History of Mach 1: Yeager Breaks the Sound Barrier

Mach 1

Captain Chuck Yeager and the Bell X-1


On June 10, 1948, The U.S. Air Force confirmed that Capt. Chuck Yeager had repeatedly attained supersonic speeds in the Bell X-1.


Yeager’s Background

But it was actually on October 14, 1947, that Chuck Yeager, who died in 2020, broke the sound barrier, Mach 1, for the first time.

I met Yeager on his 50th anniversary of that earlier date in Washington DC, on October 14, 1997 — when he retired as a military consultant and broke the sound barrier again, this time in an F-15.

On this occasion in 1997, he spoke at the Smithsonian Air and Space Museum. He told us how he did it in the room next to the gallery where the Bell X-1 rocket plane is hung. This is a man with “The Right Stuff.” Indeed, you saw his exploits in the movie by that name.

Yeager in an F-15, 1997



This is his story.

[ I recorded the following in the dark from the back row of an IMAX Theater at the Smithsonian Air & Space Museum at the 1997 event by typing on my Psion palmtop computer. The transcript is rough, and I didn’t understand all the technical parts. He’s incredibly sharp for ‘only’ having a high school education. He had a predilection for “colorful” language. ]


Yeager Hits Mach 1

“This morning before this talk, they put me in a cherry picker and hoisted me up to the X-1. Was it scary? Heck, usually I got into it several miles up in the air. 48 years ago was the last flight of the X-1. When I got in today, I found a penny on the floor from 1950.


Bell X-1 Glamorous Glennis, National Air and Space Museum

Bell X-1 at the Smithsonian Air & Space Museum

“In 1942-3, Major Cocher at Wright Field conceived the idea of supersonic flight as they were at 60-80% of Mach. NACA, the predecessor to NASA, controlled all research flying. In 1944 the Army Air Corp contracted two X-1s from Bell Aircraft Company.

“These were flown by Bell pilots. Slick Goodwin had negotiated a $150K bonus for 1.1 Mach. Before this, he had gotten just $10K for .8 Mach for Phase 1. But the Army was spending only $3M for the whole program. Wright Field offered military testers, like me, for ‘free.'”


Yeager Post-WWII

“I got home from the war in January 1945 and graduated in August. Out of 120 pilots, I, a maintenance pilot, was their first pick. At Muroc [Air Force Base], the X-1 used liquid oxygen (LOX) for a 2.5-minute flight. I was launched from a B29 from 25-26K feet up. There were 5K lbs. of liquid nitrogen to launch to pressurize the LOX and water-alcohol. We knew about subsonic turbulence from the P51, P80, and P84 in the War. Consequently [ and he used ‘consequently’ in almost every other sentence ], the B29 driver got us up to 10K feet, then I climbed in.”

I asked him afterward if it was true what we saw in the movie “The Right Stuff” that before the flight, he fell off his horse and cracked some ribs.

“No, that would be cruelty to animals! Actually, the horse ran into a fence,” he said.

Back to his story…

“A B80 chase plane followed up. We did a dive in the B29 at 240 mph. There were four switches to ignite each of four engines. It is very dark under the plane, then very bright after I launched and came out from under the B29.

“We did nine flights first. But the 7th flight was .94 Mach and the plane was pitching up. You tell somebody something often enough you start to believe it yourself. I would roll over to 2Gs (gravities) because elevator effectiveness was being lost as the shock wave was moving back but I couldn’t turn. So to the horizontal stabilizer, we put some 3-in-1 oil [and developed the “flying tail”]. The Machmeter only goes to 1.0 Mach but buffeting stopped at 1.07 Mach. This was on Oct 14. On Sept 18 the Army Air Force became the US Air Force.”


Must Go Faster

“Now this opened Pandora’s Box. We had to hit Mach 2. I’ve flown lots of GE engines, and I’m glad they sponsor these lectures so you can see how your tax dollars are spent. I didn’t mind that my flight was [previously] `classified’ because we were feeding info into research where we added a flying tail rather than a fixed horizontal stabilizer. [This helped the warplane effort,] F86 vs. MiGs were better because we shot down 10 to 1 in Korea. We offered $100K and US citizenship for a MiG and a North Korean Lieutenant flew one down. It took the French, British, and Soviets 5 years to figure it out [the flying tail].

“There was the X-1, X-2, X-3, X-4, X-15, which were dates of contract but the X-4 was most advanced from Northrop. The DH108 went to .94 Mach but if you didn’t back off when it pitched and yawed and rolled… it would go divergent.

“The X-3 Needle would dive at 1.06 but was unstable. The X-5 was the first sweep wing that went into the F111. We could sweep 20-60 degrees.”


Yeager Hits Mach 2

“The X-1A used hydrogen peroxide for steam to drive the LOX. It weighed not 12K lbs. loaded/6K lbs. empty, but 15K lbs. loaded/5K lbs. empty and could go 4 minutes [not 2.5 minutes].

“On the first of November 1953, I did the first flight, shortly after 50th anniversary (Dec 17) of Wright Brothers’ flight… 4.5 minutes of flight after being launched from B50, 3 engines at 36K feet. We’d go to 60K feet at 1.5 Mach.  Bell engineers suspected at 2.3 Mach, it would go ‘squirrelly’ because the shock wave would hit the stabilizer. On the 4th flight: 0.8 Mach at 45K feet and the pressure suit’s faceplate would fog up and I couldn’t see anything.

“I was sitting in front of the frozen gas and we didn’t do anything to heat the cabin. I’d ‘push over’ At 60k feet and I was getting level at 80K feed and I was doing 31 miles per minute.  I hit 2.3 Mach and it yawed to the left. At 40 degree, I was at full right rudder, 3 Gs. Now I was revolving twice a second [out of control]. I was hitting high Gs and was disoriented. I think my helmet hit the canopy.  I turned up the rheostat to defog the flight suit faceplate.

“At 25K feet I pulled out 60 miles away from the base.  All in 51 seconds. Here’s the [now declassified] transcript with some West Virginian colloquialisms.  [ He showed it along with and a short film of his revolutions before the camera broke loose. ]

“On December 12, before the flight at 4:30 AM that morning I went duck hunting. I got home afterward and my wife Glennis [for which the X-1 is named ‘Glamorous Glennis’] saw my bloodshot eyes from pulling Gs and she said, ‘What happened to you?’ At 5 PM that day I gave a talk at the Army-Navy Club and got home at 1 am the next morning.”


Q&A afterward with Chuck Yeager

Q: What’s your favorite plane and your least favorite?

A: “My favorite plane is always the latest plane I’ve flown. They’re like luxury cars. I’m flying the F-22 and F-23 now [in 1997]. I flew some Harriers I didn’t like.”

Q: Did you ever want to fly in the space program, the Shuttle, for example?

A: “I wouldn’t have minded the left-hand seat, but I wouldn’t want to be one of the guys in the back barfing into his beard. But I couldn’t fly the space program because it required a college degree, and I only had a high school education.”

[ It was a real treat, following his talk, to get his autograph for my son in front of a picture of the Mars Sojourner robot powered by Java. “…from generation to generation.” ]


Chuck Yeager history

  • Born in 1923 in West Virginia.
  • Started as a mechanic.
  • Flew P39 fighters.
  • Served in the 357th in the U.K.
  • Later became a test pilot for X(perimental) planes.
  • Then flew as a research pilot.
  • He flew 127 combat missions in Vietnam.
  • He was later stationed at Norton Air Force Base.
  • He has 15,000 hours in a plane.
  • He received the Medal of Honor from President Ford. This is usually awarded after you die, but in Chuck’s case, they made an exception.


Bill Petro, your friendly neighborhood historian

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About billpetro

Bill Petro writes articles on history, technology, pop culture, and travel. He has been a technology sales enablement executive with extensive experience in Cloud Computing, Automation, Data Center, Information Storage, Big Data/Analytics, Mobile, and Social technologies.

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