1935-45 WI: no 2-engined (day) fighters

The goal seemed to have been to get most of the heaviest items closet to the CoG point, the engine, the breechblock/receiver and ammo for the armament, along with the turbo-- with the fuel tanks in the wings, so no guns there

That reduces trim changes in flight, and most of the mass at the CoG gives the potential for very good maneuverability, too.

Keeps the size of the fighter down, as well, the P-47 was so large for the proper sized ducting for the turbo in the rear fuselage up to the engine.
The Model 3 was very compact for a Fighter with an intercooled Turbo setup.

Looking at the wing size of the Model 3, compact it was not. 299 sq ft wing equals the wing area of P-47, or, almost twice the wing area of the Bf 109. Bigger than the wing of the Typhoon. Wing is also thick on the Model 3, 18% at root. The P-43 was a much smaller fighter, despite the 'distributed' layout of turbo & it's ancilliaries.
P-47 started with 2800 cu in engine in the nose, sizable oil system and 300 gal fuel tanks - it will take a big fuselage just to house those two items properly. Granted, the 'distributed' layout of the ducting, that was well able to provide enough of airflow for 2800 HP vs. initially 2000 HP max, will add to the bulk.
 
Looking at the wing size of the Model 3, compact it was not. 299 sq ft wing equals the wing area of P-47, or, almost twice the wing area of the Bf 109. Bigger than the wing of the Typhoon. Wing is also thick on the Model 3, 18% at root. The P-43 was a much smaller fighter, despite the 'distributed' layout of turbo & it's ancilliaries.
Much less skin area on that fuselage, narrow and not very tall. Cockpit is low, sp very low drag.

Likely to be have been fast on 1100hp of the early Allison.

Big wing, good for high altitude where it was to be operating at. Later Bell P-39 testbeds for the Continental Hyper Engine had increased wing thickness from 15% to 18 for more volume for fuel tanks, and to increase strength of the wing, carried over to the P-63 that had very effective ailerons, to one of the fastest rolling US aircraft of the war
 
One possible reason for no twin engine fighters while still having twin engine bombers:. Maneuverability.

While more powerful, a twin engine plane will have a wider turning radius that a single engine fighter. If tactics are still in turn-and-burn, twin engine planes might be seen as a liability in a dogfight and just never be designed. Single engines are just considered the norm
 

Errolwi

Monthly Donor
The goal seemed to have been to get most of the heaviest items closet to the CoG point, the engine, the breechblock/receiver and ammo for the armament, along with the turbo-- with the fuel tanks in the wings, so no guns there

Note that the Bell P-39 has all the heavy stuff in the middle (BTW the recent NZ restoration has no guns, but lead and batteries forward of the cockpit). It's quite small, so must be quite twitchy to fly - no weight at the extremities to provide inertia.
 

DougM

Donor
Yes but at the time twin engine fighters were being designed you couldn’t actually replace them with single engine aircraft, Thatcis why we got twins. No one LIKED twins at the time. As stated the are more expensive, use more resources and take more maintenance and are not as maneuverable and present a bigger target.
But a less maneuverable twin is a better option to fight your enemies with then an airplane that had to turn back 200 miles ago.
And twins will ALLWAS have more range (all technology being equal) as they have more power and can carry more fuel as a result, It is only when the power/fuel efficiency of a single gets to the point that it can do the job needed at the range required that they go out of favor. The obvious example being the long range escort of the Mustang. But even that had its limit as witnessed by the Twin Mustangs.
So the only way you are going to eliminate twins is by either having a short ranged war (or at least expecting a short ranged war) or by somehow inventing a more powerful fuel efficient engine a lot sooner. And even that probably won’t work. As the US (at least) has very long distance between it an potentially enemies. With those big ponds. And the US was getting into long range bombing so until the fighters could escort the bombers all the way the US was going to keep pushing for greater range (as in the twin mustang).
So until the range of bombers and fighter match you will see interest in longer ranged fighters and bigger fighters can carry more fuel but need more power and thus two engines can help...
 
Only the US has the issue of dealing with oceanic raids and their answer the P38 wasn't introduced until 1941. By that time the European twin engine day fighters had all failed (as did the P38's the US sold Britain) and it wouldn't have been unreasonable for the US to conclude the concept was a dud an cancel them.
 
Much less skin area on that fuselage, narrow and not very tall. Cockpit is low, sp very low drag.

Likely to be have been fast on 1100hp of the early Allison.

We can use the XP-39 as reality check. As rolled out from Bell factory, it was good for 340 mph, unarmed. So it got shipped to NACA for a clean-up job, who made a full list of recomendations in order to bring it to the promissed 390 mph at 20000 ft. XP-39 have had a far smaller wing, and much thinner (15% at root vs. 18%).
So let's say Bell rolls out the Model 3, and it does 325 mph. Shipped to NACA, tested and modifed, they manage 375 mph after all is said and done. Then we add armament - 360 mph?

Big wing, good for high altitude where it was to be operating at. Later Bell P-39 testbeds for the Continental Hyper Engine had increased wing thickness from 15% to 18 for more volume for fuel tanks, and to increase strength of the wing, carried over to the P-63 that had very effective ailerons, to one of the fastest rolling US aircraft of the war

I have no problem with wing being big and thick if engine makes abundant power at desired altitude. 1100 HP will not cut it just because 2000 will.
Unike the XP-39E, the P-63 have had laminar-flow wing, and still was barely good for 400 mph in A version.

Yes but at the time twin engine fighters were being designed you couldn’t actually replace them with single engine aircraft, Thatcis why we got twins. No one LIKED twins at the time. As stated the are more expensive, use more resources and take more maintenance and are not as maneuverable and present a bigger target.
But a less maneuverable twin is a better option to fight your enemies with then an airplane that had to turn back 200 miles ago.
And twins will ALLWAS have more range (all technology being equal) as they have more power and can carry more fuel as a result, It is only when the power/fuel efficiency of a single gets to the point that it can do the job needed at the range required that they go out of favor. The obvious example being the long range escort of the Mustang. But even that had its limit as witnessed by the Twin Mustangs.

How much of range is needed? We have not just the Zero, but also Ki-43 and Ki-61 having combat radius (= fly out, escort bombers, fight, RTB) of beyond 600 statute miles at low altitudes, on engine and aerodynamics from late 1930s. That is more than enough for UK, Germany, Italy, Japan and Soviet Union. And USA, once they figure out that bombers actually need escort.
Not just Japanese did it, French produced D.520 with 50% more fuel than what will Hurri/Spit/109E carry, ditto for the Italians with Re.2001, and for the US with P-36/40. Even the P-39C was carrying 170 gals internally.
Mustang was carrying 180 US gals of fuel with V-1710-39, a 2nd or 3rd rate engine by standards of 1942.

So the only way you are going to eliminate twins is by either having a short ranged war (or at least expecting a short ranged war) or by somehow inventing a more powerful fuel efficient engine a lot sooner. And even that probably won’t work. As the US (at least) has very long distance between it an potentially enemies. With those big ponds. And the US was getting into long range bombing so until the fighters could escort the bombers all the way the US was going to keep pushing for greater range (as in the twin mustang).
So until the range of bombers and fighter match you will see interest in longer ranged fighters and bigger fighters can carry more fuel but need more power and thus two engines can help...

As noted above, USA was the only power contemplating international bombing campaig, and even the post-war Twin Mustang will be unable to escort B-36s from CONUS to Europe. Pre-war, nobody in the USAAF was thinking of bombers needing escorts, and accordingly was not requiring any of the like from industry to design & produce.
 
We can use the XP-39 as reality check. As rolled out from Bell factory, it was good for 340 mph, unarmed. So it got shipped to NACA for a clean-up job, who made a full list of recomendations in order to bring it to the promissed 390 mph at 20000 ft. XP-39 have had a far smaller wing, and much thinner (15% at root vs. 18%).
So let's say Bell rolls out the Model 3, and it does 325 mph. Shipped to NACA, tested and modifed, they manage 375 mph after all is said and done. Then we add armament - 360 mph?

Overlooking fuselage drag, lot less of it on the Model 3 to what became the P-39, with the lower windscreen and canopy line, and no ugly carburetor intake.

Back to the wing, much higher aspect, looks to be 38 foot, so not far off the High altitude Spitfire wing. Between the Turbo and that wing, would definitely get it's best speed above 25-35k, so a little higher than your estimates.

So the USAAC could have a high altitude bomber interceptor.

Problem is, it really doesn't have need of that, and would not be good at other roles. Some L-L'ed to the UK for their Ju-86 problem?
Gun nose replaced with cameras?
 

DougM

Donor
You don’t need intercontinental bombers to need longer ranged fighters. All 4 engined bombers out ranged single engined fighters (and usually Twins). Range has always been an issue with fighters, And will stay an issue until in flight refueling.
I just don’t see how you get around this issue, The Germans had problems with range and they didn’t even have 4 engines heavy bombers. But they had huge issues fighting over england. So I just don’t see the designers saying. “Nah, we don’t want to design a twin engine fighter, they are (fill in blank here). Sure any give company may skip twins, but everyone? Sorry this is not happening.
The advantages of twins are to evident and the disadvantages are to hard to see until you try fighting with them. And even with the disadvantages they have their uses.
So how do you get EVERYONE to decide to just dump on a perfectly valid design concept.
I am all for alternative history but it needs to be possible and this just isn’t.
 
So how do you get EVERYONE to decide to just dump on a perfectly valid design concept.
Because twin engine day fighters failed and had enough trouble protecting themselves let alone the bombers they were supposed to escort. Hell often enough the twin engine fighters escorting the bombers needed single engine fighters to escort them. Even the P38 failed as an escort, if it hadn't the USAAF wouldn't have been forced to adopt the P51 for that role.
 
The Germans had problems with range and they didn’t even have 4 engines heavy bombers. But they had huge issues fighting over england.
Awhile ago, had the Thread of the Germans having the A6M, long range fighter over the UK, a fighter with twice the range of the 110.

European nations thought 500 miles was a long way.
US and Japan knew better.
 
Awhile ago, had the Thread of the Germans having the A6M, long range fighter over the UK, a fighter with twice the range of the 110.

European nations thought 500 miles was a long way.
US and Japan knew better.
In Europe 500 miles IS a long way, unlike the US and Japan their enemies are across the river not thousands of miles away.
 
In Europe 500 miles IS a long way, unlike the US and Japan their enemies are across the river not thousands of miles away.
until you find that even flying from the French coast, your main fighter only has a 10min combat endurance over London.

A Zero could do that, taking off from Berlin.

By 1938, it was known that the UK would be an enemy, and most of their targets are further way than London
 
I doubt it could once it had been given the modifications needed to allow it to survive in Europe.
The A6M and Hawk 75 that the French were using, were not all that different in 1940. No armor, no self sealing tanks.

The Hawk 75 survived, and thrived against the Luftwaffe 1939-1940. The A6M chewed up Hurricanes II over Malaya, and Spitfire Vc over Darwin
 
Overlooking fuselage drag, lot less of it on the Model 3 to what became the P-39, with the lower windscreen and canopy line, and no ugly carburetor intake.

Back to the wing, much higher aspect, looks to be 38 foot, so not far off the High altitude Spitfire wing. Between the Turbo and that wing, would definitely get it's best speed above 25-35k, so a little higher than your estimates.
So the USAAC could have a high altitude bomber interceptor.

We can take a look at HF Spitfires indeed. ~240 sq ft wing vs. 299 for the Model 3, 13% thickness at root vs. 18% - we can easily see that Model 3's wing will make much more drag. HF Spitfire Vs, engine Merlin 47 (hi-alt version of the Merlin 45 with bigger supercharger), were topping out at 22000-23000 ft with around 360 mph.
Location of coolers of the Model 3 is still unknown - 3-way drawing does not show them, Birch states those are in wing roots. We still need to have a lot of faith that Bell engineers will not bungle up the turbocharger and cooling installations, like they did at XP-39.

USAAC already has the bird in the hand - the P-43 - if they want a hi-alt fighter that badly.

until you find that even flying from the French coast, your main fighter only has a 10min combat endurance over London.

A Zero could do that, taking off from Berlin.

By 1938, it was known that the UK would be an enemy, and most of their targets are further way than London

My take is that any of the major powers was capable to make a 500 mile fighter on 1 engine and deploy it in numbers before 1940, catch was lack of impetus. Merlin 3 or X were no worse engine than DB 601A/Ha 40, or R-1830 than the Sakae, yet it were Japanese that designed capable LR fighters around the Ha 40 and Sakae, not the British around Merlin or Germans around their engines.
 
I doubt it could once it had been given the modifications needed to allow it to survive in Europe.
Yup thats the problem you can have range/performance or armor/survivability but not both. Saw an article once that said give the Zero self sealing tanks and its range halved ( may have been other tweaks as well I don't remember ). Other issue can be reliability , two engines means one can fail and you still get home, quite important for long range maritime aircraft with nowhere to land mid flight.
 
The A6M and Hawk 75 that the French were using, were not all that different in 1940. No armor, no self sealing tanks.

The Hawk 75 survived, and thrived against the Luftwaffe 1939-1940. The A6M chewed up Hurricanes II over Malaya, and Spitfire Vc over Darwin
Hawk-75 after 1940 was dogmeat, all about realizing they were fragile and playing on heavier fighters strengths. Same for the Zero's, they had better pilots in the main and even then, once pilots stopped trying to fight them like 109's and went boom and zoom , the ratio shifted quickly.
 
the ratio shifted quickly
In 1942 things still were not that much better.
So that's a couple of years where that did work-- the Hawk 75 had the most success of any French type in 1940
So there is a window up to that point, to make big gains.

An the point of the Nazi effort, is to get things done quickly, can't afford a long war
 
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