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Yokosuka H5Y Type 99 Flying Boat "Cherry"
Role Flying boat
Manufacturer Yokosuka
First flight 1936
Introduction 1939
Primary user Imperial Japanese Navy Air Service (IJNAS)
Produced 1938 - 1941
Number built 20

The Yokosuka H5Y (short designation) or Yokosuka Navy Type 99 Flying Boat Model 11 (九九式飛行艇, 99shiki hikōtei) (long designation), given the allied code name Cherry, was an IJNAS flying boat in service from 1938.

Design and development

The H5Y was designed by Yokosuka to meet an IJNAS requirement for a twin-engine maritime reconnaissance flying boat, which was intended to match the performance of contemporary four-engine flying boats, while being cheaper to build and easier to maintain. Two prototypes were built at the 11th Naval Arsenal, Hiro, being completed in 1936.[1] The H5Y was a twin-engine parasol wing aircraft, and thus resembled a scaled-down version of the Kawanishi H6K "Mavis". Performance was found to be poor however, with the aircraft underpowered and suffering from structural problems which delayed production. Only 20 were built between 1936 and 1941. Yokosuka Naval Air Arsenal built the aircraft at the Dai-Juichi Kaigun Kokusho facility.[1][2][3]

Operational history

The H5Y was accepted for production in 1938 as the Type 99 Flying Boat Model 11, production deliveries starting in 1939.[1] However, production was quickly cancelled owing to the poor performance, only 20 being built.[4] Although some were used for coastal anti-submarine patrols early in World War II, they were quickly transferred to second line duties such as transport or training.[1]


2 Prototypes constructed at the Hiro Naval Arsenal
Production model, 18 built.
Yokosuka Navy Type 99 Flying Boat Model 11
The long formal designation of the H5Y.



Specifications (Yokosuka H5Y1)

Data from Warplanes of the Second World War, Volume Five: Flying Boats[1]

General characteristics

  • Crew: 6
  • Length: 20.53 m (67 ft 4 in)
  • Wingspan: 31.57 m (103 ft 7½in)
  • Height: 6.71 m (22 ft 0 in)
  • Wing area: 107.7 m² (1,159 ft²)
  • Empty weight: 7,070 kg (15,554 lb)
  • Max. takeoff weight: 11,500 kg (25,353 lb)
  • Powerplant: 2 × Mitsubishi MK1A Shinten-21 14-cylinder air-cooled radials, 895 kW (1,200 hp) each


  • Maximum speed: 303 km/h (163 kn, 188 mph)
  • Range: 4,800 km (2,591 nmi, 2,980 mi)
  • Service ceiling: 5,200 m (17,000 ft)
  • Endurance: 26 hr
  • Climb to 3,000 m (9,850 ft): 24 min


  • Guns: 3× 7.7 mm (.303 in) machine guns
  • Bombs: 2× 250 kg (552 lb) bombs

See also


  1. 1.0 1.1 1.2 1.3 1.4 Green 1972, pp. 136–137.
  2. Mikesh and Abe 1990, p. 262.
  3. Francillon 1979, p. 495.
  4. Donald 1997, p. ?.
  • Donald, David (Editor). The Encyclopedia of World Aircraft. Aerospace Publishing, 1997. ISBN 1-85605-375-X.
  • Francillon, Ph.D., René J. Japanese Aircraft of the Pacific War. London: Putnam & Company Ltd., 1970 (2nd edition 1979). ISBN 0-370-30251-6.
  • Green, William. Warplanes of the Second World War, Volume Five: Flying Boats. London: Macdonald & Co.(Publishers) Ltd., 1962 (5th impression 1972). ISBN 0-356-01449-5.

External links

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