Hurtling Into a Record

Of all the problems facing those who tried to break the sound barrier, the most vexing concerned a condition known as “compressability.”

During Chuck Yeager’s seventh powered flight in the X-1, he made it 94% of the way to Mach 1, as the speed of sound was designated. He pulled back on the control column, expecting to gain altitude. Nothing happened. He shut down the engines and regained control at a lower speed.

It was determined that a shock wave was forming directly above the elevator hinge on the X-1’s tail. The elevator controlled the pitch of the craft, and the shock wave nullified its effect. If the problem could not be solved, Mach 1 would remain unattainable.

Yeager’s flight engineer, Capt. Jack Ridley, suggested that the elevator be locked down and that pitch be controlled by moving the entire horizontal stabilizer with a small air motor that was built into the X-1 and controlled in minute calibrations from the cockpit.

On his next flight, Yeager spurred the plane to .96 Mach and then to .988 Mach. The new “flying tail”--now a standard design on all supersonic aircraft--worked perfectly. The X-1 was ready.