The X B Seventy Valkyrie, the Mach Three Bomber That Folded Its Wingtips to Ride Its Own Shockwave, and the Lone Survivor Standing in Dayton

SUMMARY: The XB-70 Valkyrie was a Mach 3 bomber that folded its wingtips to ride its own shockwave - one survivor remains in Dayton, Ohio.

The North American Aviation XB-70 Valkyrie was a Mach 3 strategic bomber designed in the 1950s to cruise at 70,000 feet and 2,000 miles per hour, using folded wingtips to trap its own shockwave for extra lift. Only two were ever built, and just one survivor remains today, on display at the National Museum of the United States Air Force in Dayton, Ohio. Though it never carried a bomb or flew a combat mission, it became one of the most important research aircraft of the jet age.

What Was the XB-70 Valkyrie?

The Valkyrie was a bomber designed for a single, blunt idea that dominated 1950s air power thinking: to survive, you fly high and fast - faster than anything that could catch you. The U.S. Air Force asked industry for a bomber that could cruise at three times the speed of sound, not just dash there in a sprint. That meant sustaining Mach 3 for hours at a stretch.

For perspective, most famous fast jets can touch Mach 2 only briefly, at full throttle. The Valkyrie was built to live at Mach 3. No one had ever built a machine the size of an airliner - nearly 200 feet long - that could do it. North American Aviation won the contract.

Why Did the XB-70 Fold Its Wingtips in Flight?

The folding wingtips are the Valkyrie’s most famous feature, and they existed to exploit a phenomenon called compression lift.

At Mach 3, the aircraft generates a powerful shockwave - a hard cone of pressure trailing back beneath the fuselage. Most designers spent their careers trying to eliminate shockwaves. The Valkyrie’s engineers chose to ride theirs instead.

The outer several feet of each wingtip were hinged. On the ground and at low speed, they sat flat. As the aircraft accelerated, the tips drooped - first partway, then all the way down to 65 degrees. Folded down, they trapped the shockwave under the wing, generating free lift from the very force that was supposed to slow the aircraft down. In effect, she surfed her own thunderclap across the sky.

How Was an Aircraft Built to Survive Mach 3?

At Mach 3, air friction heats an aircraft’s skin until aluminum would soften like warm taffy. So the Valkyrie couldn’t be built from aluminum.

Most of her white skin was stainless steel, formed into a brazed honeycomb sandwich - panel after panel fitted together by hand. It was so difficult to manufacture that engineers were inventing the process as they went, and the steel fought them the entire way.

Power came from six General Electric YJ93 engines, clustered in a box beneath the tail and fed through one enormous shared inlet split down the middle. Together they produced more than 90,000 pounds of thrust. On takeoff in afterburner, they threw a sheet of flame and a wall of noise across the desert that witnesses at Edwards remembered for the rest of their lives.

Why Was the XB-70 Cancelled?

The cruel twist of the Valkyrie’s story is that its mission was already dead before it flew.

While North American wrestled with the stainless steel, the strategic picture changed. The Soviets fielded surface-to-air missiles that could reach aircraft at 70,000 feet. On May 1, 1960, they shot down a U-2 spy plane at high altitude - proof that flying high was no longer hiding. It just meant being a bigger, more predictable target.

At the same time, intercontinental ballistic missiles were maturing. A missile in a silo in Kansas could strike a target in roughly 30 minutes without risking a crew, at a fraction of the cost of a bomber fleet. Defense Secretary Robert McNamara ran the numbers and cancelled the B-70 as an operational bomber. It never carried a bomb, never wore squadron colors, and never went to war.

What Did the XB-70 Do Instead?

With two of the most advanced aircraft ever built and no combat mission, the program pivoted to research, jointly operated by the U.S. Air Force and NASA.

The timing was useful. The world was dreaming of supersonic airliners capable of crossing oceans at high Mach numbers, and the Valkyrie was the only aircraft its size that actually operated at those speeds. Every flight taught engineers something about heat, shockwaves, and how a large aircraft behaves at the edge of the possible. She became a flying laboratory for a supersonic future that, as it turned out, mostly never arrived.

She first flew in the fall of 1964. The two aircraft were known to their crews as Ship One and Ship Two. Flight testing was pure nerve - on some early flights, pieces of the honeycomb skin peeled away from heat and pounding, and pilots would land to find sections of the aircraft simply gone.

What Happened to the XB-70 on June 8, 1966?

On June 8, 1966, Ship Two - the faster of the two aircraft - was lost in a mid-air collision during a publicity photo shoot.

General Electric had built engines for several aircraft flying that day, and the plan was to photograph them in tight formation, with the huge white Valkyrie at the center. One of the smaller jets was an F-104 Starfighter, flown by veteran test pilot Joe Walker, a man who had flown the X-15 to the edge of space.

The Valkyrie’s massive delta wing trailed a powerful, invisible wingtip vortex. Walker’s Starfighter drifted too close, the vortex caught it, and the jet was flipped up and over, rolling across the Valkyrie’s tail. Joe Walker was killed instantly. The collision sheared off both of the Valkyrie’s vertical tails and tore into the wing.

The bomber flew straight and level for a few seconds, then - with no tail to hold her - rolled off and tumbled to the desert. Copilot Carl Cross, on his first flight in the aircraft, did not escape. Pilot Al White ejected in the aircraft’s clamshell escape capsule and survived, badly injured. Two men and two irreplaceable aircraft were lost for a photograph - a lasting reminder that even the most skilled pilots are vulnerable to unnecessary risk.

Where Is the Last XB-70 Valkyrie Today?

The lone survivor is Ship One, the first Valkyrie ever built.

After the accident, it continued flying research more cautiously, and then in the winter of 1969 it made its final flight - from Edwards Air Force Base in California to Wright-Patterson Air Force Base in Ohio. It has not moved under its own power since, standing on display for more than 50 years.

Today you can walk right beneath that white wing in the research and development hangar at the National Museum of the United States Air Force in Dayton, Ohio. Admission is free. Up close, the skin isn’t smooth like a modern jet - you can see the panels, seams, and hand-fitted honeycomb, the work of people inventing a manufacturing process as they built it.

By the cold logic of cost and mission, the Valkyrie was a failure: she never dropped a bomb or flew a mission that mattered to a war. And yet nearly everything learned from her - about heat, speed, and how enormous aircraft behave at the ragged edge of flight - fed directly into the aircraft that followed. Sometimes the machine that never fights teaches more than the one that does.

Key Takeaways

• The XB-70 Valkyrie was a Mach 3, 70,000-foot bomber built by North American Aviation, with skin made largely of brazed stainless steel honeycomb to survive friction heat.
• Its wingtips folded down to 65 degrees in flight to harness compression lift, trapping the aircraft’s own shockwave beneath the wing for extra lift.
• The bomber mission was cancelled by Robert McNamara because surface-to-air missiles and ICBMs made high-altitude bombers obsolete; the two aircraft became Air Force/NASA research ships.
• Ship Two was destroyed in a mid-air collision during a photo shoot on June 8, 1966, killing test pilots Joe Walker and Carl Cross; pilot Al White survived.
• The sole survivor, Ship One, has stood at the National Museum of the United States Air Force in Dayton, Ohio since its final flight in 1969, and is free to visit.