The Yokosuka MXY-7 Ohka is a Japanese rocket-powered, piloted suicide attack aircraft built for the Imperial Japanese Navy. It was carried under a Mitsubishi G4M bomber and flown into ships with a 1,200 kg warhead, and Allied crews called it the 'Baka bomb'. Developed by First Naval Air Technical Arsenal, Yokosuka.
The Yokosuka MXY-7 Ohka is a Japanese rocket-powered, piloted suicide attack aircraft built for the Imperial Japanese Navy. Developed by First Naval Air Technical Arsenal, Yokosuka.
Photo: 田中ショウリ（Tanaka Shouri), Public domainSee Specifications for full detail.
The Yokosuka MXY-7 Ohka is a Japanese rocket-powered, piloted suicide attack aircraft built for the Imperial Japanese Navy. It was carried under a Mitsubishi G4M bomber, released near the target and flown into a ship by its pilot with a 1,200 kg warhead in the nose. Allied crews called it the 'Baka bomb'. [1] [2]
The Ohka first went into action on 21 March 1945 and was used mainly around Okinawa until June. Of the 300 available there, 74 took part in operations, and postwar analysis judged their impact negligible. [1]
Ensign Mitsuo Ohta of the 405th Kokutai conceived the design in 1943, with help from the Aeronautical Research Institute at the University of Tokyo, which supplied a scale model and wind-tunnel tests. He submitted the proposal on 5 August 1944 at the First Naval Air Technical Arsenal at Yokosuka, and the Naval General Staff ordered formal development on 16 August. [1]
The project was called Marudai. The first ten production-standard Model 11s were ready by the end of September 1944, unpowered flights began in October and powered flights in November, and the Navy ordered production before testing had finished. Yokosuka built 155 Model 11s and Kasumigaura about 600. [1] [2]
The Model 11 was 19 ft 11 in (6.07 m) long with a 16 ft 10 in (5.12 m) wingspan. Its fuselage was aluminium, the wings and tail were plywood, and the instrumentation was minimal. Three Type 4 Mark 1 Model 20 solid-fuel rockets each gave 588 lbf (2.62 kN) of thrust and burned for 8 to 10 seconds. There was no landing gear. [1]
The Ohka weighed 2,140 kg at launch, of which 1,200 kg was the Ammonal warhead. It was released from a G4M2e, glided toward the target and fired its rockets for the final approach, reaching 576 mph in a terminal dive against 403 mph in sustained flight. The 37 km range was the main weakness, because the slow carrier had to come within that distance of the fleet, where Allied fighters could reach it. [1] [2]
The first two attempts to ferry Ohkas to Leyte Gulf failed when the carriers Shinano and Unryu were sunk by the US submarines Archerfish and Redfish. On the first sortie, on 21 March 1945, 18 G4Ms took part. Allied fighters intercepted them, the Ohkas that were released fell short of their targets, and all the G4Ms were lost along with 26 of 30 escort fighters. A claimed hit on USS West Virginia on 1 April was later judged a near miss. [1] [2]
On 12 April nine G4Ms attacked and the destroyer USS Mannert L. Abele was sunk, the first Allied ship sunk by an Ohka. USS Jeffers shot down an Ohka but was damaged by the blast, and USS Stanly was hit with little damage. An Ohka hit the bridge of the destroyer USS Shea on 4 May, and on 11 May the destroyer USS Hugh W. Hadley was hit and judged beyond repair. The battleship USS Tennessee was also damaged. [1] [3]
The Model 22 replaced the rockets with a Tsu-11 motorjet and carried a 600 kg warhead, making its first flight in June 1945, and 50 were built. Planned developments included the Model 33 with an Ne-20 turbojet and an 800 kg warhead, and the folding-wing Model 43A and 43B for submarine or cave launch. None of those were built. [1]
Pilots trained on the unpowered K-1, built in a run of 45, and on the two-seat Model 43 K-1 Kai Wakazakura, of which two were completed. Total production is given as 852 aircraft, with 755 of them Model 11s. [1] [2]
The Yokosuka MXY-7 Ohka has a top speed of 501 kn (576 mph / 927 km/h).
A total of 852 were built.
No, the Yokosuka MXY-7 Ohka has been retired. It retired in 1945.
The Yokosuka MXY-7 Ohka first flew on October 1st 1944.
The Yokosuka MXY-7 Ohka has a range of 23 mi (37 km, 20 nmi).
Examples survive in museums in Japan, the United States, the United Kingdom and India.
The Ohka was used only in 1945 and cannot appear on Flightradar24. Surviving examples are displayed in museums including the National Museum of the Marine Corps in Virginia, the RAF Museum in London and the Fleet Air Arm Museum at Yeovilton.
| Performance | |
| Max Speed | 501 kn (576 mph / 927 km/h) |
|---|---|
| Cruise SpeedCruise Speed — The economical speed an aircraft sustains for the bulk of a flight - lower than maximum speed, chosen for the best balance of time and fuel burn. Glossary → | Not applicable - released from a carrier aircraft, glided, then fired its rockets for the final dive |
| RangeRange — How far an aircraft can fly without refuelling. Quoted figures vary with payload, speed and reserves - see also ferry range and combat radius. Glossary → | 23 mi |
| Service CeilingService Ceiling — The highest altitude at which an aircraft can still climb at a useful rate (typically 100 ft/min). Above it, the air is too thin to keep climbing meaningfully. Glossary → | Not publicly disclosed - released from a carrier aircraft rather than flown to altitude |
| Airframe & Weight | |
| Wingspan | 16 ft 10 in |
| Length | 19 ft 11 in |
| Height | 3 ft 10 in |
| WeightMTOW — Maximum Take-Off Weight - the heaviest an aircraft is certified to be at the start of its take-off run, including fuel, crew, payload and the aircraft itself. Glossary → | empty: 970 lb; MTOW: 4,718 lb |
| Power & Payload | |
| Engines | 3 x Type 4 Mark 1 Model 20 solid-fuel rockets, 588 lbf (2.62 kN) each, burning for 8 to 10 seconds |
| ArmamentArmament — The weapons an aircraft can carry: guns, missiles, bombs and rockets, whether mounted internally, on wing hardpoints, or in bomb bays. Glossary → | 1,200 kg (2,646 lb) Ammonal warhead in the nose |
| Crew | 1 |
| CapacityPayload — Everything an aircraft is carrying that isn't the aircraft or its fuel: passengers, cargo, or weapons. Payload and fuel usually trade off against each other. Glossary → | 1,200 kg (2,646 lb) warhead |
| Program & Service | |
| Manufacturer | First Naval Air Technical Arsenal, Yokosuka |
| Origin | Japan |
| First Flight | October 1st 1944 |
| Service Entry | March 21st 1945 |
| Retired | 1945 |
| Number Built | 852 |
| Unit Cost | Not publicly disclosed - no per-aircraft price was found in the sources checked |
| Combat Losses | Of 300 Ohkas available at Okinawa, 74 took part in operations and 56 were destroyed with their carrier aircraft or during attacks. All 18 G4M carriers were lost on the first sortie on 21 March 1945. |
4 notable events involving the MXY-7 Ohka, 1945 to 1945. Curated rather than exhaustive.
Eighteen G4M carriers took part. Allied fighters intercepted them, and all the G4Ms were lost along with 26 of 30 escort fighters. The Ohkas that were released scored no hits.
The destroyer Mannert L. Abele was sunk off Okinawa, the first Allied ship sunk by an Ohka. USS Jeffers shot down an Ohka but was damaged by the blast, and USS Stanly was hit with little damage.
One Ohka hit the bridge of the destroyer USS Shea, and USS Gayety took a near miss. One of the seven G4Ms returned.
The destroyer Hugh W. Hadley was hit by an Ohka, suffered extensive damage and flooding, and was judged beyond repair.
| Model 11 | The main combat version, with three solid-fuel rockets and a 1,200 kg warhead. The first ten were ready by the end of September 1944. A total of 755 were built, 155 at Yokosuka and about 600 at Kasumigaura, and the Navy ordered production before powered testing had finished. |
| K-1 | An unpowered trainer that used water ballast, built at Yokosuka for pilot training. Most sources give 45 built, though one history gives 54. |
| Model 22 | A version with a Tsu-11 motorjet in place of the rockets and a smaller 600 kg warhead, designed to be carried by the Yokosuka P1Y Ginga bomber. The first flight was in June 1945 and 50 were built at Yokosuka. |
| Model 43 K-1 Kai Wakazakura | A two-seat trainer with a single rocket, of which two were completed. It belongs to the Model 43 family, which also included the folding-wing Model 43A and 43B for submarine or cave launch. Neither of those was built. |
| Model 33 and Model 53 | Planned turbojet versions that never entered production. The Model 33 used an Ne-20 turbojet and an 800 kg warhead and was cancelled. The Model 53 was to be towed to the target like a glider. Neither flew. |
Examples survive in museums in Japan, the United States, the United Kingdom and India. Only one Model 22 is known to survive.
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