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Mitsubishi Ki-73 (Steve)

1944 SECRET WEAPONS OF THE IJA/IJN WORLD WAR 2 X-PLANE

Mitsubishi Ki-73 (Steve) History

In May 1943, the Japanese authorities introduced new requirements for long-range, single-seat, single-engine escort aircraft to protect bomber formations from interception by Allied fighters, which gradually gained air superiority in the Pacific and Southeast Asia. Tomio Kubo's Mitsubishi Ki-73 was the result of this requirement, but the type of development did not go beyond a single, incomplete prototype until the end of the war in 1945.

Kubo succeeded with his early twin-engine Ki-46 "Dinah". And eventually developed into the promising "Ki-83" long-range twin-engine heavy fighter, of which four prototypes were eventually built when the Ki-73 was finally abandoned.

Very unique to the Japanese-origin fighter design is the use of a counter-rotating propeller arrangement involving two three-blade systems. These are powered by a single 2,600-horsepower Mitsubishi Ha-203-II liquid-cooled 24-cylinder in-line "horizontal H" engine consisting primarily of two 12-cylinder engines mating and driving a twin-propeller unit.

The rest of the overall design is conventional - the engine is in the nose, the single-blade tail is in the rear, and the cockpit is above the mid-mass. The wings are straight monoplane appendages with truncated tips, and the landing gear is a fully retractable "trail" system.

Problems arose in early prototype form, mainly focusing on complex engine fit, and growing concerns about structure and control schemes, especially at expected speeds. Eventually, work on the problematic compound engine ended, which in turn ended the development of the Ki-73.

While the Ki-73 was never officially accepted into service and never entered mass production, captured Allied documents - they believed the type would soon be available - introduced the codename "Steve" for the series, But the series never existed.

The Ki-73 has a suggested top speed of 750 km/h, or about 466 mph, making it a quick install thanks to its powerful engine configuration and counter-rotating rotor blades. The sleek, streamlined body is also clean from nose to tail.

Weapons are likely to be just cannons, in keeping with Japanese fighting traditions at the end of the war, possibly 4 x 20mm systems buried in the wings (two units per wing).