P-63 "Kingcobra"
Related to the P-39 family the "Kingcobras" maintain the P-39's excellent energy retention and build upon its excellent speed despite being physically larger in every direction. All Kingcobras out-accelerate and have higher top speeds than the P-39's that came before them. The P-63's all have a unique quirk, im not entirely sure where this comes from, none of them have access to propeller pitch control. This means I'm competing directly with the AEC algorithm which already does a fantastic job as is. Out of all the planes in the study the P-63 is affected by MEC the least.
P-63A-5
AEC:The A-5 tends to over heat in the last hair pin but the overheating cycle isn't tremendously harsh. The Kingcobra overall takes a long time to overheat and when it does, attempts to cool it down are rapid. The turn performance almost feels better than the P-39. As in, the P-63 compresses even less than the P-39, thanks to its airfoil adjustments. The Kingcobra in fact can cling so tightly to the trees on the inside corner of the first right turn after H1 that over turning, and subsequently crashing in the inside corner, is a genuine concern.
MEC:As I stated in the intro paragraph there's seldom the pilot can do to try and beat the AEC algorithm. Typically I would try out combinations of propeller pitch % in the hopes that running it less coarse would put less strain on the engine and it would run cooler. But since I don't have access to that, I'm at the whims of the exhaust ducts on the bottom of the plane, at least they are relatively small. There's just nothing I can do to really beat an AEC time outside of just flying a faster line.
P-63A-10
AEC:The A-10 is a straight upgrade over all the "Cobras" that come before it. Its the pinnacle of Bell racing in this game. It is stable, has incredible top-end acceleration, excellent energy retention, and rarely overheats. Even when it does overheat, going back to military power alone is enough to rapidly cool the engine, then it's like it's ready for a whole extra lap. There is no plane that represents the air racing standard better than the P-63A-10. Yes there are aircraft that fly faster than it, but it's the measuring stick for which the best racers are measured against.
MEC:Read the paragraph for MEC on the P-63A-5.
P-63C-5
AEC:Whilst not a terrible racer by any means it's easy to see why it's just a hair slower than the A-10. Its engine is packing 16 less horsepower and the cannon is carrying an extra 28 rounds of ammo. In the world of racing weight is everything, and though not a whole lot was changed with this variant those little things add up.
MEC:Read the paragraph for MEC on the P-63A-5.
Planes in game but not tested:
The USSR tech tree has all three P-63's (A-5, A-10, and C-5). Seeing as how all three are already tested in the American tech tree there's no point in testing these planes as they are copy paste. The French C-5 may have different ordnance options but performance wise is exactly the same as the American and Russian C-5's. Kingcobra:Kingcobra was the first crafting event reward and I don't have it, nor does anyone else I know, or anyone they know. Functionally the plane is no different from a C-5 and should be treated as such.
Fun Facts!
The P-63 did see some wartime service with the Soviets. They were given P-63's in 1944 on the condition that they would be used against Japan at the end of the war and said P-63's were delivered in the far east. However some Luftwaffe pilots would go on to write about seeing P-63's in air being used against them in the European theater. Outside of some anecdotal evidence the soviets never recorded anything regarding the P-63 and its usage in the European Theater.
In France the Kingcobra saw limited service in the first Indochina War, but was quickly supplanted by the F8F in 1951.
The most famous use of the P-63 in American service is likely the "Pinball" P-63's. These were bright orange, all regular armor and armament was removed, and a tons worth of metal plating was added all over the wing and nose surfaces of the plane. Underneath this light armor was a spider's web of sensors that would detect when the aircraft was shot, these sensors would trigger a light in the propeller hub (where the cannon once sat) to illuminate. The purpose of the pinball program was to help train bomber gunners more effectively. It was one thing to shoot down targets in simulations on the ground, it was better to shoot down mothballed drones, but it was better still to shoot down real maneuvering targets AND have those targets tell you when you hit them. More can be learned from Ivan L. Hickman and his book "Operation Pinball" Hickman was a pilot for these P-63's.
Just like the P-39 the P-63 was a popular air racer post war, considering there was a lot more of them to go around. There were many racers and many more pilots who flew them but the most well known were, Flying Red horse and Tipsy Miss.
If you'd like to know more about the P-63, its development and performance the Internet Archive has archived "Bell Aircraft" by A J Pelletier. Free for public viewing, pages 42-49 are all about the P-63.