B-70 program

Air Force, was an experimental high-speed, delta-wing aircraft designed to fly at three times the speed of sound and higher than 70, feet 21, kilometers. On Sept. Air Force copilot Joseph Cotton took the graceful six-engine giant up for its first flight. 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 U.

On April 10, , the Air Force cut back the B to a research program, and only two of the aircraft would be built. The inlet wedge at the front of the delta wings would create a disturbance in that shock wave, causing it to slow and build pressure under the wings, generating up to 40 pounds per square foot 1.

However, its reconnaissance capability would not have been as good as the super high altitude aircraft designed to fill the reconnaissance role. The XB was an aircraft which fulfilled the criteria it was designed to meet, but whose mission had been eliminated by defensive threat technology. The high drag of the Mach 3 airframe required a fuel load comparable to the B but limited the range to about 5, nm. It was capable of carrying both conventional and nuclear weapons internally, but due to its design and Mach 3 mission profile, it could not carry external ordnance.

The Kennedy administration felt ICBMs were more cost effective because they were less vulnerable and were cheaper operationally. Although two XB prototypes were built, with the first flight in , the program terminated in As such, two prototype aircraft were built, and designated XBA; these aircraft were used for supersonic test-flights during — In , one prototype crashed after colliding in midair with a smaller jet aircraft; the remaining Valkyrie bomber is in the National Museum of the United States Air Force, in Ohio.

The XB's maiden flight was on 21 September In the first flight test, between Palmdale and Edwards AFB, shortly after take-off one engine had to be shut down, and an undercarriage malfunction warning meant that the flight was flown with the undercarriage down as precaution, limiting speed to mph - about half that planned.

As seen in the film on landing, the rear wheels of the port side main gear locked, the tires ruptured, and a fire started. The Valkyrie first became supersonic Mach 1. The wing tips were also lowered partially in this flight. XB No. The first aircraft was found to suffer from weaknesses in the honeycomb panels, primarily due to inexperience with fabrication and quality control of this new material.

The deficiencies discovered on AV-1 were almost completely solved on the second XB, which first flew on 17 July On 3 January , XB No. AV-2 reached a top speed of Mach 3. On 19 May , AV-2 reached Mach 3. Testing was planned to cover a range of sonic boom overpressures on the ground similar to but higher than the proposed American SST. In , AV-2 was selected for the program and was outfitted with test sensors.