posted May 13, 2012 07:03 AM               

Above: A flown cover for Chuck Yeager's Mach 2.4 flight in USAF Bell aircraft 48-1384, December 12, 1953, over Edwards Air Force Base, California, is shown in excellent condition after being found in a box of low end space covers going to auction. Refer to volume 2 of the Ellington-Zwisler Rocket Mail Catalog, 1973, United States, EZ-73, for additional information concerning this pilot signed, flown, rocket powered X-1A aircraft cover.

Space Cover #161: Chuck Yeager X-1A Flown Cover, Dec. 12, 1953

A surprising flown X-1A cover signed by U.S. Air Force test pilot Chuck Yeager was recently found and of interest to the Space Cover of the Week community. The Yeager pilot signed cover was flown on his high-Mach rocket plane flight, December 12, 1953, over Edwards Air Force Base, California. Yeager was flying this fourth and final X-1A speed record attempt, hoping to beat test pilot Scott Crossfield's Mach 2.005 speed record set in the Douglas Skyrocket only three weeks earlier.

The USAF Bell X-1A aircraft was powered by a hot, uprated 8,000 pound thrust XLR-11 rocket engine. At the time of Yeager's epic flight, there was no possibility of pilot egress nor was there a pilot ejection means to bail out. Safety had taken a back seat to the test pilot's mission of testing the operational capability of the rocket plane for this flight.

After launch on December 12, 1953, under rocket power, Yeager quickly climbed to 62,000 feet altitude over Edwards Air Force Base, California. Leveling out at 76,000 feet altitude at a speed of Mach 1.9, Yeager went to full thrust pushing his aircraft forward to Mach 2.44 on rocket power at 1,650 miles per hour. After throttling back and cutting his rocket engine, Yeager's X-1A aircraft began a slow roll and yaw to the left. As Yeager corrected for the anomaly, his aircraft then rolled sharply right. With a subsequent correction, his aircraft snapped back to the left and then began to tumble violently, out of control. In test pilot language, Chuck Yeager was in deep trouble, and he knew it. He was experiencing something new at hypersonic speed in the X-1A. The inflight phenomenon would later be known as "inertial coupling."

Yeager's aircraft was snapping, rolling, and spinning about all three flight axes as he plummeted through 50,000 feet altitude. He lost consciousness, unable to break out of his death spiral back to Earth. And then, inexplicably at 25,000 feet altitude, he regained consciousness and was able to do something almost impossible. He was able to break out of the aircraft's inertial coupling and was able to bring the X-1A back under his control. After landing and successfully completing his flight, Yeager again had made his mark as a legendary test pilot, who in a dire, inflight emergency was able to save his experimental, rocket powered aircraft and himself. His X-1A flight to Mach 2.44, wresting it from certain failure, and bringing it back under control and unbelievable success on December 12, 1953, over Edwards Air Force Base, California, indeed, may have been Chuck Yeager's finest hour.

And in an accumulation in a box of Skylab, space shuttle, rocket engine test, and recent unmanned space satellite covers proceeding to auction, was this incredible flown X-1A cover, signed by pilot Chuck Yeager on his aircraft's test flight date, December 12, 1953, Edwards Air Force Base, California.