The Kawasaki Ki-100 was basically a Ki-61 (Allied code name "Tony") with a radial engine. It was unique among operational Japanese aircraft in lacking an Allied code name; in Meatballs and Dead Birds, James Gallagher retroactively called it “Radial Tony.” The Ki-100 resulted from a need for a substitute for the liquid-cooled powerplant for the planned Ki-61-II. The Japanese aircraft industry had much greater capability for producing air-cooled engines, so inline-engined aircraft were uncommon in Japanese service. The Ki-61 was an exception. Its 1100 hp Ha-40 powerplant was a license-built DB601A adapted to Japanese production techniques, lending it a casual resemblance to the Messerschmitt Bf 109. (Early Ki-61 sightings in the Southwest Pacific theater contributed to the mistaken belief that the Japanese were producing Bf 109 copies, codenamed “Mike.”) The Ki-100 in turn bore some resemblance to the Focke Wulf Fw 109, and not incidentally. Kawasaki engineers had access to an imported Fw 109A, which gave them insight into how to mount a radial engine to a narrow fuselage.

The need for better performance, particularly at high altitude, led to the development of the Ki-61-II and its 1500 hp Ha-140 powerplant, an uprated version of the Ha-40. The Ki-61-II was slightly longer with 10% more wing area and a larger rudder to handle the increase in power. However, due to production problems the Ha-140 seldom performed at full rated power, and on 19 January 1945, B-29s destroyed the plant that was manufacturing it. This left 275 Ki-61-II airframes with no engines. Acting quickly (so quickly, in fact, that one suspects a contingency plan), Kawasaki engineers adapted the airframe to accept a 1500 hp Mitsubishi Ha-112-II 14-cylinder two-row radial engine, which was the only powerplant available with suitable performance, and the new Ki-100 made its first flight on 1 February 1945. In accelerated flight testing, the performance of the Ki-100 proved comparable to the rated performance of the Ki-61-II in all areas except top speed, which was slightly less due to the frontal area of the radial engine. The Ki-100 was markedly better than the production Ki-61-II due to the reliable performance and lower weight of its radial engine. It kept the armament common to late Ki-61s of two 20mm cannon and two 12.7mm machine guns. All 275 Ki-61-II airframes without engines were thus completed as Ki-100-Ia by the end of June and supplied to the 5^th, 17^th, 18^th, 59^th, 111^th, and 244^th Sentais, where they proved to be excellent fighters, capable of intercepting bombers at altitude and taking on fighters, but easy-handling enough for inexperienced pilots.

The Ki-100 has long been a gap in my collection of 1/72 Japanese fighters and having missed the Fine Molds and RS offerings when they were more easily (or more cheaply) available, I didn’t hesitate to pre-order when Aoshima came out with the Ki-100 in razorback (-Ia) and bubbletop (-Ib) versions. This kit (the Ki-100-Ia) comes in the long tray box common for Japanese models, with two bags of fairly hard grey and clear styrene. One bag has a tree of just the fuselage halves and the tree of clear parts, with their concave sides facing in to prevent scratching. The clear parts comprise a segmented canopy including two sliding sections (one of them wider to permit an open canopy, evidently because of the thickness of the part), the armored glass behind the pilot, the gunsight, a landing light, and seven tiny navigation lights, of which only five seem to be used in the directions—just as well, as these would be irresistible to the carpet monster. The landing light is a bit unusual. The real thing consists of a plexiglas cover over a lamp, but in a bit of cleverness Aoshima has cast this as one solid part with a dimple in the back to represent the lamp. Building the model will reveal how well this represents a landing light.

The opaque parts are fairly smooth and panel lines and some screws are fairly lightly engraved. I was happy to see that fillets, which are usually lap-jointed, are shown that way, and are not flush to the adjacent surfaces. All control surfaces are molded in place, and while no attempt is made at reproducing a fabric surface, they have odd looking raised ribs representing the underlying structure. A softly molded pilot is provided to sit in the 12-piece cockpit, which isn’t quite state-of-the-art, but more than good enough for a closed cockpit. The two-part engine is pretty basic, as are the wheel wells. Landing gear is also pretty basic, but the struts are where molding problems often show, like mold seam steps, and there’s none of that. Also no flash, just a slight mold seam that will be easy to shave off. Ejector pin marks are also where no one will care. Landing gear doors are unavoidably thick, but have detail on both sides, and the retraction mechanism for the wheel covers is a separate part. More than detail, however, I’m concerned with accuracy—it’s much easier to add details than to correct inaccuracies. My first order of business on opening the box was to measure the span of the one-piece lower wing. Near as I could measure, which is about 1/64”, it’s exactly to scale compared to the 8m wingspan given by Francillon. The length is harder to measure as it’s composed of the fuselage halves, the one-piece cowl ring, and the two-part prop spinner. Adding these measurements, the model seemed about 1/16” too short, but it’s hard to be certain without assembling it. The profile of the fuselage and tail looks to be the right shape compared to photos (but not compared to the Ki-100-I drawing Francillon has on p. 132, in which the fuselage looks too deep near the tail). The wing planform and horizontal stabilizer are a perfect match to Francillon’s plan view of the similar Ki-100-II (except of course for the Ki-100-II’s wing-root air scoop) .

Instructions are mainly in Japanese with clear assembly diagrams and the usual paint color table with numbers for GSI Creos paints (Mr. Color and Aqueous Hobby Color). Decals are provided for five aircraft of the 59^th Sentai, with only one diagram in the instructions for placement and no explanation of what markings go with what pilots or units, unless I’m missing it because it’s in Japanese. White rings around fuselage hinomaru are separate white discs on the decal sheet, leaving it to the modeler to achieve perfect registration. Printing is nice and sharp and both the red (A/N16) and deep yellow (A/N20) look right to me.

For modelers who must have a Ki-100 in their collections, Aoshima has provided another choice to the kits out there, and the kit looks like it will produce a very accurate scale model. The bubbletop version is also available and it remains to be seen if Aoshima also produces the Ki-100-II being developed as the war ended. By buying directly from Japan, I got this kit two months before its US release and even saved a little money.

Francillon, René J. Japanese Aircraft of the Pacific War, 2^nd edition, Naval Institute Press, 1979.

Gallagher, James P. Meatballs and Dead Birds, Stackpole Books, 2004.

http://en.wikipedia.org/wiki/Ki-100

Ed Bailey

February 2014

Thanks to my wallet for this kit and to AmiAmi for discounting the price.