Mitsubishi Ki-67

Template:Infobox Aircraft The Mitsubishi Ki-67 Hiryū (飛龍, "Flying Dragon"; Allied code name "Peggy) was a twin-engined medium bomber produced by Mitsubishi and used by the Imperial Japanese Army Air Force in World War II. Its Army designation was "Type 4 Heavy Bomber" (四式重爆撃機).

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 heavy bomber with the maneuverability of a fighter. The Ki-67 was designed by Ozawa Kyonosuke, chief engineer at Mitsubishi, and was first encountered by Allied forces in a sea battle off Formosa in October 1944.

The Ki-67 had 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 1,900 hp 18-cylinder air-cooled radial engines, the Ki-67 was perhaps one of the most sturdy and damage-resistant Japanese aircraft of WWII.

The Ki-67's bomb load of 1,070 kg (2,360 lb) (carried in its internal bomb bay) would classify it as a medium bomber for the US (the B-25 Mitchell could carry up to 6,000 lb, the B-26 Marauder up to 4,000 lb, and the A-20 Havoc up to 2,000 lb, for example). Its performance was remarkable compared to US medium bombers; the Ki-67 had a level-flight top speed of 334 mph (against 275 mph for the B-25, 287 for the B-26, and 338 for the A-20), good maneuverability in dives up to high speed (up to nearly 400 mph), excellent sustained rate of climb, and outstanding ability to turn (excellent turn rate, small turn radius, and ability to turn at low speeds). The maneuverability of the Ki-67 was so good that the Japanese used the design as the basis for the 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 WWII, the Japanese Navy also used the design as the basis for the Q2M1 "Taiyo" radar-equipped anti-submarine plane.

Another interesting feature of the Ki-67 was that the gun in the dorsal gunner's turret position was a 20 mm cannon. (In addition to twin 12.5 mm machine guns in the tail, one 12.5 mm MG in the nose, and one 12.5 mm MG at each waist-gun position.) The 20 mm cannon is an unusually powerful defensive armament for a bomber. Until the introduction of the B-29 Superfortress, US bombers did not have cannon in defensive gunner positions, instead typically having one or two 0.50 caliber machine guns.

The Ki-67.

File:Ki67InFlight.jpg

A Ki-67 in flight.

File:Ki67Pilot.jpg

Picture of pilot in a Ki-67, with view of other Ki-67 in flight.

Operations

The Ki-67 was used for level bombing and (as the Yasakuni Type) 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 Navy 3rd Fleet during its strikes against Formosa and the Ryukyu Islands. It was later used at Okinawa, in China, and against B-29 airfields in Saipan, Tinian, and Guam in support of Giretsu (a special unit of the Japanese Imperial Army) strikes. 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 degrees for firing toward the ground, a 20 mm cannon in the tail, 13.2 mm 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 WWII, special attack versions of the Ki-67 (the I KAI and Sakura-dan models) were used in Kamikaze missions. (References include information from Lt. Sgt. Seiji Moriyama, a crew member in Fugaku Special Attack Unit, who witnessed Ki-67's being converted into To-Go suicide planes with two 800 kg bombs during Okinawa operations.)

By the end of WWII, 767 Ki-67's had been produced. Other sources relate that 698 Ki-67's were manufactured, excluded the KAI and Sakura-dan conversions.

Variants

• Ki-67 I : Prototypes. Diverse models with various types of weapons. 19 produced.
• Ki-67 I "Hiryu" Army Heavy Bomber Type 4, Model 1: Main production model. The majority (420+) were modified in the factory as land-based torpedo bombers. Produced by Mitsubishi: 587; by Kawasaki: 91; by bu 1° Army Arsenal of Tachikawa: 1.
• Ki-67 I: Experimental model equipped with Mitsubishi Ha-104 Ru engines. 3 produced.
• Ki-67 I "Go-IA" : Experimental type for carrying guided missiles. 1 produced.
• Ki-67 KAI (also known as "To-Go" or "Tai-atari") Army special attack aircraft type 4: Improved version of the Ki-67 I for suicide strikes, unarmed, without turrets, and with two bombs of 800 or 2,900 kg in belly compartment.
• Ki-67 "Sakura-dan" : Special attack version equipped with one thermite bomb of 2,900 kg (6,400 lb) 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 984 feet. The bomb was designed to breach emplacements as well as to destroy massed formations of armor. 2 produced.
• Ki-67 ground attack variant: Version armed with three remote-control ground-firing 30 degree 20mm cannons, 20mm defensive cannon in the tail position, three 13.2 mm MG's 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 2,400 hp each. 2 produced.
• "Yasakuni": Naval torpedo-bomber version of the Ki-67 I. Created from Ki-67 I's transferred from the IJAAF.
• Ki-109 : Night Fighter prototypes. Ki-67 I modified for night fighting for operating in pairs, one with a radar/reflector (similar to the Douglas Havoc II "Turbinlite") for radar transmission and detection (the Ki-109a) and the other armed with heavy cannon for destroy the objective (Ki-109b). Only a project.
• Ki-109 : Day Fighter prototypes. Ki-67 I modified for daylight fighting. One fixed Type 88 75 mm Heavy Cannon in the nose and one mobile Ho-103 Type 1 12.7 mm MG in the tail. Equipped with Mitsubishi Ha-104 engines of 1900 hp each or Ha-104 Ru with turbochargers and 1900 hp 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. Had a revised version of tail gun. 22 constructed by Mitsubishi.
• Q2M1 "Taiyo" : A Navy variant based on the Ki-67 I, specifically designed for antisubmarine warfare. Equipped with radar units (Type3 Model 1 MAD (KMX), Type 3 Ku-6 Model 4 Radar, and ESM Antenna equipment). Had two Mitsubishi Kasei 25 Otsu engines of 1850 hp each with six-blade propellers. Carried torpedoes or depth charges. Only a project.

Specifications (Ki-67-Ib)

General characteristics

• Crew: 6-8

Performance Armament

• 1 × 20 mm Ho-5 cannon in dorsal turret
• 5 × 12.7 mm Type 1 machine gun, one in nose, 2 in the tail, and 1 in each beam position
• 1,070 kg (2,360 lb) of bombs in internal bay, some Kamikaze versions carried 6,000 lb (2,700 kg) of bombs

References

Bibliography

• Francillon, Rene J. Japanese Aircraft of the Pacific War. Annapolis, Maryland: Naval Institute Press, 1995.
• Green, William. Warplanes of the Second World War, Volume Three: Fighters. London: Macdonald & Co. (Publishers) Ltd., 1961 (seventh impression 1973). ISBN 0-356-01447-9. (On the Ki-109 Fighter version)

Scale Modelling

• Swanny's Models review of Ki-67 model kit with background information on aircraft.

External links

• Rod's WarBirds - Many WWII pictures of the Ki-67.
• Pictorial of Ki-67's used in a multiplayer air-combat simulation.