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Kawasaki Ki-100-I Koh (Tony). 1:48


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Kawasaki Ki-100-I Koh (Tony)

1:48 Hasegawa



Originally powered by a Kawasaki Ha-140 inline engine and designated the Ki-61 the aircraft was redesigned in October 1944 to be fitted with a Mitsubishi Ha-112 twin row radial engine and re-designated the Ki-100. The ability to fit a wide radial into a narrow fuselage came from studying an imported Fw-190. At first, there were problems with the aircraft now being found to be very tail-heavy, but the removal of a large lead counterbalance, which had been placed in the Ki-61-II-KAI's rear fuselage to balance the increasingly heavy Ha-140 engine, restored the center of gravity (cg).

As a result, on 1 February 1945, the new model was flown for the first time. Without the need for the heavy coolant radiator and other fittings required for a liquid-cooled engine, the Ki-100 was 329 kg (725 lb) lighter than the Ki-61-II, reducing the wing loading from 189 kg/m² (38.8 lb/ft²) to 175 kg/m² (35.8 lb/ft²). This had an immediate positive effect on the flight characteristics, enhancing landing and takeoff qualities as well as imparting increased manoeuvrability and a tighter turning circle. The army general staff was amazed by the flight characteristics of the plane, which surpassed the Hien's in all but maximum speed (degraded by a maximum of 29 km/h [18 mph] by the larger area of the radial engine's front cowling), and the model was ordered to be put in production as the Army Fighter Type 5. The company's name was Ki-100-1-Ko. All of the airframes were remanufactured from Ki-61-II Kai and Ki-61-III airframes; the integral engine mount/cowling side panel was cut off the fuselage and a tubular steel engine mount was bolted to the firewall/bulkhead. Many of the redundant fittings from the liquid-cooled engine, such as the ventral radiator shutter actuator, were still kept. The first 271 aircraft, or Ki-100-1-Ko, with the raised "razorback" rear fuselage were rolled out of the factory between March and June 1945. A further 118 Ki-100 I-Otsu were built with a cut-down rear fuselage and new rear-view canopy from May through to the end of July 1945. This version also featured a modified oil cooler under the engine in a more streamlined fairing.

The engine was reliable in contrast to the mechanical nightmares of the Nakajima Ki-84, Kawasaki Ki-61, and Kawanishi N1K-J that kept many aircraft grounded. Although slow in level flight for 1945, unlike most Japanese fighters, the Ki-100 could dive with P-51 Mustangs and hold the speed on pullout. Two problems which hampered the effective employment of Japanese fighters towards the end of the war were unreliable electrical systems; that of the Ki-100 were less problematic than most other aircraft types, although the fuse-boxes caused problems; and poor radio communications, which was generic throughout the war. The armament was two fuselage-mounted 20 mm Ho-5 cannons, each with 200 rpg. These were complemented by two wing-mounted 12.7 mm (.50 in) Ho-103 machine guns with 250 rpg.

Army units to be equipped with this model included the following Sentai: 5th, 17th, 18th, 20th, 59th, 111th, 112th, 200th and 244th and the 81st Independent Fighter Company. Along with the previously named Army air units, pilots were trained through the Akeno and Hitachi (Mito) Army Flying Schools. Many of the Akeno and Hitachi instructors, who were often seconded from operational units, flew combat missions (this deployment was a notable spreading out of the very few fighters that were operational, but many of these wings were only partially re-equipped).

The Ki-100 made its combat debut on the night of 9 March 1945 and suffered its first loss on 7 April 1945, when a Ki-100 flown by Master Sergeant Yasuo Hiema of the 18th Sentai was shot down by a B-29 after "attacking the formation again and again". Allied aircrews soon realised that they were facing a formidable new fighter. Although far fewer Ki-100s were available than the Ki-84s, it was perceived to be one of the most important fighters in the inventory. However, during interception of the high-flying B-29s (the B-29 raids soon became low-level missions) the new Japanese fighters struggled as the Ha-112-II engine performance decreased at high altitudes. The most effective way to attack the Superfortress was by making very dangerous head-on attacks, changing their approach path as they neared the bombers. A failure while attempting this was deadly, because of the concentration of defensive fire from the bombers. In this type of combat, the Navy's Mitsubishi J2M Raiden was superior.

An overall assessment of the effectiveness of the Ki-100 rated it highly in agility, and a well-handled Ki-100 was able to outmanoeuvre any American fighter, including the formidable P-51D Mustangs and the P-47N Thunderbolts which were escorting the B-29 raids over Japan by that time, and was comparable in speed, especially at medium altitudes. In the hands of an experienced pilot, the Ki-100 was a deadly opponent and, together with the Army's Ki-84 and the Navy's Kawanishi N1K-J, the only other Japanese fighters being able to defeat the latest Allied types.

The Model

The original version of this kit was released in 1996 but other than the 1999 release of the re-tooled version with the cut down rear fuselage there isn’t any other information on the provenance of the moulds. But, judging on the simple nature of the build it looks to date from the original. That said, if this kit is from the original moulds then they are holding up very well. There is no sign of flash or sink marks and only a few moulding pips. On the inside of each wing tip there are a number of small nodules which will need removing to ensure a good fit. The six sprues of grey styrene and three sprues of clear are very well moulded with finely reproduced panel lines and fasteners. The styrene does appear to be rather soft, so be gentle when sanding and filing.




The instructions are well printed, clear and easy to read. The build takes place over twelve operations and looks fairly straight forward. The build begins with the cockpit, which consists of the floor, seat back, seat bucket, seat adjustment lever, rudder pedals, and front bulkhead. Before the cockpit can be fitted to the fuselage, the two side walls need to be installed, along with the hydraulic valve control box, (most parts are actually labelled in the instructions), on the port side wall. With these and the cockpit fitted the instrument panel, with associated decal is fitted to the underside of the coaming. Also fitted at this stage are the upper cannon barrels, exhausts, oil cooler intake, single piece engine cylinders, and gearbox cover. The fuselage halves can then be closed up. To complete the fuselage the cowling nose ring and cannon troughs are attached.



The single piece lower wing and two upper wing sections are joined together, after which they can be fitted to the fuselage, along with the horizontal tail planes. Each main undercarriage is made up of a single piece oleo, including the scissor link, single piece main wheel/tyre and the outer bay door. Also constructed at this point are the two drop tanks, each made up of two halves and the pylon. With the model on its back the main undercarriage can be fitted along with the inner bay doors and their associated retraction links, single piece tail wheel, belly fairing, drop tanks and oil cooler exhaust door.

The final parts to be attached are the three piece propeller, consisting of the three bladed prop, back plate and spinner, the rear decking after of the cockpit, including radio and headrest, single piece canopy, aerial, pitot probe and landing light cover. Other than painting, the build is complete.



The Hasegawa printed decals look pretty good, although perhaps a tad thick, so will need some softener and setting solution to get them to bed down properly. Register is good as in the opacity, and there isn’t much in the way of carrier film. Two aircraft are depicted on the decals, both flying with the 59th Flight Regiment, aircraft No 47 and aircraft No. 153



I’ve usually chosen the Ki-61 as one of my favourite Japanese aircraft and didn’t realise the Ki-100 was derived from it. That said it’s a good looking aircraft and will look great next to the inline engined variant. It isn’t a complex kit by any stretch of the imagination, but with a nice paint job, it will look good in any collection. Recommended

Review sample courtesy of
logo.jpg UK distributors for logo.jpg

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