The Ishikawajima Tsu-11 was a
motorjet
A motorjet is a rudimentary type of jet engine which is sometimes referred to as ''thermojet'', a term now commonly used to describe a particular and completely unrelated pulsejet design.
Design
At the heart the motorjet is an ordinary pist ...
produced in small numbers in
Japan
Japan ( ja, 日本, or , and formally , ''Nihonkoku'') is an island country in East Asia. It is situated in the northwest Pacific Ocean, and is bordered on the west by the Sea of Japan, while extending from the Sea of Okhotsk in the north ...
in the closing stages of
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 vast majority of the world's countries—including all of the great powers—forming two opposin ...
. It was principally designed to propel the Japanese
Yokosuka MXY7 Ohka
The Yokosuka MXY-7 was a purpose-built, rocket-powered aircraft, 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, t ...
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 for ...
, a
kamikaze
, officially , were a part of the Japanese Special Attack Units of military aviators who flew suicide attacks for the Empire of Japan against Allied naval vessels in the closing stages of the Pacific campaign of World War II, intending to d ...
weapon.
Design and development
The Tsu-11 used a four-cylinder inverted inline
Hitachi Hatsukaze
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 i ...
''Toku'' Model 13 piston engine — a license-built version of the German
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 ...
inverted, inline-four cylinder air-cooled engine, with the "model 13" version indicating its adaptation to drive a single-stage
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 transp ...
. A fuel injection system was fitted behind the compressor. In operation, fuel would be mixed with the compressed air and the resulting mixture ignited, creating thrust.
The engine was designed to overcome the major shortcoming of the Ohka Type 11 weapons, that of limited range. The Type 11 was powered by solid-fuel rocket motors, which provided tremendous acceleration, but had a very short burn time. The upshot of this was that the Ohka's carrier aircraft would have to fly very close to the target, making it vulnerable to interception. In practice, most Ohka-carrying bombers were shot down before they ever had the opportunity to launch their weapons. It was reasoned that a jet engine would provide high speed as well as enough range to keep the carrier plane safe long enough to release the Ohka and leave the area.
The engine was first tested hung underneath a
Yokosuka P1Y
The Yokosuka P1Y ''Ginga'' (銀河, "Galaxy") was a twin-engine, land-based bomber developed for the Japanese Imperial Navy in World War II. It was the successor to the Mitsubishi G4M and given the Allied reporting name "Frances".
Design and d ...
bomber sometime in 1944 and was deemed successful enough to order into production. The Ohka was adapted to accommodate the engine in a lengthened fuselage with jet intakes added at the sides. This configuration was designated Ohka Type 22. The Tsu-11 was also selected to power the
Yokosuka MXY9
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 J8 ...
''Shuka'' ("Autumn Fire") - a trainer intended to prepare pilots for the
Mitsubishi J8M
The Mitsubishi J8M ''Shūsui'' (Japanese: 三菱 J8M 秋水, literally "Autumn Water", used as a poetic term meaning "Sharp Sword" deriving from the swishing sound of a sword) was a Japanese World War II rocket-powered interceptor aircraft close ...
rocket-powered interceptor. Neither of these aircraft entered service, however, as their development took place too late in the war.
A single example of a Tsu-11 engine exists, preserved at the
National Air and Space Museum
The National Air and Space Museum of the Smithsonian Institution, also called the Air and Space Museum, is a museum in Washington, D.C., in the United States.
Established in 1946 as the National Air Museum, it opened its main building on the Nat ...
in
Washington, DC
)
, image_skyline =
, image_caption = Clockwise from top left: the Washington Monument and Lincoln Memorial on the National Mall, United States Capitol, Logan Circle, Jefferson Memorial, White House, Adams Morgan ...
. In 1997 it was installed in the museum's Ohka 22 during its restoration. Engineering analysis of the engine during the restoration process suggested that the fuel injection and combustion probably contributed little to the power of the engine, with most of the thrust actually being produced by the compressor.
Applications
*
Yokosuka MXY7 Ohka
The Yokosuka MXY-7 was a purpose-built, rocket-powered aircraft, 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, t ...
*
Yokosuka MXY9
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 J8 ...
See also
References
Bibliography
*
{{IHI aeroengines
Motorjet engines
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 ...