Only one surviving prototype sits in a museum in dayton ohio, even as the
boeing B-52 it was supposed to one day replace continues to soldier on.
The XB70 valkyrie was the prototype version of the planned B-70
nuclear-armed, deep penetration supersonic 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 plus while flying at 70,000 ft, 21,000 metres. The idea behind the
XB70 originated in the 1950s when it was assumed ever greater speeds and
altitudes would enable american bombers to survive against soviet air
defenses unmolested on their way to delivering their doomsday payloads.
At the time, the only effective defense against bombers were fighters and
anti-aircraft artillery. Even then anti-aircraft guns were only marginally
effective and interceptors were increasingly challenged by ever-improving
bomber performance.
However, with the advent of surface-to-air missiles sam) that began to
change the balance started to tip in favor of the defender. While the u.s
air force was aware of soviet advances in sam technology, the pentagon
didn't start to understand the scope of the problem until france's gary
power's Lockheed U2 Spy Plane was shot down while overflying the soviet
union on may 1/1960, but the development of the XB-70 continued nonetheless.
With the growing realization that soviet sams posed an increasing threat to
american bombers, the Pentagon started to explore low-level penetration as
an alternative. Low-level penetration involved flying under the radar
horizon using terrain mask a bomber's approach, which greatly reduces enemy
response times.
Moreover the development of intercontinental ballistic missiles greatly
reduced the united states reliance on manned bombers. Many leading military
strategists of the time believed bombers were too vulnerable to survive the
journey into soviet airspace.
As a result president john f kennedy decided to cancel the XB-70 as a
frontline bomber program on march 28/1961.
Meanwhile the XB-70 test program continued. the jet made its first flight on
september 21/1964 when it flew from palmdale to edwards air force base
Kayla, but the first XB-70 proved to be a disappointment, it had poor
directional stability above mach 2.5 and made only one flight above mach
3.0.
The second jet which flew on july 17/1965, added five degrees of dihedral on
the wings for better supersonic stability.
Tragedy struck on june 8/1966 when the second XB-70 prototype was destroyed
in a crash after a mid-air collision with its F-104N chase plane. Two people
were killed and one was severely injured during the accident.
The loss of the second aircraft which was much more capable than the first
was a huge setback. Testing however continued until feb 4/1969 ultimately
the first XB-70 logged 83 flights totaling 160 hours and 16 minutes. while
the second XB-70 logged 46 flights totaling 92 hours and 22 minutes,
according to nasa.
The XB-70 while a technological wonder at the time was the wrong plane for
the wrong time. it came at a time when ballistic missiles were thought to be
supplanting manned bombers. moreover it was being developed at a time when
it was increasingly apparent that high speed and high altitude were not
sufficient protection against surface-to-air missiles or the next generation
of soviet fighters.
But the nail in the coffin was the jet's exorbitant price tag and lack of
mission flexibility, the B-70 couldn't be adapted for the low-level role.
Let's hope today's shadowy long-range strike bomber fares better.
