Kawasaki Ki-60

Infobox Aircraft
name = Ki-60



caption = The first of three prototype KI-60s.
type = Fighter
national origin = Japan
manufacturer = Kawasaki Aircraft Engineering
designer =
first flight = March 1941
introduction =
retired =
status = Prototype
primary user =
more users =
produced =
number built = 3
program cost =
unit cost =
developed from =
variants with their own articles = The Kawasaki Ki-60 was a Japanese World War 2 fighter aircraft that used a license-built (Kawasaki) DB 601 liquid-cooled engine. The majority of Japanese aircraft at that time used air-cooled radial engines.

Design and history

The Ki-60 was designed by Takeo Doi and his deputy Shin Owada of Kawasaki Kokuki Kogyo K.K. (Kawasaki Heavy Industries) in response to a 1939 "Koku Hombu" (Army Air Headquarters) requirement for a heavily armed specialised interceptor fighter to be powered by the liquid-cooled Daimler-Benz DB 601 inverted V12 engine, which had been selected for license production by Kawasaki as the Ha-40. The emphasis in the requirements was for a high speed and a good rate of climb, along with a cannon armament. This was a complete change from the usual IJAAF penchant for lightly armed, highly manoeuvrable fighters with lightweight structures, epitomised by the Ki-27 and the later Ki-43. A requirement was issued at the same time for a lighter, less heavily armed, general-purpose fighter which was to be designed almost in parallel with the Ki-60; this became the Ki-61. Priority was to be given to the Ki-60, design of which started in February 1940.Green and Swanborough 1976, pp. 18-20]

The first prototype of the Ki-60 emerged in March 1941 as a compact, all metal, stressed skin monoplane with a relatively deep fuselage (1.46 m (4 feet 9.5 in)) and tapered wings with rounded tips built around a system of three spars; a Warren truss main spar and two auxiliary spars. The rear spar carried the split flaps and long, narrow chord ailerons, while the front spar incorporated the undercarriage pivot points. The undercarriage track was 3 metres (9 ft 10 in). The pilot's seat was mounted high over the rear spar, giving the fuselage a distinctive "humped" profile; the hood featured a framed, rear sliding canopy and an elongated rear transparent section. The main coolant radiator was housed in a long ventral bath under the wing centre-section and central fuselage, while the oil cooler was mounted under the engine with a long air intake. The prototype was powered by an imported DB 601A as production of the Ha-40 had not yet started. A total fuel capacity of 410 l (90.2 Imp gallons)) was carried.

The armament carried was two fuselage mounted 12.7 mm caliber Ho-103 machine guns which were set in a "staggered" configuration (the port weapon slightly further forward than that to starboard) in a bay just above and behind the engine. One German made Mauser MG 151/20 20 mm cannon was housed in a weapons bay in each wing. With a normal loaded weight of 2,890 kg (6,371 lb) and a gross wing area of 15.9 m² (171.15 ft²) the wing loading was 181.76 kg/m² (37.23 lb/ft²), which was extremely high by Japanese standards (the standard IJAAF fighter, the Ki-27, had a wing loading of 70 kg/m² (14.33 lb/ft²).

From the start of flight testing it became apparent that the design was seriously flawed in several key areas. The take-off run was unacceptably long, while in flight the aircraft displayed some lateral instability, excessively heavy controls and poor control response. The spinning characteristics were described as "dangerous" and the stalling speed was extremely high. Although a top speed of 600 km/h (373 mph) had been projected the Ki-60 was only able to achieve 548 km/h (340 mph).

As a result the second and third prototypes, which were still being built, were hurriedly modified in an attempt to mitigate some of the more undesirable traits. Some 100 kg (220 lb) was removed, primarily by replacing the MG151 cannon with Ho-103 machine guns, reducing the normal loaded weight to 2,750 kg (6,063 lb). Coupled with a slight increase in wing area to 16.20 m² (174.376 ft²) this resulted in a slightly lower wing loading of 169.7nbsp;kg/m² (34.76 lb/ft²). Detail changes were made to airframe sealing and to the contours of the air intakes and radiator bath. Flight tests were still disappointing, with both of the modified prototypes displaying most of the shortcomings of the first. A top speed of only 560 km/h (348 mph) was reached, with a climb rate still well below specifications. By this time the Nakajima Ki-44, which had also been designed as a dedicated interceptor, was beginning to show some promise and the "Koku Hombu" selected this in fulfilment of its requirements. From early 1941 the full attention of Takeo Doi and Shin Owada was focused on the Ki-61; the Ki-60 became important in that the Ki-61 design was able to be improved using the lessons learned from the poor characteristics of the Ki-60.

pecifications (Ki-60)

aircraft specification
plane or copter?=plane
jet or prop?=prop
ref= Green, William. "Warplanes of the Second World War, Volume Three: Fighters"; Green, William and Swanborough, Gordon. "WW2 Aircraft Fact Files: Japanese Army Fighters, Part 1".
crew= One
length main= 8.40 m
length alt= 27 ft 9.5 in
span main= 9.78 m
span alt= 34 ft 5.5 in
height main= 2.75 m
height alt= 9 ft 10 in
area main= 16.20 m² (15.9 m² first prototype)
area alt= 174.376 ft² (171.15 ft²)
empty weight main= 2,150 kg
empty weight alt= 4,740 lb
loaded weight main= 2,750 kg (2,890 kg first prototype)
loaded weight alt= 6,063 lb (6,371 lb)
engine (prop)= DB 601
type of prop= liquid-cooled inverted V-12
number of props= 1
power main= 875 kW
power alt= 1,175 hp

max speed main= 560 km/h
max speed alt= 348 mph
max speed more= at 4,500 m (14,765 ft)
range main=
range alt=
ceiling main= 10,000 m
ceiling alt= 32,810 ft
climb rate main=
climb rate alt=
loading main=
loading alt=
power/mass main=
power/mass alt=
more performance=

Time to altitude: 6.0 min to 5,000 m (16,405 ft)

armament=
* 2x 20 mm Mauser MG 151 cannon or 2x 12.7 mm (0.50 in) Ho-103 machine gun in the wings
* 2x 12.7 mm (0.50 in) Ho-103 machine gun in the fuselage

ee also

aircontent
see also=*Engine cooling

related=
*Kawasaki Ki-61

similar aircraft=

lists=*List of military aircraft of Japan

References

Notes

Bibliography

* Bueschel, Richard M. "Kawasaki Ki.61/Ki.100 Hien in Japanese Army Air Force Service, Aircam Aviation Series No.21". Canterbury, Kent, UK: Osprey Publications Ltd, 1971. ISBN 0-85045-026-8.
* Francillon, Réne 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 Three: Fighters". London: Macdonald & Co. (Publishers) Ltd., 1961 (seventh impression 1973). ISBN 0-356-01447-9.
* Green, William and Swanborough, Gordon. "WW2 Aircraft Fact Files: Japanese Army Fighters, Part 1". London: Macdonald and Jane's, 1976. ISBN 0-356-08224-5.
* Januszewski, Tadeusz and Jarski, Adam. "Kawasaki Ki-61 Hien, Monografie Lotnicze 5" (in Polish). Gdańsk, Poland: AJ-Press, 1992. ISSN 0867-7867.
* Tanimura, Masami; Tanaka, Kozo; Kishida, Yuji; Oda, Makoto; Nakano, Yoshiharu and Kawasaki, Saburo. "Kawasaki Ki-61 (Tony)". Blaine, WA: Paul Gaudette, Publisher, 1967.