Tag Archives: NACA High Speed Flight Station

8 September 1954

Albert Scott Crossfield, NACA Test Pilot. (LIFE Magazine via Jet Pilot Overseas)
Albert Scott Crossfield, NACA Test Pilot. (Allan Grant/LIFE Magazine via Jet Pilot Overseas)

8 September 1954: Scott Crossfield, a NACA Aeronautical Research Pilot at the High Speed Flight Station, Edwards Air Force Base, California, took the North American Aviation F-100A-5-NA Super Sabre, 52-5778, on its first NACA test flight—and his first flight in an F-100.

Tests of the prototype and early production Super Sabres revealed directional stability problems, a very dangerous inertia coupling characteristic that could cause the aircraft to go violently out of control (and which would result in the death of North American’s chief test pilot, George Welch, in just another three weeks). The highly swept wings could stall at high angles of attack, causing the airplane to pitch up in the deadly “Sabre dance”. NACA wanted to explore the causes of these aerodynamic problems and design solutions.

Scott Crossfield pre-flights a North American Aviation F-100A Super Sabre. Note the extended leading-edge "slats". (LIFE Magazine via Jet Pilot Overseas.)
Scott Crossfield pre-flights a North American Aviation F-100A Super Sabre. Note the extended leading-edge “slats”. (Allan Grant/LIFE Magazine via Jet Pilot Overseas.)

During the flight there was an engine fire warning and Crossfield shut down the Pratt & Whitney J57-P-7 turbojet engine. The F-100A had no flaps and North American’s own test pilots did not think a “dead stick” landing was possible due the very high landing speed required.

Scott Crossfield signs the maintenance forms for an F-100, certifying the airplane ready for flight. (LIFE Magazine via Jet Pilot Overseas)
Scott Crossfield signs the maintenance forms for an F-100, certifying the airplane ready for flight. (Allan Grant/LIFE Magazine via Jet Pilot Overseas)

Scott Crossfield tells the story in his autobiography:

. . . As a matter of fact, North American tests pilots were then flipping coins to see who would bring an F-100 in dead-stick to fulfill a requirement of the Air Force acceptance tests. I was not concerned. Dead-stick landings in low L-over-D [Lift-over-Drag] airplanes were my specialty. Every test pilot develops a strong point. I was certain that my talent lay in dead-stick landings.

With the engine idling and generating no energy to the plane’s systems, I was running out of hydraulic pressure to operate the controls. Following the handbook instructions, I pulled a lever which extended a miniature “windmill” into the slipstream. This “windmill” churned, building up pressure in the hydraulic lines. Unknown to me, there was a major leak in the line. The windmill was not helping, but hurting me. It was pumping hydraulic fluid overboard as fast as it could turn.

Scott Crossfield climbs into the cockpit of a North American Aviation F-100A-5-NA Super Sabre. (LIFE Magazine via Jet Pilot Overseas)
Scott Crossfield climbs into the cockpit of a North American Aviation F-100A-5-NA Super Sabre. (Allan Grant/LIFE Magazine via Jet Pilot Overseas)

I called Edwards tower and declared an emergency. All airborne planes in the vicinity of the base were warned away from the lake area. I held the ailing F-100 on course, dropping swiftly, following the glide path that I used for the dead-stick Skyrocket. [Douglas D-558-II Skyrocket] I flared out and touched down smoothly. It was one of the best landings I have ever made, in fact. Seconds later, while the F-100 was rolling out, the remaining bit of hydraulic pressure in the control lines drained out and the controls froze.

I then proceeded to violate a cardinal rule of aviation: never try tricks with a compromised airplane. The F-100 was still rolling at a fast clip, coming up fast on the NACA ramp, when I made my poor decision. I had already achieved the exceptional, now I would end it with a flourish, a spectacular wind-up. I would snake the stricken F-100 right up the ramp and bring it to a stop immediately in front of the NACA hangar. This trick, which I had performed so often in the Skyrocket, was a fine touch. After the first successful dead-stick landing in an F-100, it would be fitting.

Instrument panel of a North American Aviation F-100 Super Sabre. (U.S. Air Force)
Instrument panel of a North American Aviation F-100 Super Sabre. The fire warning light and hydraulic pressure gauge are at the upper right corner. (U.S. Air Force)

According to the F-100 handbook, the hydraulic brake system—a separate hydraulic system from the controls—was good for three “cycles,” engine out. This means three pumps on the brake, and that proved exactly right. The F-100 was moving at about fifteen miles an hour when I turned up the ramp. I hit the brakes once, twice, three times. The plane slowed, but not quite enough. I was still inching ahead ponderously, like a diesel locomotive. I hit the brakes a fourth time—and my foot went clear to the floorboards. The hydraulic fluid was exhausted. The F-100 rolled on, straight between the yawning hangar doors!

The good Lord was watching over me—partially anyhow. The NACA hangar was then crowded with expensive research tools—the Skyrocket, all the X-1 series, the X-3, X-4 and X-5. Yet somehow, my plane, refusing to halt, squeezed by them all and bored steadily on toward the side wall of the hangar.


The nose of the F-100 crunched through the corrugated aluminum, punching out an eight-inch steel I-beam. I was lucky. Had the nose bopped three feet to the left or right, the results could have been catastrophic. Hitting to the right, I would have set off the hangar fire-deluge system, flooding the hangar with 50,000 barrels of water and ruining all the expensive airplanes. Hitting to the left, I would have dislodged a 25-ton hangar-door counterweight, bringing it down on the F-100 cockpit, and doubtless ruining Crossfield.

Chuck Yeager never let me forget the incident. He drew many laughs at congregations of pilots by opening his talk: “Well, the sonic wall was mine. The hangar wall was Crossfield’s.” That’s the way it was at Edwards. Hero one minute, bum the next. That I was the first pilot to land an F-100 dead-stick successfully, and memorized elaborate and complete instrument data on the engine failure besides, was soon forgotten.

The F-100 is a tough bird. Within a month NACA’s plane was flying again, with Crossfield back at the helm. In the next few weeks I flew forty-five grueling flights in the airplane, pushing it to the limits, precisely defining the roll coupling. (On one flight the coupling was so severe that it cracked a vertebra in my neck.) These data confirmed, in actual flight, the need for a new F-100 tail, which North American was planning to install on later models of the airplane.

Every night after landing, I taxied the F-100 slowly to the NACA ramp. At the bottom, placed there on orders of Walt Williams, there was a large new sign, symbolic of the new atmosphere at Edwards. It said:

PLEASE COME TO A COMPLETE STOP BEFORE TAXIING UP RAMP 

Always Another Dawn, The Story Of A Rocket Test Pilot, by A. Scott Crossfield with Clay Blair, Jr., The World Publishing Company, Cleveland and New York, 1960. Chapter 20 at Pages 196–199.

North American F-100A-5-NA Super Sabre parked on Rogers Dry Lake, 1959. It had been repaired and returned to service after running through the NACA hangar wall at Edwards AFB, 8 September 1954. In 1960, FW-778 was retired to Davis-Monthan AFB, Tucson, AZ. (NASA)
North American Aviation F-100A-5-NA Super Sabre 52-5778 parked on Rogers Dry Lake, 1959. It had been repaired and returned to service after running through the NACA hangar wall at Edwards AFB, 8 September 1954. In 1960, FW-778 was retired to Davis-Monthan AFB, Tucson, AZ. (NASA)
North American Aviation F-100A-5-NA Super Sabre 52-5778. (NASA)
North American Aviation F-100A-5-NA Super Sabre 52-5778. (NASA)
North American Aviation F-100A-5-NA Super Sabre 52-5778. (NASA)
North American Aviation F-100A-5-NA Super Sabre 52-5778. (NASA)
North American Aviation F-100A-5-NA Super Sabre 52-5778 parked on the ramp in front of the NACA hangar, Edwards Air Force Base, California, 1959. (NASA)
North American Aviation F-100A-5-NA Super Sabre 52-5778 parked on the ramp in front of the NACA hangar, Edwards Air Force Base, California, 1959. (NASA)

© 2015, Bryan R. Swopes

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14 April 1947

Douglas test pilot Gene May with a D-558-I Skystreak high-speed research airplane. (Douglas Aircraft Company)
Douglas Aircraft Company test pilot Eugene Francis May. (Photograph courtesy of Neil Corbett, Test and Research Pilots, Flight Test Engineers)

14 April 1947: Douglas Aircraft Company test pilot Eugene Francis (“Gene”) May took the Number 1  U.S. Navy/NACA/Douglas D-558-I Skystreak high-speed research aircraft, Bu. No. 37970, for its first flight at at Muroc Army Airfield. The aircraft had been transported from the Los Angeles factory to Muroc by truck.

The Skystreak was a joint United States Navy/National Advisory Committee for Aeronautics (NACA) research aircraft designed to explore flight at high subsonic speed. The Phase I Skystreak was designed by a team led by Douglas Chief Engineer Edward Henry Heinemann. Flight testing was conducted at the NACA High Speed Flight Station at Muroc Army Airfield (later known as Edwards Air Force Base). Three D-558-Is were built, followed by the Phase II, swept-wing, Mach 2, D-558-II Skyrocket rocketplane.

The D-558-I carried extensive flight test instrumentation for its time. The wings had 400 orifices for air pressure sensors. During the test series, aircraft stability in the range of 0.82–0.99 Mach was investigated. One of the Skystreaks may have briefly exceeded Mach 1 as it came out of a dive.

Unlike some of the other experimental high speed aircraft of the time, it took off from the ground under its own power rather than being carried aloft by a mother ship. While those other aircraft could briefly reach much higher speeds, the D-558-I was able to fly for extended periods in the high-subsonic range, providing scientists and engineer with a tremendous amount of data.

The research airplane was a single-place, single-engine, low-wing monoplane with retractable tricycle landing gear. The fuselage of the D-558-I was constructed of an aluminum framework covered with sheet magnesium. It was designed for an ultimate load factor of 18 gs. The wings and tail surfaces were aluminum. The airplane was painted scarlet (not orange, like its contemporary, the Bell X-1) and was known as “the crimson test tube.” The D-558-I was 35 feet, 1.5 inches (10.706 meters) long with a wingspan of 25 feet, 0 inches (7.620 meters) and overall height of 12 feet, 1.6 inches (3.698 meters). Gross weight 10,105 pounds (4,584 kilograms). It carried 230 gallons (871 liters) of kerosene in its wings.

A Douglas D-558-I Skystreak being inspected by U.S. Navy personnel at tehe Douglas Aircraft Company plant in Los Angeles, California. [Modelers: Note the GREEN anti-glare panel.] (Getty Imamages/Bettman)
The D-558-I was powered by a single Allison J35-A-11 turbojet engine. The J35 was a single-spool, axial-flow turbojet with an 11-stage compressor section, 8 combustion chambers and single-stage turbine. The J35-A-11 was rated at 5,000 pounds of thrust (22.24 kilonewtons). The engine was 12 feet, 1.0 inches (3.683 meters) long, 3 feet, 4.0 inches (1.016 meters) in diameter and weighed 2,455 pounds (1,114 kilograms).

Bu. No. 37970 made 101 of the 228 Phase I flights. It set a world speed record 1,031.178 kilometers per hour (640.744 miles per hour), flown by Commander Turner F. Caldwell Jr., U.S. Navy,  20 August 1947.¹ (Major Marion E. Carl, U.S. Marine Corps, flew the second Skystreak, Bu. No. 37971, to 1,047.356 kilometers per hour (650.797 miles per hour),² breaking Caldwell’s record.)

After Douglas completed the contractor’s test series, the Number 1 Skystreak was turned over to the NACA High Speed Flight Station and designated NACA 140. It was not as highly instrumented as the Number 2 and Number 3 Skystreaks and was not flown, but was used as a source for spare parts for the other D-558-Is.

Douglas D-558-I Skystreak Bu. No. 37970 is on display at the National Naval Aviation Museum, NAS Pensacola, Florida.

Douglas D-558-I Skystreak, Bu. No. 37970, at the National Naval Aviation Museum, Naval Air Station Pensacola, Florida. (U.S. Navy)

¹ FAI Record File Number 9864

² FAI Record File Number 9865

© 2017, Bryan R. Swopes

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North American Aviation, Inc., X-15A Hypersonic Research Rocketplane

Rollout AFFTC History Office
North American Aviation, Inc., X-15A-1, 56-6670, at Los Angeles Division, October 1958. (Air Force Flight Test Center History Office)

20 December 1968: After 199 flights, the National Aeronautics and Space Administration cancelled the X-15 Hypersonic Research Program. A 200th X-15 flight had been scheduled, but after several delays, the decision was made to end the program. (The last actual flight attempt was 12 December 1968, but snow at several of the dry lakes used as emergency landing areas resulted in the flight being cancelled.)

The X-15A rocketplane was designed and built for the U.S. Air Force and the National Advisory Committee for Aeronautics (NACA, the predecessor of NASA) by North American Aviation, Inc., to investigate the effects of hypersonic flight (Mach 5+). Design work started in 1955 and a mock-up had been completed after just 12 months. The three X-15s were built at North American’s Los Angeles Division, at the southeast corner of Los Angeles International Airport (LAX), on the shoreline of southern California.

The first flight took place 8 June 1959 with former NACA test pilot Albert Scott Crossfield in the cockpit of the Number 1 ship, 56-6670.

While earlier rocketplanes, the Bell X-1 series, the the Douglas D-558-II, and the Bell X-2, were airplanes powered by rocket engines, the X-15 was a quantum leap in technology. It was a spacecraft.

Like the other rocketplanes, the X-15 was designed to be carried aloft by a “mothership,” rather than to takeoff and climb to the test altitude under its own power. The carrier aircraft was originally to be a Convair B-36 intercontinental bomber but this was soon changed to a Boeing B-52 Stratofortress. Two B-52s were modified to carry the X-15: NB-52A 52-003, The High and Mighty One, and NB-52B 52-008, Balls 8.

From 8 June 1959 to 24 October 1968, the three X-15s were flown by twelve test pilots, three of whom would qualify as astronauts in the X-15. Two would go on to the Apollo Program, and one, Neil Alden Armstrong, would be the first human to set foot on the surface of the Moon, 20 July 1969. Joe Engle would fly the space shuttle. Four of the test pilots, Petersen, White, Rushworth, and Knight, flew in combat during the Vietnam War, with Bob White being awarded the Air Force Cross. Petersen, Rushworth and White reached flag rank.

One pilot, John B. (“Jack”) McKay, was seriously injured during an emergency landing at Mud Lake, Nevada, 9 November 1962. Michael James Adams, was killed when the Number 3 ship, 56-6672, went into a hypersonic spin and broke up on the program’s 191st flight, 15 November 1967.

North American Aviation, Inc. X-15A 56-6670 on Rogers Dry Lake, Edwards Air Force Base, California. (NASA)
North American Aviation, Inc., X-15A-1 56-6670 on Rogers Dry Lake, Edwards Air Force Base, California. (NASA Image E-5251)

Flown by a single pilot/astronaut, the X-15 is a mid-wing monoplane with dorsal and ventral fin/rudders and stabilators. The wing had no dihdral, while the stabilators had a pronounced -15° anhedral. The short wings have an area of 200 square feet (18.58 square meters) and a maximum thickness of just 5%. The leading edges are swept to 25.64°. There are two small flaps but no ailerons. The entire vertical fin/rudder pivots for yaw control.

Above 100,000 feet (30,840 meters) altitude, conventional aircraft flight control surfaces are ineffective. The X-15 is equipped with a system of reaction control jets for pitch, roll and yaw control. Hydrogen peroxide was passed through a catalyst to produce steam, which supplied the control thrusters.

The forward landing gear consists of a retractable oleo strut with steerable dual wheels and there are two strut/skids at the rear of the fuselage. The gear is retracted after the X-15 is mounted on the NB-52 and is extended for landing by its own weight.

 North American Aviation X-15A 56-6672 touches down on Rogers Dry Lake. (NASA)
North American Aviation, Inc., X-15A-3 56-6672 just before touch down on Rogers Dry Lake. (NASA Image E-7469)

The rocketplane’s cockpit featured both a conventional control stick as well as side-controllers. It was pressurized with nitrogen gas to prevent fires. The pilot wore an MC-2 full-pressure suit manufactured by the David Clark Company of Worcester, Massachusetts, with an MA-3 helmet. The suit was pressurized below the neck seal with nitrogen, while the helmet was supplied with 100% oxygen. This pressure suit was later changed to the Air Force-standardized A/P22S.

X-15A cockpit with original Lear Siegler instrument panel. (NASA)
X-15 cockpit with original Lear Siegler instrument panel. (NASA image E63-9834)

The X-15 is 50.75 feet (15.469 meters) long with a wing span of 22.36 feet (6.815 meters). The height—the distance between the tips of the dorsal and ventral fins—is 13.5 feet (4.115 meters). The stabilator span is 18.08 feet (5.511 meters). The fuselage is 4.67 feet (1.423 meters) deep and has a maximum width of 7.33 feet (2.234 meters).

Since the X-15 was built of steel rather than light-weight aluminum, as are most aircraft, it is a heavy machine, weighing approximately 14,600 pounds (6,623 kilograms) empty and 34,000 pounds (15,422 kilograms) when loaded with a pilot and propellants. The X-15s carried as much as 1,300 pounds (590 kilograms) of research instrumentation, and the equipment varied from flight to flight. The minimum flight weight (for high-speed missions): 31,292 pounds (14,194 kilograms) The maximum weight was 52,117 pounds (23,640 kilograms) at drop (modified X-15A-2 with external propellant tanks).

Initial flights were flown with a 5 foot, 11 inch (1.803 meters)-long air data boom at the nose, but this would later be replaced by the “ball nose” air sensor system. The data boom contained a standard pitot-static system along with angle-of-attack and sideslip vanes. The boom and ball nose were interchangeable.

Neil Armstrong with the first North American Aviation X-15A, 56-6670, on Rogers Dry Lake after a flight, 1960. His hand is resting on the rocketplane's ball nose sensor. (NASA)
NASA Research Test Pilot Neil A. Armstrong with the first North American Aviation X-15A, 56-6670, on Rogers Dry Lake after a flight, 1960. His right hand is resting on the rocketplane’s ball nose sensor. (NASA Image E60-6286)

The X-15s were built primarily of a nickel/chromium/iron alloy named Inconel X, along with corrosion-resistant steel, titanium and aluminum. Inconel X is both very hard and also able to maintain its strength at the very high temperatures the X-15s were subjected to by aerodynamic heating. It was extremely difficult to machine and special fabrication techniques had to be developed.

Delays in the production of the planned Reaction Motors XLR99 rocket engine forced engineers to adapt two vertically-stacked Reaction Motors XLR11-RM-5 four-chamber rocket engines to the X-15 for early flights. This was a well-known engine which was used on the previous rocketplanes. The XLR-11 burned a mixture of ethyl alcohol and water with liquid oxygen. Each of the engines’ chambers could be ignited individually. Each engine was rated at 11,800 pounds of thrust (58.49 kilonewtons) at Sea Level.

Two Reaction Motors Division XLR11-RM-5 four-chamber rocket engines installed on an X-15. (NASA)
Two Reaction Motors Division XLR11-RM-5 four-chamber rocket engines installed on an X-15. (NASA)

The Reaction Motors XLR99-RM-1 rocket engine was throttleable by the pilot from 28,500 to 60,000 pounds of thrust. The engine was rated at 50,000 pounds of thrust (222.41 kilonewtons) at Sea Level; 57,000 pounds (253.55 kilonewtons) at 45,000 feet (13,716 meters), the typical drop altitude; and 57,850 pounds (257.33 kilonewtons) of thrust at 100,000 feet (30,480 meters). Individual engines varied slightly. A few produced as much as 61,000 pounds of thrust (271.34 kilonewtons).

The XLR99 burned anhydrous ammonia and liquid oxygen. The flame temperature was approximately 5,000 °F. (2,760 °C.) The engine was cooled with circulating liquid oxygen. To protect the exhaust nozzle, it was flame-sprayed with ceramic coating of zirconium dioxide. The engine is 6 feet, 10 inches (2.083 meters) long and 3 feet, 3.3 inches (0.998 meters) in diameter. It weighs 910 pounds (413 kilograms). The Time Between Overhauls (TBO) is 1 hour of operation, or 100 starts.

Thiokol Reaction Motors Division XLR-RM-1 rocket engine. (U.S. Air Force)
Thiokol Corporation Reaction Motors Division XLR99-RM-1 rocket engine. (U.S. Air Force)

The XLR99 proved to be very reliable. 169 X-15 flights were made using the XLR99. 165 of these had successful engine operation. It started on the first attempt 159 times.

The highest speed achieved during the program was with the modified number two ship, X-15A-2 56-6671, flown by Pete Knight to Mach 6.70 (6,620 feet per second/4,520 miles per hour/ kilometers per hour) at 102,700 feet (31,303 meters). On this flight, the rocketplane exceeded its maximum design speed of 6,600 feet per second (2,012 meters per second).

The maximum altitude was reached by Joe Walker, 22 August 1963, when he flew 56-6672 to 354,200 feet (107,960 meters).

The longest flight was flown by Neil Armstrong, 20 April 1962, with a duration of 12 minutes, 28.7 seconds.

North American Aviation X-15A-1 56-6670 is on display at the Smithsonian Institution National Air and Space Museum. X-15A-2 56-6671 is at the National Museum of the United States Air Force.

A North American Aviation F-100 Super Sabre chase plane follows NB-52A 52-003 prior to launch of an X-15. (NASA)
A North American Aviation F-100 Super Sabre chase plane follows NB-52A 52-003 prior to launch of an X-15. (NASA)

Recommended reading:

Always Another Dawn: The Story of a Rocket Test Pilot, by A. Scott Crossfield and Clay Blair, Jr., The World Publishing Company, Cleveland and New York, 1960

At The Edge Of Space, by Milton O. Thompson, Smithsonian Institution Press, 1992

X-15 Diary: The Story of America’s First Spaceship, by Richard Tregaskis, E.F. Dutton & Company,  New York, 1961; University of Nebraska Press, 2004

X-15: Exploring the Frontiers of Flight, by David R. Jenkins, National Aeronautics and Space Administration http://www.nasa.gov/pdf/470842main_X_15_Frontier_of_Flight.pdf

The X-15 Rocket Plane: Flying the First Wings into Space, by Michelle Evans, University of Nebraska Press, Lincoln and London, 2013

Screen Shot 2016-06-07 at 21.18.14
North American Aviation, Inc., X-15A-2 56-6671 accelerates after igniting its Reaction Motors XLR99-RM-1 rocket engine (NASA)

© 2016, Bryan R. Swopes

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20 November 1953

NACA test pilot Scott Crossfield in the cockpit of the Douglas D-558-II Skyrocket after his record-setting flight, 20 November 1953. (NASA) 20 November 1953: At Edwards Air Force Base, California, NACA’s High Speed Flight Station test pilot Albert Scott Walker rode behind the flight crew of the Boeing P2B-1S Superfortress as it carried the Douglas Aircraft Company D-558-II Skyrocket supersonic research rocketplane to its launch altitude. As the four-engine bomber climbed through 18,000 feet (5,486 meters), Crossfield headed back to the bomb bay to enter the Skyrocket’s cockpit and prepare for his flight.

The Douglas D-558-II was Phase II of a U.S. Navy/Douglas Aircraft Company/National Advisory Committee on Aeronautics joint research project exploring supersonic flight. It was a swept-wing airplane powered by a single Reaction Motors LR8-RM-6 four-chamber rocket engine. The Skyrocket was fueled with alcohol and liquid oxygen. The engine was rated at 6,000 pounds of thrust (26.69 kilonewtons) at Sea Level.

There were three Phase II aircraft. Originally, they were also equipped with a Westinghouse J34-W-40 turbojet engine which produced 3,000 pounds of thrust (13.35 kilonewtons) and the Skyrockets took off from the surface of Rogers Dry Lake. Once the D-558-II reached altitude, the rocket engine was fired for the speed runs. As higher speeds were required, the program shifted to an air launch from a B-29 (P2B-1S) “mothership”. Without the need to climb to the test altitude, the Skyrocket’s fuel load was available for the high speed runs.

NACA 144. a Douglas D-558-II Skyrocket, Bu. No. 37974, on Rogers Dry Lake. (NASA)
NACA 144. a Douglas D-558-II Skyrocket, Bu. No. 37974, on Rogers Dry Lake. (NASA)

The D-558-II was 42.0 feet (12.80 meters) long, with a wingspan of 25.0 feet (7.62 meters). The leading edge of the wing was swept at a 35° angle and the tail surfaces were swept to 40°. The aircraft weighed 9,421 pounds (4,273 kilograms) empty and had a maximum takeoff weight of 15,787 pounds (7,161 kilograms). It carried 378 gallons (1,431 liters) of water/ethyl alcohol and 345 gallons (1,306 liters) of liquid oxygen.

The mothership, NACA 137, was a Boeing Wichita B-29-95-BW Superfortress, U.S. Air Force serial number 45-21787. It was transferred to the U.S. Navy, redesignated P2B-1S and assigned Bureau of Aeronautics number 84029. Douglas Aircraft modified the bomber for its drop ship role at the El Segundo plant.

Douglas D-558-II Skyrocket, Bu. No., 37974, NACA 144, is dropped from the Boeing P2B-1S Superfortress, Bu. No. 84029, NACA 137. (NASA)
Douglas D-558-II Skyrocket, Bu. No. 37974, NACA 144, is dropped from the Boeing P2B-1S Superfortress, Bu. No. 84029, NACA 137. (NASA)

Going above the planned launch altitude, the Superfortress was placed in a slight dive to build to its maximum speed. At the bomber’s critical Mach number (Mcr), the Skyrocket was just above its stall speed. At 32,000 feet (9,754 meters), Crossfield and the Skyrocket were released. The rocketplane fell for about 400 feet (122 meters) until the rocket engine ignited and then it began to accelerate.

Crossfield climbed at a steep angle until he reached 72,000 feet (21,946 meters), and then leveled off. Now in level flight, the D-558-II accelerated, quickly passing Mach 1, then Mach 1.5. Crossfield pushed the nose down and began a shallow dive. The Skyrocket, still under full power, built up speed. As it passed through 62,000 feet (18,998 meters) the Skyrocket reached its maximum speed, Mach 2.005, or 1,291 miles per hour (2,078 kilometers per hour).

Scott Crossfield and the Douglas D-558-II Skyrocket, with their support team: two North American F-86 Sabre chase planes and the Boeing P2B-1S Superfortress mothership, at the NACA High Speed Flight Station, Edwards Air Force Base, California, 1 January 1954. (NASA)
Scott Crossfield and the Douglas D-558-II Skyrocket, with their support team: two North American F-86 Sabre chase planes and the Boeing P2B-1S Superfortress mothership, at the NACA High Speed Flight Station, Edwards Air Force Base, California, 1 January 1954. (NASA)

Scott Crossfield was the first pilot to fly an aircraft beyond Mach 2, twice the speed of sound. During his career as a test pilot, he flew the Douglas D-558-II, the Bell X-1, Bell X-2 and North American X-15. He made 112 flights in rocket-powered aircraft, more than any other pilot.

NACA Test Pilot Albert Scott Crossfield on Rogers Dry Lake. (NASA)
NACA Test Pilot Albert Scott Crossfield on Rogers Dry Lake. (NASA)

© 2016, Bryan R. Swopes

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6 November 1958

Bell X-1E 46-063 on Rogers Dry Lake. (NASA)
Bell X-1E 46-063 on Rogers Dry Lake, 1955. (NASA)

6 November 1958: NASA Research Test Pilot John B. (Jack) McKay made the final flight of the X-1 rocketplane program, which had begun twelve years earlier.

Bell X-1E 46-063 made its 26th and final flight after being dropped from a Boeing B-29 Superfortress over Edwards Air Force Base on a flight to test a new rocket fuel.

John B. McKay, NACA/NASA Research Test Pilot. (NASA)
John B. McKay, NACA/NASA Research Test Pilot. (NASA)

When the aircraft was inspected after the flight, a crack was found in a structural bulkhead. A decision was made to retire the X-1E and the flight test program was ended.

The X-1E had been modified from the third XS-1, 46-063. It used a thinner wing and had an improved fuel system. The most obvious visible difference is the cockpit, which was changed to provide for an ejection seat. Hundreds of sensors were built into the aircraft’s surfaces to measure air pressure and temperature.

The Bell X-1E was 31 feet (9.449 meters) long, with a wingspan of 22 feet, 10 inches (6.960 meters). The rocketplane’s empty weight was 6,850 pounds (3,107 kilograms) and fully loaded, it weighed 14,750 pounds (6,690 kilograms). The rocketplane was powered by a Reaction Motors XLR11-RM-5 rocket engine which produced 6,000 pounds of thrust (26.689 kilonewtons). The engine burned ethyl alcohol and liquid oxygen. The X-1E carried enough propellants for 4 minutes, 45 seconds burn.

The Bell X-1E rocketplane being loaded into a Boeing B-29 Superfortress mothership for another test flight. (NASA)
The Bell X-1E rocketplane being loaded into NACA 800, a Boeing B-29-96-BW Superfortress mothership, 45-21800, for another test flight. (NASA)

The early aircraft, the XS-1 (later redesignated X-1), which U.S. Air Force test pilot Charles E. (“Chuck”) Yeager flew faster than sound on 1 October 1947, were intended to explore flight in the high subsonic and low supersonic range. There were three X-1 rocketplanes. Yeager’s Glamorous Glennis was 46-062. The X-1D (which was destroyed in an accidental explosion after a single glide flight) and the X-1E were built to investigate the effects of frictional aerodynamic heating in the higher supersonic ranges from Mach 1 to Mach 2.

Bell X-1E loaded aboard Boeing B-29 Superfortress, circa 1955. (NASA)
Bell X-1E 46-063 loaded aboard NACA 800, a Boeing B-29-96-BW Superfortress, 45-21800, circa 1955. (NASA)

The X-1E reached its fastest speed with NASA test pilot Joseph Albert Walker, at Mach 2.24 (1,450 miles per hour/2,334 kilometers per hour), 8 October 1957. Walker also flew it to its peak altitude, 70,046 feet (21,350 meters) on 14 May 1958.

NACA test pilot Joseph Albert Walker made 21 of the X-1E's 26 flights. In this photograph, Joe Walker is wearing a David Clark Co. T-1 capstan-type partial-pressure suit with a K-1 helmet for protection at high altitudes. (NASA)
NACA test pilot Joseph Albert Walker made 21 of the X-1E’s 26 flights. In this photograph, Joe Walker is wearing a David Clark Co. T-1 capstan-type partial-pressure suit with a K-1 helmet for protection at high altitudes. (NASA)

There were a total of 236 flights made by the X-1, X-1A, X-1B, X-1D and X-1E. (A planned X-1C was not built.) The X-1 program was sponsored by the National Advisory Committee on Aeronautics, NACA, which became the National Aeronautics and Space Administration, NASA, on 29 June 1958.

The X-1E is on display in front of the NASA administration building at the Dryden Flight Research Center, Edwards Air Force Base, California.Bell X-1E 46-063 on display at Dryden Flight Research Center© 2016, Bryan R. Swopes

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