Mitsubishi Ki-51

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Mitsubishi Ki-51-1.jpg
Mitsubishi Ki-51
Role Light bomber/dive bomber
Manufacturer Mitsubishi Jukogyo KK
First flight mid-1939
Primary user Imperial Japanese Army Air Service
Number built 2,385[1]

The Mitsubishi Ki-51 (Army designation "Type 99 Assault Plane"; Allied nickname "Sonia") was a light bomber/dive bomber in service with the Imperial Japanese Army during World War II. It first flew in mid-1939. Initially deployed against Chinese forces, it proved to be too slow to hold up against the fighter aircraft of the other Allied powers. However, it performed a useful ground-attack role in the China-Burma-India theater, notably from airfields too rough for many other aircraft. As the war drew to a close, the Japanese began using them in kamikaze attacks. Total production was around 2,385 units.

On the day Hiroshima was destroyed by an atomic bomb, two Ki-51s were responsible for the last Japanese sinking of a US warship, sinking USS Bullhead (SS-332) with all hands.

Charles Lindbergh, flying a P-38 Lightning, shot down a Ki-51.[2]


  • Prototypes: two built
  • Service trials: 11 built
  • Ki-51: 2,372 built (Manufacturers: Mitsubishi (1,462), Tachikawa Army Air Arsenal (913))
  • Mansyu Ki-71: three prototypes of a tactical reconnaissance variant built by Mansyu with a retractable landing gear, did not enter production.[3]
  • Reconnaissance Version Ki-51A
  • Assault Version Ki-51B. The assault version had armor plating protecting the pilot and oil tanks, and bomb racks to carry 441 lbs of bombs. This version could be modified in the field to carry an aerial camera.


  • Indonesian Air Force - In 1945, Indonesian People's Security Force (IPSF) (Indonesian anti-Dutch Militia) captured a small number of aircraft at numerous Japanese air bases, including Bugis Air Base in Malang (repatriated 18 September 1945). Most aircraft were destroyed in military conflicts between the Netherlands and the newly proclaimed-Republic of Indonesia during the Indonesian National Revolution of 1945–1949. With 2 units of Yokosuka K5Y "Cureng", one surviving Mitsubishi Ki-51 "Guntei" also involved in bombing operation against Dutch on July 29, 1947.
  • Communist Chinese (captured): The last 4 Ki-51s retired in 1953.
 Republic of China
 North Korea
  • After their independence, obtained from the Soviet Union.

Specifications (Ki-51)[edit]

Mitsubishi Ki-51 planes at the Seoul airport, 1945

Data from Japanese Aircraft of the Pacific War[4]

General characteristics

  • Crew: 2
  • Length: 9.21 m (30 ft 3 in)
  • Wingspan: 12.1 m (39 ft 8 in)
  • Height: 2.73 m (8 ft 11 in)
  • Wing area: 24 m2 (260 sq ft)
  • Empty weight: 1,873 kg (4,129 lb)
  • Gross weight: 2,798 kg (6,169 lb)
  • Max takeoff weight: 2,920 kg (6,437 lb)
  • Powerplant: 1 × Mitsubishi Ha-26-II 14-cylinder air-cooled radial piston engine, 710 kW (950 hp)
  • Propellers: 3-bladed variable-pitch propeller


  • Maximum speed: 424 km/h (263 mph, 229 kn) at 3,000 m (9,843 ft)
  • Range: 1,060 km (660 mi, 570 nmi)
  • Service ceiling: 8,270 m (27,130 ft)
  • Time to altitude: 5,000 m (16,404 ft) in 9 minutes 55 seconds
  • Wing loading: 117 kg/m2 (24 lb/sq ft)
  • Power/mass: 0.24 kW/kg (0 hp/lb)


  • Guns:
  • Bombs: 200 kg (441 lb) bombs (normal operations); 250 kg (551 lb) for suicide operations[4]

See also[edit]

Aircraft of comparable role, configuration, and era

Related lists


  1. ^ Angelucci, Enzo (1988). Combat aircraft of World War II. p. 26. ISBN 0-517-64179-8.
  2. ^ "Charles Lindbergh and the 475th Fighter Group." Lightning Strikes.
  3. ^ Francillon 1979, p. 180.
  4. ^ a b Francillon 1979, p. 181.

External links[edit]