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The Mitsubishi Ki-51 Type 99 Assault Plane (Allied codename: Sonia) was a military attack aircraft used during WWII by the Imperial Japanese Air Force. It first flew in 1939 and a total of 2,385 planes were built. A couple of these aircraft claimed a few USN submarines and ended up getting the last kills by the Japanese of WWII.

Contents 1 History 1.1 Development and construction 1.2 Operational Service 1.3 Variants 2 Specifications 3 References 3.1 Notes 3.2 Sources 4 Bibliography

HistoryEdit

Development and constructionEdit

Designed to meet the requirement for a ground attack aircraft for the Imperial Japanese Army, two prototypes of the Ki-51, powered by a single Mitsubishi Ha-26-II engine, were tested in the Summer of 1939. The Ki-51 differed from the similar Mitsubishi Ki-30 Type 97 Light Bomber due to the new type's low set wing and revised cockpit.^{[N 1]} The 11 service trials aircraft which followed the prototypes introduced armour protection for both the engine and the crew, together with aerodynamic improvements to improve the type's handling qualities at low speeds. Of the 2,385 examples built, 1,472 were built by Mitsubishi, with the remaining 913 built by the Tachikawa 1st Army Air Arsenal.^[1]

Operational ServiceEdit

Following it's introduction in China, the Ki-51 served throughout the Pacific War, mainly in secondary theatres due to the type's vulnerability to Allied fighters, before being used for Kamikaze attacks.^[1]

VariantsEdit

One example was converted into a Ki-51a tactical reconnaissance aircraft. Mitsubishi designed a dedicated reconnaissance variant under the Ki-71 designation. Limited to three prototypes built by Tachikawa, this version had retractable landing gear and a 1,500 hp (1,119 Kw) Mitsubishi Ha-112-II engine.^[1]

SpecificationsEdit

• Crew: Two
• Length: 9.21 m (30 ft 2⅝ in)
• Wingspan: 12.1 m (39 ft 8⅜ in)
• Height: 2.73 m (8 ft 11½ in)
• Wing area: 24.0 m² (259 ft²)
• Empty Weight: 1,873 kg (4,129 lb)
• Loaded weight: 2,798 kg (6,169 lb)
• Max. Takeoff Weight: 2,920 kg (6,415 lb)
• Powerplant: One Mitsubishi Ha-26-II 14 cylinder air cooled radial engine rated at 709 kW (950 hp)
• Max. Speed: 424 km/h at 3 000 m (263 mph at 9,840 ft)
• Range: 1,060 km (574 nmi, 660 mi)
• Service Ceiling: 8,270 m (27,130 ft)
• Wing Loading: 117 kg/m² (23.8 lb/ft²)
• Power to Mass Ratio: 0.24 kW/kg (0.15 hp/lb)
• Climb to 5,000 m (16,400 ft): 9 min 55 sec
• Gun Armament:
  • Two fixed, forward-firing 7.7 mm (.303 in) Type 89 MGs (replaced with two 12.7 mm (.5 in) Ho-103 MGs in later variants)
  • One 7.7 mm (.303 in) Te-4 MG rearward-firing machine gun.
• Bombload: 200 kg (441 lb) of unguided bombs or 250 kg (551 lb) of unguided bombs for suicide attacks.

ReferencesEdit

NotesEdit

1. ↑ The Ki-30 had a mid set wing to allow the fitting of an internal bomb bay, which was not required for the smaller Ki-51.^[1]

SourcesEdit

1. ↑ ^{1.0 1.1 1.2 1.3} World Aircraft Information Files File 901 Sheet 34 (A_Z of Aircraft: Mitsubishi Ki-51 (Type 99 Assault Plane) to Mitsubishi MU-2, Marquise and Solitare)

BibliographyEdit

• World Aircraft Information Files Aviation Partwork. Midsummer Books Ltd.

v • d • e Bomber and Assault Aircraft of Imperial Japanese Air Forces Single-Engine Aichi B7A • Aichi D3A • Nakajima B6N • Nakajima B5N • Yokosuka D4Y • Kawasaki Ki-32 • Mitsubishi Ki-30 • Mitsubishi Ki-51 Twin-Engine Kawasaki Ki-48 • Mitsubishi Ki-67 • Mitsubishi G4M • Mitsubishi Ki-21 • Nakajima Ki-49 • Watanabe Q1W • Yokosuka P1Y • Kawasaki Ki-102 • Mitsubishi G3M Seaplanes Kawanishi H6K • Kawanishi H8K Four Engine Nakajima G5N Experimental Nakajima G8N • Mitsubishi B5M