P-39-style fighter by other people? (2 Viewers)

[bf109xxl]

Soviets - they might want to install three Shvaks initially? A more powerful engine than the M-105 will be needed, so the Mikulin's V12s get used.

Actually, the Gu-1 had a Mikulin engine (AM-37, more precisely, its geared version AM-41), but it was not mass-produced. It can be safely excluded from the list - as well as low-altitude AM-38 and -42, no one will allow to take away production facilities or finished engines from the mass series IL-2/-10.
Mikulin engines were heavy, none of high-altitude engines developed in Minulin's design bureau were brought to an acceptable condition by 1946.
After the extremely unsuccessful attempt with the Gu-1, the Soviets had zero interest in building their own fighters based on the Cobra scheme.

 

[Admiral Beez]

Here's the The 8,000 hp (5,966 kw) Arsenal 24H Tandem.

Some interesting info here Post World War II – Old Machine Press

 

[Howard Gibson]

Basically a fighter that has the engine behind the pilot so the space in the nose is devoted to the installation of the substantial guns' firepower; engine being connected to the tractor prop by the extension shaft. U/C can be a tricycle, but it is not mandatory. Of a modest size - talk something that is not bigger than a Spitfire, with a better-than-average cooling sytem layout for a lower drag, and a fully retractable and covered U/C. Wing is 15-ish % thick at root, and uses the airfoil that is in vogue at the respective design bureau.
If one feels adventurous, the engine of choice can be a radial, like it was the case with the Piaggio P.119, but also a big liquid-cooled engine in the 2000+ HP class, like the Sabre or the V-3420, however these will require a bigger airframe.

Countries of interest are UK (the future Class S was supposed to be an airborne gun to kill enemy fighters), Japan (so they - both IJA and IJN - can install powerful guns on an 1-engined fighter), USA (again, but this time with the better chance to succeed than the 50-series fighters or the P-75), Germany, Soviet union, indeed Italy etc.

Yes, I'm aware of the Me-509, and the Soviet and Japanese etc. attempts on creating the similar A/C.

Service use starts in 1941/42, or in 1943 at latest, all depending on the country, so the design phase needs to start several years earlier.

The P-39 had its radiators in the wings, very much like a Mosquito. They were way faster than an A6M at low altitude, so the airframe was pretty good. Why did they lose the turbocharger?

A disadvantage of placing the engine in the middle of the aircraft is that you want your consumables like fuel, ammunition, and paratroopers placed close to the centre of mass. The Spitfire's fuel tanks are a near optimal installation,. as long as the pilot does not mind being burned when they catch fire.

For a mid-engined aircraft, the gas tanks can be in the wing roots. The radiators can be anywhere out on the wings. If the wings are laminar flow, they can be fairly thick, like those of the Mustangs.

A radial engine does not work for me. You want those at the front of the aircraft where there is airflow. A Merlin or Griffin with a two-stage supercharger sounds like a better idea. You really want something awesome shooting through the propeller boss. 40mm Vickers? An MK103?

 

[wuzak]

The P-39 had its radiators in the wings, very much like a Mosquito.

The P-39's radiator was in the fuselage, under the engine, fed by ducts in the leading edge.

Why did they lose the turbocharger?

The turbo was unreliable at that time, and the XP-39's installation was poor, especially the duct for the intercooler.