The Nakajima Ki-115 Tsurugi was a one-man kamikaze aircraft developed by the Imperial Japanese Army Air Force in the closing stages of World War II in 1945.
The Imperial Japanese Navy called this aircraft Tōka.
The aircraft’s intended purpose was to be used in kamikaze attacks on Allied shipping and the invasion fleet expected to be involved in the invasion of Japan, Operation Downfall, which in the end did not take place.
Because the Japanese High Command thought that Japan did not have enough obsolete aircraft to use for kamikaze attacks, it was decided that huge numbers of cheap, simple suicide planes should be constructed quickly in anticipation of the invasion of Japan.
The aircraft was very simple, being made from “non-strategic” materials (mainly wood and steel).
To save weight, it was to use a jettisonable undercarriage (there was to be no landing), so a simple welded steel tube undercarriage was attached to the aircraft.
This, however, was found to give unmanageable ground-handling characteristics, so a simple shock absorber was then incorporated.
The cross section of the fuselage was circular and not elliptical as were most planes of this size and type; such a fuselage was easier to make.
Tsurugi had an instrument panel with some flight instruments, rudder pedals, a joystick type control column and a place for a radio.
Flight controls included both ailerons and elevators and (in production versions) flaps.
The Ki-115 was designed to be able to use any engine that was in storage for ease of construction and supply, and to absorb Japan’s stocks of obsolete engines from the 1920s and 1930s.
The initial aircraft (Ki-115a) were powered by 858-kilowatt (1,151 hp) Nakajima Ha-35 radial engines
It is not known if any other engine was ever actually fitted.
After testing the first production aircraft were fitted with the improved undercarriage and two rocket units.
These may have assisted with take-off or may have been designed for the final acceleration towards the target.
Variants
Ki-115 Tsurugi
Single-seat suicide attack aircraft, production version.
Specifications
Crew
1
Length
8.55 m (28 ft 1 in)
Wingspan
8.6 m (28 ft 3 in)
Height
3.3 m (10 ft 10 in)
Wing area
12.4 m2 (133 sq ft)
Empty weight
1,640 kg (3,616 lb)
Gross weight
2,580 kg (5,688 lb)
Max take-off weight
2,880 kg (6,349 lb) with 800 kg (1,764 lb) bomb
Powerplant
1 × Nakajima Ha-35 Model 23,
14-cylinder air-cooled radial piston engine,
840 kW (1,130 hp) for take-off
980 hp (731 kW) at 6,000 m (20,000 ft)
Powerplant
2 × solid rocket attack boosters (optional)
Propellers
3-bladed fixed-pitch metal propeller
Performance
Maximum speed
550 km/h (340 mph, 300 kn) at 2,800 m (9,186 ft) with undercarriage jettisoned
