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Mitsubishi A5M

The Mitsubishi A5M, Navy designation Mitsubishi Navy Type 96 Carrier-based Fighter, experimental Navy designation Mitsubishi Navy Experimental 9-Shi Carrier Fighter, company designation Mitsubishi Ka-14, was a Japanese carrier-based fighter aircraft.

It was the world’s first low-wing monoplane shipboard fighter to enter service

In 1934, the Imperial Japanese Navy prepared a specification for an advanced fighter, requiring a maximum speed of 350 km/h (220 mph) at 3,000 m (9,800 ft) and able to climb to 5,000 m (16,000 ft) in 6.5 minutes.

This 9-shi (1934) specification produced designs from both Mitsubishi and Nakajima.

Mitsubishi assigned the task of designing the new fighter to a team led by Jiro Horikoshi (original creator of the similar but unsuccessful Mitsubishi 1MF10, and later responsible for the famous A6M Zero).

The resulting design, designated Ka-14 by Mitsubishi, was an all-metal low-wing fighter, with a thin elliptical inverted gull wing and a fixed undercarriage, which was chosen as the increase in performance (estimated as 10% in drag, but only a mere 3% increase in maximum speed) arising from use of a retractable undercarriage was not felt to justify the extra weight.

The first prototype, powered by a 447 kW (600 hp) Nakajima Kotobuki 5 radial engine, flew on 4 February 1935.

The aircraft far exceeded the requirements of the specification, with a maximum speed of 450 km/h (280 mph) being reached.

The second prototype was fitted with a revised, ungulled wing, and after various changes to maximize manoeuvrability and reduce drag, was ordered into production as the A5M.

With the Ka-14 demonstrating excellent performance, the Imperial Japanese Army Air Force ordered a single modified prototype for evaluation as the Ki-18.

While this demonstrated similar performance to the Navy aircraft and hence was far faster than the IJAAF’s current fighter, the Kawasaki Ki-10 biplane, the type was rejected by the army owing to its reduced manoeuvrability.

The Army then produced a specification for an improved advanced fighter to replace the Ki-10.

Mitsubishi, busy turning the Ka-14 into the A5M, submitted a minimally changed aircraft as the Ki-33, this being defeated by Nakajima’s competing aircraft, which was ordered into service as the Ki-27.



Six prototypes with various engines and design modifications.


Navy carrier-based fighter, Model 1

First production model with 633 kW (850 hp) Kotobuki 2 KAI I engine.

A5M2/2a/Model 21

More powerful engine.

A5M2b/Model 22

First production examples with NACA cowling and 477 kW (640 hp) Kotobuki 3 engine.


Prototypes with 448 kW (601 hp) Hispano-Suiza 12 Xcrs engine.


Model 24 (ex-Model 4): The A5M2b with different engine, closed cockpit, additional detachable fuel tank. The last production models (Model 34) with Kotobuki 41 KAI engine.


780 constructed by Mitsubishi. 39 constructed by Watanabe, 161 manufactured by Naval Ohmura Arsenal.


Two-seat trainer version of A5M4, 103 constructed by Naval Ohmura Arsenal.

Mitsubishi Ki-18

Single prototype land-based version for IJAAF, based on the A5M. 410 kW (550 hp) Kotobuki 5 engine.

Mitsubishi Ki-33

Two prototypes, a development of Ki-18 with a different engine, and closed cockpit.

Total Production (all variants): 1,094





7.565 m (24 ft 10 in)


11 m (36 ft 1 in)


3.27 m (10 ft 9 in)

Wing area

17.8 m2 (192 sq ft)



B-9 mod. (16%)


B-9 mod (9%)

Empty weight

1,216 kg (2,681 lb)

Gross weight

1,671 kg (3,684 lb)


1 × Nakajima Kotobuki 41 or 41 KAI,

9-cylinder air-cooled radial piston engine,

530 kW (710 hp) for take-off

585 kW (785 hp) at 3,000 m (9,843 ft)


3-bladed metal propeller


Maximum speed

435 km/h (270 mph, 235 kn) at 3,000 m (9,843 ft)


1,201 km (746 mi, 648 nmi)

Service ceiling

9,800 m (32,200 ft)

Time to altitude

3,000 m (9,843 ft) in 3 minutes 35 seconds

Wing loading

93.8 kg/m2 (19.2 lb/sq ft)


0.3161 kW/kg (0.1923 hp/lb)



2× 7.7 mm (0.303 in) Type 97 aircraft machine gun fuselage-mounted synchronized machine guns firing through the engine cylinders and propeller at about 1 and 11 o’clock.


2 x 30 kg (66 lb) bombs


1x 160 l (42.27 US gal; 35.20 imp gal) drop-tank.



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