In history there are people whose legacy becomes larger than life. Ask anyone who built and flew the first airplane, and you’d be hard-pressed to find someone who isn’t at least aware of the accomplishments of the Wright brothers. In a similar vein, Chuck Yeager’s pioneering trip into supersonic territory with the Bell X-1 airplane made his name essentially synonymous with the whole concept of flying faster than the speed of sound. This wasn’t the sole thing he did, of course: he also fought in WWII and Vietnam and worked as an instructor and test pilot, flying hundreds of different airplanes during his career.

Yeager’s insistence on making that first supersonic flight, despite having broken two ribs days earlier, became emblematic of the man himself: someone who never let challenges keep him from exploring the limits of the countless aircraft he flew, while inspiring others to give it their best shot. Perhaps ironically, it could be said that the only thing that ever held Yeager back was only having a high school diploma.

On December 7, 2020, Chuck Yeager died at the age of 97, leaving behind a legacy that will continue to inspire many for decades to come.

The Right Stuff

During the second World War, airplanes had undergone many changes to improve their performance, but the propeller-based airplanes of the time encountered practical limits even as they tried to fly ever faster and higher. While the advent of rocket and turbojet engines got around some of these limitations, one soon became aware of the dangers posed when approaching the speed of sound sound — the so-called transonic region.

The aerodynamics of this transition from subsonic to supersonic flight were poorly understood in the 1940s when the US began a joint research project on supersonic aircraft. The Bell X-1 was a research aircraft which was used to investigate this transonic region. Lacking solid data on what airplane shape would work best across sub- and supersonic speeds, a shape was picked which was known to be stable at supersonic speed: a Browning .50-caliber machine gun bullet.

Having solved this problem, all that was left was finding a test pilot who would want to fly this rocket-powered plane through the sound barrier. This term was coined during WW2 when fighter pilots would encounter the effects of compressibility: when nearing the speed of sound the aerodynamics acting upon the airplane would change dramatically, limiting them to around 800 km/h (even in a dive) above which they risked instability due to stalled control surfaces and other control issues which would result in a loss of the airplane.

Test pilots in the late 1940s were exposed to a lot of risk considering the countless airplane designs that had been dreamed up, built, and thrust into production in a matter of months during the war. But by all accounts this was a new frontier.

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