Tag Archives: Flight Test

26 April 1948

Aviation, , , , , , , , , , , , ,
est Pilot George Welch flying the prototype North American Aviation XP-86 Sabre, 45-59597. (U.S. Air Force)
North American Aviation test pilot George S. Welch, flying the first of three XP-86 prototypes, serial number 45-59597. (North American Aviation, Inc.)

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, C.B.E, D.S.O. and Bar, D.F.C. 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 U.S. Air Force released a statement that George Welch had flown beyond Mach 1 earlier, but gave the date as 26 April 1948.

Test pilot George S. Welch, wearing his distinctive orange helmet, in the cockpit of the prototype XP-86. This photograph was taken 14 October 1947. (U.S. Air Force)
Test pilot George S. Welch, wearing his distinctive orange helmet, in the cockpit of the prototype XP-86. This photograph was taken 14 October 1947. (U.S. Air Force)

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 a North American Aviation F-100A Super Sabre, 12 October 1954.

Test pilot George S. Welch with a North American Aviation F-86 Sabre. (San Diego Air and Space Museum Archives)

© 2018, Bryan R. Swopes

21 March 1962

Aviation, , , , ,
Yogi, an American black bear used as a test subject.
Yogi, an American black bear used as a test subject.

21 March 1962: A black bear named “Yogi” was ejected from a supersonic Convair B-58A Hustler to test the B-58’s escape capsule. Ejected at 35,000 feet (10,668 meters) from a B-58 flying at Mach 1.3 (approximately 870 miles per hour/1,400 kilometers per hour), the bear landed unharmed 7 minutes, 49 seconds later.

Previous testing with human subjects had resulted in fatalities so it was decided to continue with animal subjects while problems were resolved. Black bears (Ursus americanus) were used for these tests because their internal organs are arranged similar to humans.

An escape capsule is launched from teh Defensive Systems Officer position of a Convair B-58 Hustler. (U.S. air Force)
An escape capsule is launched from the Defensive Systems Officer position of a Convair B-58 Hustler. (U.S. Air Force)

The rocket booster carried the capsule 225 feet (69 meters meters) above the B-58 before beginning its descent.

Regrettably, although the bears survived the ejection tests, they were killed so that their organs could be examined. This would not be acceptable today.

© 2016, Bryan R. Swopes

7 March 1961

Aviation, Space Flight, , , , , , , , , , , , , ,
Major Robert M. White exits the cockpit of an X-15 at Edwards AFB. (U.S. Air Force)
Major Robert M. White, U.S. Air Force, climbs out of the cockpit of an X-15 after landing on Rogers Dry Lake at Edwards Air Force Base. (U.S. Air Force)

7 March 1961: Launched over Silver Lake, a dry lake bed near the California/Nevada border, at 10:28:33.0 a.m., Pacific Standard Time, test pilot Major Robert M. White, U.S. Air Force, flew the number two North American Aviation X-15 hypersonic research rocketplane, 56-6671, to Mach 4.43 (2,905 miles per hour/4,675 kilometers per hour) and 77,450 feet (23,607 meters), becoming the first pilot to exceed Mach 4.

This was the first flight for the number two X-15 with the Reaction Motors XLR99-RM-1 engine, which was rated at 57,000 pounds of thrust (253.55 kilonewtons).

The flight plan called for a burn time of 116 seconds, an altitude of 84,000 feet (25,603 meters) and a predicted maximum speed of Mach 4.00. The actual duration of the engine burn was 127.0 seconds. Peak altitude was lower than planned, at 77,450 feet (23,607 meters). The longer burn and lower altitude translated into the higher speed.

The total duration of the flight, from the air drop from the Boeing NB-52B Stratofortress carrier, 52-008, to touchdown at Edwards Air Force Base, was 8 minutes, 34.1 seconds.

Major Robert M. White, U.S. Air Force, with one of the three North American Aviation X-15s on Rogers Dry Lake, 1961. (NASA)
Major Robert M. White, U.S. Air Force, with a North American Aviation, Inc., X-15 rocketplane on Rogers Dry Lake, 1961. White is wearing a David Clark Co. MC-2 full-pressure suit with an MA-3 helmet. (NASA)

© 2017, Bryan R. Swopes

14 February 2012

Aviation, , , , , , , , , , , , , ,
Boeing YAL-1A, 00-0001, Airborne Laser Test aircraft, departing Edwards AFB, 14 February 2012. (U.S. Air Force)
Boeing YAL-1A, 00-0001, Airborne Laser Test Aircraft, departing Edwards AFB, 14 February 2012. (U.S. Air Force)
Terrier Black Brant IX two-stage sounding rocket. (NASA)
Terrier Black Brant IX two-stage sounding rocket. (NASA)

14 February 2012: Boeing YAL-1A Airborne Laser Test Bed, serial number 00-0001, departed Edwards AFB for the last time as it headed for The Boneyard at Davis-Monthan Air Force Base, Tucson, Arizona.

The Boeing YAL-1A was built from a 747-4G4F, a converted 747-400F freighter, serial number 30201, formerly operated by Japan Air Lines and registered JA402J. It carried two solid state lasers and a megawatt-class oxygen iodine directed energy weapon system (COIL).

On 3 February 2010, it destroyed a Terrier Black Brant two-stage sounding rocket in the boost phase as it was launched from San Nicolas Island, off the coast of Southern California.

Boeing YAL-1A 00-0001, Airborne Laser test aircraft, in flight. The laser aiming turret is directed toward the photo aircraft. (U.S. Air Force)
Boeing YAL-1A Airborne Laser Test Aircraft, 00-0001, in flight. The laser aiming turret is directed toward the photo aircraft. (U.S. Air Force)

The 747-400 was a major development of the 747 series. It had many structural and electronics improvements over the earlier models, which had debuted 18 years earlier. New systems, such as a “glass cockpit”, flight management computers, and new engines allowed it to be flown with a crew of just two pilots, and the position of Flight Engineer became unnecessary.

The most visible features of the –400 are its longer upper deck and the six-foot tall “winglets” at the end of each wing, which improve aerodynamic efficiency be limiting the formation of wing-tip vortices.

Japan Air Lines’ Boeing 747-400F, JA402J. (Konstantin von Wedelstaedt/Wikimedia)

The Boeing 747-400F is the freighter version of the 747-400 airliner. It has a shorter upper deck, no passenger windows and the nose can swing upward to allow cargo pallets or containers to be loaded. It is 231 feet, 10 inches (70.663 meters) long with a wingspan of 211 feet, 5 inches (64.440 meters) and overall height of 63 feet, 8 inches (19.406 meters). Empty weight is 394,100 pounds (178,761 kilograms). Maximum takeoff weight (MTOW) is 875,000 pounds (396,893 kilograms).

Boeing YAL-1A Airborne Laser Test Aircraft, 00-0001. (U.S. Missile Defense Agency)

The YAL-1A was powered by four General Electric CF6-80C2B5F turbofan engines, producing 62,100 pounds of thrust (276.235 kilonewtons), each. The CF6-80C2B5F is a two-spool, high-bypass-ratio turbofan engine. It has a single-stage fan section, 18-stage compressor (4 low- and 14 high-pressure stages) and 7-stage turbine section (2 high- and 5 low-pressure stages). The fan diameter is 7 feet, 9.0 inches (2.362 meters). The engine is 13 feet, 4.9 inches (4.087 meters) long with a maximum diameter of 8 feet, 10.0 inches (2.692 meters). It weighs 9,760 pounds (4,427 kilograms).

It had a cruise speed of 0.84 Mach (555 miles per hour, 893 kilometers per hour) at 35,000 feet (10,668 meters) and maximum speed of 0.92 Mach (608 miles per hour, 978 kilometers hour). Maximum range at maximum payload weight is 7,260 nautical miles (13,446 kilometers).

Boeing YAL-1A in storage at Davis-Monthan Air Force Base, 27 August 2014. The airframe was disassembled and finally broken up 25 September 2014. (Soracat)

© 2017, Bryan R. Swopes

5 January 1956

Aviation, , , , , , , , , , , ,
Piasecki YH-16A-PH Transporter 50-1270 hovers in ground effect.
Piasecki YH-16A-PH Transporter 50-1270 hovers in ground effect. (Piasecki Aircraft Corporation)

5 January 1956: The prototype Piasecki Helicopter Company YH-16A-PH Transporter twin-turboshaft, tandem-rotor helicopter, serial number 50-1270, was returning to Philadelphia from a test flight, when, at approximately 3:55 p.m., the aft rotor desynchronized, collided with the forward rotor and the aircraft broke up in flight. It crashed at the Mattson Farm on Oldman’s Creek Road, near Swedesboro, New Jersey, and was completely destroyed.

Test pilots Harold W. Peterson and George Callahan were killed.

It was determined that a bearing associated with an internal coaxial shaft supporting test data equipment had seized, causing the rotor shaft to fail.

Harold W. Peterson (left) and George Callahan, with the prototype Piasecki YH-16A Turbo Transporter, 50-1270. (Photograph courtesy of Neil Corbett, Test and Research Pilots, Flight Test Engineers)
Harold W. Peterson (left) and George Callahan, with the prototype Piasecki YH-16A Turbo Transporter, 50-1270. (Photograph courtesy of Neil Corbett, Test and Research Pilots, Flight Test Engineers)

At the time, the YH-16 was the largest helicopter in the world. The United States Air Force intended it as a very-long-range rescue helicopter, while the U.S. Army expected it to serve as a heavy lift cargo and troop transport.

The YH-16A had a fuselage length of 78 feet (23.774 meters), and both main rotors were 82 feet (24.994 meters) in diameter. With rotors turning, the overall length was 134 feet (40.843 meters). Their operating speed was 125 r.p.m. Overall height of the helicopter was 25 feet (7.62 meters). The helicopter’s empty weight was 22,506 pounds (10,209 kilograms) and the gross weight was 33,577 pounds (15,230 kilograms).

YH-16 50-1269 was powered by two 2,181.2-cubic-inch-displacement (35.74 liter) air-cooled, supercharged Pratt & Whitney Twin Wasp E2 (R-2180-11) two-row, fourteen-cylinder radial engines with a Normal Power Rating of 1,300 horsepower at 2,600 r.p.m. at 8,000 feet (2,438 meters), and 1,650 horsepower at 2,600 r.p.m., for Takeoff.

Piasecki YH-16A 50-1270 during a test fight.

The second YH-16A, 50-1270, was modified while under construction and was powered by two Allison Division YT38-A-10 turboshaft engines which produced 1,800 shaft horsepower, each. This made the YH-16A the world’s first twin-engine turbine-powered helicopter.

The Piasecki YH-16A Transporter was the world's largest helicopter in 1956. (Piasecki Aircraft Corporation)
The Piasecki YH-16A Transporter was the world’s largest helicopter in 1956. (Piasecki Aircraft Corporation)

The cruise speed of the YH-16A was 146 miles per hour (235 kilometers per hour). In July 1955, Peterson and Callahan had flown 50-1270 to an unofficial record speed of 165.8 miles per hour (266.83 kilometers per hour). The service ceiling was 19,100 feet (5,822 meters) and the maximum range for a rescue mission was planned at 1,432 miles (2,305 kilometers).

After the accident, the H-16 project was cancelled.

Prototype Piasecki YH-16A Transporter 50-1270, hovering in ground effect at Philadelphia Airport, 1955. (Piasecki Aircraft Corporation)
Prototype Piasecki YH-16A Transporter 50-1270, hovering in ground effect at Philadelphia Airport, 1955. (Piasecki Aircraft Corporation)

© 2017, Bryan R. Swopes