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Mitsubishi Ko 1

The Mitsubishi Army Type Ko 1 Trainer was a licence-built version of the Nieuport 81-E2, one of the standard training aircraft in the early expansion of Japanese Army aviation.

Forty 81-E2s were imported from France from January 1919.

As the original aircraft were damaged or destroyed, and the need for training aircraft began to increase, the Japanese Army decided to manufacture the 81-E2 and 83-E2 itself, but this arrangement only lasted for a short period.

The army then gave Mitsubishi a contract to produce the 81-E2.

The first Mitsubishi-produced 81-E2 was completed in May 1922.

During the planning process the Mitsubishi-produced aircraft were known as the 81-E2, but in 1921 the Japanese Army introduced a new designation system for aircraft of foreign origin.

Each manufacturer was given a symbol, Ko in the case of Nieuport, and each new aircraft type was given a number.

These numbers were linked to the foreign manufacturer and not the Japanese company.

The 81-E2 became the Ko 1.

The Ko 2 was the 83-E2 trainer, which was produced in Japan by Nakajima.

The designation system didn’t take into account the role of aircraft, so the Nakajima Ko 3 was a licence-built version of the Nieuport 24.C 1 fighter.

A total of 57 Ko 1s were built.

They were used at the Tokorozawa Army Flying School, which was opened in 1922, and in small numbers at other institutions.

They remained in use with the Army until 1926, and many of the surviving aircraft were then transferred to civilian flying schools.


1st Flight 1922




7.10 m (23 ft 4 in)


9.00 m (29 ft 6 in) measurements of survivor indicate 9.15 m (30.0 ft)


2.70 m (8 ft 10 in)

Wing area

22.00 m2 (236.8 sq ft)

Empty weight

550 kg (1,213 lb)

Gross weight

825 kg (1,819 lb)

Fuel capacity

120 kg


1 × Clerget 9Z 9 cylinder air-cooled rotary engine,

82 kW (110 hp)


2-bladed 2.50 m (8 ft 2 in) Régy 274


2.55 m (8 ft 4 in) Régy 289 or 2.53 m (8 ft 4 in)

Eclair 2 wood fixed pitch propeller.


Maximum speed

146 km/h (91 mph, 79 kn) at 2,000 m (6,600 ft)


500 km (310 mi, 270 nmi)


3 hours

Service ceiling

4,000 m (13,000 ft)

Time to altitude

14 minutes 15 seconds to 2,000 m (6,600 ft)


1 × .303 in (7.7 mm) Lewis gun on Etévé gun ring in rear cockpit


Occasionally a second one on the upper wing.


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