14 October 1947 - Chuck Yeager breaks the sound barrier On 14 October 1947, Captain Chuck Yeager broke the sound barrier for the first time. He flew the Bell X-1 (which he named Glamorous Glennis) at Mach 1.06 (that's 700 miles per hour or 1,100 km/h) at an altitude of 13,700m (or 45,000ft) over the Mojave Desert. Chuck Yeager was selected for this flight after the test pilot from Bell Aircraft, the manufacturer of the rocket powered plan, demanded a $150,000 bonus (about $1.2 million in 2017 dollars) to break the sound barrier. The flight was part of an NACA (NASA predecessor) program to research high speed flight. Because this was part of highly classified research, the story was kept a secret till it leaked late December of 1947. Two days before the test flight, Yeager broke two ribs in a horse riding accident. Afraid this was going to keep him from completing the test, he kept quite and simple had his ribs taped up. On the occasion of the 65th birthday of the breaking the sound barrier, the 89-year old Chuck Yeager stayed reenacted the performance. Together with a co-pilot, he broke the sound barrier once again.