Kit No. FB15
Decals: Markings for five versions – all Imperial Japanese Navy, 1945
Comments: Engraved panel llines; Highly detailed kit of late WWII rocket-powered Japanese suicide weapon
In the Summer of 1944 a number of Japanese Naval officers of all ranks, increasingly concerned with the course of the war and the overwhelming material strength of the Allied forces advancing towards the Home Islands, began to advocate for the use of drastic new combat methods in light of the poor likelihood of staving off defeat by conventional means. One such officer was Ensign Mitsuo Ohta, a transport pilot serving with the 405th Kokutai, who conceived the idea of a rocket-propelled suicide aircraft that would be more or less invulnerable to interception.
With the help of personnel from the Aeronautical Research Institute of the University of Tokyo, Ensign Ohta proceeded to draft preliminary plans for his proposed aircraft, and in August 1944 submitted his drawings to the Dai-Ichi Kaigun Koku Gijitsusho at Yokosuka. Ensign Ohta’s proposal was favorably received by the Imperial Japanese Navy, which decided to proceed with the project and assigned the preparation of detailed drawings to a team of engineers led by Masao Yamana, Tadanao Mitsugi and Rokuro Hattori.
Designated MXY7, the Ohka, or Cherry Blossom, was primarily designed as an anti-invasion or coastal defense weapon to be launched from a mother ship such as a twin-engined Mitsubishi G4M (Allied code name: Betty). Once released, after an initial glide, the Ohka was to accelerate towards its target with the help of three solid-propellant rockets mounted in the tail, fired individually or in unison. The tiny aircraft — it was just shy of 20 feet long, with a wingspan of slightly more than 16 feet, 9 inches — was built of wood and non-critical metal alloys. Great care was taken in its design to enable it to be mass-produced by unskilled labor.
Instrumentation in the cockpit was kept to a minimum, and good maneuverability was demanded to achieve reasonable accuracy in the attacks for which it was designed. By September 1944, ten MXY7’s had been built. Given the formal designation of Navy Suicide Attacker Ohka Model 11, the initial version carried a 1,200 kg (2,646 lb.) warhead in the nose, and was to be transported in the modified bomb bay of a G4M2e bomber (Navy Type 1 Attack Bomber Model l24J). The powerplant was three Type 4 Mark 1 Model 20 rockets, producing a combined thrust of 1,764 lbs. for 8-10 seconds. Unpowered and powered flight trials began respectively in October and November 1944. These were successful, demonstrating that the Ohka would achieve a top speed of 403 mph at full rocket thrust.
Meanwhile, the Imperial Japanese Navy had put the Ohka into full production without waiting for the conclusion of the trials, and a total of 755 machines were completed by March 1945. On March 21, 1945, the Ohka had its combat debut with the 721st Kokutai, but the sixteen G4M2e mother ships were intercepted and forced to release their Ohkas short of the target. This highlighted the critical weakness preventing the Ohka from being a more effective weapon: Because of its short range, it was dependent on other, slower aircraft to get into the target area — and those aircraft were often vulnerable to enemy fighters. By this stage of the war, Japan’s fighter force had been bled white, and was unable to provide systematic, effective escort for Ohka missions. On April 1, 1945, the United States invaded Okinawa, the southernmost of the Japanese Home Islands, just over 400 miles from the nearest land mass in the chain. This day marked the Ohka’s first success, when they damaged the battleship West Virginia and three transport vessels. An Ohka also sank the destroyer Manner L. Abele off Okinawa on April 12th.
Due to the MXY7 Model 11’s critical flaw – short range, production of this type ceased in March 1945. Forty-five examples of an unpowered gilder version, dubbed the Ohka K-1, were produced for training purposes. These replaced the warhead in the nose with water ballast to duplicate the handling characteristics of the armed versions, with the pilots being able to release the water ballast in the last stages of flight to reduce the landing speed as the trainer came in on specially mounted skids.
The Ohka Model 22 was planned as an improved version of the Model 11. The Model 22 was smaller than the Model 11, having a shorter wingspan and a smaller warhead of 1, 323 llbs., and increased range due to the installation of a Campini-type jet engine with a 100 hp Hitachi four-cylinder in-line engine as a gas generator. Fifty of these new aircraft were delivered by the Dai-Ichi Kaigun Koku Gijitsusho, and a test flight was completed in July which proved fatal for the pilot when auxiliary rockets installed under the wings went off accidentally, causing a stall from which he could not recover. Plans were also developed for a larger version, dubbed Model 33, powered by an Ne-20 turbojet and carrying a 1,720 llb. warhead. The Model 33 was to be carried into battle by the Navy Attack Bomber Renzan (G8N1), which was faster than Mitsubishi’s G4M, but the low priority accorded G8N1 production doomed the Model 33. Yet another version, the Model 43A, was to be still larger and catapulted from the decks of surfaced submarines, and the Model 43B was similar to the 43A and would have been catapulted from caves in an invasion of the main Home Islands.
While an impressive technological achievement, the Ohka proved to be of little strategic value due to the critical deficiency of poor range. While the Japanese made efforts to correct this flaw, they ran out of time as the war ended before the engineering challenges presented by the early versions could be overcome. Highly recommended for those who appreciate detailed late war Kamikaze weapons.
Fine Molds’ Ohka is injection molded in grey and consists of 68 parts, three of which are clear plastic for the multi-part canopy. The instructions are clearly illustrated and indicated specific colors for painting at the various construction stages, but do not reference any particular paint manufacturer. The Ohka’s exterior is richly detailed with engraved panel lines, flush rivets, and other surface details, and appears to be highly accurate, worth every penny of its $30.00 price tag. The cockpit is spartan but with a modicum of detail, featuring a plain bucket seat for the pilot, but a control yoke, rudder pedals, and choice of instrument panels (early or late MXY7 versions), all of which were painstakingly molded with raised details.
The fuselage halves bear interior detail consisting of internal ribbing for the cockpit, onto which sidewall instrumentation is cemented. There is a great deal of attention to the Ohka’s internal workings; the 2600 lb. warhead which formed the Ohka’s payload is faithfully recreated, consisting of five parts that once assembled will resemble what in the actual Ohka was probably a naval artillery shell; and there is a fairly detailed assembly for the three-rocket powerplant that, like the warhead, must be cemented inside the fuselage halves before they themselves are cemented. The kit includes small external details for the control surfaces, as well as a towing dolly. There are decals for five versions, three of them for Naval Special Attack units based at Okinawa in April 1945, a fourth based at Atsugi in August 1945, and the fifth for an Ohka belonging to the 721st Air Group, 3rd Kamikaze Ohka Special Attack Unit based at Kanoya in April 1945. All versions are to be painted an overall scheme of Imperial Japanese Navy Grey.
Fine Molds have produced the most detailed kit of the Ohka on the market, a quantum leap over the old Testors kit. Highly recommended.
- Japanese Aircraft of the Pacific War by R.J. Francillon; Copyright 1970, Putnam & Company; London