Mitsubishi Ki-67


The Mitsubishi Ki-67 Hiryū was a twin-engine medium bomber produced by Mitsubishi and used by the Imperial Japanese Army Air Service and Imperial Japanese Navy Air Service in World War II. Its Army long designation was "Army Type 4 Heavy Bomber". Japanese Navy variants included the P2M and Q2M.

Design

The Ki-67 was the result of a 1941 Japanese army specification for a successor to the Nakajima Ki-49. This new aircraft was specified to be a high-speed twin-engined heavy bomber suitable for possible conflicts with the Soviet Union over the Manchuria-Siberia border, and unlike many Japanese warplanes, was required to have good defensive armament and the ability to survive heavy battle damage. It was also required to be highly maneuverable allowing it to carry out dive-bombing attacks and escape at low level.
The Ki-67 was designed by a team led by Kyūnojō Ozawa, chief engineer at Mitsubishi, and was a mid-winged monoplane of all-metal construction, with a retractable tailwheel undercarriage. It was fitted with self-sealing fuel tanks and armor, features common in US fighters and bombers but frequently lacking in Japanese aircraft. With these features and its two 1,417 kW 18-cylinder air-cooled radial engines, the Ki-67 was perhaps one of the most sturdy and damage-resistant Japanese aircraft of World War II.
The Ki-67's bomb load of 1,070 kg would classify it as a medium bomber for the US. The B-25 Mitchell could carry up to 2,722 kg, the B-26 Marauder up to 1,814 kg, and the A-20 Havoc up to 907 kg, for example, but they rarely carried a maximum load; when they did, their range was reduced significantly. Japanese aircraft almost invariably had greater range ; this gave them a strategic capability unlike that of Allied twin-engine bombers, which were considered tactical bombers. The Ki-67's performance was remarkable compared to US medium bombers; the Ki-67 had a level-flight top speed of 537 km/h/334 mph, good manoeuvrability in high-speed dives, excellent sustained rate of climb, and outstanding agility. The manoeuvrability of the Ki-67 was so good that the Japanese used the design as the basis for the Mitsubishi Ki-109 twin-engine fighter, originally designed as a night fighter, and later for use as a daylight heavy fighter. In the last stages of World War II, the Japanese Navy also used the design as the basis for the Mitsubishi Q2M1 "Taiyo" radar-equipped anti-submarine aircraft.
Armament of the Ki-67 included a dorsal turret with a 20mm Ho-5 cannon, in addition to 12.7mm Ho-103 machine guns in the tail, nose, and beam positions. Some aircraft were fitted with a 20mm gun in the tail position, and early models used 7.7mm Type 89 machine guns in the beam positions.

Operations

The Ki-67 was used for level bombing and torpedo bombing. The Ki-67 was initially used by the Japanese Army and Navy Air Services against the US 3rd Fleet during its strikes against Formosa and the Ryukyu Islands. It was later used at Okinawa, in Mainland China, French Indochina, Karafuto and against B-29 airfields in Saipan and Tinian. One special ground-strike version used in the Giretsu missions was a Ki-67 I with three remote-control 20 mm cannons angled at 30° for firing toward the ground, a 20 mm cannon in the tail, 13.2 mm Type 3 machine guns in the lateral and upper positions, and more fuel capacity. Even with more fuel, the Giretsu missions were one-way only because of the long range. In the last stages of World War II, special attack versions of the Ki-67 were used in kamikaze missions.
By the end of World War II, 767 Ki-67s had been produced. Other sources relate that 698 Ki-67's were manufactured, excluded the KAI and Sakura-dan conversions.

Variants

Wartime