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Republic XF-103

The XF-103 was developed as a high-speed high-altitude aircraft specifically designed to intercept incoming enemy bombers. The XF-103 was proposed in the same contract competition that resulted in the Convair F-102--Project MX-1554 Interceptor Fighter Airplane. The Republic design, Model AP-57, underwent a design performance evaluation conducted by the Air Material Command (AMC). The results showed an estimated top speed of 1438 knots. A limiting Mach number of 3.0 was quoted due to excessive (estimated) turbine inlet air temperature.

The Republic XF-103 Model AP-57 had a Delta wing swept-back 55 degrees at the leading edge and incorporates a variable incidence feature. The horizontal tail is of the Delta configuration with a sweep-back angle of 60 degrees at the leading edge. The alighting gear was of the tricycle type and retracts into the fuselage. The turbo-jet was a Wright Aeronautical Corporation XJ-67-W-1 power plant with afterburner. A Ferri type two-dimensional engine air inlet is used. The thrust of the turbo-jet engine was limited at high Mach numbers by the allowable turbine inlet temperature. The air bypassed the engine compressor and turbine, and using the afterburner as a ram-jet combustion chamber, the available thrust is greatly increased above a Mach number of 2.0

Six (6) MX-904 missiles and 36 2.75 in. FFA rockets internally stowed were proposed. The missile launching system was complex with six (6) individual tracks and actuating cylinders. Accessibility of all launchers for loading was adequate, though rockets and especially missiles were poorly located in the immediate area of the engine air scoop. Most of the Electronic and Control system were located in a compartment adjacent to the radar equipment. Fuel was contained in five pressurized fuel cells. No self-sealing or armor was proposed for the fuel system.

The USAF canceled the XF-103 development contract on 21 August, 1957 when the aircraft was in the mock-up phase.


Span 35 ft. 10 in.
Length 81 ft. 11 in.
Height 18 ft. 4 in.
Weight In excess of 40,000 lbs.
  • 36 unguided 2.75 inch "Mighty Mouse" FFAR rockets and
  • six MX-904 "Falcon" guided missiles
  • Engine
  • One Wright XJ67-W-1 rated at 15,000 lbs. thrust and
  • one XRJ55-W-1 ramjet (afterburner section of the XJ67) of 18,800 lbs. thrust when operated at altitudes above 50,000 ft.
  • Crew One
    Maximum speed Mach 3+
    Combat speed Mach 2.2 at 75,000 ft.
    Combat radius Approximately 450 miles
    Service Ceiling Approximately 80,000 ft.

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    Maintained by Steven Aftergood
    Updated Tuesday, June 29, 1999 5:25:49 PM