Mitsubishi Ka-14 / A5M / Type 96/ Ki-18 / Ki-33
Among several 9-Shi requirements, in February 1934, the Imperial Navy issued an outline specification for a single-seat fighter. Carrier compatibility was not demanded, it being assumed that accommodating the dictates of deck use from the outset would inhibit the design team in achieving an advance in the state of the fighter design art although it was self-evident that the service would have no use for a fighter incapable of shipboard operation. In view of his experience with the earlier 7-Shi fighter, design responsibility was assigned to Jiro Horikoshi who created an all-metal semi-monocoque stressed-skin monoplane of inverted gull form designated Ka- 14. Powered by a 600 hp Nakajima Kotobuki (Congratulation) 5 nine-cylinder radial and carrying two 7,7-mm guns, the first Ka-l4 was flown on 4 February 1935. Latent doubts concern-ing the wing gulling had, meanwhile, led to elimination of this feature from the wing of the second prototype Ka-14 which also embodied split flaps and switched to a 715 hp Kotobuki 3 engine. This prototype was to provide the basis for the series production A5M 1 (Type 96) fighter, the first Ka-14 being fitted with a close-fitting, long-chord cowling as part of a drag reduction programme.
An Imperial Japanese Navy specification of 1934 for a single-seat fighter with a maximum speed of 350km/h then seemed an almost unattainable target. Mitsubishi's Ka-14 prototype was designed to this requirement, and flown for the first time on 4 February 1935. It demonstrated a top speed of 450km/h in early trials but had some aerodynamic shortcomings. The inverted gull-wing of this aircraft was replaced by a conventional low-set monoplane wing in the second prototype which, with a 436kW Nakajima Kotobuki 2-KAI-1 radial engine, was ordered into production as the Navy Type 96 Carrier Fighter Model 1 (Mitsubishi A5M1).
The generally similar A5M2a which followed, powered by the 455kW Kotobuki 2-KAI-3 engine, and the A5M2b with the 477kW Kotobuki 3 engine, were regarded as the Japanese navy's most important fighter aircraft during the Sino-Japanese War.
Two experimental A5M3 aircraft were flown with the Hispano-Suiza 12Xcrs engine, but the final and major production version was the A5M4, built also as the A5M4-K tandem two-seat trainer.
All versions of the A5M were allocated the Allied codename 'Claude', and when production ended a total of 788 had been built by Mitsubishi, including prototypes; a further 303 were built by Watanabe (39) and the Omura Naval Air Arsenal (264). The Japanese army had also shown interest in the A5M, resulting in the evaluation of a Ki-18 prototype generally similar to the Ka-14, but although fast this was considered to be lacking in manoeuvrability. Mitsubishi produced two re-engined and improved Ki-33 prototypes but they, too, were considered insufficiently manoeuvrable and no army production contract resulted. At the beginning of the Pacific war the A5M4 was in first-line use, but its performance was found inadequate to confront Allied fighters and by the summer of 1942 all had been transferred to second-line duties, many surviving A5M4 and A5M4-Ks being used in kamikaze attacks in the closing months of the war.
The acceptance of the Ka-14 9-Shi fighter by the Imperial Navy and evaluation of a modified prototype of this aircraft as the Ki-18 by the Imperial Army encouraged the formulation by the latter service during 1935 of a requirement for what was termed an "advanced fighter". Kawasaki, Mitsubishi and Nakajima were each asked to produce prototypes of a fighter surpassing the performance of the Ki-18. Whereas both Kawasaki and Nakajima produced fighters of entirely new design to meet the requirement (as the Ki-28 and Ki-27 respectively), Mitsubishi, preoccupied with refining the Ka-14 for series production for the Navy, lacked sufficient design capacity to develop yet a further fighter. The Ki-18, with comparatively minor changes, was therefore resubmitted.
As the Ki-33, the modified fighter was powered by a Nakajima Ha-l-Ko engine rated at 745hp at 3700m and enclosed by a broader-chord cowling. An aft-sliding part-canopy was added, the aft fuselage decking was raised and the vertical tail surfaces were modified. Completed during the early summer of 1936, the Ki-33 was submitted to comparative trials with the Ki-27 and Ki-28 from November 1936 until the spring of 1937. It was found to offer marginally superior max speeds between 2500m and 3500m over the 167kg lighter Ki-27, but the Ki-33 revealed an inferior turn rate and climb to those of the Nakajima contender which was selected for series production.
Engine: Nakajima Kotobuki (Congratulation) 5 nine-cylinder radial, 600 hp
Max speed, 276 mph (444 km/h) at 10,500 ft (3200 m)
Time to 16,405 ft (5 000 m), 5.9 min
Loaded weight, 3,087 lb (1373kg)
Span, 36ft l¼ in (11,00m)
Length: 25ft 2 in (7,67 m)
Height, l0 ft 8½ in (3,26 m)
Wing area, 172.23 sq ft (16,00 sq.m)
Armament: two 7,7-mm guns
Engine: Kotobuki 3, 715 hp
Engine: 1 x Nakajima "Kotobuki-41", 530kW
Max take-off weight: 1671 kg / 3684 lb
Empty weight: 1216 kg / 2681 lb
Wingspan: 11 m / 36 ft 1 in
Length: 7.57 m / 24 ft 10 in
Height: 3.27 m / 10 ft 9 in
Wing area: 17.8 sq.m / 191.60 sq ft
Max. speed: 430 km/h / 267 mph
Ceiling: 9800 m / 32150 ft
Range: 1200 km / 746 miles
Armament: 2 x 7.7mm machine-guns, 2 x 30-kg bombs
Engine: 1 x Nakajima Ha-l-Ko, 745hp at 3700m
Wingspan: 11.00 m / 36 ft 1 in
Length: 7.54 m / 24 ft 9 in
Height: 3.19 m / 10 ft 6 in
Wing area: 17.80 sq.m / 191.60 sq ft
Max take-off weight: 1462 kg / 3223 lb
Empty weight: 1132 kg / 2496 lb
Max. speed: 474 km/h / 295 mph