Fifty years ago this month, the USAF/North American X-15 made its first free flight with test pilot A. Scott Crossfield at the controls.
While bred for hypersonic flight, the aircraft still had to handle well enough at low speeds for a pilot to land it dead-stick. As a result, history records that the X-15’s first free flight was an unpowered affair which lasted 296.6 seconds from drop to touchdown.
The launch aircraft for this first X-15 mission was the USAF NB-52A (52-0003) with Captain Charlie Bock as command pilot and Captain Jack Allavie in the right seat.
The B-52A slowly climbed high into the skies above Edwards Air Force Base, California carrying Crossfield and the X-15, Ship No. 1 (56-6670) to the drop point over Rosamond Dry Lake. The X-15’s first free flight began at 37,550 feet above mean sea level and a Mach number of 0.79.
As it was released from the pylon, the NB-52A’s local flowfield caused the X-15 to roll 20 to 30 degrees clockwise as it fell away from the mothership. Crossfield quickly went to work in an attempt to learn how to fly the black rocket plane in real-time.
All proceeded well enough until Crossfield was on final approach to Rodgers Dry Lake.
As he neared the ground, Crossfield had the distinct sense that the X-15 was unstable in pitch as it went through wild, porpoising swings in angle-of-attack. It was all Crossfield could do to get the aircraft on the ground in one piece. Using the word “landing” to describe the aircraft’s return to earth would be much too kind a way of expressing it.
Post-flight analysis showed that the hydraulically-boosted pitch controls were not tuned correctly and thus deprived Crossfield of the expected level of pitch control authority. This key flight system was subsequently adjusted and the problem never surfaced again.
However, on 08 June 1959, the aircraft that would eventually fly as high as 354,200 feet and attain a speed of 4,530 mph, almost took a pratfall in its debut on the grand stage of American aviation.