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Fisher XP-75

blackkite

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Glad I could help, blackkite. There is a lot of missing information on the XP-75.

I think the Ta 152H would have outclassed the P-75A. The Ta 152H was faster, especially at altitude, and had a higher ceiling. I think the Ta 152 was designed specifically for high-altitude, while the P-75 was a long-range fighter. The Ta 152 was a much more conventional design, and no one seemed to like how the P-75 flew, noting it as unstable and sluggish.

A few other points on the engine installation that led me to believe the info I posted previously.

In the engine installation image, note that there is a fair amount of room above the engine that could accommodate an induction system. However, the upper exhaust manifolds are not installed, and they would take up some of that room. Also, space is limited toward the rear of the engine were the induction pipe connects the first (auxiliary) stage and second (engine) stage superchargers. I believe an intercooler was planned for this location, and that would have further limited the space.

The image of the engine behind the P-75 wing shows the upper exhaust manifolds attached. There is enough room between them for an induction pipe, but this pipe would have been surrounded by the hot exhaust. Also, the induction would have to connect to the circular cover at the back of the engine, which is the auxiliary supercharger. This would require a fair amount of room and two 90-degree bends. It makes more sense (to me) to bring in air from the belly scoop, but I have not seen any images that confirm this.

The engine image provides a good view of the inlet/impeller of the auxiliary supercharger. Air existed the first stage via the silver pipe above the engine. This is where an intercooler was to be incorporated. The air was then fed through an injection carburetor and into the second, engine supercharger. The engine supercharger was coupled to the engine’s right crankshaft, and you can see its round housing with the horizontal ribs. You can also see the main induction manifold leading from the engine supercharger to between the right engine Vee.

The placement of the supercharger favors the right belly scoop providing induction air. Also, the right scoop just had a coolant radiator, while the left scoop had a coolant radiator and an oil cooler. Lastly, the exhaust manifolds on the display engine are not the same as those installed on the P-75.

I realize some of it is speculation, but it is the best I have.
Thanks for excellent and detailed opinion again.
 

blackkite

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Please check this video from 2minutes after start by enlarged mode and you can see the difference between two air intakes very clearly.
As if you see hole in right side(starboard side) air intake and you see radiator front face in left side(port side) air intake,

 

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blackkite

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Hi!

"A two-section scoop was located under the fuselage, just behind the wings. The left section held an oil radiator, and coolant radiators were positioned in both the left and right sections."

So right section had some room for ram air intake?
 

blackkite

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