Tag Archives: Reaction Motors XLR99-RM-1

17 July 1962

With the X-15 under its right wing, the Boeing NB-52A, 52-003, takes of from Edwards Air Force Base, 17 July 1962. The rocketplane's belly is covered with frost from the cryogenic propellants. (U.S. Air Force)
With Major Robert M. White and the X-15 under its right wing, the Boeing NB-52A Stratofortress, 52-003, takes of from Edwards Air Force Base, 17 July 1962. The rocketplane’s belly is covered with frost from the cryogenic propellants. (U.S. Air Force)

17 July 1962: At 9:31:10.0 a.m., the Number 3 North American Aviation X-15, 56-6672, was airdropped from a Boeing NB-52A Stratofortress, 52-003, over Delamar Dry Lake, Nevada. Air Force project test pilot Major Robert M. (“Bob”) White was in the cockpit. This was the 62nd flight of the X-15 Program, and Bob White was making his 15th flight in an X-15 hypersonic research rocketplane. The purpose of this flight was to verify the performance of the Honeywell MH-96 flight control system which had been installed in the Number 3 ship. Just one minute before drop, the MH-96 failed, but White reset his circuit breakers and it came back on line.

North American Aviation X-15 56-6672 immediately after being dropped by the Boeing NB-52 Stratofortress. (NASA)
North American Aviation X-15 56-6672 immediately after being dropped by the Boeing NB-52 Stratofortress. (NASA)

After dropping from the B-52’s wing, White fired the X-15’s Reaction Motors XLR-99 rocket engine and began to accelerate and climb. The planned burn time for the 57,000-pound-thrust engine was 80.0 seconds. It shut down 2 seconds late, driving the X-15 well beyond the planned peak altitude for this flight. Instead of reaching 280,000 feet (85,344 meters), Robert White reached 314,750 feet (95,936 meters). This was an altitude gain of 82,190 meters (269,652 feet), which was a new Fédération Aéronautique Internationale (FAI) world record.¹ The rocketplane reached Mach 5.45, 3,832 miles per hour (6,167 kilometers per hour).

Because of the increased speed and altitude, White was in danger of overshooting his landing at Edwards Air Force Base in California. He passed over the north end of Rogers Dry Lake and crossed the “high key”—the point where the X-15 landing maneuver begins—too high and too fast at Mach 3.5 at 80,000 feet (24,384 meters). Without power, White made a wide 360° turn over Rosamond Dry Lake then came back over the high key at a more normal 28,000 feet (8,534.4 meters) and subsonic speed. He glided to a perfect touch down, 10 minutes, 20.7 seconds after being dropped from the B-52.
A North American Aviation X-15 rocketplane just before touchdown on Rogers dry Lake. A Lockheed F-104 Starfighter chase plane escorts it. The green smoke helps the pilots judge wind direction and speed. (NASA)
North American Aviation X-15 56-6672 just before touchdown on Rogers Dry Lake. A Lockheed F-104 Starfighter chase plane escorts it. The green smoke helps the pilots judge wind direction and speed. (NASA)

This was the first time that a manned aircraft had gone higher than 300,000 feet (91,440 meters). It was also the first flight above 50 miles. For that achievement, Bob White became the first X-15 pilot to be awarded U.S. Air Force astronaut wings. His 314,750-foot altitude (95,936 meters) also established a Fédération Aéronautique Internationale (FAI) world altitude record, which will probably never be broken. To qualify, a new record would have to exceed White’s altitude by at least 3%, or more than 324,419 feet (98,882.9 meters). As the FAI-recognized boundary of Space is 328,083.99 feet (100,000 meters), any prospective challenger would have to hit a very narrow band of the atmosphere.

Command Pilot Astronaut insignia, United States Air Force
Command Pilot Astronaut insignia, United States Air Force

Major White had been the first pilot to fly faster than Mach 4, Mach 5 and Mach 6. He was the first to fly over 200,000 feet, then over 300,000 feet. He was a graduate of the Air Force Experimental Test Pilot School and flew tests of many aircraft at Edwards before entering the X-15 program. He made at total of sixteen X-15 flights.

A P-51 Mustang fighter pilot with the 355th Fighter Group in World War II, he was shot down by ground fire on his fifty-third combat mission, 23 February 1945, and captured. He was held as a prisoner of war until the war in Europe came to an end in April 1945.

After the war, White accepted a reserve commission while he attended college to earn a degree in engineering. He was recalled to active duty during the Korean War, and assigned to a P-51 fighter squadron in South Korea. Later, he commanded the 22nd Tactical Fighter Squadron (flying the Republic F-105 Thunderchief supersonic fighter bomber) based in Germany, and later, the 53rd TFS. During the Vietnam War, Lieutenant Colonel White, as the deputy commander for operations of the 355th Tactical Fighter Wing, flew seventy combat missions over North Vietnam in the F-105D, including leading the attack against the Paul Doumer Bridge at Hanoi, 11 August 1967, for which he was awarded the Air Force Cross.

He next went to Wright-Patterson AFB where he was director of the F-15 Eagle fighter program. In 1970 he returned to Edwards AFB as commander of the Air Force Flight Test Center. White was promoted to Major General in 1975.

General White retired from the U.S. Air Force in 1981. He died 10 March 2010.

Major Robert M. White, U.S. Air Force, with a North American Aviation X-15 on Rogers Dry Lake, 1961. (NASA)
Major Robert M. White, U.S. Air Force, with a North American Aviation X-15 on Rogers Dry Lake, 1961. (NASA)

¹ FAI Record File Number 9604

© 2017, Bryan R. Swopes

29 June 1965

Captain Joe Henry Engle, United States Air Force
Captain Joe Henry Engle, United States Air Force

29 June 1965: At 10:21:17.6 PDT, Captain Joe H. Engle, United States Air Force, flying the Number Three North American Aviation X-15A-3 research rocketplane, 56-6672, was air-dropped from the NB-52B Stratofortress mothership, Balls 8, over Delamar Dry Lake in Nevada. This was the 138th flight of the X-15 Program, and Joe Engle’s 12th. He fired the Reaction Motors XLR99-RM-1 engine for 81.0 seconds and accelerated to Mach 4.94 (3,432 miles per hour, 5,523 kilometers per hour). The X-15 climbed to an altitude of 280,600 feet (85,527 meters, 53.14 miles). He touched down at Edwards Air Force Base after 10 minutes, 34.2 seconds of flight. His parents were at Edwards to witness his flight.

Captain Engle qualified for Astronaut wings on this flight, the third and youngest Air Force pilot to do so.

Command Pilot Astronaut insignia, United States Air Force
Command Pilot Astronaut insignia, United States Air Force

From 1963 and 1965, Joe Engle made 14 flights in the three X-15s. After leaving the X-15 Program, he was assigned to the Apollo Program, the only NASA astronaut with prior spaceflight experience. He was the back-up Lunar Module pilot for Apollo 14 and he was the designated LM pilot for Apollo 17 but was replaced by Harrison Schmidt when Apollo 18 was cancelled. Next he went on to the Space Shuttle Program. He was a Mission Commander for the Enterprise flight tests and for Columbia‘s second orbital flight, during which he became the only pilot to manually fly a Mach 25 approach and landing. Finally, he commanded the Discovery STS 51-1 mission.

Joe Engle retired from the Air Force in 1986. He was then promoted to the rank of Major General and assigned to the Kansas Air National Guard. He has flown at least 185 aircraft types and accumulated 14,700 flight hours, with 224 hours in space.

Captain Joe H. Engle, U.S. Air Force, with the North American Aviation X-15A-2, 56-6671, at Edwards Air Force Base, California, 1965. (NASA)
Captain Joe H. Engle, U.S. Air Force, with the North American Aviation X-15A-2, 56-6671, at Edwards Air Force Base, California, 1965. (NASA)

© 2016, Bryan R. Swopes

27 June 1963

27 June 1963: At 09:56:03.0 PDT, Major Robert A. Rushworth, United States Air Force, flying the Number Three North American Aviation X-15 research rocketplane, 56-6672, was air-dropped from the NB-52B Stratofortress mothership, Balls 8, over Delamar Dry Lake in Nevada.

This was the 87th flight of the X-15 Program, and Bob Rushworth’s 14th.

North American Aviation X-15 56-6672 immediately after being dropped by the Boeing NB-52 Stratofortress. (NASA)
North American Aviation X-15 56-6672 immediately after being dropped by the Boeing NB-52 Stratofortress. (NASA)

Rushworth fired the Reaction Motors XLR99-RM-1 engine for 80.1 seconds and accelerated to Mach 4.89 (3,425 miles per hour, 5,512 kilometers per hour). The X-15 climbed to an altitude of 285,000 feet (86,868 meters, 53.98 miles). Rushworth touched down at Edwards Air Force Base after 10 minutes, 28.0 seconds of flight.

Major Rushworth qualified for Astronaut wings on this flight, the second X-15 pilot to do so.

From 1960 and 1966, Bob Rushworth made 34 flights in the three X-15s, more than any other pilot.

Command Pilot Astronaut insignia, United States Air Force
Command Pilot Astronaut insignia, United States Air Force

© 2015, Bryan R. Swopes

23 June 1961

Bob White exits the cockpit of an X-15 on Rogers Dry Lake. (NASA)

23 June 1961: Major Robert Michael White, United States Air Force, became the first pilot to exceed Mach 5 in an aircraft. This was the 38th flight of the X-15 Program. Flights during this phase incrementally increased the speed and altitude of the X-15 up to its design limits of Mach 6 and 250,000 feet (76,200 meters).

The second North American Aviation X-15A, 56-6671, was air-dropped from the NB-52A Stratofortress mothership, 52-003, over Mud Lake, Nevada at 2:00:05.0 p.m., Pacific Daylight Time (21:00 UTC). White fired the Reaction Motors XLR99-RM-1 engine for 78.7 seconds, reaching Mach 5.27 (3,603 miles per hour, 5,799 kilometers per hour) and climbed to 107,700 feet (32,827 meters). 10 minutes, 5.7 seconds after being dropped from the B-52, White touched down on Rogers Dry Lake at Edwards Air Force Base.

Bob White was the first pilot to exceed Mach 4, Mach 5 and Mach 6. He also flew an X-15 to an altitude of 314,750 feet (95,936 meters), qualifying for U.S. Air Force astronaut wings.

After leaving the X-15 program, Major White flew 70 combat missions in the Republic F-105D Thunderchief fighter bomber during the Vietnam War. He lead the attack against the heavily-defended Paul Doumer Bridge in Hanoi, 11 August 1967, for which he was awarded the Air Force Cross.

Major General White retired from the U.S. Air Force in 1981. He died 10 March 2010.

56-6671 is in the collection of the National Museum of the United States Air Force. The mothership, 52-003, is on display at the Pima Air and Space Museum, Tucson, Arizona.

North American Aviation X-15A 56-6671. (NASA)

© 2016, Bryan R. Swopes

10 June 1969

North American Aviation, Inc., X-15A-1 56-6670 hypersonic research rocketplane on display at the National Air and Space Museum. (Photo by Eric Long, National Air and Space Museum, Smithsonian Institution)

10 June 1969: The U.S. Air Force donated the first North American Aviation X-15, serial number 56-6670, to the Smithsonian Institution for display at the National Air and Space Museum.

The North American Aviation, Inc., X-15A-1, 56-6670, being brought into the Arts and Industries building, June 1969. (Smithsonian Institution Archives SI-A-4145-23-A)
The North American Aviation, Inc., X-15A-1, 56-6670, being brought into the Arts and Industries building, June 1969. The wings and sections of the dorsal and ventral fins have been removed. (Smithsonian Institution Archives SI-A-4145-23-A)

The first of three X-15A hypersonic research rocketplanes built by North American for the Air Force and the National Advisory Committee (NACA, the predecessor of NASA), 56-6670 made the first glide flight and the first and last powered flights of the X-15 Program. It made a total of 82 of the 199 X-15 flights.

Scott Crossfield, North American’s Chief Engineering Test Pilot, made the first unpowered flight 8 June 1959 and the first powered flight, 17 September 1959. NASA Research Test Pilot William H. “Bill” Dana made the final X-15 flight on 24 October 1968.

North American Aviation, Inc., X-15A-1 56-6670 at the National Air and Space Museum, Washington, D.C. (D. Ramey Logan via Wikipedia)
The first North American Aviation, Inc., X-15A, 56-6670, at the National Air and Space Museum, Washington, D.C. Above and behind the X-15 is the Douglas D558-II Skyrocket that Scott Crossfield flew to Mach 2.005, 20 November 1953. (D. Ramey Logan via Wikipedia)

© 2018, Bryan R. Swopes