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The XB-70A Valkyrie
The XB-70A Valkyrie, built by the North American Aviation (NAA) Los Angeles Division for the US Air Force (USAF), was an experimental high-speed, delta-wing aircraft designed to fly at three times the speed of sound and higher than 70,000 feet (21,000 meters).
On Sep. 21, 1964, 5,000 employees and guests at Air Force Plant 42 in Palmdale, Calif., watched as NAA Chief Pilot Alvin White and USAF copilot Joseph Cotton took the graceful six-engine giant up for its first flight. It was the culmination of an effort that began in 1954, when both Boeing and NAA submitted designs for the Air Force Weapon System 110A competition, and on Dec. 23, 1957, NAA won the competition.
However, federal budget cutbacks and advances in Soviet air defenses resulted in an emphasis on less expensive and theoretically more survivable intercontinental ballistic missiles as the mainstay of US nuclear forces. On Apr. 10, 1961, the Air Force cut back the B-70 to a research program, and only two of the aircraft would be built. After the first XB-70 (Air Vehicle 1 or AV 1), a second Valkyrie (AV 2) flew on Jul. 17, 1965 but in June 1966, it was destroyed following an accidental mid-air collision. A third Valkyrie (AV 3) was not completed.
Emergency landing on “tip-toe”
AV 1 continued to fly and generate valuable test data in the research program until it was brought to the National Museum of the US Air Force in 1969. As we have already explained on Mar. 7, 1966 the aircraft had to perform an emergency landing on “tip-toe” following hydraulic problems.
Not to outdone, AV 2 also experienced a landing gear problem — this time on Apr. 30, 1966 the 37th flight. Shortly after takeoff, Joe Cotton retracted the landing gear. However, as told by Graham M. Simons in his book Valkyrie: The North American XB-70- The USA’s Ill-Fated Supersonic Heavy Bomber, a short-circuit in the landing gear retraction system permitted wind forces to blow the nose gear back into the partially-retracted gear well door, slashing the tires. An attempt to lower the gear using the normal hydraulic system failed. Trying the backup electrical system, Cotton heard a ‘pop’ as that system went dead.
Al White first brought the XB-70 around for a touch-and-go, hoping that a hard impact on the main gear would knock the nose gear loose and let it fall to the extended position. Even after a second try, however, the nose gear remained jammed. At this point, bailing out and losing the aircraft was quickly becoming the only option.
XB-70A Valkyrie emergency landing
But there was fuel to burn, so White and Cotton circled around Edwards while engineers on the ground attempted to sort things out and come up with a solution. After more than two hours the problem with the backup system was traced, so they hoped, to a circuit breaker. Now all Cotton had to do was find a way to short circuit the unit. Of course, the Valkyrie had no onboard toolkit — that would have made things too simple. But Cotton had brought along his briefcase with his various notes and plans, and opening it, he found a binder-type paperclip. Straightening out the paperclip, then grasping the middle of it with a leather glove. Cotton carefully reached in and short circuited the breaker.
It did the trick.
However, the malfunction also caused hydraulic pressure to remain on three of the four main wheel brakes, which were thus locked when the aircraft landed at 173 knots. Fire fighters at Edwards prevented any serious damage to the aircraft, which flew again a little over two weeks later.
The following video shows AV 2 coming to a halt on the main runway at Edwards AFB after the so called “paperclip flight” described in this article.
Photo credit: U.S. Air Force