
North American XB-70 Valkyrie | |
|---|---|
| Country | USA |
| Role | Strategic bomber – Supersonic research aircraft |
| First flight | 21 September 1964 |
| Built | 2 |
The North American Aviation XB-70 Valkyrie was the prototype version of the planned B-70 nuclear-armed, deep-penetration strategic bomber for the United States Air Force Strategic Air Command. Designed in the late 1950s by North American Aviation, the six-engined Valkyrie was capable of cruising for thousands of miles at Mach 3+ while flying at 70,000 feet (21,000 m).
| North American XB-70 Valkyrie Walk Around | |
|---|---|
| Photographers | John Heck, Vladimir Yakubov |
| Localisation | The National Museum of the USAF |
| Photos | 134 |
See also:
General Characteristics and Role
The North American XB-70 Valkyrie was the prototype version of the planned B-70 strategic bomber for the United States Air Force (USAF). Developed during the height of the Cold War, its radical design was intended to create an aircraft capable of penetrating Soviet airspace at sustained speeds of Mach 3 (three times the speed of sound) and altitudes above 70,000 feet (21,000 m). Its role was to serve as a high-speed, high-altitude strategic nuclear bomber, making it theoretically invulnerable to interception by Soviet fighters and early surface-to-air missiles of the time. However, the program faced rapid technological obsolescence and cost overruns, leading to its cancellation and reassignment as a research vehicle.
| Property | Typical Value (XB-70A) |
|---|---|
| Role | Experimental Strategic Bomber Prototype |
| National Origin | United States |
| Manufacturer | North American Aviation (now part of Boeing) |
| First Flight | 21 September 1964 |
| Crew | 2 (Pilot and Co-pilot) |
| Length | 57.6 m (189 ft 0 in) |
| Wingspan | 32.0 m (105 ft 0 in) |
| Maximum Takeoff Weight | 249,500 kg (550,000 lb) |
Powerplant and Unique Aerodynamics
- Engines: 6 x General Electric YJ93-GE-3 turbojet engines (in a common engine bay).
- Maximum Speed: Mach 3.1.
- Cruise Speed: Mach 3.0.
- Thrust (Each Engine): 31,000 lbf (138 kN) with afterburner.
- Compression Lift: The Valkyrie utilized a revolutionary design where the shockwave generated by the fuselage at Mach 3 was channeled under the large, fixed delta wing, providing up to 30% of its lift.
- Movable Wing Tips: The outer 20 feet (6.1 m) of the wings could be folded down by up to 65 degrees at high speeds. This increased directional stability and, critically, helped trap the compression lift shockwave underneath the wing.
- Construction: Largely built from stainless steel and titanium to withstand the extreme heat generated by sustained supersonic flight (thermal soak).
Program History and Legacy
- Cancellation Drivers: The development of effective Soviet high-altitude surface-to-air missiles (like the S-75 Dvina, or SA-2 Guideline) made the high-altitude Mach 3 profile vulnerable. Coupled with the massive development cost, the bomber program was canceled in 1961.
- Research Role: After cancellation, the two built prototypes (AV-1 and AV-2) were used as Mach 3 research aircraft for the supersonic transport (SST) program.
- Tragedy: The second prototype, XB-70A AV-2, was destroyed in 1966 after a mid-air collision with an F-104 chase plane during a photo shoot.
- Legacy: Although it never became an operational bomber, the XB-70 program provided invaluable aerodynamic, materials science, and flight control data crucial for future high-speed military and civilian aircraft development.
- Preservation: The sole surviving aircraft, XB-70A AV-1, is preserved and displayed at the National Museum of the United States Air Force at Wright-Patterson AFB in Dayton, Ohio.
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