THE FASTES MANNED FLIGHT EVER: It flew at nearly Mach 7, seven times the speed of sound and twice the speed of a rifle bullet. The speed record it set 47 years ago today still stands today. It flew so high its pilots earned Air Force astronaut wings: 280,500 feet or 53.1 miles above the earth. It pioneered technologies that were used on the SR-71 Blackbird, the space shuttle and the reusable spacecraft in Richard Branson’s future Virgin Galactic passenger space program. And it killed test pilots in an era before redundant flight control systems and modern safety protocols for hypersonic flight. It was the North American X-15. Today is the 47th anniversary of its fastest ever manned, powered flight. 10:30 Hr.s Local, Tuesday, 3 October, 1967. Edwards Air Force Base This X-15 is different than the only other two aircraft of the same type. The other two X-15’s are painted black and have a yellow NASA band on their vertical stabilizer with U.S. Air Force markings on the fuselage and wings. The X-15 Pete Knight is strapping himself into is an “X-15A-2”. It has no exterior markings. It is covered with a milky white ablative coating to resist heat and carries a pair of giant anhydrous ammonia tanks under its fuselage. The rocket plane is made of a special, ultra strong alloy called “Inconel-X”. As Inconel-X heats up it actually becomes stronger. The X-15A-2 burns a volatile mixture of deadly ammonia and liquid oxygen as fuel. When ignited, its single XLR99 engine burns 7 tons of fuel in just over a minute and generates half a million horsepower, nearly 60,000 pounds of thrust. By comparison a modern day F-16 fighter generates about 30,000 pounds of thrust in full afterburner. Today’s flight profile has one objective: speed. It is an attempt to set a maximum manned-flight speed record. The X-15 will be a piloted projectile blasting through a violent acceleration from 500 MPH to nearly 5,000 MPH in only 75 seconds. Six times the speed of sound. On the downside of this flight profile the X-15A-2 will decelerate so violently that a rearward-facing crash pad is installed in the canopy, in front of the pilot, so Pete Knight’s helmet can slam into something soft as the friction of the atmosphere slows the plane after its explosive fuel burns out. But over the next 75 seconds Pete Knight accelerates past the sound barrier- and keeps on accelerating. Mach 2…3…4… There is no secondary sonic boom as Mach speed accumulates. No dramatic acknowledgement of a new speed frontier being crossed. Mach 5. Five tons of anhydrous ammonia and liquid oxygen have burned in a barely controlled explosion 15 feet behind Knight’s ejector seat. Two tons remain. Mach 5.5. A by-product of speed in the atmosphere is friction, and a by-product of friction is heat. Pete Knight’s X-15A-2 begins to melt. The leading edge of the wings glow at over a thousand degrees. Even at high altitude the air molecules can’t get out of the way fast enough to dissipate heat. So chunks of Knight’s X-15 begin to burn and fall off. Big chunks. During flight, shock waves burn through the leading edge of the lower ventral fin igniting a series of small fires in the engine housing. Near the explosive nitrogen tanks. Mach 6. He passes through Mach 6.5. Mach 6.6. A big part of the X-15A-2’s ventral fin ignites and burns completely through. It flies off the aircraft, tracing a bright, burning arc to the desert floor. Mach 6.7. Fuel burn complete. Flight profile nominal. Powered flight terminated, ballistic flight initiated. Knight is still alive and at the controls of the world’s fastest glider. The X-15A-2 had reached its maximum velocity, a new manned flight speed record by a huge margin. It arcs over the Nevada-California border, over a mile a second, leading edges still glowing from heat. Accumulated heat detonates the separation charges on the dummy scramjet carried for test purposes. It explodes away from the X-15A-2 over Edwards bombing range as Knight decelerates through Mach 1 and 32,000 feet, more charred junk toppling to earth. Knight continues to descend, burning fragments dropping off the aircraft as he flies. William J. “Pete” Knight’s speed record remained unbroken by any winged craft until the space shuttle Columbia’s reentry from space on April 14, 1981. His speed record still remains intact for a non-orbital aircraft. Pete Knight had become the fastest pilot to fly inside the atmosphere in powered, controlled flight. A record that officially remains today.
Posted on: Thu, 16 Oct 2014 14:12:49 +0000
Trending Topics
Recently Viewed Topics
© 2015