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. 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.
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)
XB-70A-2-NA Valkyrie 62-0207 leading a formation of aircraft powered by General Electric engines. Joe Walker’s F-104 is just below the B-70’s right wing tip. (U.S. Air Force)
8 June 1966: During a publicity photo formation flight, a Lockheed F-104N Starfighter, N813NA, flown by NASA Chief Research Test Pilot Joseph A. Walker, was caught in the wingtip vortices of the North American Aviation XB-70A-2 Valkyrie, 62-0207, the second prototype Mach 3+ strategic bomber. The Starfighter rolled up and across the Valkyrie. The two airplanes collided, with the F-104 taking off the Valkyrie’s vertical fins, then exploding.
Lockheed F-104N N813NA collided with North American Aviation XB-70A-2 Valkyrie 62-0207 and exploded, 8 June 1966. (U.S. Air Force)
The Valkyrie continued to fly straight and level for 16 seconds before it began to roll inverted. The B-70’s pilot, Alvin S. White, was able to eject, though he was severely injured. Joe Walker and B-70 co-pilot Major Carl S. Cross, United States Air Force, were killed.
The B-70 is out of control and going down in this photograph. A large section of the left wing is missing. JP-8 fuel is spraying out of damaged tanks. (U.S. Air Force)
Still photographs and motion picture film of the formation were being taken from Clay Lacy’s Gates Lear Jet. The photos were for a General Electric publicity campaign showing U.S. military aircraft that were powered by GE engines. Air Force procedures for requesting and approval of publicity flights were not properly followed and it is likely this flight would not have been approved had they been.
The XB-70A-2 Valkyrie has rolled inverted and pitched nose down. The outer section of the left wing is missing. The trailing edge and tip tank of the Lear Jet photo plane’s right wing are in the foreground. (U.S. Air Force)
Reportedly, just prior to the collision, Walker radioed, “I’m opposing this mission. It is too turbulent and it has no scientific value.”
The wreckage of the North American Aviation XB-70A-2 Valkyrie 62-0207 burns on the desert floor at N. 35° 03′ 47″, W. 117° 01′ 27″, north of Barstow, California, 8 June 1966. (U.S. Air Force)
Scott Crossfield prepares for a flight in the North American Aviation X-15A.
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.
North American Aviation Chief Engineering Test Pilot Albert Scott Crossfield in the cockpit of an X-15 before a flight. (LIFE Magazine via Jet Pilot Overseas)
In his autobiography, Scott Crossfield described the first flight:
“Three” . . . “Two” . . . “One” . . .
“DROP”
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.”
X-15A 56-6670 under the wing of NB-52A 52-003 at high altitude. Scott Crossfield is in the cockpit of the rocketplane. (Air Force Flight Test Center History Office, U.S. Air Force)
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. . . .
X-15A 56-6670 drops from the wing of the B-52 mothership, 8 June 1959. The vapor trail is from venting hydrogen peroxide used to power the aircraft pumps and generators. Note the roll to the right as the X-15 drops away from the Stratofortress. (NASA)
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.
This photograph shows the second North American Aviation X-15A, 56-6671, flaring to land on Rogers Dry Lake, Edwards Air Force Base, California. The rear skids are just touching down. The white patches on the aircraft’s belly are frost from residual cryogenic propellants remaining in its tanks after a powered flight. (U.S. Air Force)
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.
A. Scott Crossfield, wearing a David Clark Co. XMC-2 full-pressure suit, which he helped to design and test, with the first of three North American X-15s, 56-6670. (North American Aviation, Inc.)
Captain Charles F. Blair, Jr., standing in the cockpit of Pan American World Airways’ North American Aviation P-51C Mustang, Excalibur III, Bardufoss, Norway, 29 May 1951. (National Air and Space Museum, Smithsonian Institution.)
29 May 1951: Pan American World Airways Captain Charles F. Blair, Jr., flew a modified North American Aviation P-51C-10-NT Mustang, NX12012, Excalibur III, from Bardufoss, Norway to Fairbanks, Alaska, via the North Pole. He flew the 3,260 miles (5,246.5 kilometers) non-stop in 10 hours, 27 minutes.
After departing Bardufoss at 3:58 p.m., Captain Blair flew north along the E. 20° meridian until crossing the North Pole at an altitude of 22,000 feet (6,706 meters), then south along the W. 160° meridian until reaching N. 70° latitude, and then southeast to Fairbanks.
During the transpolar flight, the Mustang was subjected to air temperatures as low as -25 °F. (-31.6 °C.).
Captain Charles F. Blair, Jr., checks his astrocompass shortly before beginning his transpolar flight, 29 May 1951. ( National Air and Space Museum, Smithsonian Institution)
Captain Blair navigated by using a system of pre-plotted sun lines calculated by Captain Phillip Van Horns Weems, U.S. Navy (Ret.), as a magnetic compass was useless near the Pole and there were no radio navigation aids available.
Charles Blair used this Astrocompass Mark II on his transpolar flight. It is in the collection of the Smithsonian Institution National Air and Space Museum. (NASM2012-02107)
Blair was presented the Harmon International Trophy by President Harry S. Truman, in a ceremony at the White House, 18 November 1952. The Harmon awards are for “the most outstanding international achievements in the art and/or science of aeronautics for the previous year, with the art of flying receiving first consideration.”
Excalibur III being fueled at Bardufoss, Norway, May 1951. (Arkivverkets digitale fotoarkiv)
Charles Blair was commissioned in the United States Naval Reserve in 1931. He was promoted to lieutenant, junior grade, in 1937. During World War II, Blair served as a transport pilot in the U.S. Navy and rose to the rank of captain.
Blair resigned from the Navy in 1952 and the following year accepted a commission in the U.S. Air Force Reserve with the rank of colonel. In 1959 he was promoted to brigadier general.
While serving as a reserve officer, Charlie Blair continued his civilian career as an airline pilot for United Airlines, American Overseas Airlines, and then with Pan American.
Captain Blair was married to actress Maureen O’Hara, whom he had met during one of his 1,575 transatlantic crossings.
Excalibur III is a Dallas, Texas-built North American Aviation P-51C-10-NT Mustang, one of a group of 400 fighters which had been contracted on 5 March 1943. Its North American Aviation serial number is 111-29080, and the U.S. Army Air Forces assigned it serial number 44-10947.
After World War II, 44-10947 was purchased by Paul Mantz, and the Civil Aeronautics Administration registered it as NX1202. Mantz had it painted red and named it Blaze of Noon. Paul Mantz flew NX1202 to win the 1946 and 1947 Bendix Trophy Races. Flown by Linton Carney and renamed The Houstonian, NX1202 placed second in the 1948 Bendix race, and with “Fish” Salmon in the cockpit, it took third place in 1949. Paul Mantz had set several speed records with the Mustang before selling it to Pan American World Airways, Inc., Blair’s employer. Blair named the Mustang Stormy Petrel, but later changed it to Excalibur III.
To increase the Mustang’s range for these long-distance flights, Mantz had removed the standard 90-gallon pressure-molded Firestone self-sealing tanks from each wing and converted the entire wing to a fuel tank (what is known as a “wet wing”).
Test pilot Herman “Fish” Salmon awaits the starter’s signal at the beginning of the 1949 Bendix Trophy Race on Rosamond Dry Lake, California. Paul Mantz had won the 1946 and 1947 races with this P-51C, NX1202, “Blaze of Noon.” (San Diego Air and Space Museum Archive)
The P-51B and P-51C Mustang are virtually Identical. The P-51Bs were built by North American Aviation, Inc, at Inglewood, California. P-51Cs were built at North American’s Dallas, Texas plant. They were 32 feet, 2.97 inches (9.829 meters) long, with a wingspan of 37 feet, 0.31-inch (11.282 meters) and overall height of 13 feet, 8 inches (4.167 meters) high. The fighter had an empty weight of 6,985 pounds (3,168 kilograms) and a maximum gross weight of 11,800 pounds (5,352 kilograms).
North American Aviation P-51C-10-NT 44-10947, “Excalibur III,” at the Steven F. Udvar-Hazy Center, National Air and Space Museum.
P-51Bs and Cs were powered by a right-hand tractor, 1,649-cubic-inch-displacement (27.04-liter) liquid-cooled, supercharged, Packard V-1650-3 or -7 Merlin single overhead cam (SOHC) 60° V-12 engine which produced 1,380 horsepower at Sea Level, at 3,000 r.p.m and 60 inches of manifold pressure (V-1650-3) or 1,490 horsepower at Sea Level, turning 3,000 r.p.m. with 61 inches of manifold pressure (V-1650-7). (Military Power rating, 15 minute limit.) These engines were license-built versions of the Rolls-Royce Merlin 63 and 66. The engine drove a four-bladed Hamilton Standard Hydromatic constant-speed propeller with a diameter of 11 feet, 2 inches (3.404 meters) through a 0.479:1 gear reduction.
The P-51B/C had a cruise speed of 362 miles per hour (583 kilometers per hour) and the maximum speed was 439 miles per hour (707 kilometers per hour) at 25,000 feet (7,620 meters), slightly faster than the more numerous P-51D Mustang. The service ceiling was 41,900 feet (12,771 meters). With internal fuel the combat range was 755 miles (1,215 kilometers).
Identical to the Inglewood, California-built North American Aviation P-51B Mustang, this is a Dallas, Texas-built P-51C-1-NT, 42-103023. (North American Aviation, Inc.)
In military service, armament consisted of four Browning AN/M2 .50-caliber machine guns, mounted two in each wing, with 350 rounds per gun for the inboard guns and 280 rounds per gun for the outboard.
1,988 P-51B Mustangs were built at North American’s Inglewood, California plant and another 1,750 P-51Cs were produced at Dallas, Texas. This was nearly 23% of the total P-51 production.
Though the P-51D with its bubble canopy was built in far greater numbers during World War II, the earlier P-51B and P-51C Mustangs were actually faster, so many surplus airplanes were used for racing and record attempts after the war.
In 1952, Pan American World Airways donated Excalibur III to the Smithsonian Institution. Today, completely restored, it is on display at the Steven F. Udvar-Hazy Center in Chantilly, Virginia.
North American Aviation P-51C-10-NT Mustang, Excalibur III, at the Steven F. Udvar-Hazy Center, National Air and Space Museum. (NASM)
George S. Welch with North American YF-100A 52-5754. (North American Aviation, Inc.)
25 May 1953: North American Aviation Chief Test Pilot George S. Welch took the YF-100A Super Sabre, U.S. Air Force serial number 52-5754, for its first flight at Edwards Air Force Base. The airplane reached Mach 1.03.
Development of the Super Sabre began with an effort to increase the speed of the F-86D and F-86E Sabre fighters. The wings had more sweep and the airfoil sections were thinner. A much more powerful engine would be needed to achieve supersonic speed in level flight. As design work on the “Sabre 45” proceeded, the airplane evolved to a completely new design. Initially designated XF-100, continued refinements resulted in the first two aircraft being redesignated YF-100A.
North American Aviation Chief Test Pilot George S. Welch in the cockpit of YF-100A 52-5754 at Los Angeles International Airport. (North American Aviation, Inc.)
The two YF-100As, 52-5754 and 52-5755, were 46 feet, 2.4 inches (14.082 meters) long with a wingspan of 36 feet, 9.6 inches (11.217 meters) and height of 14 feet, 4.8 inches (4.389 meters). The Super Sabre had a 49° 2′ sweep to the leading edges of the wings and horizontal stabilizer. The wings were swept to 45° at 25% chord, and had 0° angle of incidence, 0° dihedral, and no twist. The total wing area was 376 square feet (34.932 square meters). The ailerons were placed inboard on the wings to eliminate their twisting effects at high speed. The airplane had no flaps, resulting in a high stall speed in the landing configuration. The horizontal stabilizer was moved to the bottom of the fuselage to keep it out of the turbulence created by the wings at high angles of attack. The pre-production prototypes weighed 18,279 pounds (8,291 kilograms) empty; had a combat weight of 24,789 pounds (11,244 kilograms); and maximum takeoff weight of 28,965 pounds (13,138 kilograms).
The YF-100A had a fuel capacity of 757 U.S. gallons (2,866 liters) in five fuselage tanks, and could carry two external drop tanks for another 550 gallons (2,082 liters).
The new air superiority fighter was powered by a Pratt & Whitney Turbo Wasp XJ57-P-7 engine. The J57 was a two-spool axial-flow turbojet which had a 16-stage compressor section (9 low- and 7 high-pressure stages) and a 3-stage turbine (2 high- and 1 low-pressure stages). The XJ57-P-7 had a Normal Power rating of 7,250 pounds of thrust (32.250 kilonewtons) at 5,570 r.p.m., N1/9,630 r.p.m, N2; Military Power rating was 8,450 pounds thrust (37.587 kilonewtons) at 5,850 r.p.m./9,630 r.p.m., for 30 minutes; and 13,200 pounds thrust (587.717 kilonewtons) at 5,850 r.p.m./9,630 r.p.m. with afterburner, limited to five minutes. The engine was 20 feet, 3.0 inches (6.172 meters) long, 3 feet, 5.0 inches (1.014 meters) in diameter, and weighed 5,126 pounds (2,325 kilograms). Later production aircraft used a J57-P-39 engine, which had the same ratings.
Cutaway illustration of a North American Aviation F-100A Super Sabre. (Boeing)North American Aviation YF-100 Super Sabre 52-5754, 19 May 1953. (North American Aviation, Inc.)The prototype North American Aviation YF-100A Super Sabre, 52-5754, with the North American F-100 team. Chief Test Pilot George S. Welch is in the center of the front row, seated. (North American Aviation, Inc.)
The YF-100A had a maximum speed of 634 knots (730 miles per hour/1,174 kilometers per hour) at Sea Level, and 573 knots (659 miles per hour/1,061 kilometers per hour) at 43,350 feet (13,213 meters). The service ceiling was 46,000 feet (14,021 meters). The combat radius was 422 nautical miles (486 statute miles/782 kilometers), and maximum ferry range, 1,410 nautical miles (1,623 statute miles/2,611 kilometers).
During testing, 52-5754 reached Mach 1.44 in a dive. On 29 October 1953, Colonel Frank K. Everest set a world speed record of 1,215.298 kilometers per hour (755.151 miles per hour) with 52-5754.¹
In service with the United States Air Force, the Super Sabre’s mission changed from air superiority fighter to fighter bomber. It was used extensively during the Vietnam War. North American Aviation, Inc., built 2,294 single and tandem-seat Super Sabres between 1954 and 1959.
The F-100 pushed the State of the Art in the 1950s. There was a very steep learning curve back then. They remained in service with the USAF until 1979, and with the Republic of China Air Force until 1988. They also flew for France and Turkey.
In USAF service, 889 were destroyed in accidents, resulting in the death of 324 pilots. During the Vietnam War, the F-100s flew more combat sorties that all of the 15,000+ P-51 Mustangs during World War II. 186 Super Sabres were shot down by antiaircraft fire, but none were lost to enemy fighters.
North American Aviation YF-100A Super Sabre 52-5754 over Edwards Air Force Base, California, 25 May 1953. (North American Aviation, Inc.)North American Aviation YF-100A Super Sabre 52-5754 lands on the dry lake at Edwards Air Force Base, California. (North American Aviation, Inc.)
George Welch was born George Lewis Schwartz, in Wilmington, Delaware, 10 May 1918. His parents changed his surname to Welch, his mother’s maiden name, so that he would not be effected by the anti-German prejudice that was widespread in America following World War I. He studied mechanical engineering at Purdue, and enlisted in the Army Air Corps in 1939.
North American Aviation YF-100A Super Sabre 52-5754 banks away from a chase plane during a flight test. (U.S. Air Force)
George S. Welch is best remembered as one of the heroes of Pearl Harbor. He was one of only two fighter pilots to get airborne during the Japanese surprise attack on Hawaii, 7 December 1941. Flying a Curtiss P-40B Warhawk, he shot down three Aichi D3A “Val” dive bombers and one Mitsubishi A6M2 Zero fighter. For this action, Lieutenant General H.H. “Hap” Arnold recommended the Medal of Honor, but because Lieutenant Welch had taken off without orders, an officer in his chain of command refused to endorse the nomination. He received the Distinguished Service Cross. During the War, Welch flew the Bell P-39 Airacobra and Lockheed P-38 Lightning on 348 combat missions. He had 16 confirmed aerial victories over Japanese airplanes and rose to the rank of Major.
Suffering from malaria, George Welch was out of combat, and when North American Aviation approached him to test the new P-51H Mustang, General Arnold authorized his resignation. Welch test flew the P-51, FJ-1 Fury, F-86 Sabre and F-100 Super Sabre. He was killed 12 October 1954 when his F-100A Super Sabre came apart in a 7 G pull up from a Mach 1.5 dive.
North American Aviation pre-production prototype YF-100A Super Sabre 52-5754 with drag chute deployed on landing at Edwards Air Force Base, California. The extended pitot boom is used to calibrate instruments early in the flight test program. (U.S. Air Force)North American Aviation YF-100 Super Sabre 52-5754 with external fuel tanks, parked on the dry lake at Edwards Air Force Base, California. (U.S. Air Force)
