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Kayaba Ka-1
Role Autogyro
Manufacturer Kayaba Industry
First flight 26 May 1941
Primary user Imperial Japanese Army Air Force
Produced 1941-1945
Number built 240

The Kayaba Ka-1 was a Japanese autogyro, seeing service during World War II.

Design and development[edit | edit source]

The Imperial Japanese Army developed the Ka-1 autogyro for reconnaissance, artillery-spotting, and anti-submarine uses. The Ka-1 was based on an American design, the Kellett KD-1A, which had been imported to Japan in 1939, but which was damaged beyond repair shortly after arrival.[1] The Kayaba Industry was then asked by the Army First to develop a similar machine, and the first prototype was flying on 26 May 1941.[2] The craft was initially developed for use as an observation platform and for artillery spotting duties. The Japanese Army liked the craft's short take-off span, and its low maintenance requirements. The production began in 1941 and the first autogyros were assigned to artillery units for artillery spotting. These carried two crewmen: a pilot and a spotter.

Later, the Japanese Army commissioned a small aircraft carrier, Akitsu Maru, intended for coastal antisubmarine (ASW) duties. The Ka-1 was modified by eliminating the spotter's position in order to carry one small depth charge.[3] The carrier was later sunk by American submarines on November 15, 1944.

The prototype, Ka-1 was essentially the repaired Kellett KD-1A. The Ka-1 had a change of the engine to the 240 hp Argus As 10c. But only about 20 Ka-1 were made. The Ka-1 employed similar aspects to the Focke-Wulf Fw 61, which was first flown in 1936.[4]

The production of the remainder were all Ka-2. The Ka-2 returned to the same Jacobs L-4MA-7 engine as the Kellett KD-1. Total Ka-1 and Ka-2 production was approximately 240.[5]

Specifications (Ka-1)[edit | edit source]

Data from Japanese Aircraft of the Pacific War[5]

General characteristics

  • Crew: 1-2
  • Length: 9.2 m (30 ft 2⅛ in)
  • Rotor diameter: 12.2 m (40 ft 0¼in)
  • Height: ()
  • Disc area: 117 m² (10.9 ft²)
  • Empty weight: 775 kg (1,709 lb)
  • Max. takeoff weight: 1,170 kg (2,574 lb)
  • Powerplant: 1 × Argus As 10c air-cooled inverted V8 engine, 180 kW (241 hp)


  • Maximum speed: 165 km/h (89 knots, 102 mph)
  • Cruise speed: 115 km/h (62 knots,71 mph)
  • Range: 280 km (151 nm, 174 mi)
  • Service ceiling: 3,500 m (11,500 ft)
  • Rate of climb: 5 m/s (980 ft/min)


  • 1x 60 kg (132 lb) depth charges[6]
  • References[edit | edit source]

    1. Francillon 1979, p. 143.
    2. Francillon 1979, p. 144.
    3. Francillon 1979, pp. 144–145.
    4. "European Helicopter Pioneers". www.vectorsite.net. http://www.vectorsite.net/avheli_1.html#m4. Retrieved 15 August 2010. 
    5. 5.0 5.1 Francillon 1979, p. 145.
    6. When Operated as a single seater.

    External links[edit | edit source]

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