The Sound Barrier

T

OWARD the end ol World War II, aircraft entered a new age ol speed. In 1944 and 1945, German pilots flew the first jet-powered lighter in combat, the Alesserschmitt Ale 262. Allied pilots were astonished to spot it zooming over 100 miles an hour laster than any Allied lighter, and with no propellers!

Alter the war, many pilots tried to fly taster th an the speed of sound. On October 14, 1947, American test pilot Chuck Yeager flew an orange bullet-shaped plane with a rocket engine. It was the Bell X-l, designed to break the sound barrier. Carried up by a B-29 mother plane to save fuel, the X-l was dropped in the air. Yeager lired the rocket engine anil pushed the plane to over 700 miles an hour, past Alach 1 —the speed ot sound. The plane bulleted, then blasted through the sound barrier. Once past Alach 1. it was so smooth, said Yeager, “Grandma could be sitting up there sipping lemonade.”

‘Suddenly the Alach needle began to fluctuate…then lipped right off the ocale, I thought / wao oeeuig thi ago! We were flying ouperoonic:

—Chuck Yeager describing flying
through the sound barrier

Bell X-i

Test pilot Chuck Yeager stands beside his rocket-powered Bell X-1, named the Glamorous Glennis for his wife. The plane now hangs in the National Air and Space Museum. Streamlined for speed, it is shaped like a.50 caliber bullet.

Charles “Chuck" Yeager (1923- )

A World War II fighter pilot. Chuck Yeager became an Air Force test pilot after the war. He made history as the first person to break the sound barrier in 1947. At the time, many believed a plane flying through the sound barrier would be ripped apart by the shock wave. Yeager later rose to the rank of brigadier general.

Famous Flight

On October 14,1947, the Bell X-1 accelerates and races toward the sound barrier. Flying at 43,000 feet, pilot Chuck Yeager became the first person to travel faster than sound, at Mach 1.06.

< MaCHMETER

Mach numbers measure the speed of an aircraft in relation to the speed of sound. Mach 1 is the speed of sound, which increases with temperature because sound travels faster in warmer air. At

40,0 feet, Mach I is 657 miles an hour.

► The Sound Barrier

Moving through the air, a plane makes pres­sure waves. When the plane catc hes up with its own pressure waves, they bunch together, building into a shock wave. Passing the speed of sound, the plane flies ahead of its pressure waves, forming a cone-like shock wave.

Frank Whittle (1907-1996)

Frank Whittle was a young British pilot who patented the first turbojet engine in 1931. It used a jet of hot gases instead of propellers. Soon after, German engineer Hans von Ohain invented a similar engine Germany first produced a jet fighter in 1943, the Messerschmitt Me 262. A year later, the British began flying a jet fighter, the Gloster Meteor. Its engines were based on a Whittle design.

f Messerschmitt Me 262

The first jet-propelled fighter used in combat, the German Messerschmitt Me 262 Schwalbe (swallow) was flown during World War II. Four 30 mm cannons made it a fearsome opponent. This