AP 118 · No. 11 Section II · Aircraft Plate 112 / 370

Plate 112 of 370 · Second World War · Heavy bomber

Mitsubishi Ki-21-IIb

Ki-21-IIb manufacture number 4318, painted as Mitsubishi Ki-21-IIb ‘Sally’ manufacture number 4318 of the 2nd Chutai, 14th Sentai, Imperial Japanese Army Air Service, abandoned at Lae in New Guinea in July 1943 and photographed there by the Allies after its capture that September: a twin-engined heavy bomber with two Mitsubishi Ha-101 fourteen-cylinder radials in long nacelles driving three-bladed propellers, a glazed nose with a ball-mounted gun, a stepped glazed cockpit, the IIb’s conical dorsal gun turret, a mid-mounted wing spanning 22.5 m and a single fin and rudder, shown tail down on its wheels: dark green upper surfaces and fuselage sides, grey-green undersides, blue-black cowlings, brown propellers, a white-edged hinomaru on the fuselage, a white band round the rear fuselage and the 14th Sentai’s stylised ‘4’ in red outlined in white across the fin and rudder; no Ki-21 survives, the photographs are black and white and show only the rear fuselage and tail, so the colours are the standard 1942–43 Army finish, and the wing hinomaru, the turret, the starboard tail marking and the cowling and propeller colours follow photographs of other Ki-21-IIbs and standard practice (shape from a Japanese factory three-view scaled to the published span and length, with Ki-21-II changes from a second set of drawings and photographs).

3D model

Turn it over

A procedural model built in Blender from published dimensions, drawings and photographs, painted as Mitsubishi Ki-21-IIb ‘Sally’ manufacture number 4318 of the 2nd Chutai, 14th Sentai, Imperial Japanese Army Air Service, abandoned at Lae in New Guinea in July 1943 and photographed there by the Allies after its capture that September: a twin-engined heavy bomber with two Mitsubishi Ha-101 fourteen-cylinder radials in long nacelles driving three-bladed propellers, a glazed nose with a ball-mounted gun, a stepped glazed cockpit, the IIb’s conical dorsal gun turret, a mid-mounted wing spanning 22.5 m and a single fin and rudder, shown tail down on its wheels: dark green upper surfaces and fuselage sides, grey-green undersides, blue-black cowlings, brown propellers, a white-edged hinomaru on the fuselage, a white band round the rear fuselage and the 14th Sentai’s stylised ‘4’ in red outlined in white across the fin and rudder; no Ki-21 survives, the photographs are black and white and show only the rear fuselage and tail, so the colours are the standard 1942–43 Army finish, and the wing hinomaru, the turret, the starboard tail marking and the cowling and propeller colours follow photographs of other Ki-21-IIbs and standard practice (shape from a Japanese factory three-view scaled to the published span and length, with Ki-21-II changes from a second set of drawings and photographs). Drag to orbit, scroll or pinch to zoom · download .glb (1.5 MB)

Data plate

Specification

First flight, number built and top speed are for the whole family (Ki-21-I & II (Allied name ‘Sally’)); engine, crew and dimensions are for the Ki-21-IIb manufacture number 4318 modelled here.

History

The Ki-21-IIb ‘Sally’

In 1936 the Imperial Japanese Army asked Mitsubishi and Nakajima for a modern heavy bomber to replace its Ki-20s and the slow Mitsubishi Ki-1: a twin-engined monoplane with a crew of four or more, a bomb load of 750 kg and an endurance of five hours. Mitsubishi’s Ki-21, a clean, all-metal mid-wing design with retractable main wheels, a glazed nose and a single fin, first flew on 18 December 1936 and beat Nakajima’s Ki-19 in comparative trials. It entered service in 1938 as the Army Type 97 Heavy Bomber, with Nakajima building it under licence as well.

Ki-21s went to war in China in 1938 and joined the long bombing campaign against Chongqing, the Chinese wartime capital, where losses to Chinese fighters showed the early version was lightly armed and too vulnerable. The Ki-21-II, which flew in 1940, had more powerful Mitsubishi Ha-101 radials in longer cowlings, a larger tailplane and more armour and fuel tank protection; from 1942 the Ki-21-IIb replaced the long glazed dorsal canopy with a conical turret carrying a 12.7 mm machine gun. The Allies gave the type the code name ‘Sally’.

At the start of the Pacific War, Ki-21s supported the invasions of Malaya, the Philippines and Burma, and their raids on Rangoon in December 1941 met the American Volunteer Group’s P-40s and the RAF’s Buffaloes, who shot many down. By 1943 the Ki-21 was outclassed, and it was increasingly flown on night raids and as a transport, though it served to the end of the war over Burma, New Guinea and China; Thailand also flew it. A civil transport version, the MC-21, flew with Japanese airlines. 2,064 were built, 351 of them by Nakajima, and no complete Ki-21 survives.

This airframe

Ki-21-IIb manufacture number 4318, 14th Sentai

4318The airframe modelled

Manufacture number 4318 is a Ki-21-IIb completed by Mitsubishi in January 1942 and flown by the 2nd Chutai of the 14th Sentai, a heavy bomber unit that moved from Burma and the East Indies to New Guinea. It was left unserviceable at Lae on 13 July 1943 and found there when Australian troops took the town on 16 September 1943; two USAAF photographs taken soon afterwards show its rear fuselage and tail at close range, and a US intelligence report records its number and build date. It is modelled because no complete Ki-21 survives, and 4318 is the only Ki-21-IIb found whose identity, unit and markings are all documented. None is in a UK museum. The model shows it standing tail down on its wheels: dark green upper surfaces and fuselage sides, grey-green undersides, a white-edged hinomaru on the fuselage, one white band round the rear fuselage and the 14th Sentai’s stylised ‘4’ in red, the 2nd Chutai colour, outlined in white across the fin and rudder. Its shape comes from a Japanese factory three-view scaled to the type’s span and length, with the Ki-21-II’s larger tailplane, slimmer cowlings and turret from a second set of drawings and photographs. The front fuselage was wrecked and is not in the photographs, which are black and white, so the colours are the standard 1942–43 Army finish; the dorsal turret follows photographs of other Ki-21-IIbs in flight, and the wing hinomaru, the blue-black cowlings, the brown propellers and the starboard tail marking, which the photographs do not show, follow standard practice.

Where to see one

Not on charge

No complete Ki-21 survives.

All 370 plates

Profiles and models are procedural interpretations built in Blender from published dimensions, three-view drawings and photographs of each airframe. Treat the museum aircraft as the reference.