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The Yokosuka MXY-7 was a purpose-built,
rocket-powered A rocket-powered aircraft or rocket plane is an aircraft that uses a rocket engine for propulsion, sometimes in addition to airbreathing jet engines. Rocket planes can achieve much higher speeds than similarly sized jet aircraft, but typicall ...
human-guided ''
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 ...
'' attack aircraft employed by Japan against Allied ships towards the end of the
Pacific War The Pacific War, sometimes called the Asia–Pacific War, was the theater of World War II that was fought in Asia, the Pacific Ocean, the Indian Ocean, and Oceania. It was geographically the largest theater of the war, including the vast ...
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 vast majority of the world's countries—including all of the great powers—forming two opposin ...
. Although extremely fast, the very short range of the ''Ohka'' meant that it had to be carried into action as a
parasite aircraft A parasite aircraft is a component of a composite aircraft which is carried aloft and air launched by a larger carrier aircraft or mother ship to support the primary mission of the carrier. The carrier craft may or may not be able to later recov ...
by a much larger bomber, which was itself vulnerable to carrier-borne fighters. In action during the
Battle of Okinawa The , codenamed Operation Iceberg, was a major battle of the Pacific War fought on the island of Okinawa by United States Army (USA) and United States Marine Corps (USMC) forces against the Imperial Japanese Army (IJA). The initial invasion of ...
in 1945, ''Ohkas'' were able to sink or damage some escort vessels and transport ships but no major warships were ever sunk. Improved versions which attempted to overcome the aircraft's shortcomings were developed too late to be deployed.
Allied An alliance is a relationship among people, groups, or states that have joined together for mutual benefit or to achieve some common purpose, whether or not explicit agreement has been worked out among them. Members of an alliance are called ...
troops referred to the aircraft as "Baka Bombs".


Design and development

The MXY-7 Navy Suicide Attacker ''Ohka'' was a manned
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 ...
that was usually carried underneath a Mitsubishi G4M2e Model 24J "Betty"
bomber A bomber is a military combat aircraft designed to attack ground and naval targets by dropping air-to-ground weaponry (such as bombs), launching aerial torpedo, torpedoes, or deploying air-launched cruise missiles. The first use of bombs dropped ...
to within range of its target. On release, the pilot would first glide towards the target and when close enough he would fire the ''Ohka''s three
solid-fuel rocket A solid-propellant rocket or solid rocket is a rocket with a rocket engine that uses solid propellants ( fuel/oxidizer). The earliest rockets were solid-fuel rockets powered by gunpowder; they were used in warfare by the Arabs, Chinese, Persian ...
s, one at a time or in unison, and fly the missile towards the ship that he intended to destroy. The design was conceived by Ensign Mitsuo Ohta of the 405th
Kōkūtai A ''Kōkūtai'' () was a term used by the Imperial Japanese Navy Air Service (IJNAS) to designate a military aviation unit, similar to the Air Groups in other air arms and services of the time. (''Group'' in the British Royal Air Force, ''Gruppe ...
, aided by students of the Aeronautical Research Institute at the University of Tokyo. Ohta submitted his plans to the Yokosuka research facility. 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 ...
decided the idea had merit and Yokosuka
engineers Engineers, as practitioners of engineering, are professionals who invent, design, analyze, build and test machines, complex systems, structures, gadgets and materials to fulfill functional objectives and requirements while considering the limit ...
of the
Yokosuka Naval Air Technical Arsenal had many names, each depending on the period of its existence, and the circumstances at that time. Many of the names were acronyms that were derived from its military name or designation, which changed from time to time. The arsenal was sometim ...
(Dai-Ichi Kaigun Koku Gijitsusho, or in short ''Kugisho'') created formal blueprints for what was to be the MXY7. The only variant which saw service was the Model 11, and it was powered by three Type 4 Mark 1 Model 20 rockets. 155 ''Ohka'' Model 11s were built at Yokosuka, and another 600 were built at the Kasumigaura Naval Air Arsenal. The final approach was difficult for a defender to stop because the aircraft gained high speed ( in level flight and or even in a dive. Later versions were designed to be launched from coastal air bases and caves, and even from
submarine A submarine (or sub) is a watercraft capable of independent operation underwater. It differs from a submersible, which has more limited underwater capability. The term is also sometimes used historically or colloquially to refer to remotely op ...
s equipped with aircraft catapults, although none were actually used in this way. The was the first Allied ship to be sunk by ''Ohka'' aircraft, near
Okinawa is a prefecture of Japan. Okinawa Prefecture is the southernmost and westernmost prefecture of Japan, has a population of 1,457,162 (as of 2 February 2020) and a geographic area of 2,281 km2 (880 sq mi). Naha is the capital and largest city ...
on 12 April 1945. Over the course of the war, ''Ohka''s sank or damaged three ships beyond repair, significantly damaged three more ships, with a total of seven U.S. ships damaged or sunk by ''Ohka''s. The ''Ohka'' pilots, members of the ''Jinrai Butai'' (Thunder Gods Corps), are honored in Japan at ''Ohka'' Park in Kashima City, the ''Ohka'' Monument in Kanoya City, the Kamakura ''Ohka'' Monument at Kenchō-ji Zen temple in Kamakura, Kanagawa, and the
Yasukuni Shrine is a Shinto shrine located in Chiyoda, Tokyo. It was founded by Emperor Meiji in June 1869 and commemorates those who died in service of Empire of Japan, Japan, from the Boshin War of 1868–1869, to the two Sino-Japanese Wars, First Sino-Japane ...
in Tokyo. The only operational ''Ohka'' was the Model 11. Essentially a bomb with wooden wings, powered by three Type 4 Model 1 Mark 20 solid-fuel rocket motors, the Model 11 achieved great speed, but with limited range. This was problematic, as it required the slow, heavily laden mother aircraft to approach within of the target, making it very vulnerable to defending fighters. There was one experimental variant of the Model 11, the Model 21, which had thin steel wings manufactured by Nakajima. It had the engine of the Model 11 and the airframe of the Model 22. The Ohka K-1 was an unpowered trainer version with water ballast instead of warhead and engines, that was used to provide pilots with handling experience. Unlike the combat aircraft, it was also fitted with flaps and a landing skid. The water ballast was dumped before landing but it remained a challenging aircraft to fly, with a landing speed of . Forty-five were built by Dai-Ichi Kaigun Koku Gijitsusho. The Model 22 was designed to overcome the short standoff distance problem by using a
Campini Secondo Campini (August 28, 1904 – February 7, 1980) was an Italian engineer and one of the pioneers of the jet engine. Campini was born at Bologna, Emilia-Romagna. In 1931 he wrote a proposal for the Italian Air Ministry on the value of jet pro ...
-type motorjet engine, 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 The ...
. This engine was successfully tested, and 50 Model 22 ''Ohka''s were built at Yokosuka to accept this engine. The Model 22 was to be launched by the more agile Yokosuka P1Y3 ''Ginga'' "Frances" bomber, necessitating a shorter wing span and much smaller warhead. The first flight of a Model 22 Ohka took place in June 1945; none appear to have been used operationally, and only approximately 20 of the experimental Tsu-11 engines are known to have been produced. The Model 33 was a larger version of the Model 22 powered by an
Ishikawajima Ne-20 The Ishikawajima Ne-20 ( ja, 石川島 ネ-20) was Japan's first turbojet engine. It was developed during World War II in parallel with the nation's first military jet, the Nakajima Kikka. Design and development The decision to manufacture this ...
turbojet The turbojet is an airbreathing jet engine which is typically used in aircraft. It consists of a gas turbine with a propelling nozzle. The gas turbine has an air inlet which includes inlet guide vanes, a compressor, a combustion chamber, and ...
with an warhead. The mothership was to be the Nakajima G8N ''Renzan''. The Model 33 was cancelled due to the likelihood that the ''Renzan'' would not be available. Other unbuilt planned variants were the Model 43A with folding wings, to be launched from submarines, and the Model 43B, a catapult/rocket assisted version, also with folding wings so that it could be hidden in caves. A trainer version was also under development for this version, the two-seat Model 43 K-1 Kai Wakazakura (Young Cherry), fitted with a single rocket motor. In place of the warhead, a second seat was installed for the student pilot. Two of this version were built. Finally, the Model 53 would also use the Ne-20 turbojet, but was to be towed like a glider and released near its target.


Operational history

The Yokosuka MXY7 ''Ohka'' was used mostly against U.S. ships invading Okinawa, and if launched from its mothership, could be effective because of its high speed in the dive. In the first two attempts to transport the ''Ohkas'' to Leyte Gulf using aircraft carriers, the carriers and were sunk by the U.S. submarines and . Attacks intensified in April 1945. On 1 April 1945, six G4Ms attacked the U.S. fleet off Okinawa. At least one made a successful attack; its ''Ohka'' was thought to have hit one of the 406 mm (16 in) turrets on the battleship , causing moderate damage. Postwar analysis indicated that no hits were recorded and that a near-miss took place. The transports , , and were also hit by ''kamikaze'' aircraft, but it is unclear whether any of these were ''Ohkas'' from the other G4Ms. None of the G4Ms returned. The U.S. military quickly realized the danger and concentrated on extending their "defensive rings" outward to intercept the G4M/''Ohka'' combination aircraft before the suicide mission could be launched. On 12 April 1945, nine G4Ms attacked the U.S. fleet off Okinawa. The destroyer was hit, broke in two, and sank. destroyed an ''Ohka'' with AA fire 45 m (50 yd) from the ship, but the resulting explosion was still powerful enough to cause extensive damage, forcing ''Jeffers'' to withdraw. The destroyer was attacked by two ''Ohka''s. One struck above the waterline just behind the ship's bow, its charge passing completely through the hull and splashing into the sea, where it detonated underwater, causing little damage to the ship. The other ''Ohka'' narrowly missed (its pilot probably killed by anti-aircraft fire) and crashed into the sea, knocking off the ''Stanly''s ensign in the process. One Betty returned. On 14 April 1945, seven G4Ms attacked the U.S. fleet off Okinawa. None returned. None of the ''Ohka''s appeared to have been launched. Two days later, six G4Ms attacked the U.S. fleet off Okinawa. Two returned, but no ''Ohka''s had hit their targets. Later, on 28 April 1945, four G4Ms attacked the U.S. fleet off Okinawa at night. One returned. No hits were recorded. May 1945 saw another series of attacks. On 4 May 1945, seven G4Ms attacked the U.S. fleet off Okinawa. One ''Ohka'' hit the bridge of a destroyer, , causing extensive damage and casualties. was also damaged by an ''Ohka''s near miss. One G4M returned. On 11 May 1945, four G4Ms attacked the U.S. fleet off Okinawa. The destroyer was hit and suffered extensive damage and flooding. The vessel was judged beyond repair. On 25 May 1945, 11 G4Ms attacked the fleet off Okinawa. Bad weather forced most of the aircraft to turn back, and none of the others hit targets. On 22 June 1945, six G4Ms attacked the fleet. Two returned, but no hits were recorded. Postwar analysis concluded that the ''Ohka''s impact was negligible, since no U.S. Navy capital ships had been hit during the attacks because of the effective defensive tactics that were employed.Kightly, James. "Yokosuka Ohka Kamikaze Pilot." ''Aeroplane'', Volume 39, No. 7, Issue no. 459, July 2011, pp. 30–31. In total, of the 300 ''Ohka'' available for the Okinawa campaign, 74 actually undertook operations, of which 56 were either destroyed with their parent aircraft or in making attacks. The Allied nickname for the aircraft was "
Baka Baka, baká or BAKA may refer to: Ethnicities and languages * Baka people (Cameroon and Gabon), an African ethnic group * Baka people (Congo and South Sudan), an African ethnic group * Baka language, a dialect cluster of Cameroon and Gabon * Baka ...
", a Japanese word meaning "foolish" or "idiotic".


Variants

;MXY-7: Rocket powered suicide attacker, unpowered glider prototypes; ten built ;Navy Suicide Attacker ''Ohka'' Model 11: Long designation of the operational attacker ;''Ohka'' Model 11: Suicide attacker powered by 3 × Navy Type 4 Mark 1 Model 20 solid-fueled rocket motors, firing for 8–10 seconds; 755 built ;''Ohka'' Model 21: Suicide attacker, fitted with steel-built wings built by Nakajima; one built ;''Ohka'' Model 22: Suicide attacker, powered by an
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 ...
thermo-jet engine with reduced span wings and warhead, to be carried by Yokosuka P1Y1 Ginga bombers. 50 built by the ;''Ohka'' Model 33: Suicide attacker, powered by an
Ishikawajima Ne-20 The Ishikawajima Ne-20 ( ja, 石川島 ネ-20) was Japan's first turbojet engine. It was developed during World War II in parallel with the nation's first military jet, the Nakajima Kikka. Design and development The decision to manufacture this ...
turbojet engine, with an warhead, to be carried by the Nakajima G8N1 Renzan bomber ;''Ohka'' Model 43A ''Ko'': Suicide attacker, powered by a Ne-20 turbojet engine, with folding wings, to be catapult launched from submarines ;''Ohka'' Model 43B ''Otsu'': Suicide attacker similar to the Model 43A for catapult launching from caves ;''Ohka'' Model 53: Suicide attacker for aerotow launch, powered by a Ne-20 turbojet engine ;''Ohka'' K-1: Suicide attack training glider ;''Ohka'' Model 43 K-1 : Two-seat suicide attack glider trainer with flaps and retractable skid undercarriage, fitted with a single Type 4 Mark 1 Model 20 rocket motor, for limited powered flight ;"Suzuka-24" (Japanese designation unknown): Alleged interceptor version with warhead replaced by a fuel tank and two 20 mm cannon mounted on top. Supposedly employed at least twice against B-29 formations in April 1945


Surviving aircraft


India

* Model 11 on static display at the Indian Air Force Museum in Palam, New Delhi.


Japan

;On display * Model 11 on static display at Iruma Air Force Base in
Iruma, Saitama 260px, Tea fields in Iruma 260px, Kasumi River in Iruma is a city located in Saitama Prefecture, Japan. , the city had an estimated population of 147,166 in 66,516 households and a population density of 3300 persons per km². The total area of ...
. * On static display at the
Kawaguchiko Motor Museum is a museum located in Yamanashi prefecture, Japan. Founded in 1981J-HangarSpace - ...
in
Narusawa, Yamanashi is a village located in Yamanashi Prefecture, Japan. , the village had an estimated population of 3,152 in 1257 households, and a population density of 32.6 persons per km². The total area of the village is . Geography Narusawa is located in ...
. * Model 11 on static display a
Usashi Heiwa Museum
in Usa, Oita


United Kingdom

;On display * Model 11 on static display at the
Fleet Air Arm Museum The Fleet Air Arm Museum is devoted to the history of British naval aviation. It has an extensive collection of military and civilian aircraft, aero engines, models of aircraft and Royal Navy ships (especially aircraft carriers), and paintin ...
in
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. * Model 11 on static display at the
Imperial War Museum Imperial War Museums (IWM) is a British national museum organisation with branches at five locations in England, three of which are in London. Founded as the Imperial War Museum in 1917, the museum was intended to record the civil and military ...
in
London London is the capital and largest city of England and the United Kingdom, with a population of just under 9 million. It stands on the River Thames in south-east England at the head of a estuary down to the North Sea, and has been a majo ...
. * Model 11 on static display at the Royal Air Force Museum Cosford in Cosford, Shropshire. * Model 11 on static display at the
Science and Industry Museum The Science and Industry Museum in Manchester, England, traces the development of science, technology and industry with emphasis on the city's achievements in these fields. The museum is part of the Science Museum Group, a non-departmental pub ...
in
Manchester Manchester () is a city in Greater Manchester, England. It had a population of 552,000 in 2021. It is bordered by the Cheshire Plain to the south, the Pennines to the north and east, and the neighbouring city of Salford to the west. The t ...
.


United States

;On display * Model 11 on static display at the National Museum of the Marine Corps in Triangle, Virginia. * Model 11 on static display at the
Planes of Fame Air Museum Planes of Fame Air Museum is an aviation museum in Chino, California,World Wa ...
in Chino, California. * Model 11 on static display at the Yanks Air Museum in Chino, California. * Model 22 on static display at the Steven F. Udvar-Hazy Center of 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 Chantilly, Virginia. * Model 43B K-1 Kai Wakazakura on static display at the Pima Air & Space Museum in
Tucson, Arizona , "(at the) base of the black ill , nicknames = "The Old Pueblo", "Optics Valley", "America's biggest small town" , image_map = , mapsize = 260px , map_caption = Interactive map ...
. It is on loan from 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 ...
. * K-1 on static display at the National Museum of the United States Air Force in
Dayton, Ohio Dayton () is the sixth-largest city in the U.S. state of Ohio and the county seat of Montgomery County. A small part of the city extends into Greene County. The 2020 U.S. census estimate put the city population at 137,644, while Greater Day ...
. * K-1 on static display at the National Museum of the U.S. Navy in
Washington, D.C. ) , 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, ...


Replicas on display


Japan

* Model 11 on static display at the Yūshūkan of the
Yasukuni Shrine is a Shinto shrine located in Chiyoda, Tokyo. It was founded by Emperor Meiji in June 1869 and commemorates those who died in service of Empire of Japan, Japan, from the Boshin War of 1868–1869, to the two Sino-Japanese Wars, First Sino-Japane ...
in
Tokyo Tokyo (; ja, 東京, , ), officially the Tokyo Metropolis ( ja, 東京都, label=none, ), is the capital and largest city of Japan. Formerly known as Edo, its metropolitan area () is the most populous in the world, with an estimated 37.468 ...
.


United States

* Model 11 on static display at the National Warplane Museum in
Geneseo, New York Geneseo is a Administrative divisions of New York#Town, town in Livingston County, New York, Livingston County in the Finger Lakes region of New York (state), New York, United States. It is at the south end of the five-county Rochester metropol ...
.


Specifications (Ohka 11)


See also


References


Notes


Bibliography

* Ellis, Ken. ''Wreck & Relics, 23rd Edition'' Manchester: Crecy Publishing Ltd, 2012. * * * Maloney, Edward T. and the Aeronautical Staff of Aero Publishers, Inc. ''Kamikaze (Aero Series 7)''. Fallbrook, California: Aero Publishers, Inc., 1966. * . * * Sheftall, M.G. ''Blossoms in the Wind: Human Legacies of the Kamikaze''. New York: New American Library, 2005. . * Stafford, Edward P. ''Little Ship, Big War: The Saga of DE343.'' Annapolis, Maryland: Naval Institute Press, 2000. . *


External links

*
Baka... Flying Warhead
, ''C.I.C. (Combat Information Center)'', U.S. Office of the Chief of Naval Operations, June 1945.


''Popular Science'',August 1945, ''Japanese Gamble On Human Bombs''



The Mysterious Second Seat – Air & Space Magazine
{{DEFAULTSORT:Yokosuka Mxy7 Ohka 1940s Japanese attack aircraft Kamikaze Parasite aircraft World War II suicide weapons of Japan MXY7 Rocket-powered aircraft Aircraft first flown in 1944