The Nakajima Army Type 91 Fighter was a Japanese fighter of the 1930s. It was a single-engine, single-seat

parasol An umbrella or parasol is a folding canopy (building), canopy supported by wooden or metal ribs that is usually mounted on a wooden, metal, or plastic pole. It is designed to protect a person against rain or sunburn, sunlight. The term ''umbr ...

monoplane A monoplane is a fixed-wing aircraft configuration with a single mainplane, in contrast to a biplane or other types of multiplanes, which have multiple planes. A monoplane has inherently the highest efficiency and lowest drag of any wing con ...

with a fixed,

tailwheel Conventional landing gear, or tailwheel-type landing gear, is an aircraft undercarriage consisting of two main wheels forward of the center of gravity and a small wheel or skid to support the tail.Crane, Dale: ''Dictionary of Aeronautical Term ...

undercarriage.

Development

Designed in response to an

Army An army (from Old French ''armee'', itself derived from the Latin verb ''armāre'', meaning "to arm", and related to the Latin noun ''arma'', meaning "arms" or "weapons"), ground force or land force is a fighting force that fights primarily on ...

requirement of 1927, the Type 91 was developed from the NC series of fighter prototypes. The prototype was the sixth machine under that designation but was a fundamentally distinct airframe design. Compared to the earlier NC, the Type 91 had a smaller wing, relocated

fuel tank A fuel tank (also called a petrol tank or gas tank) is a safe container for flammable fluids. Though any storage tank for fuel may be so called, the term is typically applied to part of an engine system in which the fuel is stored and propelle ...

and wing-bracing

strut A strut is a structural component commonly found in engineering, aeronautics, architecture and anatomy. Struts generally work by resisting longitudinal compression, but they may also serve in tension. Human anatomy Part of the functionality o ...

Townend ring A Townend ring is a narrow- chord cowling ring fitted around the cylinders of an aircraft radial engine to reduce drag and improve cooling. Development The Townend ring was the invention of Dr. Hubert Townend of the British National Physica ...

-type

cowling A cowling is the removable covering of a vehicle's engine, most often found on automobiles, motorcycles, airplanes, and on outboard boat motors. On airplanes, cowlings are used to reduce drag and to cool the engine. On boats, cowlings are a cove ...

, new design tail and undercarriage. It first flew in 1931.

Operational history

The Army ordered the new aircraft as the Nakajima Army Type 91 Fighter and the first deliveries took place late in 1931. However, issues arose with both directional stability and

centre of gravity In physics, the center of mass of a distribution of mass in space (sometimes referred to as the balance point) is the unique point where the weighted relative position of the distributed mass sums to zero. This is the point to which a force ma ...

, with the result that the type was delayed entering service. Between 1931 and 1934, 420 aircraft were constructed (including 100 by Ishikawajima; 23 of the total were Type 91-2, powered by a 432 kW (580 hp)

Nakajima Kotobuki The Nakajima Ha1 Kotobuki (寿, "Longevity") was an aero-engine developed by Nakajima. It was a radial piston developed under licence from the Bristol Jupiter. Design and development In 1917, Chikuhei Nakajima set up the "Airplane Institute" a ...

radial engine The radial engine is a reciprocating type internal combustion engine configuration in which the cylinders "radiate" outward from a central crankcase like the spokes of a wheel. It resembles a stylized star when viewed from the front, and is ...

. This version first flew in July 1934. The Type was supplanted in service by the Kawasaki Army Type 95 Fighter in 1936–1937.

Variants

;Nakajima NC :prototype & pre-serie version, powered by 336 kW (450 hp)

Jupiter Jupiter is the fifth planet from the Sun and the largest in the Solar System. It is a gas giant with a mass more than two and a half times that of all the other planets in the Solar System combined, but slightly less than one-thousandth t ...

radial engine, having a top speed of 268 km/h and larger wing. 8 built. ;Nakajima Army Type 91-1 Fighter :Main production version, powered by 336 kW - 390 kW (450 hp - 520 hp) Nakajima built

radial engine. ;Nakajima Army Type 91-2 Fighter :Improved version, powered by

. 21 built.

Operators

; *The Chinese Nationalist Air Force purchased 12 Type 91-1 fighters which would later end up fighting against the Japanese during the

Second Sino-Japanese War The Second Sino-Japanese War (1937–1945) or War of Resistance (Chinese term) was a military conflict that was primarily waged between the Republic of China and the Empire of Japan. The war made up the Chinese theater of the wider Pacific Th ...

. ; *

Imperial Japanese Army Air Force The Imperial Japanese Army Air Service (IJAAS) or Imperial Japanese Army Air Force (IJAAF; ja, 大日本帝國陸軍航空部隊, Dainippon Teikoku Rikugun Kōkūbutai, lit=Greater Japan Empire Army Air Corps) was the aviation force of the Im ...

; *

Manchukuo Imperial Air Force The Manchukuo Imperial Air Force (') ( was the air force of the Empire of Manchuria, a puppet state of Imperial Japan. The air force's predecessor was the Manchukuo Air Transport Company (later renamed the Manchukuo National Airways), a paramilit ...

Survivors

The Tokorozawa Aviation Museum in

Tokorozawa, Saitama is a city located in Saitama Prefecture, Japan. , the city had an estimated population of 344,194 in 163,675 households and a population density of 4800 persons per km². The total area of the city is . Geography Tokorozawa is located in the ...

has a fuselage on display. Also, at a gate of Yanagisawa Shrine in

Yamatokōriyama is a city in Nara Prefecture, Japan. , the city has an estimated population of 84,059 and 38,944 households. Geography Yamato Koriyama is located in the northern part of the Nara Basin and stretches approximately 9 km from east to west and ...

Nara Prefecture is a prefecture of Japan located in the Kansai region of Honshu. Nara Prefecture has a population of 1,321,805 and has a geographic area of . Nara Prefecture borders Kyoto Prefecture to the north, Osaka Prefecture to the northwest, Wakayam ...

there is a propeller preserved.

Specifications (Nakajima Army Type 91-1 Fighter)

References

Bibliography

* * {{Nakajima aircraft Type 91, Nakajima High-wing aircraft Type 91 Single-engined tractor aircraft