Kawasaki Ha-40

Ha40
Preserved Daimler-Benz DB 601.
Type	Piston V12 aircraft engine
National origin	Japan
Manufacturer	Kawasaki
First run	1930s
Major applications	Kawasaki Ki-61
Developed from	Daimler-Benz DB 601

The Kawasaki Ha40, a.k.a. Army Type 2 1,100 hp Liquid Cooled In-line and Ha-60, was a license-built Daimler-Benz DB 601Aa 12-cylinder liquid-cooled inverted-vee aircraft engine. The Imperial Japanese Army Air Service (IJAAS) selected the engine to power its Kawasaki Ki-61 fighter.

The Daimler-Benz DB 601Aa was a development of the earlier DB 600, with direct fuel injection replacing the carburetor. Like all DB 601s, it had a 33.9 litre displacement. The first prototype with the direct fuel injection was test run in 1935, and an order for 150 engines was placed in February 1937.

A manufacturing license was granted to Aichi, for production of this engine for the IJN as the Atsuta and to Kawasaki for production of this engine for the IJAAF as the Ha40. Under the 1944 Unified System, this engine was re-designated as the Kawasaki Ha-60.

The Kawasaki Ha40 and the Aichi Atsuta were based on the engine that powered Germany's Messerschmitt Bf 109 fighter.

A new high-horsepower narrow-profile engine was required for the Kawasaki Ki-64 experimental fighter. The aircraft design called for a narrow-profile fuselage, and the solution that Kawasaki developed was the Ha-201 engine. Although similar to the Aichi Ha-70, where two Aichi Atsuta engines, mounted side-by-side behind the cockpit driving a single large propeller — an arrangement already used by the Daimler-Benz DB 606 that powered the Heinkel He 119 reconnaissance monoplane prototypes, and later inspired Japan's own Yokosuka R2Y reconnaissance aircraft from the seventh and eighth He 119 prototypes being sold to Japan in May 1940 — for the Japanese Ki-64, its own powerplant installation design called for the two Kawasaki Ha-40 engines to be separately mounted, one in the aircraft's nose, the other behind the cockpit.

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