X-15 flights were short; each lasted about ten minutes. So that the rocketplane could use all its fuel for acceleration, it was carried beneath the wing of a NASA B-52 to 45,000 feet, where it was ...

The X-15 is now of great interest to the public and ... the distance between the two aircraft. Page 90. Scene 202: Fuel is not measured in inches. Correct terminology is “minimum fuel.” ...