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Mitsubishi F1M

The Mitsubishi F1M, also known as “Pete” by the Allied forces, served as a reconnaissance floatplane during World War II.

This aircraft, which belonged to the Imperial Japanese Navy, was the final biplane model utilized by the navy.

A total of 944 units were manufactured between the years 1936 and 1944. Within the navy, it was designated as the “Type Zero Observation Seaplane.”

In 1934, the Imperial Japanese Navy issued a specification to Mitsubishi, Aichi, and Kawanishi for a replacement for its Nakajima E8N floatplanes.

These floatplanes were utilized for short-ranged reconnaissance and observation missions from the Navy’s warships.

Mitsubishi’s design, known as the Ka-17 and designated F1M1 by the Japanese Navy, was a small all-metal biplane powered by a single Nakajima Hikari 1 radial engine.

This engine had a power rating of 610 kilowatts (820 hp), which was the same as the engine used by Aichi’s competing F1A.

The Ka-17 featured elliptical wings and meticulous efforts were made to minimize drag.

This was achieved by reducing the number of interplane struts and bracing wires. The first of the four F1M1s took flight in June 1936.

After experiencing poor stability both on the water and in the air, the F1M1 aircraft underwent a redesign to address these issues.

The wings were modified with straight tapered leading and trailing edges and greater dihedral, while the vertical fin and rudder were enlarged.

The aircraft’s floats were also enlarged to increase buoyancy, and the Hikari engine was replaced with a Mitsubishi Zuisei 14-cylinder radial engine, providing better forward visibility.

These modifications greatly improved the aircraft’s handling characteristics, resulting in the production of the Navy Type 0 observation seaplane Model 11 (F1M2).

A total of 940 F1M2 aircraft were built, with a maximum speed of 368 km/h and operating range of up to 1,072 km.

The F1M2 was armed with up to three 7.7 mm machine guns and could carry two 60 kg bombs, making it a versatile platform for the Imperial Japanese Navy.



Prototypes, Four built.


Two-seat reconnaissance floatplane for the Imperial Japanese Navy.


Two-seat training version.






9.5 m (31 ft 2 in)


11 m (36 ft 1 in)


4 m (13 ft 1 in)

Wing area

29.5 m2 (318 sq ft)

Empty weight

1,928 kg (4,251 lb)

Gross weight

2,550 kg (5,622 lb)

Max take-off weight

2,856 kg (6,296 lb)


1 × Mitsubishi MK2C Zuisei 13,

14-cylinder air-cooled radial piston engine,

652 kW (875 hp) for take-off

600 kW (800 hp) at 3,500 m (11,500 ft)


3-bladed variable-pitch propeller


Maximum speed

370 km/h (230 mph, 200 kn) at 3,440 m (11,290 ft)

Range: 740 km (460 mi, 400 nmi)

Service ceiling

9,440 m (30,970 ft)

Time to altitude

5,000 m (16,000 ft) in 9 min 36 sec

Wing loading

86.3 kg/m2 (17.7 lb/sq ft)


0.156 hp/lb (0.256 kW/kg)



2 × fixed forward-firing 7.7 mm (.303 in) Type 97 aircraft machine guns

1 × flexible rearward-firing 7.7 mm (.303 in) Type 92 machine gun


2 × 60 kg (132 lb) bombs (1 × 250 kg bomb for suicidal missions).

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