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Muroc, California · 14 October 1947 · Capt. Chuck Yeager, U.S. Air Force

Faster Than Sound

Pilots said there was a wall in the sky at the speed of sound. A 24-year-old Air Force captain with two broken ribs flew straight through it.

Capt. Chuck Yeager stands beside the Bell X-1 #46-062 "Glamorous Glennis," named for his wife.

The moment · Mid-morning · 14 October 1947

Chuck Yeager flies with two broken ribs, taped in secret. He levels off high over the Mojave and lets the rockets run. The Machmeter climbs: 0.98, 0.99, 1.02. It hesitates. Then it jumps to 1.06. The shaking stops. The ride goes smooth.

This Machmeter is all screwy.Chuck Yeager
Capt. Chuck Yeager stands beside the Bell X-1 #46-062 "Glamorous Glennis," named for his wife.. U.S. Air Force.
1.06Mach, faster than sound
700 mphat 43,000 feet
2broken ribs
14 minfrom drop to landing

By 1947, fighter pilots diving near the speed of sound reported violent shaking and controls that froze. Some never pulled out. Wind tunnels could not give engineers the answer, and the press called it the sound barrier. The Army Air Forces and the NACA chose the only sure way to find out: build a rocket plane and fly a man through it.

0 25 50 75 99 FT BELL X-1 31 FT LONG 28 FT SPAN SEEN FROM BELOW B-29 SUPERFORTRESS 141 FT WINGSPAN · 99 FT LONG
The Bell X-1 in the belly of its B-29 mothership, seen from below, drawn to scale.

  1. A bullet with wings

    The Army Air Forces signs Bell Aircraft to build three research airplanes for flight beyond the speed of sound. Larry Bell’s engineers shape the fuselage like a .50-caliber machine gun bullet, because bullets were known to fly stable faster than sound. They give it thin, straight wings and a four-chamber rocket engine of 6,000 pounds of thrust, and paint it bright orange.

  2. The team

    Col. Albert Boyd, chief of the Air Force Flight Test Division, reviews his 125 test pilots and picks Capt. Chuck Yeager, 24, to fly the X-1. Lt. Bob Hoover is his backup. Capt. Jack Ridley, an engineer with a master’s degree from Caltech, runs the numbers. Starting in August, over Rogers Dry Lake, Yeager pushes a little faster each flight: Mach 0.85, 0.89, 0.91, 0.92.

  3. The controls go dead

    With 0.94 on the Machmeter, Yeager pulls back on the stick and the nose does not move. A shock wave on the tail has made the elevator useless. Ridley works out the answer: forget the elevator and fly the airplane with its whole horizontal stabilizer, which the pilot can trim in flight. That idea, the flying tail, later became standard on supersonic airplanes.

  4. Two broken ribs

    Two nights before the next flight, Yeager and his wife Glennis go riding near the base. In the dark his horse hits a gate and throws him. Two ribs on his right side are broken. A flight surgeon would ground him, so he gets taped up off base and keeps quiet. At work he tells one man: Jack Ridley.

  5. A piece of broom handle

    Locking the X-1’s door takes a hard push with the right arm. Yeager cannot do it. Ridley saws off a short piece of broom handle for a lever that Yeager can work with his left hand. Maj. Bob Cardenas takes off in the B-29 with the X-1 in its bomb bay. Once airborne, Yeager climbs down a ladder into the cockpit and the broom handle locks him in.

  6. Drop

    At 20,000 feet over the Mojave, Cardenas counts down and releases. The X-1 falls out of the bomb bay at 250 mph. Yeager fires all four rocket chambers and the orange airplane climbs away on a column of flame. Hoover follows in a P-80 jet as chase. Yeager sets the stabilizer the way he and Ridley planned and keeps climbing toward 42,000 feet.

    A first-generation Bell X-1 rides in the modified bomb bay of its B-29 Superfortress mothership.
    A first-generation Bell X-1 rides in the modified bomb bay of its B-29 Superfortress mothership.. U.S. Air Force.

  7. Off the scale

    Yeager levels off and lets the rockets run. The Machmeter moves smoothly through 0.98, 0.99, to 1.02, hesitates, then jumps to 1.06. The buffeting stops and the ride turns smooth. The X-1 is doing 700 mph at 43,000 feet, faster than its own sound. On the desert floor, the ground crew hears a deep boom they take for thunder.

    Yeager to Ridley, by radioThis Machmeter is all screwy.

  8. Down on the lakebed

    Yeager dumps his remaining fuel and glides back to Rogers Dry Lake. Fourteen minutes after the drop, Glamorous Glennis, named for his wife, rolls to a stop on the hard clay. The airplane and its pilot are fine. Within hours, Air Force officials stamp the flight and all its data Top Secret. The United States Air Force is 26 days old.

  9. The secret gets out

    Aviation Week breaks the story. Two days later it is headline news in the Los Angeles Times. The Air Force stays silent while Yeager keeps flying past Mach 1, faster each time. On 10 June 1948, Air Force Secretary Stuart Symington makes it official: the sound barrier has been broken, again and again, by two experimental airplanes.

The team

Capt. Charles E. "Chuck" Yeager, as he looked around the time of the first supersonic flight.Age 24
Pilot, Bell X-1Chuck Yeager

Born in Myra, West Virginia, he enlisted as a private in 1941. Shot down over France in 1944, he escaped to Spain, went back to combat and downed five German fighters in one day. First to fly faster than sound. Retired a brigadier general.

Maj. Jack Ridley, X-1 flight test engineer, with the NACA Muroc team in 1948 (detail).Age 32
Project EngineerJack Ridley

Oklahoma-born engineer and test pilot with a Caltech master’s degree. He turned aerodynamics into plain words for Yeager, found the stabilizer fix that kept the X-1 under control, and cut the broom handle. Edwards Air Force Base named its mission control center for him.

Bob Hoover in flight gear with fellow North American Aviation test pilots (detail).Age 25
Backup Pilot and ChaseBob Hoover

Spitfire pilot shot down in 1944. After 16 months as a prisoner, he escaped by stealing a German Fw 190 and flying it to Holland. Backup pilot for the X-1, he flew chase in a P-80 that day, then flew air shows for decades.

Lawrence D. "Larry" Bell, founder of Bell Aircraft Corporation, which built the X-1.Age 53
Founder, Bell AircraftLarry Bell

Founded Bell Aircraft in Buffalo, New York, in 1935. His company built America’s first jet airplane, the P-59, and then the X-1. His Bell 47 became the first helicopter certified for civilian use. Shared the Collier Trophy for the X-1 with Yeager and Stack.

By the numbers

26 daysage of the U.S. Air Force on the day Yeager broke the barrier
20,000 ftwhere the B-29 dropped the X-1, at 250 mph
6,000 lbof thrust from four rocket chambers burning alcohol and liquid oxygen
0.94the Machmeter reading where the elevator quit, four days earlier
8 monthsbefore the Air Force officially confirmed the flight, in June 1948
957 mphMach 1.45, the fastest Glamorous Glennis ever flew, with Yeager on 26 March 1948
71,902 ftthe highest it ever climbed, on 8 August 1949
78flights flown by Glamorous Glennis before it went to the Smithsonian
Glamorous Glennis, the first airplane to fly faster than sound, at the Smithsonian's Steven F. Udvar-Hazy Center in 2023.
Glamorous Glennis, the first airplane to fly faster than sound, at the Smithsonian's Steven F. Udvar-Hazy Center in 2023.
Capt. Chuck Yeager in the cockpit of Glamorous Glennis, photographed by Jack Ridley on September 26, 1947.
Capt. Chuck Yeager in the cockpit of Glamorous Glennis, photographed by Jack Ridley on September 26, 1947.
Technicians service an X-1 mated to its B-29 mothership; the shackles held it until the drop.
Technicians service an X-1 mated to its B-29 mothership; the shackles held it until the drop.
The Mach 1 team at Muroc, October 28, 1947: Ed Swindell, Bob Hoover, Bob Cardenas, Chuck Yeager, Dick Frost and Jack Ridley.
The Mach 1 team at Muroc, October 28, 1947: Ed Swindell, Bob Hoover, Bob Cardenas, Chuck Yeager, Dick Frost and Jack Ridley.
The second X-1 (#46-063) on the ramp with its B-29 launch ship at NACA's Muroc station, about 1949.
The second X-1 (#46-063) on the ramp with its B-29 launch ship at NACA's Muroc station, about 1949.
Yeager, Ridley and the NACA Muroc team study Bob Hoover's photo of the X-1 in supersonic flight, 1948.
Yeager, Ridley and the NACA Muroc team study Bob Hoover's photo of the X-1 in supersonic flight, 1948.

Watch, listen, see

Films, photographs and first-hand accounts from across the web. Each opens in a new tab.

Animated still of the Bell X-1 breaking the sound barrier, from Smithsonian Channel's Aviation Nation.
Video · 4 minThe Sound Barrier Falls

14 October 1947: Chuck Yeager pushes the X-1 past Mach 1 over the Mojave.

Smithsonian Channel
Portrait of Chuck Yeager from the National Museum of the U.S. Air Force tribute video.
Video · 3 minYeager, Told by His Air Force

Curator Jeff Duford on Yeager’s sound-barrier flight and the test aircraft he flew.

National Museum of the U.S. Air Force
Gen. Chuck Yeager during his Academy of Achievement interview.
Interview · 95 minYeager in His Own Words

The full Academy of Achievement interview with Gen. Chuck Yeager, from combat flying to the X-1.

Academy of Achievement
Bob Hoover interviewed at the National Museum of the U.S. Air Force, April 2014.
Interview · 43 minBob Hoover Looks Back

The X-1’s chase pilot on escaping a POW camp, flying with Yeager and a legendary career.

National Museum of the U.S. Air Force
Glamorous Glennis suspended in the National Air and Space Museum's Milestones of Flight hall, 2018.
InteractiveGlamorous Glennis in 3D

Explore a laser-scanned 3D model of the X-1, accurate to about a millimeter.

Smithsonian National Air and Space Museum
Glamorous Glennis hanging at the National Air and Space Museum in Washington, D.C.
PhotosThe Real Glamorous Glennis

The museum’s X-1 page: more than 100 photos, its history and a cockpit panorama.

Smithsonian National Air and Space Museum
Capt. Yeager's pilot's notes from the ninth powered XS-1 flight, October 14, 1947.
DocumentYeager’s Mach 1 Flight Notes

Yeager’s declassified pilot’s notes from 14 October 1947, the first supersonic flight.

National Archives
The second X-1 (#46-063) on Rogers Dry Lake at Muroc, 1949.
DocumentX-1 at Fifty

NASA’s X-1 anniversary site: original reports, team biographies, photos and Collier Trophy history.

NASA History Office

“The greatest aeronautical achievement since the original flight of the Wright Brothers’ airplane.”

Collier Trophy for 1947, presented by President Truman at the White House, 17 December 1948

After

On 17 December 1948, 45 years to the day after the Wright brothers first flew, President Truman presented the Collier Trophy at the White House to Yeager, Larry Bell and NACA scientist John Stack.

Glamorous Glennis flew 78 times. In 1950 the Air Force gave it to the Smithsonian, and it hangs today in the National Air and Space Museum’s Milestones of Flight hall, beside Lindbergh’s Spirit of St. Louis.

Yeager went on to fly Mach 2.44 in 1953, command fighter squadrons and retire a brigadier general. On 14 October 2012, 65 years to the day, he rode an Air Force F-15 past Mach 1 over the same desert. He was 89.

Primary sources