26 April 1948: At Muroc Field (now known as Edwards Air Force Base), in the high desert of southern California, North American Aviation test pilot George Welch put the prototype XP-86 Sabre, 45-59597, into a 40° dive and broke the Sound Barrier. It is only the second U.S. aircraft to fly supersonic. The first was the Bell X-1, piloted by Chuck Yeager, only a few months earlier.
Or, maybe not.
In his book, Aces Wild: The Race For Mach 1, fellow North American Aviation test pilot Albert W. Blackburn makes the case that George Welch had taken the prototype XP-86 Sabre supersonic on its first flight, 1 October 1947, and that he had done so three times before Chuck Yeager first broke the Sound Barrier with the Bell X-1 rocketplane, 14 October 1947. Blackburn described two runs through the NACA radar theodolite with speeds of Mach 1.02 and 1.04 on 13 November 1947.
Mr. Blackburn speculates—convincingly, in my opinion—that Secretary of the Air Force W. Stuart Symington, Jr., ordered that Welch’s excursions beyond Mach 1 were to remain secret. However, during a radio interview, British test pilot Wing Commander Roland Prosper (“Bee”) Beamont CBE, DSO and Bar, DFC and Bar, stated that he had flown through the Sound Barrier in the number two XP-86 Sabre prototype (45-59598). Once that news became public, the Air Force released a statement that George Welch had flown beyond Mach 1 earlier, but gave the date as 26 April 1948.
It wasn’t long after the first flight of the XP-86 on October 1, 1947, that Welch dropped into Horkey’s[Edward J. Horkey, an aerodynamicist at North American Aviation]office at the Inglewood plant. He wanted to talk about his recent flight and some “funny” readings in the airspeed indicator. He had made a straight-out climb to more than 35,000 feet. Then, turning back toward Muroc Dry Lake, he began a full-power, fairly steep descent.
“I started at about 290 knots,” Welch was explaining to Horkey. “In no time I’m at 350. I’m still going down, and I’m still accelerating but the airspeed indicator seems stuck like there’s some kind of obstruction in the pitot tube. I push over a little steeper and by this time I’m through 30,000 feet. All of a sudden, the airspeed indicator flips to 410 knots. The aircraft feels fine, no funny noises, no vibration. Wanted to roll off to the left, but no big deal. Still, I leveled out at about 25,000 and came back on the power. The airspeed flicked back to 390. What do you think?”
“. . . You may be running into some Mach effects. . . .”
— Aces Wild: The Race For Mach 1, by Al Blackburn, Scholarly Resources Inc., Wilmington, Delaware, 1999, at Pages 147–148.
The “funny” reading of the airspeed indicator became known as the “Mach jump.” George Welch was the first to describe it.
The Sabre became a legendary jet fighter during the Korean War. 9,860 were built by North American, as well as by licensees in Canada, Australia and Japan.
George Welch had been recommended for the Medal of Honor for his actions as a P-40 Warhawk fighter pilot in Hawaii, December 7, 1941. He was killed while testing an F-100A Super Sabre, 12 October 1954.
23 April 1941: At North American Aviation’s Inglewood, California factory, test pilot Louis S. Wait takes the very first production Mustang Mk.I, AG345, (c/n 73-3098) for its first flight. The Royal Air Force had contracted with NAA to design and build a new fighter with an Allison V-1710 supercharged 12-cylinder engine producing 1,200 horsepower. The first order from the British Purchasing Commission was for 320 airplanes, and a second order for another 300 soon followed.
The Mustang Mk.I (NAA Model NA-73) was a single-place, single engine fighter primarily of metal construction with fabric control surfaces. It was 32 feet, 3 inches (9.830 meters) long with a wingspan of 37 feet, 5/16-inches (11.373 meters) and height of 12 feet, 2½ inches (3.721 meters). The airplane’s empty weight was 6,280 pounds (2,849 kilograms) and loaded weight was 8,400 pounds (3,810 kilograms).
The Mustang Mk.I was powered by a liquid-cooled, supercharged 1,710.597-cubic-inch-displacement (28.032 liter) Allison Engineering Company V-1710-F3R (V-1710-39) single overhead cam (SOHC) 60° V-12 engine which turned a 10 foot, 9 inch (3.277 meter) diameter, three-bladed, Curtiss Electric constant-speed propeller through a 2.00:1 gear reduction. The engine had a takeoff rating of 1,150 horsepower at 3,000 r.p.m. at Sea Level with 45.5 inches of manifold pressure (1.51 Bar), and a war emergency rating of 1,490 horsepower with 56 inches of manifold pressure (1.90 Bar).
This gave the Mustang Mk.I a maximum speed of 382 miles per hour (615 kilometers per hour) and cruise speed of 300 miles per hour (483 kilometers per hour). The service ceiling was 30,800 feet (9,388 meters) and range was 750 miles (1,207 kilometers).
The Mustang Mk.I was equipped with four Browning .303 Mk.II machine guns, two in each wing, and four Browning AN-M2 .50-caliber machine guns, with one in each wing and two mounted in the nose under the engine.
The Mk.I was 30 m.p.h. (48 kilometers per hour) faster than its contemporary, the Curtiss P-40 Warhawk, though both used the same engine. Below 15,000 feet (4,572 meters), the Mustang was also 30–35 m.p.h (48–56 kilometers per hour) faster than a Supermarine Spitfire, which had the more powerful Roll-Royce Merlin V-12.
Two Mustang Mk.Is, AG348 and AG354, were taken from the first RAF production order and sent to Wright Field for testing by the U.S. Army Air Force. These airplanes, assigned serial numbers 41-038 and 41-039, were designated XP-51. They would be developed into the legendary P-51 Mustang. In production from 1941 to 1945, a total of 16,766 Mustangs of all variants were built.
AG345 was retained by North American Aviation for long term testing. It was stricken off charge 3 December 1946.
20 April 1962: “Neil’s Cross-Country.” NASA Research Test Pilot Neil Alden Armstrong conducts a flight to test the MH-96 flight control system installed in the third North American Aviation X-15, serial number 56-6672. The new system combined both aerodynamic and reaction thruster flight controls in one hand controller rather than the two used in X-15s -670 and -671, simplifying the tasks for the pilot.
On its fourth flight, -672 was air-dropped from the Boeing NB-52B Stratofortress “mothership,” Balls 8, over Mud Lake, Nevada. Armstrong fired the XLR-99 engine and let it burn for 82.4 seconds. The X-15 accelerated to Mach 5.31 (3,789 miles per hour/6,098 kilometers per hour). After the engine was shut down, the rocketplane continued to its peak altitude on a ballistic trajectory, reaching 207,500 feet (63,246 meters) before going over the top and beginning its descent back toward the atmosphere. The test of the new flight control system went well.
Neil Armstrong began to pull out of the descent at about 100,000 feet (30,480 meters), but the X-15 “bounced” off the top of the atmosphere and climbed back to 115,000 feet (35,052 meters) where the aerodynamic control surfaces could not function. He used the reaction thrusters to turn toward the dry lake landing area at Edwards AFB, but although the X-15 rolled into a left bank, it would not change direction, and still in ballistic flight, went zooming by Edwards at Mach 3 and 100,000 feet in a 90° left bank.
As the X-15 dropped back into the atmosphere, Armstrong was finally able to get it slowed down, but he was far south of his planned landing site. By the time he got -672 turned around, he was 45 miles (72.4 kilometers) to the south, over the Rose Bowl in Pasadena, and gliding through 45,000 feet (13,716 meters). There was real doubt that he would be able to make the X-15 stretch its glide to reach the dry lake.
In a masterful display of airmanship, Neil Armstrong was able to get the X-15 to reach the south end of the dry lake, 12 miles (19.3 kilometers) from the planned landing spot to the north. But it was a very close call. In debriefing, the pilots of the four F-104 chase planes were asked how much clearance Armstrong had as he crossed over the Joshua trees at the edge of the lake bed. One of them answered, “Oh, at least 100 feet—on either side.”
At 12 minutes, 28.7 seconds, this was the longest flight of the entire X-15 program. It is called “Neil’s cross-country flight.”
A U.S. Navy fighter pilot who flew 78 combat missions during the Korean War, Neil Armstrong became a civilian test pilot at NACA (National Advisory Committee on Aeronautics, the predecessor to NASA) in 1955. He made 7 flights in the X-15 before transferring to NASA’s Project Gemini in 1962.
Armstrong was command pilot for Gemini 8 and Gemini 11, commander of the backup flight crew of the Apollo 8 mission, and was commander of Apollo 11.
On 20 July 1969, Neil Alden Armstrong was the First Man To Stand on the Surface of The Moon.
19 April 2006: Former experimental test pilot Albert Scott Crossfield, Jr., was enroute from Prattville, Alabama, to Manassas, Virginia. Scott Crossfield¹ was flying his personal Cessna 210A, N6579X. The Cessna was cruising at 11,000 feet (3,353 meters) under Instrument Flight Rules (IFR), under the control of the Atlanta Air Route Traffic Control Center (ARTCC).
During the flight, he encountered a Level 6 thunderstorm.
Scott Crossfield requested to deviate from his planned course to avoid the severe turbulence. Atlanta Center authorized his request and he began to turn. Approximately 30 seconds later, at 11:10 a.m., radar contact was lost near Ludville, Georgia. The last indication was that the Cessna was descending through 5,500 feet (1,676 meters).
The wreckage of N6579X was located the following day by a Civil Air Patrol search team, 3.3 nautical miles (6.1 kilometers) northwest of Ludville at an elevation of 1,269 feet (386.8 meters) above Sea Level. [N. 34° 30.767′, W. 84° 39.492′] The airplane had descended through the forest canopy nearly vertically and created a crater approximately 4½ feet (1.4 meters) deep and 6 feet (1.8 meters) across. Albert Scott Crossfield’s body was inside.
N6579X was a Cessna Model 210A, serial number 21057579, built in 1960 by the Cessna Aircraft Company, Inc., of Wichita Kansas. It was a six-place, single-engine, high-wing monoplane with external struts to brace the wings, and retractable, tricycle landing gear. The airplane was certified for instrument flight by a single pilot. At the time of the crash, N6579X had been flown 4,987.4 hours, total time since new (TTSN).
The Cessna 210A was 28 feet, 2 inches (8.585 meters) long with a wingspan of 36 feet, 6 inches (11.125 meters) and overall height of 9 feet, 7 inches (2.921 meters). The airplane had an empty weight of 1,839 pounds (834.2 kilograms) and maximum gross weight of 2,900 pounds (1,315.4 kilograms). It had a fuel capacity of 65 gallons (246 liters), with 10 gallons (37.9 liters) unusable, and 12 quarts of engine oil (11.4 liters).
N6579X was powered by an air-cooled, fuel-injected, 471.239-cubic-inch-displacement (7.722 liters) Teledyne Continental IO-470-E horizontally-opposed six-cylinder direct-drive engine with a compression ratio of 8.6:1. The engine was rated at 260 horsepower at 2,625 r.p.m. for takeoff, using 100LL aviation gasoline. It weighed 429 pounds (195 kilograms). This engine, serial number 77583-0-E, was original to the airplane and accumulated 4,987.4 hours, total time since new (TTSN). It had been overhauled by Victor Aviation, Palo Alto, California, 1,259.8 hours prior to the accident (TSO). A three-bladed McCauley constant-speed propeller with a diameter of 6 feet, 10 inches (2.083 meters) was installed in 2005.
The Cessna Model 210A has a maximum structural cruise speed of 175 miles per hour (282 kilometers), and maximum speed (Vne) of 200 miles per hour (322 kilometers per hour). Maneuvering speed, which should be used in turbulent conditions, is 130 miles per hour (209 kilometers per hour). The 210A has a maximum rate of climb of 1,300 feet per minutes (6.6 meters per second) and service ceiling of 20,700 feet (6,309 meters). Its maximum range is 1,284 miles (2,066 kilometers).
Albert Scott Crossfield, Jr., was born 2 October 1921 at Berkeley, California. He was the second of three children of Albert Scott Crossfield, a chemist who was employed as the superintendant of the Union Oil Company refinery in Wilmington, California, and Lucia M. Dwyer Crossfield.
When he was five years old, young “Scotty” contracted pneumonia. He was comatose for a while and was not expected to survive, but after several weeks he began to recover. A year later, he again became seriously ill, this time with rheumatic fever. He was confined to total bed rest for four months, and continued to require extensive bed rest until he was about ten years old. It was during this time that he became interested in aviation.
Scott Crossfield attended Boistfort Consolidated School, southwest of Chehalis, Washington, graduating in 1939, and then studied engineering at the University of Washington until taking a job at Boeing in late 1941. During this time, Scotty learned to fly in the Civilian Aviation Training Program.
The week following the attack on Pearl Harbor and the United States’ entry into World War II, Scott Crossfield enlisted as an aviation cadet in the United States Army Air Corps. After numerous delays, he joined the United States Navy on 21 February 1942, and resigned from the Air Corps. He began aviation cadet training at NAS Sand Point, near Seattle, and then was sent to NAS Corpus Christi, Texas. In December 1942, he graduated, received his gold Naval Aviator wings and was commissioned as an Ensign, United States Naval Reserve.
Ensign Crossfield was assigned to NAS Kingsville as an advanced bombing and gunnery instructor. He was promoted to Lieutenant (junior grade), 1 March 1944. He continued as a gunnery instructor for two years before being transferred to Air Group 51 in the Hawaiian Islands, which was preparing for the invasion of Japan. He was promoted to Lieutenant, 1 August 1945, while serving aboard the Independence-class light aircraft carrier USS Langley (CVL-27). With the end of World War II, though, the Navy was cutting back. Lieutenant Crossfield was released from active duty 31 December 1945.
In April 1943 at Corpus Christi, Texas, Ensign A. Scott Crossfield married Miss Alice Virginia Knoph of Seattle. They would have five children.
Following the War, Scotty returned to the University of Washington to complete his degree. He took a part time job operating the University’s wind tunnel. At the same time, he remained in the Naval Reserve, assigned to VF-74, a fighter squadron which flew both the Grumman F6F Hellcat and Chance Vought F4U Corsair out of NAS Sand Point, back where his naval career began.
Crossfield graduated from the University of Washington with a bachelor’s degree in aeronautical engineering in June 1949, and a master’s degree in 1950.
In 1950 Crossfield joined the National Advisory Committee for Aeronautics (NACA) as a research test pilot at the High-Speed Flight Station, Edwards Air Force Base, California. He flew the Republic YF-84, F-84F Thunderstreak, and North American Aviation F-86 Sabre. Crossfield made 25 flights in the delta-winged Convair XF-92A, which he described as “the worst flying airplane built in modern times.” He also flew the Northrop X-4 and Bell X-5. He made 17 flights conducting stability tests in the Douglas D-558-1 Skystreak. Scotty made 65 flights in the North American Aviation F-100A Super Sabre, including a test series which discovered a fatal flaw which led to the death of North American’s chief test pilot, George S. Welch.
Crossfield is known as a rocketplane pilot. He made 10 flights in the Bell X-1, and 89 in the Douglas D-558-II Skyrocket. He became the first pilot to exceed Mach 2 when he flew the Skyrocket to Mach 2.005, 20 November 1953.
Crossfield flew for NACA for approximately five years. During that time, approximately 500 flights were made at Edwards by NACA test pilots. Scott Crossfield flew 181 of them.
Scott Crossfield left NACA in 1956 to join North American Aviation, Inc., as chief engineering test pilot for the X-15 project. Between 8 June 1959 and 6 December 1960, he made fourteen flights in the X-15. He reached a maximum speed of Mach 2.97 and altitude of 88,116 feet (26,858 meters). Once the contractor’s flight tests were completed and the rocketplane turned over to the U.S. Air Force and NACA, the customers’ test pilots, Joe Walker and Major Robert M. White, took over.
Albert Scott Crossfield made 114 flights in rocket-powered aircraft, more than any other pilot.
After completing his work on the X-15, Crossfield followed Harrison (“Stormy”) Storms, who had been the Chief Engineer of North American’s Los Angeles Division (where the X-15 was built) to the Space and Information Systems Division in Downey, California, where he worked in quality assurance, reliability engineering and systems testing for the Apollo Command and Service Modules and the Saturn S-II second stage.
Crossfield left North American at the end of 1966, becoming Vice President for Technological Development for Eastern Air Lines. In this position, he flew acceptance tests for new Boeing 720 and 727 airliners at Boeing in Seattle.
In The X-15 Rocket Plane, author Michelle Evans quoted Crossfield as to why he had not entered NASA’s space program as an astronaut:
One question that pressed was, with his love of flight and the early responsibility of going into space with the X-15, why would Scott not apply to the NASA astronaut office? He explained, “[Dr.] Randy Lovelace and General [Donald] Flickinger were on the selection board. They took me to supper one night and asked me not to put in for astronaut. I asked them, ‘Why not?’ and they said, ‘Well, we’re friends of yours. We don’t want to have to turn you down.’ I asked, ‘Why would you have to turn me down?’ and they said, ‘You’re too independent.’ “
—The X-15 Rocket Plane: Flying the First Wings into Space, by Michelle, Evans, University of Nebraska Press, 2013, Chapter 1 at Page 33.
The remains of Albert Scott Crossfield are interred at the Arlington National Cemetery.
¹ “Scott Crossfield” is the family name, going back for several generations.
13 April 1960: Major Robert M. White, USAF, made the first flight of an X-15 by an Air Force test pilot.
Carried aloft by a Boeing NB-52A Stratofortress, serial number 52-003, the first of three X-15 hypersonic research aircraft, 56-6670, was airdropped at 0915 above Rosamond Dry Lake. Major White ignited the two Reaction Motors XLR-11 rocket engines and with a burn time of 4 minutes, 13.7 seconds, the X-15 accelerated to Mach 1.9 (1,254 miles per hour/2,018 kilometers per hour) and reached 48,000 feet (14,630 meters). Both numbers were slightly short of the planned Mach 2.0 (1,320 miles per hour/2,124 kilometers per hour) and 50,000 feet (15,240 meters).
After 8 minutes, 52.7 seconds, Bob White and the X-15 touched down at Edwards Air Force Base.
Over the next 32 months Bob White made 16 flights in the X-15. He was the first pilot to fly faster than Mach 4, Mach 5 and Mach 6. He flew it to Mach 6.04, 4,093 miles per hour (6,587 kilometers per hour) and set a Fédération Aéronautique Internationale (FAI) altitude record of 314,750 feet (95,936 meters), for an altitude gain of 82,190 meters (269,652 feet).¹
White was one of three pilots awarded astronaut wings for his flights in the X-15.