This photo illustrates how the X-15 rocket-powered aircraft was taken aloft under the wing of a B-52.
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This photo illustrates how the X-15 rocket-powered aircraft was taken aloft under the wing of a B-52. Because of the large fuel consumption, the X-15 was air launched from a B-52 aircraft at 45,000 ft and a speed of about 500 mph. This was one of the early powered flights using a pair of XLR-11 engines (until the XLR-99 became available).1959NASA Photo › X-15 Project Description