stage supercharger at any altitude which means the whole exercise becomes somewhat pointless. The Americans favored air to air intercoolers rather than air to liquid and they need even more volume.

The Bell engineers went to the P-63 for a reason, pretending you can fit everything (and more) from a P-63 into the smaller P-39 isn't facing reality.

Griffon engine in a Mustang airframe.

The pieces existed historically. Someone just needs to recognize the potential and fund development. I suspect that perfecting the engine and airframe would be a lot less expensive then perfecting the B-29 and quite a few other U.S. WWII weapon programs.

Read something yesterday in my copy of "Report of the Joint Fighter Conference, 1944" which could be food for thought for those of us who continually point out how fast some whiz bang fighter was at 30000 feet as if that is the end all be all. An Army rep at the conference reported that they had done some gunnery runs in P51s and P47s on B29s going fast at 30000 feet. None of the fighters could complete the runs before stalling out. Could it possibly be that the ability to maneuver well at 30K was more important than how fast a fighter was at that altitude and is it possible that few WW2 fighters were very effective at that altitude and that almost no combat took place that high?

davebender said:

Griffon engine in a Mustang airframe.

The pieces existed historically. Someone just needs to recognize the potential and fund development. I suspect that perfecting the engine and airframe would be a lot less expensive then perfecting the B-29 and quite a few other U.S. WWII weapon programs.

Click to expand...

I agree that would have been an exciting combination. But could it have been ready in the stipulated time-frame? I don't think the Spit 12 came into service that early, did it?

I've always wondered about the possibility of working Griffons into a P-38.

Which Griffons?

The Griffon that powered the MK XII Spitfire was a single stage engine that offered little or no power advantage over a Merlin 60 series at high altitude ( 20,000ft range). The two stage Griffon doesn't show up until the MK XIV Spitfire. It entered service with 610 Squadron in January 1944. Since the Mustangs were coming by boat from either California or from Texas you can add 1-3 months to the time from rolling out the factory door to service use in a combat zone.

A two stage Griffon weighs about 700lbs more than an Allison which should cover the weight of the turbo rather nicely. While the Griffon can make a lot more power down low it's ability to make more power at 25,000ft and up is not as clear cut.

Point of Departure. 1940.
Ford Motor Company receives U.S.A.A.C. contract to pursue development of the RR Griffon prototype.

1943.
The Griffon engine has two years of Rolls-Royce development plus three years of Ford Motor Company development. Since Ford did most of the R&D the resulting engine is a Ford Griffon Mk I and very different from any of the historical British versions. Might even have a turbocharger ILO a supercharger since the USAAC preferred turbochargers.

Okay, since the 1st fighters would be produced in January 1943, what type of engine is the best bet?

Can we please return to reality?

Where does Ford get it's supercharger experts from? Ford did ZERO development on the R-2800 even though they produced tens of thousands. They did develop new ways of making some of the parts.

Ford spent between 1 and 2 million dollars on their own V-12 ( after looking over the Merlin plans and a sample engine) and over a years time and may never had gotten an example in even test mule aircraft.

You have a lot more faith in Ford than I do when it comes to making a "new" aircraft engine.