Ohka

The Yokosuka MXY-7 "Ohka", (櫻花 "cherry blossom", Hebon-shiki transcription Ōka, ) was a purpose-built, rocket powered kamikaze aircraft employed by Japan towards the end of World War II. The United States gave the aircraft the name "Baka" (Japanese for "idiot").

It was a manned flying bomb that was carried underneath a Mitsubishi G4M "Betty", Yokosuka P1Y Ginga "Frances" (guided Type 22) or planned Heavy Nakajima G8N Renzan "Rita" (transport type 43A/B) bomber to within range of its target; on release, the pilot would first glide toward the target and when close enough he would fire the Ohka's rocket engine and guide the missile towards the ship that he intended to destroy. The final approach was almost unstoppable (especially for Type 11) because the aircraft gained tremendous speed. Later versions were designed to be launched from coastal air bases and caves, and even from submarines equipped with aircraft catapults, although none were actually used this way. It appears that the operational record of Ohkas used in action includes three ships sunk or damaged beyond repair and three other ships with significant damage. Seven US ships were damaged or sunk by Ohkas throughout the war.

Conceived by Ensign Mitsuo Ohta of the 405th Kokutai, and 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 decided the idea had merit and Yokosuka engineers of the First Naval Air Technical Bureau (Kugisho) created formal blueprints for what was to be the MXY7. The only variant which saw service was the Type 11, and was powered by three Type 4 Mark 1 Model 20 rockets. 150 were built at Yokosuka, and another 600 were built at the Kasumigaura Naval Air Arsenal.

Differing attitudes

There are sharply differing perspectives about the Ohka and her pilots inside Japan compared to perspectives outside Japan. 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 Kamakura, and the Yasukuni Shrine in Tokyo. The general Japanese view is that the Ohka pilots were heroic and selfless in the face of overwhelming odds. Others go further, such as Yoshinori Kobayashi, one of Japan's most famous manga (comic) artists, who presents in his manga books the ohka and other kamikazes as epitomizing the values that have been lost in modern Japan. [ [http://wgordon.web.wesleyan.edu/kamikaze/books/japanese/manga/kobayashi/index.htm Sensouron (On War) by Yoshinori Kobayashi] ]

Variants

The only operational Ohka was the Type 11. Essentially a 1200 kg (2,646 lb) bomb with wooden wings powered by three Type 4 Model 1 Mark 20 solid-fuel rocket motors, the Type 11 achieved great speed but with limited range. This was problematic as it required the slow heavily laden mother aircraft to approach within convert|20|nmi|km|-1 of the target, making them very vulnerable to defending fighters. There was one experimental variant of the Type 11, the Type 21, which had thin steel wings manufactured by [http://www.ne.jp/asahi/airplane/museum/nakajima/naka-cont-e.html] Nakajima.

The Ohka Type 22 was designed to overcome the short standoff distance problem by using a Campini type thermojet engine, the Tsu-11. This engine was successfully tested, and 50 Ohkas were built at Yokosuka to accept this engine. The Type 22 was to be launched by the more agile P1Y3 version of the Navy's Ginga bomber, necessitating a shorter wing span and much smaller 600 kg (1,320 lb) warhead. None appear to have been used operationally, and only three of the experimental Tsu-11s engines were known to be produced.

The Type 33, was a larger version of the Type 22 powered by an Ishikawajima Ne-20 turbojet with a 800 kg (1,764 lb) warhead. The mothership was to be the G8N Renzan four-engined bomber. The Type 33 was cancelled due to the likelihood that the Renzan would not be available.

Other unbuilt planned types were the Type 43A to be launched from submarines, and the 43B, a catapult/rocket assisted version, also with folding wings so that it could be hidden in caves. Two trainer versions were also under development for this version, the two person K-1 and the K-1 Kai, the former being a glider, and the latter fitted with a single rocket motor. In place of the warhead, a second seat was installed for the student pilot.

Finally, Type 53 was also to use the Ne-20 turbojet but was to be towed like a glider and released near its target.

Operational versions

*Kugisho/Yokosuka MXY-7 "Ohka" Type 11 Rocket Suicide Attacker. 852 built.

Non-operational versions

*Kugisho/Yokosuka "Ohka" Type 21 Rocket Suicide Attacker. Steel wings; one built.
*Kugisho/Yokosuka "Ohka" Type 22 Turbojet Suicide Attacker. Fifty built.
*Kugisho/Yokosuka "Ohka" Type 33 Turbojet Suicide Attacker. Renzan drop launch.
*Kugisho/Yokosuka "Ohka" Type 43A Ko Turbojet Suicide Attacker. Submarine launched.
*Kugisho/Yokosuka "Ohka" Type 43B Otsu Turbojet Suicide Attacker. Cave launched.
*Kugisho/Yokosuka "Ohka" Type 53 Turbojet Suicide Attacker. Towed launch.

Trainer versions

*Kugisho/Yokosuka "Ohka" K-1 Suicide Attack Trainer
*Kugisho/Yokosuka "Ohka" K-1 Kai Suicide Attack Trainer

urviving aircraft

Some 850 were built, mostly Type 11. Surviving Ohkas include:
*Type 11: Royal Air Force Museum, Cosford. Ohka is Number
*Type 11: Fleet Air Arm Museum, Yeovilton
*Type 11: Museum of Science and Industry in Manchester, Manchester
*Type 11: Defence Explosives Ordinance School, Kent
*Type 11: Indian Air Museum, New Delhi
*Type 11: Iruma Air Force Base, Iruma, Saitama
*Type 11: USMC Air Ground Museum, Quantico, Virginia
*Type 11: Planes of Fame Museum, Valle, Arizona Ohka Number
*Type 22: Smithsonian National Air and Space Museum, Washington, D.C. (restored 1993) Photo
*Type 43 K-1 (rebuilt to represent a Type 11): National Museum of the United States Air Force, Dayton, Ohio [http://www.j-aircraft.com/walk/rick_geithmann/mx.htm Exhibit photos.]
*Type 43 K-1: Navy Memorial Museum, Washington, D.C. [http://www.preservedaxisaircraft.com/Japan/Yokosuka/images/Ohka%20NMM.jpgExhibit Photo]
*Type 43 K-1 Kai: Smithsonian National Air and Space Museum, Washington, D.C.

Replicas:
*Type 11: Yasukuni Shrine, Tokyo.
*Type 11: Ohka Park in Kashima City.
*Type 11: [http://www.wingsofeagles.com/index.cfm Wings of Eagles Discovery Center] , Elmira-Corning Regional Airport, Chemung County, New York.

Operational history

* March 21 1945: Sixteen Ohka-carrying Betty G4M2e mother ships were to be escorted by 55 Zeros to attack Task Group 58.1 ("Hornet", "Bennington", "Wasp", and "Belleau Wood"). Another two Bettys were to escort and provide navigation and observation. Due to technical problems, all but 30 Zeros have to turn back or cannot take off. The Ohka attack force is intercepted by 50 F6F Hellcats and the Ohkas are immediately jettisoned by the Bettys some 70 miles (113 km) from the target. None of the Bettys return, no ships are attacked, 16 of the Jinrai Butai are dead, and only 15 damaged Zeros make it back.
* April 1 1945: Six Bettys attack the U.S. Fleet off Okinawa. At least one makes a successful attack, with its Ohka hitting one of the 16" (406 mm) turrets on the "West Virginia", causing moderate damage. "Alpine", "Achernar", and "Tyrrell" are also hit by kamikaze aircraft, but it is unclear whether any of these were Ohkas from the other Bettys. None of the Bettys return.
* April 12 1945: Nine Bettys attack the U.S. Fleet off Okinawa. "Mannert L. Abele" is hit, breaks in two, and sinks. Witnessed by LSMR-189 CO James M. Stewart. "Jeffers" destroys an Ohka with AA fire 50 yards (45 m) from the ship, but the resulting explosion is still powerful enough to cause extensive damage, forcing "Jeffers" to withdraw. "Stanly" is targeted by two Ohkas. One strikes just above the waterline, with the charge punching through the other side of the hull before detonating, causing little damage to the ship, and the other Ohka narrowly missed and crashed into the sea, knocking off the "Stanly"'s ensign in the process. One Betty returns.
* April 14 1945: Seven Bettys attack the U.S. Fleet off Okinawa. None return. None of the Ohkas appear to have been launched.
* April 16 1945: Six Bettys attack the U.S. Fleet off Okinawa. Two return, but no Ohkas hit their targets.
* April 28 1945: Four Bettys attack the U.S. Fleet off Okinawa at night. One returns. No hits.
* May 4 1945: Seven Bettys attack the U.S. Fleet off Okinawa. One Ohka hits the bridge of "Shea", causing extensive damage and casualties. "Gayety" is also damaged by a near-miss by an Ohka. One Betty returns.
* May 11 1945: Four Bettys attack the U.S. Fleet off Okinawa. "Hugh W. Hadley" is hit, suffers extensive damage and flooding. Vessel judged beyond repair.
* May 25 1945: Eleven Bettys attack the U.S. Fleet off Okinawa. Bad weather forces most of the aircraft to turn back, and none of the others score hits.
* June 22 1945: Six Bettys attack the U.S. Fleet off Okinawa. Two return, but no hits were scored.

pecifications (Type 11)

aircraft specification

plane or copter?=plane
jet or prop?=jet
crew=One
length main=6.10 m
length alt=20 ft 0 in
span main=5.10 m
span alt=16 ft 8 in
height main=1.20 m
height alt=3 ft 11 in
area main=6 m²
area alt=65 ft²
empty weight main=
empty weight alt=
loaded weight main=2,140 kg
loaded weight alt=4,720 lb
max takeoff weight main=kg
max takeoff weight alt= lb
more general=
engine (jet)=rocket motors
type of jet=
number of jets=3
thrust main=2.60 kN
thrust alt=587 lbf
max speed main=630 km/h
max speed alt=390 mph
range main=36 km
range alt=23 mi
ceiling main=
ceiling alt=
climb rate main=
climb rate alt=
loading main=356 kg/m²
loading alt=72 lb/ft²
thrust/weight=0.38
more performance=

Dive speed (3×Rocket motors Full-Boost): 1,040 km/h (650 mph)
armament=
* 1,200 kg (2,650 lb) trinitroaminol warhead

ee also

*Japanese Special Attack Units
*Secret and special weapons in Showa Japan
*Flying bomb
*"The Cockpit", an anthology of short films containing one about an Ohka pilot, reflecting Japanese sentiments of themaircontent
related=

similar aircraft=
Fieseler Fi 103 (V-1 flying bomb)

sequence=
MXY-4 -
MXY-5 -
MXY-6 -MXY-7 -
MXY-8 -
MXY-9

Notes

External links

* [http://www.morinoske.com/ Morinoske: Pilot testimonials - and more]
* [http://wgordon.web.wesleyan.edu/kamikaze/books/general/naito/index.htm "Thunder Gods"] 1989 book about Ohka squadron
* [http://wgordon.web.wesleyan.edu/kamikaze/books/general/hagoromo/index.htm "The Cherry Blossom Squadrons"] 1973 book about Ohka squadron
* [http://www.geocities.jp/torikai007/1945/ohka.html| The History of Kamikaze "Ohka" 桜花] ja icon