Mitsubishi Ki-67 Type 4 Hiryu by LS

1/72 scale
Kit No. 151-450
Retail: $33.00
Decals: One version
Comments: Engraved panel lines, recessed rivet detail, full cockpit interior, full complement of bombs, opening bomb bay doors, rotating dorsal turret, complete engine assemblies, positionable ailerons, four-bladed propellers with separate spinners

History

The Mitsubishi Ki-67 Type 4 Hiryu (Flying Dragon) was the most advanced bomber to enter service with the Japanese military during World War II. Although classed by the Japanese themselves as a heavy bomber, its twin engines and the fact that it could carry a bomb load of only 1,764 lbs (800 kg), compared to the average B-17 bomb load of 4,500 lbs. (2000 kg), rendered it more comparable in performance (by Western standards) to the Martin B-26 Marauder, a medium bomber. THe Ki-67 originated from a December 1940 specification conceived by the Koku Hombu (Imperial Japanese Army Aviation Headquarters) for a potential successor to the Nakajima Ki-49 then undergoing service trials.

At that time the Japanese Army Air Force were still preparing themselves for an eventual conflict against the Soviet Union along the Manchukuo-Siberia border and wanted what they considered a tactical heavy bomber. The Koku Hombu finalized its specifications in February 1941 and instructed Mitsubishi to design and build three prototypes meeting the following requirements: Maximum speed 342 mph (550 kph), Operating altitude 13,125 ft to 22,965 ft (4000-7000 meters), Range 870 miles (700 km), Maximum bomb load of 1,764 lbs (800 kg), Crew of six to ten men, and defensive armament of three 7.62 mm machine guns (nose, port and starboard positions) and two 12.7 mm machine guns in dorsal and tail turrets. The powerplant would consist of two radial engines of either 1,870 hp (Nakajima’s Ha-103) or 1,900 hp (Mitsubishi’s Ha-104).

Chief engineer Ozawa designed a slender, clean mid-wing monoplane powered by Mitsubishi Ha-104’s driving two four-bladed propellers. The wing and tail bore a resemblance to Mitsubishi’s G4M1 bomber then entering service with the Imperial Japanese Navy, but it was otherwise a unique design. In a departure from traditional Japanese design methods, Ozawa emphasized ease of construction: construction by sub-assemblies was adopted from the start, and operational safety was a consistent feature, with self-sealing fuel and oil tanks and armor protection.

The first prototype was completed by December 1942. It took its maiden flight on December 27th at Kagamigahara. Despite some longitudinal stability problems and excessive sensitivity of the controls under some flight conditions, it handled very well and the Mitsubishi team were pleased. Its maximum speed of 342 mph at 19,980 ft (550 kph at 6,090 meters) fell slightly below specifications, the Ki-67 exceeded all other requirements. Service trials aircraft, which had been modified based on reports from early flight testing, were highly maneuverable — without bombs the Ki-67 could easily make loops and vertical turns, and controls remained smooth and effective at speeds up to 600 kph (373 mph indicated airspeed, very likely in dives).

Armament would later be improved to replace the 7.62mm machine gun in the nose with a 12.7mm, and the gun in the dorsal turret was upgraded to a 20mm. Fuel capacity increased from 2,566 to 3,886 liters (565 to 855 Imperial gallons) with a corresponding increase in range. From the time of the first flight of the prototype it was suggested that the Ki-67 be modified as a torpedo bomber, and in January 1943 Mitsubishi was instructed to fit torpedo racks on 100 production aircraft. Soon afterward, two aircraft and their crews were sent to Yokosuka Naval Air Station for torpedo launching trials.

The trials were so successful that Mitsubishi was directed to fit torpedo racks on all subsequent production models starting with the 161st aircraft. The Koku Hombu agreed to release a number of these aircraft for IJN service, and these were designated Yasukuni, after a shrine dedicated to an Unknown Soldier. Meanwhile the Army were so pleased with the aircraft that they began planning a series of modifications, so many that any standardization of the type was jeopardized. The Koku Hombu was forced to freeze the design, telling Mitsubishi in December 1943 to produce a single version with improved armament carrying 12.7mm machine guns in side blisters. This became the Army Type 4 Heavy Bomber Model I Hiryu (Ki-67-I).

LS took the unusual step of not only providing a color plate of the Ki-67, but an internal schematic as well.

Operational History

The Ki-67, designated “Peggy” by the Allies, first appeared in combat in torpedo attacks during the air-sea battle off Taiwan in October 1944. These were joint Army and Navy air operations involving the Army’s 7th and 98th Sentais and the Navy’s 762nd Kokutai. This battle established a precedent of Army and Navy Ki-67 units operating side-by-side in many future operations, and they were especially active during the American landing on Okinawa. The Ki-67 was operated by the Imperial Japanese Army in its original role of heavy bomber in China, and Kiryus based in Hamamatsu, Japan using Iwo Jima as a staging point, made repeated attacks against B-29 airfields in the Marianas Islands.

The Ki-67 was so capable that production was assigned highest priority so that in addition to Mitsubishi’s works at Nagoya, five other aircraft plants were included in the production program (Mitsubishi’s Chita and Kumamoto plants, Kawasaki’s plant at Gifu, as well as two Tachikawa factories). However, production was seriously impaired by B-29 raids and the earthquake of December 1944 which particularly affected engine production; as a result, only 698 Ki-67’s had been built when the war ended.

The Kit

LS Models Ki-67 Hiryu is injection molded in green and black plastic and consists of 131 parts, including 16 clear parts for the windscreen, glazed nose and tail, side blisters, windows and machine gun turrets. The kit is replete with engraved panel lines and recessed rivet detail all along its exterior surface. The cockpit features three aircrew figures with separate seats and control yokes for the pilot and co-pilot, as well as a backed stool for the navigator/radio operator, along with a partial bulkhead into which a table and radio are integrally molded.

While they are not terribly detailed, there are machine guns for the glazed nose and tail positions as well as the dorsal gun turret. There is a bomb bay for which eight bombs are provided, along with a one-piece dolly containing an additional bomb. The kit appears to have rather unique engineering for the bomb bay doors, which must not be cemented in place as they are apparently intended to slide open, up into the fuselage. Careful study of the instructions on this point is strongly advised, as they are not as clear as they could be. In addition, a rear crew access door in the ventral surface of the fuselage should not be cemented in place, but rather attached to internal hinges.

Crew figures and seats are provided for the bombardier in the nose and the tail gunner, and the kit features separately mounted flaps and ailerons. There are radial engine assemblies consisting of four parts each, which include engine mounts to be cemented to firewalls which in turn are cemented into the nacelle interiors. As an alternative, the kit offers an option to motorize the engines with the installation of motors and lead wires (not included in the kit)– if this option is chosen, the instructions recommend fitting the cowlings onto the nacelles rather than cementing them, and cover how best to do this. In addition, if the motorization option is chosen, the assembled engines may be displayed separately.

A partially cannibalized Ki-67 near the end of the war. Note that the machine guns have been removed from the glazed nose as well as the barbettes on the fuselage sides. The tail wheel appears to be missing also.

The four-bladed propellers feature separately mounted spinners, and there are parts for at least two ground crew figures as well as something rarely seen, chocks for the tires of the landing gear. While the instructions reference a fuel truck that contains batteries to power the motors, the truck is not included in the kit.

Finally, the kit includes two color plates. One is a 7.5 x 5.75 inch illustration of two Ki-67’s flying in formation with a Mitsubishi Ki-109, which was a Ki-67 modified for the bomber interceptor role and fitted with a single 75mm cannon in its nose. The nearer Ki-67 features cutaways of the fuselage interior (revealing the cockpit, bomb bay, and all gunner’s positions) as well as one of the nacelles featuring a view of its radial engine and landing gear folded for flight.

The second color plate offers a four-view drawing of the Ki-67 appearing in a scheme of Mitsubishi Green over Gray-Green under surfaces, as well as tail markings for six different flying groups, a seventh tail marking for a Special Attack Plane (Kamikaze), and an eighth marking for an aircraft of the Hamamatsu Flying School.

Markings

Despite their age, the kit markings appear fully serviceable. They have good color, are completely in register with a decent semi-gloss finish and do not appear to have suffered much oxidation. Notwithstanding the variety of markings seen on the second color plate, the kit provides decals for only four machines: the 100th Flying Group, 1st Squadron (white circle with extending arms ); the 60th Flying Group, 2nd Squadron (single red flash); the 74th Flying Group, 1st Squadron (White 146), and the 14th Flying Group, 3rd Squadron (an orange-yellow triangular figure). No details are provided in the instructions, color plates or decal sheets as to where any of these units are based, or when — at least not in English, as the second color plate contains some information in Japanese.

Conclusion

This is an interesting kit of an often overlooked bomber of the Pacific War. Had it entered service sooner, given its design innovations, it might have been a game-changer for the Japanese. Luckily for the Allies, it did not fully enter the fight until late 1944, by which time the Japanese were irreversibly on the defensive throughout the Pacific. Highly recommended for its historical value and above average engineering.

Reference

• Japanese Aircraft of the Pacific War by R.J. Francillon; Copyright 1970 by Putnam & Company Limited, London.
• www.aviastar.org