Mitsubishi Ki-46 III Type 100 by Hasegawa

1/72 Scale
Kit No. 00807
Decals: Two versions – both for 17th Company Independence Flight of the Imperial Japanese Army, based at Chofu Airfield (8 miles west of Tokyo), 1945
Comments: Engraved panel lines; two-part greenhouse nose and canopy

History

From the time of the Japanese invasion of Manchuria in 1931, the Imperial Japanese Army had an ongoing requirement for reconnaissance aircraft combining high speed and long range. In 1937, although immediate requirements were being met by the Mitsubishi Ki-15, Major Fujita and Engineers Tanaka and Ando of the Technical Branch of the Koku Hombu issued to Mitsubishi a specification calling for a long-range reconnaissance aircraft able to complete its missions without being intercepted. The specifications required a maximum speed of 373 mph at 13,125 ft. (600 km/h at 4,000 meters), with a choice of single or twin-engined configuration. The designers chose the 850 hp Mitsubishi Ha-26 radial in a twin-engine arrangement, prevailing upon the Aeronautical Research Institute of the University of Tokyo to develop close fitting cowlings specifically for the chosen powerplant, which reduced drag by improving the nacelles’ aerodynamics, and improved the pilot’s sideways vision.

To meet the stringent performance requirements, Tomio Kubo designed a thin wing section and a small-diameter fuselage with a large internal fuel tank close to the plane’s center of gravity. The pilot and radio operator-gunner were in two cockpits separated by the fuselage fuel tank. After extensive wind tunnel testing, the prototype was completed in November 1939, and the first flight occurred the same month with Major Fujita at the controls.

The prototype was satisfactory during test flights, but when service trials began, the Ki-46 failed to achieve its design speed by 40 mph, making only 335.5 mph at 13,125 ft. (540 km/h). Despite falling short of desired specifications, it was received enthusiastically by the Army, as it was still faster than the Nakajima Ki-43, the newest fighter about to be delivered, as well as the IJN’s A6M2 fighter. Production was authorized under the designation Army Type 100 Command Reconnaissance Plane Model 1 (Ki-46 I).

As with any new type, there were bugs to be worked out. Ground crews complained that the Ki-46, considerably more complex than the Ki-15 it replaced, was difficult to maintain in the field. Vapor locks occurred often in heat and humidity, and special tests had to be conducted on Taiwan (then called Formosa) during June 1940. A change from 87-octane to 92-octane fuel and relocating the fuel lines around the engines corrected the problem.

The first Ki-46 II with more powerful Ha-102 engines featuring two-speed superchargers and developing 1,080 hp at take-off, appeared in March 1941. It reached a speed of 375 mph at 19,030 ft., slightly exceeding the maximum speed initially specified. It was quickly delivered to several air units in Manchuria and China, where its high speed enabled it to avoid interception by the fighters then available to the Chinese Air Force.

In the weeks preceding the attacks on Pearl Harbor, Malaya and the Philippines, a unit of Ki-46 II’s were transferred to French Indo-China. On October 20 and 22, 1941, its commanding officer, Captain Ikeda, reconnoitered the area chosen by the Japanese High Command for the amphibious landings in Malaya.
When hostilities erupted, Ki-46 units were deployed throughout Southeast Asia. These units operated with almost total impunity, to the point that the Imperial Japanese Navy negotiated the acquisition of a small number of the type. Some naval Ki-46’s flew regular recon missions over Northern Australia from bases in Timor, while their Army counterparts operated as far west as the Bay of Bengal.

The subject of this kit, the Ki-46 III, was introduced in response to a situation the Koku Hombu had anticipated: the eventual introduction of newer Allied fighters (such as the Lockheed P-38F Lightning and Spitfire Mk V) capable of intercepting the type. Back in May 1942, Mitsubishi had been instructed to install its new 1,500 hp Ha-112 II engine in an improved version of the aircraft. This increased maximum speed to 404 mph (650 km/h) and endurance by one hour. The Ki-46 III also differed from its predecessors in featuring a redesigned fuel system with an extra fuel tank in front of the pilot, increasing capacity by 52 Imperial gallons or 220 liters; engine nacelles were slightly larger to accommodate the Ha-112, which had fuel injection; strengthened landing gear; and the most significant external change was the redesign of the forward fuselage with a new canopy over the cockpit, without the step between the nose and the top of the fuselage — giving the Type III a sleeker, more streamlined appearance.

Completed in December 1942, the Ki-46 III went through accelerated flight trials and entered service soon thereafter. Priority in delivery of the new type was given to areas where the Allies had achieved air superiority, but often they operated alongside the II, which it never completely replaced. Once maintenance problems with its fuel injection system were cured, it became a thorn in the Allies side since only the faster climbing fighters assisted by radar control could intercept them as they kept constant watch over well-defended areas such as the B-29 bases in the Marianas. Despite this record, by war’s end even the III was not free from interception and losses began to rise alarmingly.

The obvious question is why, with such impressive performance, the Japanese never developed the Ki-46 III into a fighter. In fact, a high-altitude interceptor version was developed by the Rikugun Kokugijutsu Kenkyujo (Army Aerotechnical Research Institute) as a stopgap until a specialized aircraft could be produced, with design work going into high gear from May 1944. But production was delayed by disappointing engine performance resulting in insufficient climbing speed, and resulted in the need for a redesign incorporating turbosuperchargers, which gave the Ki-46 IV superior performance at altitude. Efforts to perfect the turbosuperchargers so that they would be reliable under combat conditions proved difficult, and with the steadily deteriorating war situation, what might have been an outstanding interceptor was dropped in favor of less problematic designs such as the J2M Raiden (which was not without its own teething problems) to meet the increasing onslaught of American B-29 raids.

The remarkably clean lines of the Mitsubishi Ki-46 III. Photo Credit: Imperial Japanese Army Air Force

The Kit

First released with the “17th Company Independence Flight” box art featuring the red/rust paint scheme in 2006, this kit is a re-issue with new parts of the Hasegawa Ki-46 Dinah initially released in 2000. The kit is injection molded in grey plastic and consists of 63 parts. It features engraved panel lines, recessed hinge detail on the under surfaces of the ailerons, and ribbed detail for the cabin on the interior fuselage surfaces. One of the key features is a two-part greenhouse canopy, which gave the Ki-46 III its distinctive, highly aerodynamic appearance.

A key point to note is that one of the sprues is mislabeled as Sprue C, when in fact it is Sprue B — so there are a total of three sprues labelled C, two of which are nearly identical and contain duplicate parts, some of which can go into your spares box. For example, four propellers are provided for this twin-engine kit, and there is an extra seat and extra control yoke. The good news is that although a sprue is mislabeled, there are no missing parts.

The slender cockpit has the pilot up front with separate parts for his bucket seat, control yoke, and a rear bulkhead. Aft of that are two oddly shaped parts that are likely photographic equipment, a second seat for the observer/photographer, and a second rear bulkhead. Directly ahead of the cockpit assembly is the separate nose assembly, which will contain the pilot’s instrument panel for which a decal is provided. Each engine assembly consists of 5 parts, not including the separate cowlings, and features a detailed radial engine face. The landing gear doors can be positioned open or closed, giving modelers the option of an in-flight display.

As this is a reconnaissance aircraft, clear plastic parts are provided for apertures for cameras in the belly, and also for the nose, but this clear part in the nose may or may not be for reconnaissance purposes, given that according to the instructions, one of the kit’s version of the Ki-46 III was a bomber interceptor, based on the fixed 20mm cannon mounted at an oblique angle on the dorsal spine of the plane between the pilot and observer/rear gunner — this part is in white metal for some reason. Since this version was based at an airfield near Tokyo, it is possible that it was pressed into an interceptor role against B-29’s given the Ki-46’s speed and altitude performance.

Markings

The kit decals are in register, have a nice semi-gloss sheen and do not appear to have fallen victim to the yellowing that often plagues Hasegawa decals, so they are fully serviceable. The first version is for a machine of the 17th Company Independence Flight of the Imperial Japanese Army, based at Chofu Airfield near Tokyo in 1945. Its paint scheme according to the instruction sheet consists of rust red upper surfaces, a color achieved by mixing Mahogany and Wood Brown at a ratio of 60% to 40%, respectively — with Grey-Green under surfaces. Reference is made to Gunze Sangyo colors only. This version is characterized by red flashes on the tail fin, laid over a vertical blue flash, and three broad white horizontal stripes on the rudder. It also features the red Hinomaru (the Japanese national insignia) against a bone-white background on the fuselage and wings.

The second version has an identical paint scheme, but features paint red Hinomarus on the upper and lower wings, with a red Hinomaru surrounded by a white border on the fuselage. It also features a black bird (perhaps a raven) on a white circular background on the tail. This version lacks the dorsal 20mm cannon.

Conclusion

This is a highly detailed kit of perhaps the sleekest and most aerodynamically attractive aircraft fielded by the Japanese military during World War II. Given time, the Japanese might have perfected this high performance reconnaissance platform into a formidable fighter, as the British had done with the de Havilland Mosquit0. Highly recommended.

Reference

Japanese Aircraft of the Pacific War by R.J. Francillon; Copyright 1970 Putnam & Company, Ltd.; London

One of the few heavily armed interceptor versions of the Ki-46 III ever built. Photo Credit: warthunder.com