Mitsubishi A5M 'Claude'

Introduction and Developments
Service Record

Introduction and Developments

The Mitsubishi A5M 'Claude' was the first monoplane fighter to enter service with the Imperial Japanese Navy, and helped Japan to win air superiority over China in 1937-39, but had largely been replaced in front line units by the start of the Pacific War.

Mitsubishi A5M from the right
Mitsubishi A5M from the right

The A5M1 was developed in a second attempt to replace the existing Nakajima biplane fighters used by the Japanese Navy. The first attempt, which began in 1932, had seen the development of a Nakajima parasol monoplane and a Mitsubishi low-wing monoplane, but neither was accepted, and the Nakajima A2N1 was instead replaced by a similar biplane, the Nakajima A4N1.

This was only ever seen as an interim measure, and in 1934 a 9-Shi specification was issued for a new naval fighter. The new fighter was to have a top speed of 217mph at 9,845ft (350km/h at 3,000m), to be able to climb to 16,405ft (5,000m) in 6 min 30 secs, be no wider than 11m (36ft 1in) and no longer than 8m (26ft 3in). It was to be armed with two 7.7mm machine guns. Rather oddly the specification didn't include a requirement that the new fighter should be able to operate from aircraft carriers.

Mitsubishi responded with a monoplane, with a low-mounted inverted gull-wing (as seen later on the Corsair). The Mitsubishi Ka-14 had a fixed undercarriage, but great efforts were made to reduce drag in other areas, and the aircraft had a small cross-section and was of aluminium stressed-skin construction, with flush rivets. The prototype was powered by a 550hp Nakajima Kotobuki 5 radial engine.

Flight tests with the first prototype began on 4 February 1935. The new aircraft reached a top speed of 280mph, well above the requirements, but it was sometimes unstable in flight and tended to balloon when landing, a most undesirable attribute in a potential carrier fighter.

As a result of these problems the second prototype was given a new wing, this time with a level centre section and dihedral on the outer sections. A 640hp Nakajima Kotobuki 3 engine was used and trailing-edge flaps were added. Four more prototypes, most with different engines, were built, and the aircraft was accepted for production as the Navy Type 96 Carrier Fighter Model 1 (A5M1)


A5M1 (Navy Type 96 Carrier Fighter Model 1)

The first production of the A5M, the A5M1 was powered by the 580hp Nakajima Kotobuki 2 KAI I engine.

A5M2a (Navy Type 96 Carrier Fighter Model 2-1)

The A5M2a was powered by the Nakajima Kotobuki 2 KAI 3A

A5M2b (Navy Type 96 Carrier Fighter Model 2-2)

The A5M2b had an enclosed cockpit, 640hp Kotobuki 3 engine powering a three-bladed propeller and a NACA cowling with cooling flaps. The enclosed cockpit was unpopular with the pilots, and was removed on later aircraft.


The A5M3a was a version powered by a 610hp Hispano-Suiza twelve-cylinder liquid cooled engine, with a 20mm cannon firing through the propeller hub. Two prototypes were built, and this was the fastest version of the aircraft but the Japanese navy didn't want to become dependent on imported engines, so it didn't enter production.

A5M4 (Navy Type 96 Carrier Fighter Model 4, later Model 24)

The A5M4 was similar to the A5M2b, but with a Kotobuki 41 engine and an open cockpit. It could carry a 35 gallon ventral drop tank, increasing its range. At first it was designated as the Model 4, but later became the Model 24, indicating the second airframe version and fourth engine. This was the most numerous version of the aircraft. Mitsubishi built it until 1940, and then 200 were built by K.K. Watanabe Tekkoshoa and Dai-Nikuichi Kaigun Kokusho (21st Naval Air Arsenal) at Omura.

A5M4 (Navy Type 96 Carrier Fighter Model 34)

The A5M4 Model 34 introduced some minor airframe changes and a Kotobuki 41 KAI engine.


The A5M4-K was a two-seat trainer, produced at the 21st Naval Air Arsenal where work began on the design in 1940. The A5M4-K used the Kokobuki 41 engine, and had two open cockpits with large headrests and a roll-bar between them. It also had a small horizontal fin on the fuselage, introduced to improve stability.

Service Record

The first A5Ms entered service early in 1937, replacing the Nakajima A2N and Nakajima A4N. The aircraft arrived just in time to take part in the Second China-Japanese War, and made its large scale debut on 19 September 1937, when eighteen A5Ms clashed with a larger Chinese force over Nakajima. The Japanese pilots claimed 26 victories for no losses, and although the claims were exaggerated there was no doubt that the A5M was superior to the Hawk IIIs and Boeing 281s in Chinese service.

The A5M units were used to support the attacks on Nanking, Shanghai and Nanchang. During this period they began to clash with Soviet Polikarpov I-152 biplanes and I-16 monoplanes, with both sides claiming then and since to have had the better fighters. In general the two sides were fairly equally matched in early clashes, but the Japanese had the better of the fighting during 1938, and Soviet losses in China began to mount.

As the Chinese withdrew into the interior of their vast country, the Japanese reacted in two ways. Shorter range A5M2s used landing fields at Shanghai and Nanking, while the longer range A5M4, with a fuel drop tank, was introduced. Even with these changes there were very few clashes between Japanese and Chinese fighters during 1939.

During 1941 the Navy began to pull out of China in preparation for the wider Pacific War that was expected to erupt at any time. At the same time the A6M Zero began to enter service, and the A5M was rapidly phased out in front line units. The A5M was only involved in a few clashes with Allied aircraft. Aircraft from the carrier Ryujo took part in the attack on Davao on Mindanao, and the invasion of the Dutch East Indies, before receiving A6Ms after returning to Japan in April 1942. Land based aircraft in the Marshall Islands clashed with attacking American aircraft from the Enterprise and Yorktown, on 1 February. Finally, on 7 May 1942 two A5Ms from the carrier Shoho managed to get airborne before she was sunk by US torpedoes and bombs. Three victories were claimed by the two A5Ms and four A6Ms that launched, but with their carrier lost the aircraft had nowhere to go - one managed to land on a nearby island but the rest ditched.

Late in the war the remaining A5M4s and A5M4-K trainers were used in kamikaze attacks around the Japanese coast.

Specifications (A5M4)

Engine: Nakajima Kotobuki 41 nine-cylinder air-cooled radial engine
Power: 710hp at take-off, 785hp at 9,845ft
Crew: 1
Wing span: 36ft 1 3/16in
Length: 25ft 1 3/8in
Height: 10ft 4in
Empty Weight: 2,447lb
Loaded Weight: 3,135lb
Max Speed: 276mph at 10,000ft
Climb to 16,405ft: 6 min 26 secs
Armament: Two 7.7mm Type 89 machine guns
Pay-load: Two 66lb bombs or one 160 litre drop tank

Japanese Aircraft of World War II 1937-1945, Thomas Newdick. A useful shorter reference work looking at the combat aircraft fielded by the Japanese during the Second World War, along with those jet and rocket powered aircraft that got closest to being completed. A useful guide to the aircraft of the Japanese Army and Navy, a key element in the rapid expansion of Japanese power, and in the increasingly desperate defence of their expanded Empire as the war turned against them. Organised by type of aircraft, with enough information on each type for the general reader, and longer sections on key aircraft such as the Zero (Read Full Review)
cover cover cover

Air War Home Page - Air War Index - Air War Links - Air War Books
WWII Home Page - WWII Subject Index - WWII Links - WWII Books - Day by Day

How to cite this article: Rickard, J (1 August 2011), Mitsubishi A5M ‘Claude’,

Help - F.A.Q. - Contact Us - Search - Recent - About Us - Privacy