Ohka

Ohka Model 11 replica at the Yasukuni Shrine

The Yokosuka MXY-7 Ohka (桜花 "cherry blossom") was a purpose-built kamikaze aircraft employed by Japan towards the end of World War II. The US gave the aircraft the Japanese name Baka ("fool").

It was a small 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 towards the target and when close enough he would fire the Ohka's engine(s) and dive against the ship 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.

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 Yokisuka research facility. The 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 Model 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 Zen temple in Kamakura, and the Yasukuni Shrine in Tokyo. The general Japanese view is not that the Ohka pilots were brainwashed and coerced youths or fanatical zealots, but 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. The contrast is drawn with the cost benefit analysis of Islamic radical fundamentalists who employ suicide bombing, for the target of the special attack groups were only military and the reason for their sacrifice was the defence of their country and loved ones. [link]

Variants

Turbojet powered Model 22

The only operational Ohka was the Model 11. Essentially a 2,646 pound bomb with wooden wings and powered by Three Type 4 Model 1 Mark 20 solid-fuel rocket motors, the model 11 achieved great speed but only very limited range. This was problematic as it required the slow heavily laden mother aircraft to approach within 20 nautical miles the target, making them very vulnerable to fighter defences. There was one experimental variant of the model 11, the model 21 which had thin steel wings manufactured by 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 Model 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 1,320 pound warhead. None appear to have been used operationally, and only 3 of the experimental Tsu-11s engines were known to be produced.

TheType 33, was a larger version of the model 22 powered by an Ishikawajima Ne-20 turbojet with a 1,764-lb. warhead. The mothership was to be the G8N Renzan four-engined bomber. The Type 33 was cancelled due to the unlikelihood the Renzan would be available.

Other unbuilt planned types was 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 turboject but was to be towed like a glider and released nearby its target.

Operational versions

Kugisho/Yokosuka MXY-7 "Ohka" Model 11 Rocket Suicide Attacker. About 800 built.

Non-operational versions

Kugisho/Yokosuka "Ohka" Model 21 Rocket Suicide Attacker- steel wings. 1 built
Kugisho/Yokosuka "Ohka" Model 22 Turbojet Suicide Attacker. Fifty built
Kugisho/Yokosuka "Ohka" Model 33 Turbojet Suicide Attacker. Renzan drop.
Kugisho/Yokosuka "Ohka" Model 43A Ko Turbojet Suicide Attacker. Sub launch
Kugisho/Yokosuka "Ohka" Model 43B Otsu Turbojet Suicide Attacker. Cave launch
Kugisho/Yokosuka "Ohka" Model 53 Turbojet Suicide Attacker. Towed launch

Trainer versions

K1 Kai rocket assist trainers

Kuugisho/Yokosuka "Ohka" K-1 Suicide Attack Trainer
Kuugisho/Yokosuka"Ohka" K-1 Kai Suicide Attack Trainer

Surviving Aircraft

Some 850 were built, mostly Type 11. Surviving Ohkas include:

Type 11 — Royal Air Force Museum, Cosford. Ohka is Number [I-13 captured 1 April 1945 at Yontan, Okinawa]
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, Saitama
Type 11 — USMC Air Ground Museum, Quantico, Virginia
Type 11 — Planes of Fame Museum, Valle, Arizona Ohka Number [I-18 captured at Yontan]
Type 22 — Smithsonian National Air and Space Museum, Washington DC (restored 1993) Photo [here.]
Type 43 K-1 (rebuilt to represent a Type 11) — National Museum of the United States Air Force, Dayton, Ohio [Exhibit photos.]
Type 43 K-1 — Navy Memorial Museum, Washington DC [Exhibit Photo]
Type 43 K-1 Kai — Smithsonian National Air and Space Museum, Washington DC

Replicas:

Type 11 — Yasukuni Shrine, Tokyo. [Photo here]
Type 11 — Ohka Park in Kashima City.

Operational history

March 21 1945 — sixteen Ohka-carrying Betty G4M2e mother ships were to be escorted by Fifty five Zeros fly to attack Task Group 58.1 (Hornet, Bennington, Wasp, Belleau Wood). Another 2 Bettys were to escort and provide navigation and observation. Due to technical problems, all but thirty zeros have to turn back or cannot take off. The Ohka attack force is intercepted by fifty F6F Hellcats and the Ohkas are immediately jettisoned by the Bettys some 70 miles from the target. None of the Bettys return, no ships are attacked, 160 of the Jinrai Butai are dead, and only 15 damaged Zeros make it back.
April 1 1945 — Six Bettys attack the US Fleet off Okinawa. At least one makes a successful attack, with its Ohka hitting one of the 16" 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 US Fleet off Okinawa. Mannert L. Abele is hit, breaks in two, and sinks. Jeffers destroys an Ohka with AA fire fifty yards 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 (collecting the Stanly's ensign!) and crashed into the sea. One Betty returns.
April 14 1945 — seven Bettys attack the US Fleet off Okinawa. None return. None of the Ohkas appear to have been launched.
April 16 1945 — six Bettys attack the US Fleet off Okinawa. Two return, but no Ohkas hit their targets.
April 28 1945 — four Bettys attack the US Fleet off Okinawa at night. One returns. No hits.
May 4 1945 — seven Bettys attack the US Fleet off Okinawa. One Ohka hits the bridge of Shea, causing extensive damage and casualties. Vessel judged beyond repair. Gayety is also damaged by a near-miss by an Ohka. One Betty returns.
May 11 1945 — Four Bettys attack the US Fleet off Okinawa. Hugh W. Hadley is hit, suffers extensive damage and flooding. Vessel judged beyond repair.
May 25 1945 — eleven Bettys attack the US 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 US Fleet off Okinawa. Two return, but no hits were scored.

Specifications (Type 11)

External links

Wikimedia Commons has media related to:

[Special]

[Thunder Gods] 1989 book about Ohka squadron
[The Cherry Blossom Squadrons] 1973 book about Ohka squadron

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