X-15

Beginning in 1944, development of a rocket powered plane began.  The first was the Bell X-1 in 1946.   This is the plane Charles "Chuck" Yeager piloted to mach 1.06 on 14 October 1947, breaking the sound barrier for the first time.  Later planes were developed to fly higher and faster. (See The X-Planes for more information on the X-Plane programs and a X-Plane gallery.)

Credit - Boeing Co.

The North American X-15 was the first plane which could actually be flown into space. By definition in the United States, pilot-astronaut wings are awarded to those who fly above 80 km/50 mi. By FAI definition, only flights above 100 km (Karman Line) qualify as astronaut flights. Only two flights, 90 and 91, meet FAI requirements. During the life of the X-15 program (199 flights between 8 June 1959 and 24 October 1968), 13 flights above 80 km earned 8 pilots their astronaut wings. Joseph H. Engle, who later went on to fly the Space Shuttle, made 3 of these flights. Following are the "astronaut" flights.

The original X-15's were designated as X-15A's. When vehicle #2 was seriously damaged in a crash landing, it was rebuilt as an X-15A-2 with a stretched fuselage and drop tanks. This vehicle was also later covered with a white heat ablative coating. North American also proposed an X-15B (never built) which could have taken off vertically, flown a single orbit around the earth, then returned and been ditched in the ocean after the pilot had ejected. The vehicle would have then been lost.

* Fatal accident, aircraft destroyed. After reaching peak altitude, entered spin at Mach 5. Entered dive at 30,000 m, began high frequency pitch oscillations, aircraft disintegrated when these reached 15 Gs.

X-15 Vital Statistics

Contractor: North American Aviation, Inc.
Number Built: 3
Powerplant: One Reaction Motors XLR99 Pioneer (throttleable between 25,000 to 50,000 lbs thrust). Prior to November 1960, two Reaction Motors XLR11-RM-5 rockets with 8,000 lbs thrust each were used.
Wingspan: 22 ft, 4 in
Length: 52 ft, 5 in
Height: 12 ft, 7 in
Weight: 56,130 lbs gross
Cost: $300 million for design, development, and testing of 3 aircraft
Max Speed: Mach 6.70 (4,520 mph)
Ceiling: 324,200 ft (98,800 m)
Flight Controls: Two sets of guidance controls were used. Airplane flight controls were used while flying in the lower, thicker air. Thrusters were used for control at the edge of space.

The X-15 hull is made of Iconel X, a special steel alloy (steel and nickel) made by International Nickel Company. The hull is held together by stainless steel. Aluminum is also used internally where there are no heat or load problems.

The landing gear consists of two skids under the tail of the plane and a nose wheel.

The pilot wore a MC-2 full-pressure suit. The ejection seat rocket could develop 6100 pounds of thrust for a split second and would propel the pilot up and to the rear. The seat had stabilizing fins for the drop to 15,000 feet where the pilot would be released. If the ejection altitude was below 15,000 feet, the pilot was released after 3 seconds. After release from the seat, the pilot would descend with a 25 foot circular parachute.

There were a total of 199 X-15 flights between 8 June 1959 and 24 October 1968.

Where are the X-15's now?

Vehicle #1 is at the National Air and Space Museum. Vehicle #2 is at the US Air Force Museum in Dayton, Ohio. Vehicle #3 was destroyed in a crash.

X-15 Photos

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