High Altitude Fighter
In accordance with this new specification, in November 1942, Nakajima was awarded a contract for the production of three prototypes and seven pre-production aircraft. Prototypes were to be completed between November 1944 and January 1945, with preparation for serial production of the aircraft in February-April 1945.
An 18-cylinder radial air-cooled Na-44-11 engine with a turbocharger installed on the starboard side was used as a power plant on the fighter. At the ground, the engine developed a take-off power of 2,400 hp. The turbocharger was a turbine and compressor connected by a common shaft. To cool the engine, a 16-blade fan was used, connected to a 4-blade propeller and rotating one and a half times faster than the propeller.
Since the Ki-87 was designed to operate at high altitude, the aircraft had to be equipped with a pressurized cabin, but the prototype was not equipped with it.
The armament strictly corresponded to the specification and consisted of a pair of synchronous 20 mm No-5 cannons at the root of the wing, and two 30-mm Ho-155 cannons in each wing, outside of the plane swept by the propeller. A suspension of a 250 kg bomb or a dropped fuel tank under the fuselage was provided.
In the course of fine-tuning, all problems were not resolved until the end of hostilities. Especially a lot of trouble was caused by the turbocharger of the engine, they also could not debug the cleaning system - the landing gear. The other two prototypes remained unfinished, and the Ki-87-II did not leave the design stage.