The Mitsubishi Ki-67 Hiryū was a twin-engine heavy bomber produced for the Imperial Japanese Army Air Service and Imperial Japanese Navy Air Service in World War II.
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 armour, features common in US fighters and bombers but frequently lacking in Japanese aircraft.
With these features and its two 1,417 kW (1,900 hp) 18-cylinder air-cooled radial engines, the Ki-67 was perhaps one of the sturdiest and damage-resistant Japanese aircraft of World War II.
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 North American B-25 Mitchell could carry up to 2,722 kg (6,000 lb), the Martin B-26 Marauder up to 1,814 kg (4,000 lb), and the Douglas A-20 Havoc up to 907 kg (2,000 lb), 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 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 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.
Variants
Ki-67-I
Prototypes
Diverse models with various types of weapons.
Ki-67-Ia “Hiryu” Army Type 4 Heavy Bomber Model 1
Main production model.
The majority (420+) were modified in the factory as land-based torpedo bombers.
Ki-67-Ib
Late production model
Reinforced the tail gun turret (2 × 20 mm).
Ki-67-I KAI
Experimental model equipped with Mitsubishi Ha-104 Ru engines.
Ki-67-I AEW variant
Equipment the early warning radar “Taki 1 Model II”.
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 (1,760 lb) bombs in belly compartment.
Ki-67 Guided missile Mothership
Experimental type for carrying guided missiles.
Ki-67 long-range bomber variant
Equipped with widened wings and without turrets.
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 (.51 in) machine guns in lateral and upper positions, and more fuel capacity for long range.
Ki-67-II
Prototypes.
Modified version of the Ki-67-I, with two Mitsubishi Ha-214 engines of 1,603 kW (2,150 hp) each.
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-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 (0.5 in) Ho-103 Type 1 machine gun in the tail.
Equipped with Mitsubishi Ha-104 engines of 1,417 kW (1,900 hp) each or turbocharged Ha-104 Ru with 1,417 kW (1,900 hp) each.
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, with a revised version of tail gun.
Ki-112
Bomber escort fighter made with a wooden construction.
Armed with 8 x 12.7mm’s 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 (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 300 m (980 ft).
The bomb was designed to breach emplacements as well as to destroy massed formations of armour.
Q2M1 Taiyo
Navy variant of Ki-67-I, for antisubmarine warfare.
Specifications
Crew
6–8
Length
18.7 m (61 ft 4 in)
Wingspan
22.5 m (73 ft 10 in)
Height
7.7 m (25 ft 3 in)
Wing area
65.85 m2 (708.8 sq ft)
Empty weight
8,649 kg (19,068 lb)
Gross weight
13,765 kg (30,347 lb)
Powerplant
2 × Mitsubishi Ha104,
18-cylinder air-cooled radial piston engines,
1,400 kW (1,900 hp) each for take-off
1,350 kW (1,810 hp) at 2,200 m (7,200 ft)
1,201 kW (1,610 hp) at 8,300 m (27,200 ft)
Propellers
4-bladed constant-speed metal propellers
Performance
Maximum speed
537 km/h (334 mph, 290 kn) at 6,090 m (19,980 ft)
Cruise speed
400 km/h (250 mph, 220 kn) at 8,000 m (26,000 ft)
Range
2,800 km (1,700 mi, 1,500 nmi)
Ferry range
3,800 km (2,400 mi, 2,100 nmi)
Service ceiling
9,470 m (31,070 ft)
Time to altitude
6,000 m (20,000 ft) in 14 minutes 30 seconds
Wing loading
209 kg/m2 (43 lb/sq ft)
Power/mass
0.205 kW/kg (0.125 hp/lb)
Armament
Guns
1 × 20 mm (0.79 in) Ho-5 cannon in dorsal turret
5 × 12.7 mm (.50in) Ho-103 (Type 1) machine guns,
One in nose, 1 in the tail and 1 in each beam position (late models);
Early models carried magazine-fed 7.7 mm (.303in) Type 89 machine guns in the beam positions.
Bombs
800 kg (1,764 lb) of bombs in internal bay or one torpedo,
Kamikaze versions carried 2,900 kg (6,400 lb) of bombs.
