a s initially planned the xb70a which was powered by six general electric yj93s of thirty thousand
pounds thrust each with an afterburner was to have a maximum speed of mach 3.1 2056 miles per hour or
3 309 kilometers per hour at 35 000 feet 10 668 meters it could reach mach 1.90 1254 miles per
hour or 2018 kilometers per hour while at its service ceiling of seventy five thousand five
hundred fifty feet twenty three thousand twelve meters it had a maximum speed of mach 3.00 1982
miles per hour or 3190 kilometers per hour the planned combat range of the b 70 was to be 3
419 miles 5502 kilometers with a maximum range of 4290 miles 6904 kilometers it was
a testament to the progress made in aviation design in the first half of the 20th century
the xb70a built by the north american aviation na los angeles division for the u.s air force
was an experimental high-speed delta wing aircraft designed to fly at mach 3 3 times
the speed of sound and higher than 70 thousand feet 21 000 kilometers the goal of the program was
to develop a high altitude nuclear strike bomber that could outrun any interceptor sent against it
the plan b 70 was to be a nuclear-armed deep penetration supersonic strategic bomber for
the strategic air command with its delta wing profile it isn't hard to see the similarities
in the overall design of the experimental xp 70 and the british french turbojet-powered concord
supersonic passenger airline that was operated from 1976 until 2003 however the b-70 had actually
been conceived well before any consideration was likely given to the high-speed passenger airliner
a s initially planned the xb-70a which was powered by six general electric yj93s of thirty thousand
pounds thrust each with an afterburner was to have a maximum speed of mach 3.1 2056 miles per hour
or 3 309 kilometers per hour at 35 000 feet 10 668 meters it could reach mach 1.90 1254 miles
per hour or 2018 kilometers per hour while at its service ceiling of seventy five thousand
five hundred fifty feet twenty three thousand twelve meters it had a maximum speed of mach three
point zero zero one thousand nine hundred eighty two miles per hour or 3190 kilometers per hour
the planned combat range of the b 70 was to be 3 419 miles 5 502 kilometers
with a maximum range of 4290 miles 6904 kilometers the belief among military planners was that the
bomber could simply fly so high and fast that any enemy notably the soviet union
couldn't have easily defended against it however the one thing that the xb-70
valkyrie couldn't outrun was the progress that was being made with missile technology
in fact by the early 1960s surface-to-air missiles sams technology had vastly improved
which in turn threatened the survivability of even high speed high altitude bombers at the same time
less costly nuclear armed items intercontinental ballistic missiles
were entering service as a result in 1961 the expensive b-70 bomber program was cancelled
before any valkyries had been completed it was also expected that each aircraft
would cost an estimated dollar 24.5 million nearly dollar 240 million in today's money
which proved simply far too expensive for such an aircraft that could have been the end of the line
for the valkyrie but the united states air force still moved forward with the program and bought
2xb70 as to test aerodynamics propulsion and other characteristics of large supersonic aircraft
the xb-70 valkyrie proved to be a perfect test bed for ssd research which was being
conducted jointly by nasa and the air force it was the same size as the projected ssd designs
and used similar structural materials such as braised stainless steel honeycomb and titanium