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Mitsubishi Ki-73 (Steve)

Imperial Japan (1944)
Picture of Mitsubishi Ki-73 (Steve) Long Range Escort Fighter Proposal

The Mitsubishi Ki-73 made it to the design stage and no further - Allied intelligence reports assigned it the name of Steve believing it was to enter service soon.


Detailing the development and operational history of the Mitsubishi Ki-73 (Steve) Long Range Escort Fighter Proposal.  Entry last updated on 9/21/2015. Authored by Staff Writer. Content ©www.MilitaryFactory.com

During May of 1943, Japanese authorities delivered a new requirement for a single-seat, single-engine long-range escort fighter to protect bomber formations from interception by Allied warplanes beginning to gain the advantage in the skies over the Pacific and Southeast Asia. The Mitsubishi Ki-73 by Tomio Kubo was one result of this requirement but the type was not furthered beyond a sole, incomplete prototype before the war's end in 1945. Kubo managed to find success with his earlier twin-engine Ki-46 "Dinah" and eventually moved on to the promising "Ki-83" twin-engine, long-range heavy fighter design of which four prototypes ultimately emerged when the Ki-73 was abandoned for good.

Rather unique for a Japanese-originated wartime fighter design was the use of a contra-rotating propeller arrangement in which two three-bladed systems were in play. These were driven by a single Mitsubishi Ha-203-II 24-cylinder, liquid-cooled "horizontal H" inline piston engine of 2,600 horsepower which was essentially two 12-cylinder engines paired and driving the twin propeller units. The rest of the overall design arrangement was conventional - the engine in the nose, a single-finned tail at rear and the cockpit set over center mass. Wings were straight monoplane appendages with clipped tips and the undercarriage was a "tail-dragger" system made fully retractable.

Issues with the early prototype form arose centering on the complex engine fit and there were growing concerns about the structure and control scheme particularly at the speeds anticipated. Eventually work on the troublesome compound engine was ended which, in turn, ended development of the Ki-73. While the Ki-73 was never formally adopted for service and never entered serial production, captured documents by the Allies - who believed the type was to come online soon - ushered in the codename of "Steve" for the series which never was.

The proposed maximum speed for the Ki-73 was 750 kilometers per hour, about 466 miles per hour, making it one fast mount aided through its powerful engine setup and contra-rotating blades. The slender, streamlined fuselage was also clean from nose to tail. Armament would have most likely been all-cannon in keeping with Japanese fighter traditions late in the war, perhaps 4 x 20mm systems buried in the wings (two units per wing).

Any available statistics for the Mitsubishi Ki-73 (Steve) Long Range Escort Fighter Proposal are showcased in the areas immediately below. Categories include basic specifications covering country-of-origin, operational status, manufacture(s) and total quantitative production. Other qualities showcased are related to structural values (namely dimensions), installed power and standard day performance figures, installed or proposed armament and mission equipment (if any), global users (from A-to-Z) and series model variants (if any).






Our Data Modules allow for quick visual reference when comparing a single entry against contemporary designs. Areas covered include general ratings, speed assessments, and relative ranges based on distances between major cities.

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Relative Maximum Speed Rating
Hi: 500mph
Lo: 250mph
    This entry's maximum listed speed (466mph).

    Graph average of 375 miles-per-hour.
Aviation Era
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Unit Production Comparison
Comm. Market HI*: 44,000 units
Military Market HI**: 36,183 units
0
0


  * Commercial Market High belongs to Cessna 172.

  ** Military Market High belongs to Ilyushin Il-2.


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National Flag Graphic
Origin: Imperial Japan
Year: 1944
Type: Long Range Escort Fighter Proposal
Manufacturer(s): Mitsubishi - Imperial Japan
Production: 0
Global Operators:
Imperial Japan (cancelled)
Historical Commitments / Honors:

Military lapel ribbon for Operation Allied Force
Military lapel ribbon for the Arab-Israeli War
Military lapel ribbon for the Battle of Britain
Military lapel ribbon for the Battle of Midway
Military lapel ribbon for the Berlin Airlift
Military lapel ribbon for the Chaco War
Military lapel ribbon for the Cold War
Military lapel ribbon for the Cuban Missile Crisis
Military lapel ribbon for the Falklands War
Military lapel ribbon for the French-Indochina War
Military lapel ribbon for the Golden Age of Flight
Military lapel ribbon for the 1991 Gulf War
Military lapel ribbon for the Indo-Pak Wars
Military lapel ribbon for the Iran-Iraq War
Military lapel ribbon for the Korean War
Military lapel ribbon for the 1982 Lebanon War
Military lapel ribbon for the Malayan Emergency
Military lapel ribbon for the attack on Pearl Harbor
Military lapel ribbon for the Six Day War
Military lapel ribbon for the Soviet-Afghan War
Military lapel ribbon for the Spanish Civil War
Military lapel ribbon for the Suez Crisis
Military lapel ribbon for the Vietnam War
Military lapel ribbon for Warsaw Pact of the Cold War-era
Military lapel ribbon for the WASP (WW2)
Military lapel ribbon for the World War 1
Military lapel ribbon for the World War 2
Military lapel ribbon for the Yom Kippur
* Ribbons not necessarily indicative of actual historical campaign ribbons. Ribbons are clickable to their respective campaigns/operations.
Measurements and Weights icon
Structural - Crew, Dimensions, and Weights:
Unless otherwise noted the presented statistics below pertain to the Mitsubishi Ki-73 (Steve) model. Common measurements, and their respective conversions, are shown when possible.

Operational
CREW


Personnel
1

Engine icon
Installed Power - Standard Day Performance:
1 x Mitsubishi Ha-203-II 24-cylinder horizontal H liquid-cooled inline piston engine developing 2,600 horsepower.

Performance
SPEED


Miles-per-Hour
466 mph


Kilometers-per-Hour
750 kph


Knots
405 kts

Supported Weapon Systems:

Graphical image of an aircrat automatic cannon
Armament - Hardpoints (0):

ESTIMATED:
4 x 20mm cannons in wings (two per wing element)
Variants: Series Model Variants
• Ki-73 "Steve" - Base Series Designation