The X B Seventy Valkyrie, North American's Mach Three White Bird, and the Lone Survivor That Sits in Dayton After a Camera Killed Its Twin

The XB-70 Valkyrie was a Mach 3, six-engine strategic bomber built by North American Aviation in the early 1960s to fly faster and higher than any Soviet defense could reach. Only two were ever built, and only one survives today - Air Vehicle 1, on display at the National Museum of the United States Air Force near Dayton, Ohio. Its twin was destroyed in a June 8, 1966 mid-air collision during a publicity photo shoot that killed two airmen.

What Was the XB-70 Valkyrie?

In the late 1950s, at the height of the Cold War, the U.S. Air Force wanted a bomber that could cruise at three times the speed of sound at roughly 70,000 feet - fast enough and high enough that nothing in the Soviet arsenal could touch it. The contract went to North American Aviation, the same company behind the P-51 Mustang and the F-86 Sabre.

What they produced still looks decades ahead of its time. The Valkyrie was a delta-wing giant nearly 200 feet long - about two-thirds the length of a football field. Its six General Electric engines were clustered side by side in the tail, all fed by a single enormous box air intake beneath the fuselage. Witnesses said the combined engine start wasn’t so much a sound as a pressure you felt in your chest.

Why Was the XB-70 Painted White?

The Valkyrie was painted chalk white on purpose - to reflect heat. At Mach 3, air doesn’t simply flow past the airframe; it compresses and burns. The nose reached well over 400 degrees in cruise, with the leading edges hotter still.

Because ordinary aluminum would soften at those temperatures, engineers built the aircraft from stainless steel honeycomb and titanium. In the early 1960s - before the first Moon landing - a team in California designed an airplane that essentially cooked itself on every flight and held together anyway.

How Did the Wingtips Fold Down?

The most remarkable feature was the wingtips. The outer sections of the delta wing folded downward in flight, drooping as much as 65 degrees - nearly straight down - using hydraulic actuators.

The reason was a phenomenon called compression lift. At Mach 3, the aircraft drags a shock wave beneath it. Normally that shock wave is just drag - wasted energy. North American’s engineers folded the wingtips down to trap that shock wave under the wing, letting the airplane effectively ride, or “surf,” the pressure it created. The drooping tips also improved high-speed stability and shifted the aircraft’s balance where it needed to be. It worked.

The Two Valkyries: Air Vehicle 1 and Air Vehicle 2

The first Valkyrie rolled out in 1964, and two aircraft were built:

Air Vehicle 1 had early trouble, including skin panels tearing loose at high speed, which limited its performance.
Air Vehicle 2 was the strong performer. It sustained Mach 3 for more than half an hour in the thin, cold upper atmosphere.

By the mid-1960s, though, the Valkyrie’s original mission had already evaporated. High-altitude surface-to-air missiles had improved enough that flying fast and high was no longer a shield. Air combat strategy shifted to flying low, under the radar. The bomber never entered service. Instead, both aircraft became flying laboratories for NASA and the Air Force, gathering data for a hoped-for American supersonic airliner.

What Happened on June 8, 1966?

On the clear morning of June 8, 1966, over the Mojave Desert in Southern California, Air Vehicle 2 was lost in a mid-air collision during a publicity photo shoot arranged by General Electric, which had built the engines for every aircraft in the formation.

Five aircraft flew in tight formation for the camera: the Valkyrie in the center, with an F-4 Phantom, an F-5, a T-38, and an F-104 Starfighter tucked in close. The Starfighter, flying just off the Valkyrie’s right wingtip, was piloted by Joe Walker - one of the finest test pilots in the country, a veteran of the X-15 rocket plane program.

Investigators believe the Valkyrie’s massive wingtip vortex - an invisible, powerful spiral of air shed off a wing that large - caught Walker’s Starfighter. The F-104 rolled up and over the Valkyrie’s wing, sheared off both vertical tails, and exploded. Joe Walker was killed instantly.

Stripped of its tails, the Valkyrie flew straight and level for a few seconds before rolling uncontrollably onto its back and falling into the desert. Pilot Al White ejected in his escape capsule and survived with serious injuries. The co-pilot, Air Force Major Carl Cross - on his first flight in the aircraft - was unable to escape and was killed.

Why the Accident Still Matters to Pilots

The 1966 collision is one of the most needless tragedies in flight-test history, and its lessons remain current:

Wake turbulence is real and lethal. A large aircraft sheds vortices powerful enough to roll a fighter out of control. Formation and trailing aircraft must respect that invisible hazard.

Formation flying is unforgiving. Tight formation leaves no margin for a sudden upset.

The pressure to “get the shot” kills. The flight existed only to produce a photograph. Cockpit discipline isn’t timidity - it’s what brings crews home.

The Lone Survivor in Dayton

After the crash, Air Vehicle 1 - the troublesome first aircraft - became the only Valkyrie left on Earth. NASA flew it for research for another two years, chasing supersonic-transport data for an airliner the United States ultimately never built; the Boeing SST was canceled, and the Concorde came from Europe.

Its final flight came in February 1969, when it was flown from California to Wright-Patterson Air Force Base near Dayton, Ohio - fittingly, close to the home of the Wright brothers. It has remained there ever since, in the research and development gallery of the National Museum of the United States Air Force, the largest and oldest military aviation museum in the world. Admission is free.

Visitors routinely stop in their tracks at the sight of it. The white nose towers overhead like the prow of a ship, the fuselage stretches back nearly 200 feet, and the six engine nozzles are large enough to climb into. It stands as a monument to an era of extraordinary ambition - and to the two men lost on a clear June morning over the Mojave.

Key Takeaways

The XB-70 Valkyrie was a Mach 3, six-engine bomber built by North American Aviation, designed to cruise at about 70,000 feet beyond the reach of Soviet defenses.
It used folding wingtips (drooping up to 65 degrees) to harness compression lift, effectively riding its own shock wave, and was built from titanium and stainless steel honeycomb to survive 400°+ temperatures.
Only two were built; Air Vehicle 2 was destroyed in a June 8, 1966 collision during a General Electric photo shoot, killing pilot Joe Walker (F-104) and co-pilot Major Carl Cross. Pilot Al White survived.
The wingtip vortex and formation-flying lessons from that crash remain vital safety reminders for pilots today.
The sole survivor, Air Vehicle 1, made its last flight in February 1969 and is on display at the National Museum of the United States Air Force near Dayton, Ohio.