Tag Archives: Sound Barrier

21 August 1961

Douglas DC-8-43 N9604Z is accopmanied by a U.S. Air Force Lockheed F-104A Starfighter, near Edwards Air Force base, California.
Douglas DC-8-43 N9604Z is accompanied by a U.S. Air Force Lockheed F-104A Starfighter, near Edwards Air Force Base, California. (Douglas Aircraft Co.)

On 21 August 1961, a Douglas DC-8-43, N9604Z, c/n 45623, Line Number 130, flown by Chief Test Pilot William Marshall Magruder, Paul Patten, Joseph Tomich and Richard H. Edwards climbed to 50,090 feet (15,267 meters) near Edwards Air Force Base. Placing the DC-8 into a dive, it reached Mach 1.012 (668 miles per hour/1,075 kilometers per hour) while descending through 41,088 feet (12,524 meters). The airliner maintained this supersonic speed for 16 seconds. This was the first time that a civil airliner had “broken the Sound Barrier.”

An Air Force F-100 Super Sabre and F-104 Starfighter were chase planes for this flight. Reportedly, the F-104 was flown by the legendary test pilot, Colonel Chuck Yeager.

The Douglas DC-8 is a commercial jet airliner, a contemporary of the Boeing 707 and Convair 880. It was operated by a flight crew of three and could carry up to 177 passengers. The DC-8 was powered by four turbojet or turbofan engines mounted on pylons suspended below the wings. The wings’ leading edges were swept to 30°, as was the vertical fin and horizontal tailplane.

The DC-8-40 series is 150 feet, 6 inches (45.872 meters) long with a wingspan of 142 feet, 5 inches (43.409 meters) and overall height of 42 feet, 4 inches (12.903 meters). It had an empty weight of 124,790 pounds (56,604 kilograms) and maximum takeoff weight of 315,000 pounds (142,882 kilograms).

The DC-8-40 series had a cruising speed of 0.82 Mach (542 miles per hour/872 kilometers per hour) at 35,000 feet (10,668 meters). Its maximum range was 5,905 nautical miles (6,795 statute miles, 10,936 kilometers).

N9604Z was powered by four Rolls-Royce Conway RCo.12 Mk 509 two-shaft axial-flow turbofan engines, rated at 17,500 pounds of thrust (77.844 kilonewtons) at 9,990 r.p.m. The 509 is 11 feet, 3.9 inches (3.452 meters) long, 3 feet, 6.2 inches (1.072 meters) in diameter, and weighs 4,542 pounds (2,060 kilograms).

N9604Z was delivered to Canadian Pacific Airlines 15 November 1961, re-registered CF-CPG, and named Empress of Montreal. It later flew under CP Air as Empress of Buenos Aires. The DC-8 was scrapped at Opa Locka Municipal Airport, north of Miami, Florida, in May 1981.

© 2016, Bryan R. Swopes

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26 April 1948

est Pilot George Welch flying the prototype North American Aviation XP-86 Sabre, 45-59597. (U.S. Air Force)
Test Pilot George Welch flying the prototype North American Aviation XP-86 Sabre, 45-59597. (U.S. Air Force)

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.

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

© 2016, Bryan R. Swopes

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26 December 1948

The ç
The Lavochkin La-176 (NPO Lavochkin)

26 December 1948: Test pilot Ivan Yevgrafovich Federov (also reported as Ivan E. Fyodorov) became the first pilot in the Soviet Union to exceed Mach 1 when he flew the Lavochkin La-176 in a dive from 9,050 meters (29,692 feet) to 6,000 meters (19,685 feet).

It was first thought that the La-176’s airspeed indicator had malfunctioned, but during subsequent testing conducted the first week of January 1949, Federov repeated the dive and six times reached Mach 1.02.

The La-176 was destroyed when its canopy failed during supersonic flight. Test pilot I.V. Sokolovsky was killed.

Lavochkin La-176
Lavochkin La-176

The La-176 was a single-seat, single-engine fighter, derived from the earlier La-168. The leading edge of its wings and tail surfaces were swept at 45°. The fighter was 36 feet (10.973 meters) long with a wingspan of 28 feet, 2 inches (8.585 meters). It had an empty weight of 3,111 kilograms (6,858.6 pounds)  and loaded weight of 4,631 kilograms (10,210 pounds).

The La-176 was powered by a Klimov VK-1 centrifugal-flow turbojet, developed from the Rolls-Royce Nene. The British engines were reverse-engineered by Vladimir Yakovlevich Klimov and manufactured at Factory No. 45 in Moscow as the Klimov VK-1. The VK-1 used a single-stage axial-flow compressor, 9 combustion chambers and a single-stage axial-flow turbine. It produced a maximum 26.5 kilonewtons of thrust (5,957 pounds of thrust). The VK-1 was 2.600 meters (8 feet, 6.4 inches) long, 1.300 meters (4 feet, 3.2 inches) in diameter, and weighed 872 kilograms (1,922 pounds).

The swept-wing jet had a maximum speed of 648 miles per hour (1,042.85 kilometers per hour) and a range of 621 miles (999.4 kilometers).

Armament consisted of one Nudelman N-37 30 mm cannon and two Nudelman-Suranov NS-23 23 mm cannon.

Lavochkin La-176
Lavochkin La-176

Colonel Ivan Yevgrafovich Federov (b. 23 February 1914) was a Soviet Air Force fighter pilot who fought in the Spanish civil war (where he was known as Diablo Rojo, the Red Devil), the Russo-Finish War, World War II, China and Korea. He may have shot down as many as 135 enemy airplanes. He was personally awarded the Iron Cross by Adolf Hitler, Chancellor of Germany, in 1941. His Soviet Awards include Hero of the Soviet Union, the Order of Lenin, Order of Alexander Nevsky, Order of the Red Banner, Order of the Patriotic War 1st Degree, Order of the Patriotic War 2nd Degree, and Order of the Red Star.

Colonel Ivan Yegrafovich Federov, Soviet Air Force.
Colonel Ivan Yegrafovich Federov, Soviet Air Force.

© 2016, Bryan R. Swopes

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14 October 1997

Brigadier General Charles E. Yeager, United States Air Force (Retired), photographed at Edwards Air Force Base, California, 14 October 1997, the Fiftieth Anniversary of his historic supersonic flight. (Photograph used with permission. © 2010, Tim Bradley Imaging)

14 October 1997: On the Fiftieth Anniversary of his historic supersonic flight in the Bell X-1 research rocketplane, Brigadier General Charles Elwood (“Chuck”) Yeager, United States Air Force (Retired) once again broke the Sound Barrier when he flew over Edwards Air Force Base in a McDonnell Douglas F-15D-38-MC Eagle, serial number 84-046. Lieutenant Colonel Troy Fontaine flew in the rear seat of the two-place fighter. Glamorous Glennis III was painted on the Eagle’s nose.

An estimated 5,000 spectators were at Edwards Air Force Base in the high desert north of Los Angeles, California, to see this historic flight.

My friend, aviation photographer Tim Bradley, and I were there. Tim took the photograph above a few minutes after General Yeager landed. As he concluded his comments to the crowd, he said, “All that I am. . . I owe to the Air Force.”

Brigadier General Charles E. Yeager, U.S. Air Force (Ret.), with Glamorous Glennis III, an F-15D Eagle, 84-046, at Edwards Air Force Base, 14 October 1997. (U.S. Air Force)

© 2016, Bryan R. Swopes

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14 October 1977

Major General Thomas Stafford with Brigadier General (Retired) Charles E. Yeager, seated in a Lockheed F-104 Starfighter at Edwards AFB, 14 October 1977. (Associated Press)

14 October 1977: On the Thirtieth Anniversary of his historic supersonic flight in the Bell X-1, Brigadier General Charles E. (“Chuck”) Yeager, U.S. Air Force (Retired), returned to Edwards Air Force Base where he flew a Lockheed F-104 Starfighter to Mach 1.5.

Chuck Yeager and Bell X-1 46-062 glide back to Edwards Air Force Base for landing. (U.S. Air Force)

© 2016, Bryan R. Swopes

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