Aviation News – June 2018

60 Aviation News incorporating Jets June 2018

I

n January 2018 Boeing announced a new

concept for a turbojet and ramjet-powered

strike/reconnaissance aircraft capable of

speeds up to Mach 5. Rivalling Lockheed

Martin’s similar SR-72 Blackbird II, the

twin-tailed, unmanned hypersonic Valkyrie II

should outpace virtually all enemy defences

if it is produced. Among many innovative

design features its air intake con guration

and its name derive from a North American

design, conceived 60 years ago, which would

have performed the same mission although

at rather lower speed and without modern

stealth technology.

The North American XB-70 Valkyrie

dated back to an era when the overriding

‘faster and higher’ impetus in military aircraft

procurement produced several extraordinarily

innovative and futuristic designs, most of

which were too ambitious or potentially too

costly to leave the drawing board. In the

immediate post-war years, the belief that the

bomber was the key element in America’s

airpower still applied and the World War Two-

era heavy bombers were soon followed by

the enormous Convair B-36 Peacemaker, the

jet-powered Boeing B-47 Stratojet and B-52

Stratofortress. The B-36 was obsolete by

1950 when MiG-15s appeared unexpectedly

over North Korea and the USAF sought a

much faster heavy bomber that could outpace

 ghters at very high altitudes.

In 1950, only three years after America’s

 rst supersonic  ight, the USAF was

contemplating a supersonic bomber and

by the mid-1950s General Curtis LeMay

demanded a Mach 3 heavy bomber to

replace the B-52 in his mighty Strategic Air

Command, and convinced enough politicians

of this rather than solely relying on cheaper,

one-shot intercontinental ballistic missiles

(ICBMs).

Lacking suitable engines to achieve such

performance, two options were worked on

simultaneously for the USAF. There was the

idea of an airborne nuclear reactor to heat

air passing through a turbojet sufficiently to

provide supersonic thrust for a 450,000lb

(204,117kg) bomber. This project, Weapons

System 125A (WS-125A), saw General

Electric teamed with Convair while Pratt &

Whitney was with Lockheed.

The alternative WS-110A’s engines

would have been chemically enhanced with

The incredible North American XB-70 Valkyrie was fast,

complex, and well ahead of its time. The project was also

eye-wateringly expensive. Peter E Davies examines this

innovative aircraft and the background to its eventual axing.

XB-70 VALKYRIE

SUPERSONIC SERPENT

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