• Cardenas: Muroc tower, Air Force Eight Zero Zero taxi instructions.
• Tower: B-twenty-nine Eight Zero Zero cleared Runway six. Winds out of East seven miles an hour.
• Cardenas: We cleared to roll?
• Tower: Roger, cleared to line up and roll.
• Swindell(B-29 flight Engineer) :She's all your's, Major.
• Cardenas: All right, Swindell?
• Cardenas: Rolling.
• B-29 left side scanner: Left gear full up, left flap full up. One and two[engines] look clean on the take-off, sir.
• B-29 right side scanner: Right gear full up, right flap full up. Three and four look good on the take-off.
• Swindell: Roger.
• Cardenas: B-twenty-nine Eight Zero Zero to Muroc tower. How do you read me, over?
• Tower: Loud and clear.
• Swindell: Scanners from engineer, five thousand feet.
• Yeager: Check list complete, everything okay.
• Ridley: Roger.
• Cardenas: B-twenty-nine Eight Zero Zero. Air Force Two Zero One. Hoover, are you guys on the way up?
• Hoover: Yeah, boy.
• Cardenas: Okay, we're just closing fifteen thousand feet. About twenty south of the lake[Rogers Dry Lake]. Making a right turn now and heading south.
• Hoover: Roger.
• Frost: You over El mirage [Dry Lake], Carenas?
• Cardenas: Coming to the southern end of the lake at sixteen thousand feet.
• Frost: I'll be with you soon.
• Hoover: Air Force Two Zero One, where are you B-twenty nine?
• Cardenas: I am coming around--
• Hoover: Okay, I see you now buddy; coming up to you.
• Cardenas: Eight Zero Zero, five-minute warning.
• Yeager: Okay, Cardenas, loading first stage now. Ridley? Clear to disconnect nitrogen hose and pilot's breathing oxygen?
• Ridley: Roger.
• Cardenas: Four minutes.
• Yeager: Roger, Cardenas; pressurizing fuel tank.
• Ridley: Nitrogen hose disconnected. Pilot's breathing oxygen disconnected.
• Yeager: Roger, Jack.
• NACA Muroc: NACA radar to Air Force Eight Zero Zero, how do you read?
• Cardenas: Loud and clear. Three minutes.
• Yeager: Pressurizing lox tank. All pressurized.
• Frost: Yeager, this is Frost. I'm in position to check your jettison.
• Yeager: Roger. Fuel jettison is on.
• Frost: Fuel jettison okay.
• Yeager: Switch off.
• Frost: Shutt-off okay.
• Cardenas: Two minutes.
• Yeager: Lox jettison switch on. Switch off.
• Frost: Lox jettison and shut-off are okay.
• NACA Muroc: Was that two minutes B-twenty-nine?
• Cardenas: Roger, that was two minutes.
• Tower: Muroc Air Force Base to all aircraft. All aircraft stay clear of Muroc Dry Lake area. Test in progress. All aricraft on ground return to parking positions. Repeat: all aircraft stay clear.
• Cardenas: B-twenty-nine Eight Zero Zero to NACA radar, Muroc Tower, chase aircraft: one minute.
• NACA Muroc: NACA radar to Air Force B-twenty-nine Eight Zero Zero. You are clear to drop.
• Cardenas: Roger.
• Ridley: Yeager, this is Ridley. You all set?
• Yeager: Hell, yes, let's get it over with.
• Ridley: Remember those stabilizer settings.
• Yeager: Roger.
• Cardenas: Eight Zero Zero. Here is your countdown: 10--9--8--7--6--5--3--2--1--Drop[note: Cardenas omitted "4" in the drop count; launch occurred at 10:26am as the B-29 was flying at 20,000 feet and an indicated airspeed of 250mph].
• Yeager: Firing four[rocket chamber #4]. . . Four fired okay. . . will fire two. . . Two on. . . will cut off Four. . . Four off. . . will fire Three. . . Three burning now. . . will shut off Two and fire One. . . One on. . . will fire Two again. . . Two on. . . will fire Four.
• Ridley: How much of a drop[in chamber pressure]?
• Yeager: About forty psi. . . got a rich mixture. . . chamber pressures down. . . now going up again. . . pressures all normal. . . will fire Three again. . . Three on. . . acceleration good. . . have had mild buffet. . . usual instability. Say, Ridley, make a note here. Elevator effectiveness regained[as he passed an indicated Mach number of 0.96].
• Ridley: Roger. noted.
• Yeager: Ridley! Make another note. There's something wrong with this Machmeter. Its gone screwy!
• Ridley: If it is, we'll fix it. Personally, I think you're seeing things.
• Yeager: I guess I am, Jack. . will shut down again. . . am shutting off. . . shut off. . . still going upstairs like a bat. . . have jettisoned fuel and lox. . . about thirty percent of each remaining. . . still going up. . . have shut off now.

Source: X-1 file, National Air & Space Museum.

X-1 Technical Specifications

Length: 30'11

Wingspan: 28'0"

Height: 10'10"

Accomodation: 1[Pilot]

Gross weight: [46-062 with 8% T/C wing] 12,250 Ibs.

Empty weight: [46-062 with 8% T/C wing] 7,000 Ibs.

Powerplant: Reaction motors, Inc [RMI] XLR11-RM-3 four chamber rocket motor developing 6,000 Ibs of thrust [1,500 Ibs. per chamber]. Fuel was liquid oxygen [lox] and diluted ethyl alcohol. The engine weighed 345 Ibs.

The engine had no throttle, thrust only being variable by igniting and shutting down of the individual rocket chambers [0%-25%-50%-75%-100% thrust].

Range: 5 minutes powered endurance.

Maximum altitude: 71,902 feet

Maximum speed: Mach 1.45 [957mph]

Chuck Yeager went on to fly the X-1 thirty-four times, establishing the maximum speed for that aircraft of Mach 1.45 on March 26th 1948. The maximum altitude achieved for the original X-1 series was 71902 feet by Frank Everest on July 25th 1949. Yeager also went on to make the only ground launch of an X-designated rocket powered airplane on 5th January 1949, climbing to 23,000 feet and Mach 1.03 after only eighty seconds of powered flight!