Dan Hampton: Boom Times for Jet Pilots

The story has been around for years, in magazine articles and at least one book. Here it is again in “Chasing the Demon,” as told by Dan Hampton. Mr. Hampton is himself something of a legend—a fighter pilot who has written a well-regarded personal memoir and, more recently, “The Flight” (2017), an impressive pilot’s-eye view of Charles Lindbergh’s trans-Atlantic crossing.

Chuck Yeager and George Welch were fighter aces in World War II. Sidelined by malaria, Welch went to work for North American Aviation, the builder of the war’s best fighter plane, the P-51 Mustang. As Mr. Hampton tells us, the company’s postwar assignment was to design a turbojet fighter. The result would become the F-86 Sabre, a swept-wing beauty that dominated the skies over Korea.

Just as the war was ending, Bell Aircraft won a contract to build a rocket plane with no other purpose than to exceed the speed of sound. The so-called sound barrier—the “demon” of Mr. Hampton’s title—had lured and terrified wartime pilots who experienced buffeting, crazy controls and sometimes death at very high speeds. Bell gave its X-1 the profile of a bullet, as if to honor the Austrian physicist Ernst Mach, who in the 1880s, for his research on sound waves, had photographed a bullet traveling at supersonic speed. According to Bell’s designs, the X-1 would be carried aloft by a four-motored bomber and then cut loose, with the pilot inside, to blast through “Mach One” with the help of engines that burned for less than five minutes.

Like most 1940s aircraft, North American Aviation’s jet fighter and Bell’s rocket plane, in their first designs, had wings that stuck straight out. But U.S. scientists, benefiting from newly accessed German research, learned that a Pfeilflügel, or “arrow wing,” aircraft could reach very high speeds without shaking itself to pieces. North American promptly modified its jet fighter with wings that swept 35 degrees to the rear. Bell Aircraft, for reasons of its own, left its X-1 design in place.

In October 1947, both planes were ready for testing in California’s Mojave Desert. There the X-1, piloted by Yeager, reached Mach 1.07 (about 807 mph) on Oct. 14, in the thin air of 40,000 feet. Like the snap! of a bullet, a supersonic aircraft trails a shock wave that expresses itself as noise. Anyone below, including the hostesses at Pancho Barnes’s dude ranch and tavern near the Mojave test site, heard the ba-boom that trailed the X-1. So they knew that something remarkable happened on Oct. 14. But, as the story is told, they had also heard a sonic boom 13 days before, on Oct. 1, when Welch had tested the Sabre prototype.

That was the legend published in “Aces Wild” 52 years after the fact. Al Blackburn, test pilot and author, made his case for Welch’s primacy with invented dialogue and no hard evidence, asserting along the way that the Air Force lied to us. Mr. Hampton adopts the story wholesale, though in more dignified prose. Indeed, “Chasing the Demon” begins as a treatise on aerodynamics and the history of flight, sometimes lucidly but sometimes not. “Perhaps,” he tells us at one point, “[Otto] Lilienthal’s greatest contribution was the formulation of aerodynamic coefficients that permitted the use of dimensionless quantities to characterize forces acting on an airfoil.”

The legend of Welch’s stolen glory was most vigorously debunked by Robert Kempel, a retired NASA flight-test engineer and the author of “The Race for Mach One,” published in 2010. Mr. Kempel argued that the Sabre prototype, powered by a lackluster Chevrolet turbojet, just didn’t have the thrust to go supersonic. All the evidence to the contrary, he said, was anecdotal (those ba-booms) or wrongheaded. Welch wasn’t “clocked” from the ground, as had been claimed, because no such clocking instrument existed. Yeager’s Mach One achievement was derived from on-board instruments and the math skills of Roxanah Yancey and two other “computers” on the ground. Nor did anyone interview George Welch on the subject, for he died in 1954 in the breakup of another fast jet. The dude-ranch hostesses were also long gone, chased out by a fire and the expanding flight-test center. Still, the legend lives on in Mr. Hampton’s book.