The Empire of Japan and the nation of Germany had maintained a relationship since Prussian authorities made diplomatic contact on the Japanese mainland in 1860. However, World War 1 (1914-1918) delayed a forged alliance when Japan found itself against the German Empire and claimed several German territories in the Asia-Pacific region. During the interwar years that followed, the two nations would adopt similar militaristic-driven governments that controlled both political and military policy and this direction brought the two nations into agreement once more. Japan aligned with the Axis powers in World War 2 (1939-1945), joining Germany and Italy as principles in the fight though distances between the powers ultimately segregated combat into two defined fronts - the Pacific and European Campaigns.
During their alignment in World War 2, certain military agreements came to pass and one such resolution became availability of the technology driving the new German Messerschmitt Me 163 "Komet" rocket-powered interceptor. The Japanese government, not blind to the disastrous results of the Allied day/night bombing campaigns on Italy and Germany, understood the arrival of the high-altitude Boeing B-29 Superfortress would bring similar ruin to the Japanese mainland in time. Due to the advanced nature of the B-29, the heavy four-engined bomber could fly out of reach of available Japanese defenses including its interceptor arm. The Me 163 offered some hope - a supremely fast little aircraft outfitted with cannon armament designed exclusively to combat large bomber formations. Its rocket-powered nature ensured quick response times in achieving the required altitude prior to the bomber formation's arrival.
The Empire of Japan therefore capitulated on August 15th, 1945, officially ending World War 2 as a whole. The surrender would be signed on the deck of the American battleship USS Missouri on September 2nd 1945 and the Japanese defense industry would be dismantled for the foreseeable future. With the collapse of the Japanese Empire, the Mitsubishi J8M project also came to an end. All existing examples were confiscated by the Allies for evaluation and ultimate destruction. At war's end, some 60 training airframes had been completed while 7 of the combat-capable versions were available.
Overall, there were five defined variants in the J8M family line. The J8M1 was the initial aircraft designation armed with 2 x 30mm cannons and this was followed by the J8M2 for the IJN with its 1 x 30mm cannon armament. The J8M3 would have featured an elongated fuselage and wider wing span while being powered by a Tokuro-3 series engine of 4,400lbs thrust. Training versions by Yokosuka included the MXY-8 "Akigusa" based on the original J8M production model and the MXY-9 "Shuka", this being powered by a Tsu-11 thermojet engine - the Tsu-11 relying on a 4-cylinder inverted inline engine coupled to a single-stage compressor with fuel-injection system collectively (when ignited) producing thrust output via rather primitive means.
The Japanese end-product was highly similar to the original German Messerschmitt series complete with a short, stout fuselage housing a single-seat cockpit, well swept-back wing assemblies and a single vertical tail fin. Armament would have been 1 or 2 x 30mm cannons. The rocket engine was set within the fuselage and exhausted through a circular port under the vertical tail fin at rear. The volatile combination of T-Stoff and C-Stoff was retained and known to Japanese engineers as "Ko" and "Otsu" respectively. The pilot sat under a glazed canopy that hinged to the right side while his rear view was obscured by the raised fuselage spine. The Mitsubishi design would take off and land in much the same way as the Me 163 - via a jettisonable two-wheeled dolly for take-off and land on a skid located on the belly of the fuselage.
Overall, the rocket-propelled interceptor proved something of a technological dead-end from a tactical perspective - rocket powered vehicles being later used for weaponry, testing flight envelopes, breaking the sound barrier and ultimately reaching space. The "turbojet" engine had officially arrived and signified the new way of things, quickly supplanting the rocket engine as the next generation propulsion system. The Me 163 itself proved only a marginal success for the Germans and its reach over the skies of Japan may have met a similar fate. By mid-1945, the Pacific War was going to be won by the Allies regardless of the J8M's introduction into service - though the little aircraft provided the Empire of Japan with a fighting chance nonetheless.
19.69 ft (6 m)
31.17 ft (9.5 m)
8.79 ft (2.68 m)
3,186 lb (1,445 kg)
8,532 lb (3,870 kg)
559 mph (900 kph; 486 kts)
39,370 feet (12,000 m; 7.46 miles)
9,800 ft/min (2,987 m/min)
1 OR 2 x 30mm Type 5/Ho-155 cannons
J8M - Base series designation; primary IJN designation.
J8M1 - Initial model; 2 x 30mm cannon armament.
J8M2 - Second model intended for IJN based on the J8M1; 1 x 30mm cannon armament.
J8M3 - Intended for IJA and IJN; widened wingspan and lengthened fuselage; fitted with Tokuro-3 series engine of 4,400lbs thrust.
Ki-200 - IJA Designation of J8M
Ki-202 - Proposed Ki-200 follow-up for the IJA intended to provide increased flight time from rocket engine.
MXY-8 - Yokosuka-produced glider for training based on the J8M.
MXY-9 - Yokosuka-produced glider for training based on the J8M; fitted with Tsu-11 thermojet engine.