βοΈ Full Specifications
| Designation | F-108A Rapier |
| Manufacturer | North American Aviation |
| Country | πΊπΈ United States |
| Crew | 2 |
| Length | 27.2 m (89.2 ft) |
| Wingspan | 17.5 m (57.4 ft) |
| Height | 6.7 m (22 ft) |
| Max Takeoff Weight | 46,720 kg (103,018 lb) |
| Max Speed (Mach) | 3 |
| Max Speed | 3,186 km/h (1,980 mph) |
| Service Ceiling | 24,400 m (80,056 ft) |
| Range | 3,700 km (2,298 mi) |
| Engine | 2 Γ General Electric J93-GE-3AR |
| Thrust (each) | Dry 117 kN Β· AB 156 kN |
π Operators
π Variants
- F-108A β Proposed production interceptor (never built)
- Mockup β Full-scale wooden mockup built and destroyed
βοΈ Armament
Overview
The North American XF-108 Rapier was a proposed Mach 3 long-range interceptor designed in the late 1950s to defend North America against Soviet supersonic bombers. Sharing engines and design heritage with the XB-70 Valkyrie strategic bomber, the F-108 would have been the fastest fighter ever built β but it was cancelled in September 1959 before any flying prototype was completed. Only a full-scale mockup was constructed.
Design & Development
The F-108 was a tailless delta with a large cranked-arrow wing optimised for sustained Mach 3 flight at altitudes above 70,000 feet. Power came from two General Electric J93 turbojets β the same engines later used on the XB-70. The aircraft would have carried three GAR-9 (later AIM-47A) Falcon air-to-air missiles in internal bays, guided by the AN/ASG-18 radar β both systems later resurrected for the Lockheed YF-12.
The interior arrangement placed the two crew (pilot and weapons system officer) in tandem with separate escape capsules β necessary because of the kinetic heating environment at Mach 3, which made conventional ejection seats untenable. The design called for stainless steel and titanium throughout, foreshadowing the SR-71’s materials philosophy.
Program History
The Rapier originated from the Long Range Interceptor Experimental (LRI-X) requirement of 1957. North American won the competition in October of that year. By 1959 the program was technically feasible but politically vulnerable: improving Soviet ICBMs were making the manned interceptor mission look obsolete, and SAC was demanding budget priority. On September 23, 1959, Defense Secretary Neil McElroy cancelled the program, citing changing threats and rising costs. The full-scale mockup was destroyed shortly afterwards.
Legacy
The F-108’s development directly enabled both the XB-70 Valkyrie (shared J93 engines) and the YF-12 / SR-71 family (shared radar and missile systems). The AIM-47 became the basis for the AIM-54 Phoenix used on the F-14 Tomcat β meaning the F-108’s weapon system actually served for decades on a different airframe. The Rapier itself, however, remains one of the great “what-might-have-beens” of Cold War aviation.
References
- USAF System Development Decision, October 1957
- “North American XF-108 Rapier” by Dennis R. Jenkins
- Declassified WS-202A program documents
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