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1,998 No. 11
11 1,998

 

Valor





Valor: The Track to Survival

Someone had to find out if a pilot could eject from an airplane at supersonic speed and live.

On Oct. 14, 1947, Capt. Chuck Yeager broke the sound barrier in the experimental rocket-propelled X-1. Scientists and engineers now knew that an airplane and its pilot could safely fly faster than the speed of sound. But could a pilot bail out at such speed and survive? That was a question that had to be answered quickly, for USAF’s first supersonic fighters were just over the horizon.

It was certain that the wind blast on leaving the cockpit could dislocate limbs and break bones. There also would be rapid—almost instantaneous—deceleration, subjecting the pilot to very high g loads. Some scientists thought the human body could endure no more than 18g’s, or 18 times the force of gravity—far less than a pilot would experience in a supersonic bailout.

Two approaches to the problem were evident: First, build a complex, heavy, expensive ejection capsule for the pilot; second, find out what stresses an unprotected human could survive. The Air Force assigned the second approach to flight surgeon Lt. Col. John Paul Stapp, a bachelor with a philosophical bent, a quiet sense of humor, a love of classical music, and an unquenchable curiosity.

Under Stapp’s direction, Northrop Aircraft Inc. built at Edwards (then Muroc) AFB, Calif., a 2,000-foot rail track for a rocket-driven sled that could accelerate to nearly 1,000 mph. Toward the end of the track, scoops beneath the sled would dig into a pool of water, jerking the sled from several hundred miles an hour to a stop in just over a second, simulating the deceleration of a high-speed ejection. Early passengers were dummies.

At the end of one run, the safety harness broke and the dummy plunged through a one-inch wood windscreen, sailing 700 feet across the desert. A few more rides, a few improvements, and it was time for the first human passenger.

In December 1947, Paul Stapp began riding the sled at increasing speeds.

By May of the following year, he had rocketed down the track 16 times and withstood a force of 35g’s during deceleration. So much for the 18g limit of human endurance.

What was the sudden stop like? Stapp reported: "It felt as though my eyes were being pulled out of my head. ... I lifted my eyelids with my fingers, but I couldn’t see a thing. ... They put me on a stretcher, and in a minute or two I saw some blue specks. ... In about eight minutes ... I saw one of the surgeons wiggle his fingers at me, and I was able to count them. Then I knew that ... my retinas had not been detached, and I wasn’t going to be blind."

Stapp continued to ride the sled at Edwards until 1951. He was sent to Holloman AFB, N.M., in 1953 to work with a longer track and an improved sled called Sonic Wind. There, on Dec. 10, 1954, the 44-year-old Stapp rode the sled to a record 632 miles an hour, decelerating to zero in a second and a quarter with a force of about 35g’s. Momentarily his body weight was about 6,800 pounds. Wind blast and deceleration were equivalent to a high-altitude ejection at supersonic speed.

Out of these wild rides came improved helmets, arm and leg restraints, better aircraft seats, stronger safety harnesses, and techniques for positioning the body to help absorb unearthly forces. And for Paul Stapp? During his 29 rides came several retinal hemorrhages, cracked ribs, and two broken wrists—the second of which he set himself while walking back to the field lab that he headed.

Stapp was named winner of the Cheney Award for 1954. That award recognizes acts of "valor, extreme fortitude, or self-sacrifice in a humanitarian interest performed in connection with aircraft." That same year, he also won AFA’s Theodore von Karman Award for distinguished service in the field of aerospace science. For unassuming Paul Stapp, the greatest reward was the knowledge that he had helped make a dangerous profession a little less hazardous—that many jet pilots who had to abandon their planes were still alive and flying.

War is the breeding ground of heroes. In times of peace, few have the opportunity or the dedication and courage to risk permanent injury or death, as Lt. Col. John Paul Stapp did repeatedly, so that others may live. He exemplified in extraordinary measure "the noble quality we call valor."

First appeared in May 1983 issue.