October 14, 1947

Bell X-1

Chuck Yeager's First Documented Level Supersonic Flight

The Mach meter ran off its scale and Yeager reported no violent jolt — the instrument had to tell him he had crossed Mach 1. The Air Force classified the flight about two hours later.

10:26 a.m. over Muroc

On 14 October 1947, at 10:26 a.m., a modified B-29 released Captain Chuck Yeager's rocket-powered Bell X-1 at 20,000 feet above Muroc, California. Muroc was not renamed Edwards until 1949.

Yeager climbed and accelerated to Mach 1.06 at approximately 43,000 feet — a reported 699.4 mph — completing the first instrumented, officially documented crewed supersonic flight in level flight.

He held the speed for roughly 20 seconds, shut down the engine, and glided to a landing on Rogers Dry Lake.

The stabilizer, the ribs and the broom handle

On the 10 October test Yeager had encountered loss of elevator control near Mach 1. Flight-test engineer Jack Ridley concluded that the X-1's adjustable stabilizer could preserve pitch control, which gave the team a workable method for the 14 October attempt.

Yeager, a twenty-four-year-old Air Force captain flying his ninth powered X-1 mission, entered the cockpit with two broken ribs from a horse accident and used a ten-inch piece of broom handle to lock the hatch. Crew chief Jack Russell spread Drene shampoo inside the windscreen against the icing encountered on the previous flight.

Secret by noon, confirmed in 1948

Air Force officials classified the flight and its data Top Secret about two hours after it ended. News leaked in December 1947, and the Air Force did not officially confirm the achievement until March 1948.

Later accounts claimed George Welch had exceeded Mach 1 in an XP-86 before Yeager. NASA's historical review found no supporting flight data and reports Welch's highest documented 1947 speed as Mach 0.93.

Sources

Researched 23 Aug 2026 7 sources 2 audit passes

How this was checked

Researched from the web into a fact sheet, rewritten from that sheet, then audited against it by a different model. How the pipeline works →

What the sources leave uncertain

Later accounts claimed that George Welch exceeded Mach 1 in an XP-86 before Yeager. NASA's historical review found no supporting flight data and reports that Welch's highest documented 1947 speed was Mach 0.93. Yeager's remains the first instrumented and officially documented level supersonic flight.