North American X-15

The North American X-15 was a very special airplane that could fly faster and higher than any other plane at the time. It was powered by a rocket and was used by the United States Air Force and National Aeronautics and Space Administration to test new ideas for airplanes and spacecraft. In the 1960s, the X-15 flew so fast and so high that it reached the edge of outer space. It gave scientists important information that helped make better airplanes and spacecraft.

The X-15 flew 199 times with 12 pilots. On October 3, 1967, one pilot named William J. Knight flew the X-15 at an amazing speed of 4,520 miles per hour. This was the fastest any airplane with a person inside had ever gone, and it is still the record today. Some of the flights were so high that the pilots were considered astronauts because they went above the limit that counts as space for the Air Force. These brave pilots helped open up new possibilities for flying and exploring space.

Design and development

The X-15 was an idea by Walter Dornberger for the National Advisory Committee for Aeronautics. It was a special hypersonic research airplane. Two companies built it: North American Aviation made the body, and Reaction Motors made the engines.

The X-15 was designed to be carried up in the air and then dropped from under the wing of a big B-52 airplane, called a mother ship. When dropped, the X-15 had to be controlled even where there was very little air. It had special rocket thrusters to help with this. The airplane had a long, cylindrical body with special heat-resistant skin to protect it from high temperatures.

The X-15 was tested in many different ways. It could be attached to the launch plane, dropped, start its main engine, fly through thin air or space, come back into thicker air, glide without power, and land directly. Even without its main engine, the X-15 could still be controlled.

The X-15 had two different ways for the pilot to control it. One way used three joysticks, and the other used just one. These helped the pilot steer the airplane, especially when there was very little air to help it fly.

The other control setup used a special system called MH-96, which made it easier for the pilot by blending different controls automatically. The cockpit had many features to help the pilot, like heated windows and a special seat that could shoot the pilot out if needed.

Early X-15 flights used two smaller rocket engines. Later, most flights used one bigger engine called XLR99. This engine burned special fuels very quickly.

The X-15 had a thick wedge-shaped tail to help it stay steady when flying at very high speeds. This shape helped it stay stable, even though it made the airplane slower at lower speeds. Side panels on the tail could extend to help with stability and act as brakes.

Operational history

Before 1958, the United States Air Force and NACA talked about an idea for an orbital X-15 spaceplane, called the X-15B, that would go into outer space from a missile. This idea stopped when NACA became NASA and started Project Mercury.

By 1959, the Boeing X-20 Dyna-Soar was planned to be the main way for the Air Force to send crews into space. But this program stopped in the early 1960s before any vehicles were built. Three X-15 planes flew 199 test flights, with the last one on October 24, 1968.

The first X-15 flight was an unpowered glide by Scott Crossfield on June 8, 1959. Twelve test pilots flew the X-15, including Neil Armstrong, who later walked on the Moon, and Joe Engle, who commanded NASA Space Shuttle missions.

In 1963, pilot Joe Walker flew higher than 100 km, becoming one of the first people to reach the edge of outer space. The second X-15 plane, X-15-2, was rebuilt after a landing accident and renamed X-15A-2. It reached its top speed of 4,520 miles per hour in October 1967, flown by William "Pete" Knight of the U.S. Air Force.

Five main aircraft were used: three X-15 planes and two modified NB-52 bombers. The 200th flight was planned for November 1968 but was canceled due to problems and bad weather. The X-15 was later donated to the Smithsonian Air & Space Museum.

Aircraft on display

Two X-15 airplanes are kept at museums in the United States. You can also see three models and two special airplanes that helped carry the X-15s.

• X-15-1 (AF Ser. No. 56-6670) is shown at the National Air and Space Museum "Milestones of Flight" gallery, Washington, D.C.
• X-15A-2 (AF Ser. No. 56-6671) is at the National Museum of the United States Air Force, at Wright-Patterson Air Force Base, near Dayton, Ohio. It was moved to the museum in October 1969. The airplane is displayed with other "X-planes", including the Bell X-1B and Douglas X-3 Stiletto.

Mockups

• Dryden Flight Research Center, Edwards AFB, California, United States (painted with AF Ser. No. 56-6672)
• Pima Air & Space Museum, adjacent to Davis-Monthan AFB, Tucson, Arizona (painted with AF Ser. No. 56-6671)
• Evergreen Aviation & Space Museum, McMinnville, Oregon (painted with AF Ser. No. 56-6672). This is a full-size wooden model of the X-15, shown with one of the rocket engines.

Stratofortress mother ships

• NB-52A (AF Ser. No. 52-003) is displayed at the Pima Air & Space Museum adjacent to Davis–Monthan AFB in Tucson, Arizona. It helped launch the X-15 airplanes many times.
• NB-52B (AF Ser. No. 52-008) is on display outside the north gate of Edwards AFB, California. It launched most of the X-15 flights.

Record flights

Main article: List of X-15 flights

Highest flights

Thirteen of the X-15's 199 flights took eight pilots above 264,000 feet. This height counts as being in space according to the US Armed Forces. Five Air Force pilots earned special honors for these flights. Three NASA pilots got these honors later.

Only two flights, both by the same pilot, went above the Kármán line, the official edge of space.

^† fatal

Fastest recorded flights

Pilots

The X-15 had many skilled pilots who flew it. Some of these pilots were Joseph Engle, Robert Rushworth, John McKay, William Knight, Milton Thompson, and William Dana. They worked with the United States Air Force and NASA to test the aircraft and learn more about flying at very high speeds and heights.

Specifications

Other configurations include the Reaction Motors XLR11 equipped X-15, and the long version.

The X-15 was a special airplane made for testing. It had one pilot and was powered by a strong rocket engine. It could fly very fast and very high, reaching speeds of up to 4,520 miles per hour and heights of over 100,000 feet.

In popular culture

Main article: Aircraft in fiction § North American X-15

The X-15 aircraft has been in many stories and movies. People enjoy imagining this special plane in adventures or science fiction. It is a favorite in books, films, and games with brave pilots and space travel.