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Yokosuka R2Y Keiun

The Yokosuka R2Y Keiun was a reconnaissance aircraft prototype that was constructed in Japan towards the end of World War II.

It was commissioned by the Imperial Japanese Navy after the R1Y design was cancelled due to its unsatisfactory performance estimates.

The R2Y was equipped with coupled engines that drove a single propeller and featured a tricycle undercarriage.

The prototype was completed in April 1945 and made a brief flight on 8 May.

Unfortunately, it was destroyed in a US air raid just a few days later, thereby bringing an end to its development.

Furthermore, a proposal was put forward to transform the R2Y into a turbojet-powered light bomber by replacing its piston engines with two Mitsubishi Ne-330s.

However, the R2Y2 Keiun Kai was not constructed before the conclusion of the war.




13.04 m (42 ft 9 in)


13.99 m (45 ft 11 in)


4.23 m (13 ft 11 in)

Wing area

33.99 m2 (365.9 sq ft)

Empty weight

6,015 kg (13,261 lb)

Gross weight

8,100 kg (17,857 lb)

Max take-off weight

9,400 kg (20,723 lb)

Fuel capacity

1,555 l (411 US gal; 342 imp gal)


1 × Aichi Ha-70 (unified) 24-cylinder,

Liquid-cooled coupled V-12 piston engines,

2,500 kW (3,400 hp) for take-off

2,312 kW (3,100 hp) at 3,000 m (9,843 ft)


6-bladed constant-speed metal propeller


Maximum speed

718.5 km/h (446.5 mph, 388.0 kn) at 10,000 m (32,808 ft)

Cruise speed

463 km/h (288 mph, 250 kn) at 4,000 m (13,123 ft)

Landing speed

166 km/h (103 mph; 90 kn)


3,139 km (1,950 mi, 1,695 nmi)

Ferry range

3,611 km (2,244 mi, 1,950 nmi)

Service ceiling

11,700 m (38,400 ft)

Time to altitude

10,000 m (32,808 ft) in 21 minutes

Wing loading

238.26 kg/m2 (48.80 lb/sq ft)


0.3161 kW/kg (0.1923 hp/lb).

Japanese Aircraft, 1910-1941-Robert Mikesh & Shorzoe Abe
The Mainichi Newspapers Co Ltd
Yushukan War Memorial Museum

Japanese Aircraft of the Pacific War-R J Francillon

Japanese Military Aircraft Illustrated-Masahiko Takeda

Japanese Experimental Aircraft 1940-1949-General Books


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