North American XF-108 Rapier

XF-108 Rapier
Artist's impression of two F-108s attached to Elmendorf AFB, Alaska. Note: Top aircraft's weapons bay opening.
General information
Type	Interceptor aircraft
Manufacturer	North American Aviation
Status	Cancelled (1959)
Primary user	United States Air Force (intended)
Number built	One mockup

The North American XF-108 Rapier was a proposed long-range, high-speed interceptor aircraft designed by North American Aviation intended to defend the United States from supersonic Soviet strategic bombers. The aircraft would have cruised at speeds around Mach 3 (3,200 km/h; 2,000 mph) with an unrefueled combat radius over 1,000 nautical miles (1,900 km; 1,200 mi), and was equipped with radar and missiles offering engagement ranges up to 100 miles (160 km) against bomber-sized targets.

To limit development costs, the program shared engine development with the North American XB-70 Valkyrie strategic bomber program, and used a number of elements of earlier interceptor projects. The program had progressed only as far as the construction of a single wooden mockup when it was cancelled in 1959, due to a shortage of funds and the Soviets' adoption of ballistic missiles as their primary means of nuclear attack. Had it flown, the F-108 would have been the heaviest fighter of its era.

Prior to the project's cancellation, U.S. President Dwight D. Eisenhower noted that raising the F-108 interceptor force would have cost the U.S. taxpayer $4 billion (equivalent to $42 billion today).^[1]