The Japanese held a talent for developing excellent twin-engined aircraft during World War 2 (1939-1945). The Kawasaki Ki-45 "Toryu" was produced in over 1,700 examples from late 1941 on and the Ki-46 "Dinah", used in the fast-reconnaissance role, was another example seeing similar production totals and service life. The latter design was from Tomio Kubo and, following the success of this product, Kubo an his design team tried their hand at a single-engine, single-seat long-range escort fighter in the Mitsubishi Ki-73 - an aircraft utilizing a 24-cylinder, 2,600 horsepower inline engine driving two three-bladed propeller units in a contra-rotating arrangement in the nose.
However, issues with the engine doomed the Ki-73 and this led to Kubo and his team to work on an all-new twin-engine heavy fighter design to fulfill a 1943 requirement for such an aircraft - the key quality being inherently good operational range. A typical form was selected which saw a centralized fuselage straddled by the engine nacelles fitted to each wing element. The wing mainplanes were fitted well-forward of midships. The two-seat cockpit was held at front and the fuselage tapered to the rear, the tail consisting of a sole vertical fin with mid-mounted horizontal planes. Each engine nacelle was underslung and spanned from before the wing leading edges to beyond the wing trailing edges. A "tail dragger" undercarriage was used. Each engine would drive a four-blade propeller.
First flight was had on November 18th, 1944and the design immediately proved itself a strong platform with good handling characteristics and agility. Power came from 2 x Mitsubishi Ha-211 "Ru" 18-cylinder air-cooled radial engines outputting at 2,070 horsepower each. As a fighter, the aircraft was slated to carry a formidable front-facing array of 2 x 30mm and 2 x 20mm cannons in the nose - giving it a potent punch against any and all Allied fighters and bombers of the period. Performance specifications indicated a fast mount with a maximum listed speed of 440 miles per hour. Cruising speeds would be closer to 280mph. Operational range was out to 1,215 miles and a service ceiling of 41,500 feet being reported.
For its time, the Ki-83 represented one of the more advanced project aircraft capable of making a difference in Japanese fortunes in the war. However, the Allied bombing campaign of the Japanese homeland truly restricted what could be had and what could not. Four prototypes of the Ki-83 were ultimately realized but the Japanese surrender of August 1945 derailed any and all hopes for the line to see serial production reached. In the immediate post-war period, the Ki-83 was studied extensively by American researchers who knew nothing of the aircraft's existence until after the war.
Beyond the stated Ki-83 version, there were plans for two primary offshoots to emerge - the Ki-95 and the Ki-103. The Ki-93 is known to have been along the lines of a fast-reconnaissance platform but was never built.