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Wednesday, July 25, 2007

The First Mach 3 Flight: The XB-70A

Seeing an uncle of mine this summer reminded me to make an image of this, which is getting very old and brittle. I don't mean to bore you with my scrapbook, this is just so I have a digital copy, but maybe someone will be interested. It's a postcard, and the test pilot signatures (Al White and Joe Cotton) from the first flight to break the Mach 3 barrier:

Xb70apostcard
[click on image for a larger, clearer version]

My uncle was a civilian engineer at Edwards Air Force base and worked on this project. He sent me this card when I was eight years old.

Here's a bit more on the first test flights, and on a later crash where one of the test pilots who signed the card. Al White, was the only survivor. The postcard flew on the October 14, 1965 flight (as is evident from the postmark), which was apparently the third attempt:

Flight test history, Wiki: The first XB-70 made its maiden flight on September 21, 1964. The first aircraft was found to suffer from weaknesses in the honeycomb construction, primarily due to inexperience with fabrication and quality control of this new material. ... In flight on May 7, 1965, the divider separating the left and right halves of the engine inlet broke off and was ingested into the engines, damaging all six beyond repair. On October 14, 1965, on the first flight exceeding a speed of Mach 3, the stress again damaged the honeycomb construction, leaving two feet (0.6 m) of the leading edge of the left wing missing. These construction problems resulted in the imposition of a speed limit of Mach 2.5 on the first aircraft.

These honeycomb construction deficiencies were almost completely solved on the second aircraft, which first flew on July 17, 1965. On May 19, 1966 aircraft number two flew 2,400 miles (3,840 km) in 91 minutes, attaining Mach 3 for 33 minutes of that flight.

On June 8, 1966, aircraft number two was flown in close formation with four other aircraft, an F-4, F-5, T-38, and an F-104, for the purpose of a photo shoot at the behest of General Electric, manufacturer of the engines of all five aircraft. With the photo shoot complete, the F-104 rolled inverted, passed overtop, and struck the Valkyrie... The Valkyrie entered a spin and crashed following the mid-air collision. NASA Chief Test Pilot Joe Walker, piloting the F-104, and Carl Cross, copilot aboard the XB-70, were killed in the crash, while Al White, the XB-70's pilot, successfully ejected.

The exact cause of the collision is still debated. ... Lt. Colonel Joe Cotton, the USAF's Chief Test Pilot ..., flying a T-38 in the formation, has speculated that Walker, unfamiliar with flying in formation with such a large delta wing aircraft, lost reference to his position relative to the B-70, and simply closed up the formation until the T-Tail of the F-104 struck the Valkyrie's wingtip. Chuck Yeager has also gone on record to echo this position...

    Posted by on Wednesday, July 25, 2007 at 12:24 AM in Miscellaneous, Technology | Permalink  Comments (7)


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