Aviation of World War II

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R2Y Keiun
Reconnaissance Aircraft

R2Y Keiun

R2Y Keiun. In 1942, the Imperial Japanese Navy became interested in a long-range high-speed reconnaissance aircraft capable of evading interception by fighters, by analogy with the Imperial Army reconnaissance officer - Mitsubishi Ki-46, and issued a task to create such an aircraft with maximum speed up to 575 km/h at an altitude of 6000 m. The initial design of the aircraft, designated R1Y1 Seiyun (Japanese 青 い 雲 - blue cloud), was to receive new 24-cylinder liquid-cooled engines with a capacity of 2500 hp. with, which were developed in Mitsubishi, but the timing of their creation was constantly pushed back.

The lack of engines forced the fleet to issue new specifications, which were based on the project using the experience gained during the tests of the Heinkel He 119-V4, which was purchased by the fleet back in 1940. Like the German machine, the new reconnaissance aircraft was supposed to receive a pair of two engines Aichi 10 (70; two engines Atsuta 30), installed in the fuselage behind the cockpit and powered by a pulling propeller.

The new R2Y1 reconnaissance aircraft received the name Keyun (Cirrus Cloud), but with the defeat of the Japanese near the Mariana Islands, priorities changed: first of all, fighters and bombers were required, and the approach of war to the shores of Japan completely eliminated the need for a long-range sea reconnaissance, i.e.. the idea of ​​converting the project into a bomber breathed new life into it.

At the end of 1944, the arsenal proposed to create a jet bomber based on R2Y. For this, the twin engines in the fuselage were planned to be replaced with a fuel tank, and a pair of turbojet engines with Mitsubishi Ne-330 axial compressors with a thrust of 1320 kg would be installed under the wing. The combat load was assumed to be one 800 kg bomb under the fuselage. A battery of four 30-mm cannons was to be installed in the bow. The maximum speed was expected to be 790 km/h at 10,000 m, compared to 715 km/h for the piston engine variant; also had to increase the rate of climb of the aircraft and decrease the combat radius.

It was decided to make the R2Y1 piston as an aerodynamic prototype before the R2Y2 jet was ready. Upon completion of production, the experimental R2Y1 on April 27, 1945 was delivered for flight tests in Kisarazu, where during the runs revealed problems with the nose landing gear (front wheel shimmy) and engine overheating. The first flight of the aircraft took place on May 8, but was interrupted due to a sharp rise in engine oil temperature. The resulting replacement of the power plant was not carried out, the plane was bombed by the Americans.

The second instance of R2Y1 and the prototype R2Y2, the assembly of which continued in the Yokosuka arsenal, were not completed until the end of the war, and after the defeat of Japan, further work on the aircraft project stopped.

Yokosuka R2Y
Crew 2
Wing span, m 14.00
Wing area, m² 34.00
Length, m 13.05
Height, m 4.24
1 × PE Aichi-10 Na-70, power, hp. 1 × 3400
Weight, kg:
Empty weight 6015
Loaded weight 8100
Maximum speed, km/h 715
Cruising speed, km/h 460
Maximum rate of climb, m/min 1000
Service ceiling, m 11,700
Service range, km 3,600

Photo Description

Drawing R2Y


  • "Encyclopedia of military engineering " /Aerospace Publising/
  • "Japan Warplanes of World War II" /Oleg Doroshkevich/