Boeing revealed a hypersonic airplane design to compete with Lockheed’s Mach 6 SR-72 spyplane design. Boeing calls the project internally “Valkyrie II,” according to Guy Norris at Aviation Week.
Boeing has not yet approved development of the aircraft. If Boeing builds a hypersonic strike and spyplane then it would build a scaled, single-engine, proof-of-concept demonstrator aircraft about the size of an F-16 before moving on to a full-scale, twin-engine aircraft the size of the 107-foot-long SR-71.
Boeing and Lockheed’s designs are very similar, both planning to use a combined-cycle engine that uses a conventional turbojet to accelerate to roughly Mach 3, and then a dual ramjet/scramjet to make the jump to hypersonic speeds. Boeing is working with Orbital ATK to develop an engine, while Lockheed has partnered with Aerojet Rocketdyne.
Aviation Week reports that Boeing is constantly modifying its hypersonic design, and the bulge in the forward fuselage seen in the concept images and models is likely going to change.
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).
XB-70 No. 1 was completed on 7 May 1964 and AV-2 was completed on 15 October 1964. The third prototype (AV-3) was canceled in July 1964 before completion. The first XB-70 carried out its maiden flight in September 1964 and many more test flights followed.
Longest flight: 3:40 hours (on 6 January 1966)
Fastest speed: 2,020 mph (3,250 km/h) (on 12 January 1966)
Highest altitude: 74,000 ft (23,000 m) (on 19 March 1966)
Highest Mach number: Mach 3.08 (on 12 April 1966)
Sustained Mach 3: 32 minutes (on 19 May 1966)
Mach 3 total: 108 minutes/10 flights