RS Models 1/72 Kawasaki Ki-60

The Kawasaki Ki-60 was a Japanese WWII fighter aircraft that used a license-built DB-601  liquid-cooled engine. The majority of Japanese aircraft at that time used air-cooled radial engines. 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 specialized interceptor fighter to be powered by the liquid cooled 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, epitomized 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.

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  Imperial 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 MG151/20, 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 fulfillment 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.

  Who would have thought that a rare Japanese fighter as the ki-60 of which only three have been built would have turned up as an injection moulded kit form? Here it is, we have the RS Models to be thankful for its release. There can be two reasons, either the list of aircraft that remain not kitted is getting narrower, or may just go to prove that some manufacturers can afford to cater for the adventurous modeller who is prepared to go for anything as long as it is not a Spitfire or a Bf-109. On the contrary some may think that it is another Tony Ki-61 when in fact it was the prelude for the Hien Ki-61. The Ki-60 prototype in fact proved disappointing and was soon abandoned. Efforts were then concentrated on an alternative design, the Ki-61

 The Ki-60 comes as an injection moulded kit in tan coloured plastic, with all parts having engraved panel lines and other surface detail. Added to this the construction work is fairly straight forward. A metal fret is included which comes in fine coloured detail instrument panel which attracts all one’s attention at the sharp minute detail this has on it. It is recommended that one should study the dry fit of the 30 odd plastic pieces and two transparent items, the cockpit canopy and wing landing light. Fit of parts is not a problem at all and some of the minute metal etch pieces need to be folded as per instructions and gently positioned at their correct place inside the cockpit space. It is important that the instructions are worth to study as the brass fret has the wrong number displayed on the items and one should instead follow the numbers on the printed instructions with a prefix ‘C’ for metal parts.

Construction starts with detailing the cockpit which consists of a floor, a two part seat, control column, seat straps, rudder pedals, instrument panel, two tiny aiming sights, and instruments to fit to sides of cockpit walls. More detail parts are fitted at stage 5. You need a set of tweezers to go about stage 3 which deals with the assembly of the main undercarriage each of which consists of 6 items. The front air intake and another one to port side of nose are carefully represented and parts fit together so well that it is worthy of praise with no need for any filler anywhere and all that is needed is a little rubbing down on the fuselage joint lines.

The exhaust outlets on both sides of nose are separate items. These fit into elongated apertures and one should fit on the inside blank pieces so that the exhaust items will not fall inside or pressed too far in when being fitted in place. There is a semi-circular headrest support.  This has a nicely moulded central plate containing three round holes in it. This detail is clearly visible from the clearly moulded canopy that comes with the kit. Incidentally the canopy has a front extension so that when this is painted it leaves two rectangular spy holes which is a feature that is quite unusual on fighters.  A three bladed prop and spinner are finely reproduced.

The kit has a belly air intake and an interesting aspect added to it is that there are detail etch items to fit at the intake and another filter inside aft. I preferred to replace the wing and the fuselage aerial with steel ones. The last items to go on the kit were the control links at the aileron, elevators and rudder areas indicated on the instructions. This is another delicate step which when accomplished look very effective.

Colour detail is indicated on the kit box cover. There are plan views for either an all silver prototype or silver under surface and green mottle upper surface Ki-60 that was based in Malaya in 1942. I preferred to do the camouflaged version. I used two shades of green, giving the kit first an overall coat of the lighter shade which after allowing this to set, applied the darker green mottle to leave a very effective two tone mottle camouflage as depicted on the box art cover. The lower surfaces are aluminium with the exception of a rectangular panel at the rear underside of the cockpit area which is white. Colours are quoted as Gunze Sangyo and Agama for which I found the Humbrol equivalent. The decal sheet which caters for the two aircraft is well printed but the smaller items require very careful handling as these do not give a second chance. There is a vertical white trim which I preferred to use paint instead as it turned out that the white pigment was not as opaque as one would desire. Walkway black patches appear on both versions and these should have been included with the decals as we are used to with these high quality kits. 

 RS Models should be commended for picking this subject and for making such a first class job of it. This was an enjoyable build of an interesting and unusual model and should appeal particularly to those interested in IJA aircraft.

http://en.wikipedia.org

Carmel J. Attard

September 2008

Copyright ModelingMadness.com. All rights reserved. No reproduction in part or in whole without permission from the editor.

If you would like your product reviewed fairly and fairly quickly , please contact the editor or see other details in the Note to Contributors.