The Valkyrie

The North American Aviation XB-70 Valkyrie was an experimental bomber designed in the 1950's that was able to fly at Mach 3 at 70 000 ft. This means that it would be able to avoid interceptors (aircraft designed with speed in mind, to intercept enemy aircraft), the only effective anti-bomber weapon at the time.

Design...

The XB-70 had six engines which had a total thrust of about 168 ooo pounds with afterburner.

The Valkyrie used a tail-less, canard and delta wing combination seen in many modern planes like the Chinese J-10 and the Eurofighter Typhoon. Canard wings are small wings mounted forward of the fuselage that greatly and effectively increases maneuverability and control of the aircraft. Delta wings are triangular wings.

The plane was mostly built with stainless steel (not corrosion), sandwiched honeycomb panels (reduces weight), and titanium (strong but light).

Prototypes and Testing...

Altogether, two XB-70s were built.

The first plane was discovered to suffer from weaknesses in the honeycomb panels because of the inexperience in the fabrication and application of this new material. The second plane, however, resolved almost all honeycomb structural issues.

The maiden flight of the Valkyrie was on September 21, 1964 and testing lasted for two years (ending in Auguest 6 1966). The Valkyrie first became supersonic on the third test flight on October 12, 1964 and on October 14, 1965, surpassed Mach 3 and reached an altitude of 70 000 ft.


XB-70 #2 was, sadly, destroyed in a mid-air collision with an F-104 after a photoshoot. NASA Chief test pilot Joe Walker (F-104) and Carl Cross (XB-70 co-pilot) died while Al White (XB-70 pilot) ejected but suffered serious injuries.

Cancellation...

The Valkyrie project was cancelled was due to a combination of factors: the introduction of Intercontinental Ballistic Missiles (ICBM), the high costs, and new effective high-altitude anti-air missiles.

Aircraft on display...

XB-70 #1 is currently on display at the National Museum of the United States Air Force at Wright Patterson AFB in Dayton, Ohio.

Specifications...

Data from USAF XB-70 Fact sheet

General characteristics

• Crew: 2
• Length: 185 ft 10 in (56.6 m)
• Wingspan: 105 ft 0 in (32 m)
• Height: 30 ft 9 in (9.4 m)
• Wing area: 6,296 ft² (585 m²)
• Airfoil: Hexagonal; 0.30 Hex modified root, 0.70 Hex modified tip
• Empty weight: 210,000 lb (93,000 kg)
• Loaded weight: 534,700 lb (242,500 kg)
• Max takeoff weight: 550,000 lb (250,000 kg)
• Powerplant: 6× General Electric YJ93-GE-3 afterburning turbojet
• Dry thrust: 19,900 lbf (84 kN) each
• Thrust with afterburner: 28,800 lbf (128 kN) each

Performance

• Maximum speed: Mach 3.1 (2,056 mph, 3,309 km/h)
• Cruise speed: Mach 3.0 (2,000 mph, 3,200 km/h)
• Range: 3,725 nmi (4,288 mi, 6,900 km) combat
• Service ceiling: 77,350 ft (23,600 m)
• Wing loading: 84.93 lb/ft² (414.7 kg/m²)
• lift-to-drag: about 6 at Mach 2
• Thrust/weight: 0.314