- Education and Science
The Sound Barrier and Beyond
German V-2 Buzz Bomb Rocket
The first powered flights faster than sound may have been the Soviet phosphorus powered ramjets in 1933 and German V-2 rockets in 1942 which achieved Mach 2 and higher. But, it must be noted these were unmanned flights and the speeds attained were only during descent.
The speed of sound isn’t a constant. It changes with altitude. At sea level it’s760 mph. As altitude increases, the speed of sound, referred to as Mach 1, decreases. So at 36,000 feet it would be 659 mph.
An amazing sight associated with near supersonic and beyond is the production of a sudden visible vapor cloud around the aircraft…followed immediately after by a “sonic boom.” The name Mach comes from the nineteenth-century physicist Ernst Mach. A good example of a sonic boom is a bull whip. When the tip speed reaches the sound barrier it causes a sharp crack.
Obviously, before jet powered aircraft, pilots were unable to break the sound barrier. And in the latter part of the 1940s it was believed by some breaking the sound barrier was impossible. Surprisingly, it was the British who first began experimenting with top secret projects in 1942 to develop the world's first supersonic aircraft.
U-2 Spy Plane
But, it was Charles E. “Chuck” Yeager, a decorated American ace and test pilot, who became the first pilot to officially do so on October 14, 1947. The official record was a speed of Mach 1.015, or 670 mph, at 42,000 feet and was accomplished in an experimental aircraft called the Bell X-1 designed using some of the British research. The Bell X-1 was affectionately dubbed the “Glamorous Glennis,” after his wife.
At the time this was an amazing feat. Not long before several pilots had lost their lives as their planes disintegrated just short of reaching Mach 1. Several years later, on May 18, 1953, Jacqueline Cochran became the first woman pilot to break the sound barrier with Yeager acting as wingman.
In 1951, test pilot Bill Bridgeman managed to reach Mach 1.88 in a Douglas Skyrocket. Mach 2 now became the next speed to breech. Newer, more advanced, aerodynamic designs were needed. The answer was “pinching” the fuselage in at the wings, giving it a coke bottle look. Shortly afterwards, Scott Crossfield hit Mach 2.01 in a D-558-2 Douglas Skyrocket launched from a B-29. But Yeager closed out the year with a top speed of Mach 2.44. However, he narrowly escaped death when his plane went into a turbulent tailspin.
Then in May 1960, the Russians managed to bring down a U-2 spy plane using a surface to air missile. Something faster was needed. Thus, the Lockheed SR-71 Blackbird, supersonic spy plane, too fast for missiles was born in 1964. With newer materials, systems and fuels the SR-71 could conceivably reach Mach 7 or higher. The next record was set by William J. “Pete” Knight on October 3, 1967. He flew an X-15- 2A at 4,535 mph or Mach 6.72.
By the late 1950s, for all intents and purposes, there was no longer a sound barrier as more and more aircraft were easily capable of breaking it. Several commercial airlines such as the Concorde in the 1970s were also able to attain Mach speed.
It is rumored several newer U.S. military aircraft may be capable of greater speeds and secret tests by the USAF may have established new records since then. The newest experimental aircraft as of this writing is the X-29.
Perhaps the next goal is to travel at light speed, 186,000 miles per second and at present only attainable in science fiction. But, is it possible? Einstein’s theory of relativity states nothing can travel faster than light in a vacumn.
However, neutrino beams from CERN, the European Organization for Nuclear Research in Switzerland, were sent over 700km through the Earth's crust to a laboratory in Gran Sasso, Italy. The beams were measured at a speed just a fraction above the speed of light…