Kayaba Ka-1 Autogyro by Fine Molds

1/72 scale
Kit No. FP-16 1800
Cost: $18.00
Decals: One version – Imperial Japanese Army
Comments: Engraved panel lines


Although relatively unknown, the Kayaba Ka-1 autogyro deserves a special place in aviation history since it was the first armed machine of the autogyro/helicopter family to have been used operationally. While the Japanese did not invent the autogyro, they were the first to explore a military application for its use. The Ka-1 took its first flight at Tamagawa, Japan on May 26, 1941.

In the late 1930’s, the Imperial Japanese Army began to show considerable interest in the use of the autogyro as an artillery spotter, and in 1939 a Kellet KD-1A single engined, two-seat autogyro was imported from the United States. Powered by a 225 hp Jacobs L-4M4 seven-cylinder aircooled radial engine, the KD-1A featured an advanced version of the Kellet direct control rotor system. Unfortunately, shortly after its arrival in Japan the aircraft was seriously damaged during flight trials at low speeds.

The Japanese Army delivered the Kellet KD-1A , which had been damaged beyond repair, to K.K. Kayaba Seisakusho (Kayaba Industrial Company, Limited), a small company doing autogyro research, with instructions to develop a similar machine. At the request of the Kaigun Koku Hombu (Imperial Japanese Navy Air Service), the Kayaba engineering team developed a two-seat observation autogyro, based on the Kellet KD-1A but modified for Japanese production standards. Designated Ka-1, this autogyro was powered by a 240 hp Argus As 10c eight-cylinder inverted “V” air-cooled engine driving a two-bladed conventional propeller, and had three main rotor blades.

Completed in May 1941 at the Sendai (Miyagi Prefecture) plant of Kayaba, the Ka-1 performed remarkably well during its flight test program, taking off after a run of only 98 feet (30 meters) in still air.  By running the engine at full power and tilting the nose up fifteen degrees, the Ka-1 could be made to hover and could also execute a full 360 degree turn while hovering.  As maintenance in the field presented less difficulty than anticipated, the Ka-1 was put into production for service with artillery units.

When shipping losses began to rise alarmingly, the Japanese Army commissioned the light escort carrier Akitsu Maru, a converted merchant ship, and arranged to operate Ka-1’s as anti-submarine patrol aircraft from its deck. As the load-carrying capability of the standard two-seat Ka-1 was too limited, the carrier-borne Ka-1’s were operated as single-seaters and carried two 132 lb. (60 kg) depth charges. In this role the Ka-1 operated over Japanese coastal waters and particularly over the Tsugara and Korean Channels. At least one of these aircraft was tested with powder rockets on its rotor tips in an attempt to improve its load-carrying capability, while another aircraft was fitted with a 240 hp Jacobs L-4MA-7 seven-cylinder air-cooled engine, and designated the Ka-2.

The Kit

Fine Molds’ Ka-Go Model 1 is injection molded in grey and consists of 34 parts, including two clear parts for the windscreens for the separate pilot and observer’s positions. The construction of the original aircraft on which this model is based appears to have been a mix of aluminum panels and fabric stretched over metal tube framing, as the tail surfaces and most of the fuselage have a definite fabric-over-frame effect (R.J. Francillon in his book, Japanese Aircraft of the Pacific War, describes the Ka-1 only as being of “mixed construction”). The fuselage is quite well detailed with a mix of engraved panel lines and the aforementioned fabric effects, raised rivet detail, and coaming bordering the tandem cockpits.

There is a small amount of flash on the otherwise pristine parts, along with two unremarkable bucket seats. The cockpit floor bears some raised detail, and the dual instrument panels feature recessed circular shapes representing dials. No decals are provided for the instruments, so any cockpit detail will be up to the individual modeler’s ingenuity and scratchbuilding skills. Most of the detail on this kit appears to be external; the engine cowling and the main rotor head are fairly well detailed, as are the rotor blades themselves.

The markings are for one version only, and it is worth noting that the red hinomaru will have to be aligned perfectly on top of larger white circles that will form a white outline for the national insignia.


An interesting and little-known aircraft from World War II that highlights Japanese imagination. Highly recommended.


Japanese Aircraft of the Pacific War by R.J. Francillon; Copyright 1970; Putnam and Company, London

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