The Hitachi Hatsukaze (初風, Hatsukaze - fresh wind), also known as the Hitachi GK4 (short Navy), Hitachi Army Type 4 110hp Air Cooled Inline (Army long), Hitachi Ha47 (Army Hatzudoki) and Ha-11 model 11 (unified), was Hitachi's fourth design in a series of

aircraft engine An aircraft engine, often referred to as an aero engine, is the power component of an aircraft propulsion system. Most aircraft engines are either piston engines or gas turbines, although a few have been rocket powered and in recent years ma ...

s built in Japan prior to and during

World War II World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the World War II by country, vast majority of the world's countries—including all of the great power ...

. The original Hatsukaze was a license-built

Hirth HM 504 The Hirth HM 504 is a four-cylinder air-cooled inverted inline engine. The HM 504 was a popular engine for light aircraft of the 1930s-1940s, and it was used to power a number of Germany's trainer aircraft of World War II. The engine featured a ...

. Hatsukaze engines were air-cooled, four-cylinder, inverted inline engines developing around 82 kW (110 hp).Francillon p. 505.

Design and development

Hatsukaze engines were produced in very large numbers, as the powerplant for the license-built Bücker Bü 131 ''Jungmann'' variants that were the standard primary trainers for the

Imperial Japanese Navy The Imperial Japanese Navy (IJN; Kyūjitai: Shinjitai: ' 'Navy of the Greater Japanese Empire', or ''Nippon Kaigun'', 'Japanese Navy') was the navy of the Empire of Japan from 1868 to 1945, when it was dissolved following Japan's surrender ...

and

Imperial Japanese Army The was the official ground-based armed force of the Empire of Japan from 1868 to 1945. It was controlled by the Imperial Japanese Army General Staff Office and the Ministry of the Army, both of which were nominally subordinate to the Emper ...

. The naval version of the engine was designated GK4, the army version as Ha47. The ''Hatsukaze Model 12'' was the power section linked to a

compressor A compressor is a mechanical device that increases the pressure of a gas by reducing its volume. An air compressor is a specific type of gas compressor. Compressors are similar to pumps: both increase the pressure on a fluid and both can tr ...

to create a primitive

jet engine A jet engine is a type of reaction engine discharging a fast-moving jet (fluid), jet of heated gas (usually air) that generates thrust by jet propulsion. While this broad definition can include Rocket engine, rocket, Pump-jet, water jet, and ...

called a motorjet; the resulting

Ishikawajima Tsu-11 The Ishikawajima Tsu-11 was a motorjet produced in small numbers in Japan in the closing stages of World War II. It was principally designed to propel the Japanese Yokosuka MXY7 Ohka flying bomb, a kamikaze weapon. Design and development The ...

was intended to power

Yokosuka MXY7 Ohka The Yokosuka MXY-7 was a purpose-built, rocket-powered human-guided '' kamikaze'' attack aircraft employed by Japan against Allied ships towards the end of the Pacific War during World War II. Although extremely fast, the very short range of ...

Model 22

flying bomb A flying bomb is a manned or unmanned aerial vehicle or aircraft carrying a large explosive warhead, a precursor to contemporary cruise missiles. In contrast to a bomber aircraft, which is intended to release bombs and then return to its base fo ...

s. The standard Hatsukaze Model 11 engine was modified at a Navy arsenal by replacing the propeller drive shaft and engine front crankcase cover with a step-up gearbox. The gearbox increased engine output shaft RPM at a 1:3 ratio. At engine speed of 3,000 rpm, the compressor section was operating at 9,000 rpm. The compressed air was then ducted into a combustion chamber where a liquid fuel was sprayed and burnt. The heated compressed air then exits through the tailpipe providing static thrust of . It is likely that about 1/3 of the total thrust was contributed by adding the combustion chamber aft of the compressor. The Tsu-11 was also selected to power the

Yokosuka MXY9 Shuka The Yokosuka MXY9 ''Shuka'' (秋花, "Autumn flower") was a projected development of the MXY8 training glider, adding a small motorjet engine, the Tsu-11. It was intended to provide further training for pilots who were to fly the Mitsubishi ...

("Autumn Fire"), a trainer intended to prepare pilots for the Mitsubishi J8M rocket-powered interceptor. Neither of these aircraft entered service, however, as their development took place too late in the war.

Variants

;GK4 Hatsukaze :license-built Hirth HM 504 inverted inline four-cylinder aviation engine. ;GK4A Hatsukaze 11 :IJNAS (Imperial Japanese Navy Air Service) version, ; 339 built.Bridgeman ;Ha47 Model 11 :(long designation Army Type 4 110hp Air Cooled Inline) IJAAS (Imperial Japanese Army Air Service) version, ; 1,037 built. ;Hatsukaze Toku Model 13 : ("Toku" translates as "special") power section for the

Ishikawajima Tsu 11 The Ishikawajima Tsu-11 was a motorjet produced in small numbers in Japan in the closing stages of World War II. It was principally designed to propel the Japanese Yokosuka MXY7 Ohka flying bomb, a kamikaze weapon. Design and development T ...

motorjet engine

Applications

* Kyushu K9W1 Type 2 Momiji ("Cypress") license built Bücker Bü 131s. * Kokusai Ki-86 Type 4 ("Cypress") license built Bücker Bü 131s.

Specifications (Hatsukaze GK4A)

References

Notes

Bibliography

* Bridgeman, Leonard. "The Bücker Bü 131B 'Jungmann'." ''Jane's Fighting Aircraft of World War II''. London: Studio, 1946. . * Francillon, R.J. ''Japanese Aircraft of the Pacific War''. London, Putnam, 1970. . * * Jackson, Paul. ''Jane's All The World's Aircraft 2003–2004''. Coulsdon, UK: Jane's Information Group, 2003. {{Hitachi aeroengines Air-cooled aircraft piston engines 1930s aircraft piston engines Inverted aircraft piston engines Motorjet engines Hitachi