Very few of the combat
planes built in Japan during the war had in-line liquid-cooled engines.
This was only partly due to the greater reliability of radial engines,
which from many points of view were almost ideal for use in a theatre
of war characterized by vast expanses of ocean. In practice however,
this situation resulted from the lack of a specific technological
tradition, a lack that prevented the Empire of the Rising Sun's
aeronautical industry from keeping up with the more aeronautically
advanced nations. This is proved by the fact that the construction of
the most famous Japanese aircraft provided with an "in-line" engine
(the Kawasaki Ki-61 Hien fighter, an aircraft with a remarkable
performance) was made possible only by the availability of German
Daimler-Benz DB 601 engines (the same as those of the Messerschmitt Bf
109) built under license.
The only other
exception worthy of mention is the Ki-32 light bomber, also
manufactured by Kawasaki in the second half of the 1930s. This
aircraft, inspired by the same operative concepts that led, more or
less at the same time, to the development of the Fairey Battle in Great
Britain, was the last bomber in the Imperial army to be powered by a
liquid-cooled engine. In fact, its career was plagued by difficulties
in engine tuning that, apart from making it generally unreliable,
contributed to increasing the widespread indifference toward this type
of engine. From the second half of 1938 until May 1940, a total of 854
Kawasaki Ki-32s were built and, following their debut in combat during
the second Sino-Japanese conflict, they remained in front-line service
until the beginning of 1942, subsequently being relegated to training
and secondary roles. In the Allies' code the Ki-32 was known as "Mary."
Kawasaki Ki-32 "Mary" of the 6th Sentai (6th Attack Group) Japanese
Imperial Army Air Force - Manchuria 1941
The project was
launched in May 1936, when the Imperial Army's technical authorities
asked Kawasaki and Mitsubishi to develop a single-engine monoplane
fighter capable of carrying a maximum of 992 lbs (450 kg) of bombs at
186 mph (300 km/h) and at an altitude between 6,550 ft (2000 m) and
13,150 ft (4000 m); maximum speed was to be 250 mph (400 km/h) at 9,850
ft (3000 m) and the defensive armament was to consist of two
machine-guns. The prototypes presented were quite similar with the
formula chosen in both cases was that of an all-metal mid-wing
monoplane with fixed landing gear and a bomb hold inside the fuselage.
The only difference lay in the power plants. While the Mitsubishi Ki-30
was provided with a 950 hp Nakajima Ha-5 14-cylinder radial engine, the
Kawasaki Ki-32 was powered by an 850 hp Ha-9-11 "V-12" engine
manufactured by the company itself.
The first of eight
Ki-32 prototypes took to the air in March 1937, but right from the
start of operative tests the aircraft revealed serious problems in
tuning, caused by the unreliability of the engine, and these problems
led to the project being suspended and set aside in favour of
However, the threat of
war led to a change of idea by the army's technical authorities. In
1938, it was decided to put Kawasaki bomber into production, too, and
the first aircraft came off the assembly lines later in the year.
Paradoxically, the number of Ki-32s built was much higher than that of
its Mitsubishi rival, of which 704 were built up to September.
(Army Type 98 Single
Engine Light Bomber - Kawasaki Ki-32)
Type: Two Seat
Pilot and Radio-Operator/Bombardier in an enclosed cockpit.
Imashi and Shiro Ota
Kawasaki Kokuki Kogyo K.K. (Kawasaki Aircraft Engineering Company
Limited) which was a wholly-owned subsidiary of Kawasaki Jukogyo K.K.
(Kawasaki Heavy Industries Company Limited). Production was
concentrated in two main plants, one manufacturing aircraft and engines
at Akashi, near Kobe and the other at Kagamigahara (Gifu) near Nagoya
which produced aircraft only. Smaller plants producing complete
airframes were located at Ichinomiya, also near Nagoya and at
Miyakonojo on Kyushu.
Army Type 98 (Kawasaki Ha-9-IIb) V-12 liquid cooled piston engine rated
at 850 hp (634 kW) for take-off, 775 hp (578 kW) at sea level and 950
hp (709 kW) at 12,470 ft (3800 m) driving a three-blade variable-pitch
Maximum speed 263 mph (423 km/h) at 12,925 ft (3840 m); cruising speed
186 mph (300 km/h); climb to 16,405 ft (5000 m) in 10 minutes 55
seconds; service ceiling 29,265 ft (8920 m).
operational range of 826 miles (1300 km) with a maximum range of 1,218
miles (1965 km).
Weights & Loadings:
Empty 5,179 lbs (2349 kg) with a maximum take-off weight of 8,293
lbs (3762 kg). Normal loaded weight was 7,802 lbs (3539 kg). Wing
loading 21.3 lbs/sq ft (104.1 kg/sq m) and power loading 9.2 lbs/hp
49 ft 2 9/16 in (15.00 m); length 38 ft 2 9/32 in (11.64 m); height 9
ft 6 3/16 in (2.90 m); wing area 365.972 sq ft (34.00 sq m).
forward-firing 7.7 mm (0.303 in) Type 89 machine-gun in the engine
cowling and one trainable rearward-firing 7.7 mm (0.303 in) Type 89
machine-gun and a normal bomb-load of 661 lbs (300 kg) with a maximum
of 992 lbs (450 kg) of bombs.
production aircraft (March 1937) and 846 Ki-32 Army Type 98 production
aircraft (July 1938 - May 1940).
flight (prototype) March 1937; service delivery July 1938; production
terminated in May 1940; withdrawn from front-line service in 1942 and
then given employment in training units.
(Imperial Japanese Army).
Units: 3rd, 6th,
10th, 35th, 45th, 65th and 75th Sentais.