4 August 1960: NASA research test pilot Joseph Albert Walker set an unofficial world speed record when he flew the number one North American Aviation X-15, 56-6670, to 2,195 miles per hour (3,532.5 kilometers per hour). This was the 18th flight of the X-15 Program. It was 56-6670’s eighth flight and Walker’s fourth X-15 flight. The purpose of this test was to gradually increase the rocket plane’s speed toward its design limit.
Airdropped from the Boeing NB-52A Stratofortress mothership, 52-003, over Silver Lake, near the California-Nevada border, at 08:59:13.0 a.m., PDT, Walker fired the X-15’s two Reaction Motors XLR11-RM-13 rocket engines for 264.2 seconds. The X-15 accelerated to Mach 3.31 and climbed to a peak altitude of 78,112 feet (23,810 meters). [The two XLR11s were used as an interim powerplant until the Reaction Motors XLR99 was ready. The combined thrust of both LR11s was only slightly more than the idle thrust of the XLR99.]
Walker touched down on Rogers Dry Lake at Edwards Air Force Base, California, after a flight of 10 minutes, 22.6 seconds.
19 July 1963: Between 1960 and 1963, NASA Chief Research Test Pilot Joseph Albert Walker made 25 flights in the North American Aviation X-15A hypersonic research rocketplanes. His 24th flight was the 21st for the Number 3 X-15, 56-6672, and the 90th of the X-15 program.
At 10:20:05.0 a.m., Walker and the X-15 were airdropped from the Boeing NB-52B Stratofortress, 53-008, Balls 8, over Smith Ranch Dry Lake, Nevada. Walker fired the Reaction Motors XLR99-RM-1 rocket engine and over the next 84.6 seconds the engine’s 60,000 pounds of thrust drove the X-15 upward. The engine’s thrust on this flight was higher than expected, shutdown was 1.6 seconds late, and Walker’s climb angle was 1½° too high, so the X-15 overshot the predicted maximum altitude and its ballistic arc peaked at 347,800 feet (106,010 meters, 65.8 miles). The maximum speed was Mach 5.50 (3,714 miles per hour, 5,977 kilometers per hour).
Walker glided to a touch down at Rogers Dry Lake, Edwards Air Force Base California, after flying 311 miles in 11 minutes, 24.1 seconds of flight. On this flight, Joe Walker became the first American civilian to fly into Space.
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.
8 June 1959: At Edwards Air Force Base, California, North American Aviation’s Chief Engineering Test Pilot, A. Scott Crossfield, made the first flight of the X-15A hypersonic research rocketplane.
56-6670 was the first of three X-15s built for the U.S. Air Force and NASA. It was airdropped from a Boeing NB-52A Stratofortress, 52-003, at 37,550 feet (11,445 meters) over Rosamond Dry Lake at 08:38:40 a.m, Pacific Daylight Time.
This was an unpowered glide flight to check the flying characteristics and aircraft systems, so there were no propellants or oxidizers aboard, other than hydrogen peroxide which powered the pumps and generators.
The aircraft reached 0.79 Mach (522 miles per hour, 840 kilometers per hour) during the 4 minute, 56.6 second flight.
In his autobiography, Scott Crossfield described the first flight:
“Three” . . . “Two” . . . “One” . . .
Inside the streamlined pylon, a hydraulic ram disengaged the three heavy shackles from the upper fuselage of the X-15. They were so arranged that all released simultaneously, and if one failed they all failed. The impact of the release was clearly audible in the X-15 cockpit. I heard a loud “kerchunk.”
The X-15 hung in its familiar place beneath the pylon for a split second. Then the nose dipped sharply down and to the right more rapidly than I had anticipated. The B-52, so long my constant companion, was gone. The X-15 and I were alone in the air and flying 500 miles an hour. In less than five minutes I would be on the ground. . . .
There was much to do in the first hundred seconds of flight. First I had to get the “feel” of the airplane, to make certain it was trimmed out for landing just as any pilot trims an airplane after take-off or . . . when dwindling fuel shifts the center of gravity. Then I had to pull the nose up, with and without flaps, to feel out the stall characteristics, so that I would know how she might behave at touchdown speeds . . . My altimeter unwound dizzily: from 24,000 to 13,000 feet in less than forty seconds. . . .
The desert was coming up fast. At 600 feet altitude I flared out. . . .
In the next second without warning the nose of the X-15 pitched up sharply. It was a maneuver that had not been predicted by the computers, an uncharted area which the X-15 was designed to explore. I was frankly caught off guard. Quickly I applied corrective elevator control.
The nose went down sharply. But instead of leveling out, it tucked down. I applied reverse control. The nose came up but much too far. Now the nose was rising and falling like a skiff in a heavy sea. Although I was putting in maximum control I could not subdue the motions. The X-15 was porpoising wildly, sinking toward the desert at 200 miles an hour. I would have to land at the bottom of an oscillation, timed perfectly; otherwise, I knew, I would break the bird. I lowered the flaps and the gear. . . .
. . . With the next dip I had one last chance and flared again to ease the descent. At that moment the rear skids caught on the desert floor and the nose slammed over, cushioned by the nose wheel. The X-15 skidded 5,000 feet across the lake, throwing up an enormous rooster tail of dust. . . .
—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, Chapter 37 at Pages 338–342.
Before the drop, it was discovered that the aircraft’s Stability Augmentation System was inoperative in pitch mode. During the flight it was found that the hydraulic-assisted flight control system was responding too slowly to Crossfield’s inputs. Engineers analyzed the problem and increased the hydraulic system pressure. The problem never recurred.
Scott Crossfield was the world’s most experienced rocketplane pilot with 82 rocketplane flights before the X-15 program. “. . . he was intimately involved in the design of the aircraft and contributed immensely to the success of the design.”
—At The Edge Of Space, by Milton O. Thompson, Smithsonian Institution Press, 1992, Introduction, at Page 3.
North American Aviation X-15A 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. 56-6670 is in the collection of National Air and Space Museum at Washington, D.C.
3 June 1953: Concluding a series of speed and altitude records, Jackie Cochran set a Fédération Aéronautique Internationale (FAI) World Record for Speed Over a 15/25 Kilometer Straight Course with an average speed of 1,067.68 kilometers per hour (663.43 miles per hour) while flying the Canadair CL-13 Sabre Mk.3 No. 19200 at Edwards Air Force Base, California.¹
In the previous weeks, Jackie Cochran had flown the experimental Orenda-powered Sabre to world records over the 100 and 500 kilometer closed circuit and set an altitude record of 14,377 meters (47,169 feet).² During these flights, she became the first woman to “break the sound barrier” when the Sabre Mk. 3 exceeded Mach 1.
On the morning of 3 June, Cochran had attempted to set a new world record over the 3 kilometer straight course, which was flown at an altitude of 200 feet (61 meters). After two runs she determined that the Sabre Mk.3 would not exceed the previous record, and she abandoned the attempt.
In her autobiography, she wrote:
The plane was immediately refueled and the timing devices were shifted to the 15-kilometer course. That took about two hours and the roughness in the air was building up by the minute. A pass in each direction over the 15-kilometer course was needed for an average speed, as against four passes over the 3-kilometer course. I had fuel enough for four passes. The average of any two consecutive passes could be taken. The first pass from south to north was at a speed of 680 miles per hour. That result was relayed to me by air from my own Lodestar, which was parked on the lake bed near the judges’ equipment. The second pass from north to south, with the wind against me, was at a speed of 670 miles per hour. I determined to make a third pass, even though the plane had developed a bad left-wing down roll at high speed and was in consequence next to unmanageable over the level flight course and its approaches. On this third pass I decided to take a long dive at the conclusion of which I would level out before reaching the approach to the course. I did this but, on leveling out, the controls again “froze” on me with the plane determined to roll over to the left. I used both arms to pull on the controls and one knee as well for leverage but with no effect. Another second or two and the plane would have been over on its back and into the ground. I prevented this only by slowing it down. At the moment I pulled back on the power there was an automatic temporary compensation of the direction of the plane to the right of the course and, as a result, the timing camera did not catch me on that third pass. That ended the flight. I made a long turn for landing and “Chuck” Yeager, in his chase plane, closed in behind me. He instructed me to leave the throttle untouched as much as possible and to land on the lake bed. I wanted to put the plane down on the runway where the ground crew was waiting but “Chuck” insisted that I put it down on the lake bed where I could take a high-speed landing and a long roll. I took my oxygen mask off and smelled fuel in the cockpit. When the wheels touched ground and the roll had about stopped, “Chuck” told me to cut the throttle and switches and get out as quickly as possible because I had a bad fuel leak which he had seen from his plane. A stream of fuel about the size of one’s thumb was gushing out of the bottom of the main section of the left wing. . . .
—The Stars at Noon, by Jacqueline Cochran, Little, Brown and Company, Boston, 1954, Chapter XII, at Pages 232–233.
The Canadair Sabre Mk.3 was a one-of-a-kind CL-13 Sabre (an F-86E Sabre manufactured by Canadair Ltd. under license from North American Aviation, Inc.) built to test the prototype Avro Canada Gas Turbine Division Orenda 3 engine. Modifications to the F-86 airframe were required to install the new, larger engine.
The Orenda 3 was an axial-flow turbojet engine with a 10-stage compressor, six combustion chambers and single-stage turbine. It produced 6,000 pounds of thrust (16.69 kilonewtons), a 15% improvement over the General Electric J47-GE-13 installed in the standard F-86E. The Orenda was 121.3 inches (3.081 meters) long, 42 inches (1.067 meters) in diameter and weighed 2,650 pounds (1,202 kilograms).
Canadair Ltd. was an aircraft manufacturer located at Cartierville, Montreal, Canada, owned by the American submarine builder, Electric Boat Company. Canadair also built licensed versions of the Douglas DC-4 (powered by Rolls-Royce Merlin engines) and the Lockheed T-33 two-place jet trainer. In 1954, the company became a part of General Dynamics.
After the speed and altitude records, No. 19200 was sent to North American Aviation for evaluation. Today, it is on static display outdoors at Wetaskiwin Regional General Airport (CEX3), Alberta, Canada.
¹ FAI Record File Number 8870
² FAI Record File Numbers 13039, 13040, 9075, 9076 and 12858