Kawasaki Ki-60
| Company type | Experimental fighter aircraft |
|---|---|
| Industry | Aerospace |
| Founded | February 1940 |
| Founder | Takeo Doi, Shin Owada |
| Products | Fighter aircraft |
The Kawasaki Ki-60 was a Japanese experimental fighter developed before World War II, distinguished by its use of a license-produced (Kawasaki) DB 601 liquid-cooled engine—a notable departure from the era's standard air-cooled radial engines commonly found in Japanese fighters.
Design and development
Conceived by Takeo Doi alongside deputy Shin Owada at , the Ki-60 was created to meet a 1939 directive from the Imperial Japanese Army Aviation Bureau. Its role was that of a heavily armed, specialised interceptor fighter, powered by the liquid-cooled Daimler-Benz DB 601 V12 engine (manufactured under license as the Ha-40). Emphasis was placed on achieving high velocity, rapid climb capability, and substantial cannon firepower, marking a strategic departure from the IJAAF's traditional focus on lightweight, highly agile fighters such as the Nakajima Ki-27 and Nakajima Ki-43. Concurrently, a separate requirement for a lighter multi-role fighter led to the development of the Ki-61. Design efforts for the Ki-60 commenced in February 1940.[1]
The initial prototype took shape in March 1941,[2] presenting as a compact, all-metal stressed skin monoplane featuring a deep fuselage () and tapered wings supported by three spars. The rear spar incorporated split flaps and narrow chord ailerons, while the front spar contained undercarriage pivot points with a track measuring . Positioned high above the rear spar, the pilot operated beneath a framed sliding canopy extended with a transparent rear section. Cooling was facilitated by a ventral radiator bath located under the wing’s center-section and an oil cooler mounted beneath the engine. The prototype was equipped with an imported DB 601A engine pending domestic Ha-40 production, holding a total fuel capacity of 410 liters.[3]
Its armament consisted of two staggered 12.7 mm Ho-103 machine guns mounted in synchronization on the fuselage above the engine bay, complemented by one German Mauser MG 151/20 20 mm cannon embedded in each wing. With a typical loaded weight of and wing area measuring , the aircraft exhibited high wing loading at 181.76 kg/m2, considerably exceeding that of standard IJAAF fighters like the Ki-27.[4]
Flight evaluations uncovered significant shortcomings: extended take-off distances, lateral instability, heavy control forces, sluggish responsiveness, hazardous spinning tendencies, and an elevated stall speed. Although estimates suggested , actual maximum speed only reached .[5]
To remedy these issues, the second and third prototypes underwent modifications primarily aimed at weight reduction (~), achieved largely by substituting MG 151 cannons with Ho-103 machine guns. This lowered loaded weight to and slightly increased wing area to , reducing wing loading to 169.7 kg/m2. Additional improvements included better airframe sealing and revised air intake designs. Despite these adjustments, performance remained unsatisfactory with maximum speeds near and insufficient climb rates. Meanwhile, the Nakajima Ki-44, another interceptor contender, demonstrated promising capabilities and was ultimately chosen by Koku Hombu to meet operational demands.[6] From early 1941 onward, development efforts shifted entirely to the Ki-61, which incorporated insights gained from the Ki-60 program. Production plans for the Ki-60 were abandoned in late 1941 after only three prototypes had been completed.[7]
Further Resources
- ↑ Green & Swanborough 1976, p. 18.
- ↑ Francillon 1979, p. 111.
- ↑ Francillon 1966, p. 5.
- ↑ Green & Swanborough 1976, p. 19.
- ↑ Green & Swanborough 1976, p. 20.
- ↑ Green & Swanborough 1976, pp. 20–21.
- ↑ Berliner 2011, p. 141.