Mitsubishi Ki-67


The Mitsubishi Ki-67 Hiryū, Allied reporting name "Peggy", was a twin-engine bomber produced by Mitsubishi Aircraft Company and used by the Imperial Japanese Army Air Service and Imperial Japanese Navy Air Service in World War II. While its original official designation was "Army Type 4 Heavy Bomber", in all of its key parameters, the Ki-67 was similar to the contemporaneous medium bombers of other countries. 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 "storm dragon". 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 manoeuvrable 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 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 carried in its internal bomb bay would classify it as a medium bomber for the US. The North American B-25 Mitchell could carry up to 2,722 kg, the Martin B-26 Marauder up to 1,814 kg, and the Douglas 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 with their rated maximum load; 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 - against for the B-25, 462 km/h for the B-26, and 538 km/h for the A-20 -, 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 "Tai'yō" radar-equipped anti-submarine aircraft.
Armament of the Ki-67 included a dorsal turret with a 20 mm (.79 in) Ho-5 cannon, in addition to 12.7 mm (.50 in) Ho-103 machine guns in the tail, nose, and beam positions. Some aircraft were fitted with a 20 mm gun in the tail position, and early models used 7.7 mm (.303in) Type 89 machine guns in the beam positions.

Operations

The Ki-67 was used for level bombing and torpedo bombing; it could carry one torpedo attached under the fuselage. The Ki-67 was initially used by the Japanese Army and Navy Air Services against the US Third 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, excluding the Kai and Sakura-dan conversions.

Variants

Ki-67-I: Prototypes. Diverse models with various types of weapons. 19 produced.Ki-67-Ia "Hiryū" Army Type 4 Heavy Bomber Model 1: Main production model. The majority were modified in the factory as land-based torpedo bombers. Produced by Mitsubishi: 587; by Kawasaki: 91; by 1° Army Arsenal of Tachikawa: 1.Ki-67-Ib: Late production model. Reinforced the tail gun turret.Ki-67-I Kai: Experimental model equipped with Mitsubishi Ha-104 Ru engines. 3 produced.Ki-67-I AEW variant: Equipment the early warning radar "Taki 1 Model II". 1 produced.Ki-67 "To-Gō": Army special attack aircraft type 4: Improved version of the Ki-67 I for kamikaze, unarmed, without turrets, and with two 800 kg bombs in belly compartment.Ki-67 "guided missile mother ship": Experimental type for carrying guided missiles. 1 produced.Ki-67 long-range bomber variant: Equipped with widened wings and without turrets. Only a project.Ki-67 ground attack variant: Version armed with three remote-control ground-firing 5 × 30° 20 mm cannons, 20 mm defensive cannon in the tail position, three 13.2 mm machine guns in lateral and upper positions, and more fuel capacity for long range. Specifically designed for land strikes against B-29 bases in the Marianas. Only a project.Ki-67-II: Prototypes. Modified version of the Ki-67-I, with two Mitsubishi Ha-214 engines of each. 2 produced.
  • Ki-67 glider tug: A standard Ki67-I was used to tow the "Manazuru" transport glider in tests."Yasukuni": Naval torpedo bomber version of the Ki-67-I. Created from Ki-67-Is transferred from the IJAAF.Ki-69: Heavily armed escort fighter model. Only a project.Ki-97: Transport model. Only a project.Ki-109: Night fighter prototypes. Ki-67-I modified for night fighting for operating in pairs, the Ki-109a with a radar/reflector for radar transmission and detection and the Ki-109b, armed with twin 37 mm Ho-203 cannon in an upward-firing Schrage Musik-style fixed dorsal mount to destroy the objective. Only a project.Ki-109: Day Fighter prototypes. Ki-67-I modified for daylight fighting. One fixed 75 mm Type 88 Heavy Cannon in the nose and one mobile 12.7 mm Ho-103 Type 1 machine gun in the tail. Equipped with Mitsubishi Ha-104 engines of 1,417 kW each or turbocharged Ha-104 Ru with 1,417 kW each. 2 produced.Ki-109 Army Heavy Fighter Interceptor: First non-prototype model of series. Lacking gun positions in upper and side positions and without bomb-bay compartments. Fixed 75 mm Type 88 Heavy Cannon in the nose retained from Day Fighter prototype. Had a revised version of tail gun. 22 constructed by Mitsubishi.Ki-112: Bomber escort fighter made with a wooden construction. Armed with 8 x 12.7mm and 1 x 20mm. Only a project.Ki-167 "Sakura-dan": "Special Attack" version equipped with one shaped charge thermite bomb of 2,900 kg in the fuselage behind the crew cabin. The shape of the bomb conducted the blast forward, projecting a jet capable of reaching nearly a mile with a maximum blast radius of 300 m. The bomb was designed to breach emplacements as well as to destroy massed formations of armor. 9 produced.Q2M1 Tai'yō: Navy variant of Ki-67-I, for anti-submarine warfare. Equipped with radar. Had two Mitsubishi Kasei 25 Otsu engines of each with six-blade propellers. Carried torpedoes or depth charges. Project only.

Operators

Wartime