Tag Archives: The Lonely Sky

7 August 1951

William Barton Bridgeman. (Boris Artzybasheff/TIME Magazine)

7 August 1951: Douglas Aircraft Company test pilot William Barton Bridgeman flew the rocket-powered U.S. Navy/NACA/Douglas D-558-2 Skyrocket, Bu. No. 37974 (NACA 144), to a record speed of Mach 1.88 (1,245 miles per hour/2,034 kilometers per hour) at Muroc Dry Lake (later Edwards Air Force Base) in the high desert of southern California.

The D-558-2 was airdropped at 34,000 feet (10,363 meters) from a Navy P2B-1S Superfortress, Bu. No. 84029 (a U.S. Air Force Boeing B-29-95-BW Superfortress, 45-21787, transferred to the Navy and heavily modified as a drop ship) flown by another Douglas test pilot, George Jansen.

Douglas D-558-II Skyrocket, Bu. No., 37974, NACA 144, is dropped from the Boeing P2B-1S Superfortress, Bu. No. 84029, NACA 137. (NASA)

In his autobiography, Bridgeman described the flight:

We are at 34,000 feet. My cue. Ten cold minutes preparing the ship for flight. The trap door springs and releases the captive Skyrocket swollen with explosive propellants. She blasts into flight.

Thirty seconds and I am supersonic. Sixty-eight thousand feet and this is it. Over the rim. Easy. The electrically controlled stabilizer flies her now. It takes over for me. At .6 G I push over just enough to get my speed. I am on the ragged edge between .6 G and .8 G. It is working! Everything is going according to my plan. It is so easy this time. Surely I cannot be breaking my last record without having to pay for it. The Machmeter is moving up, fluttering toward the Number 2. . . the rockets sputter and the fuel is gone. That’s all she wrote.

Late that afternoon the official speed attained by the Skyrocket reduced from data and film came out  of the aerodynamicists’ office. Mach 1.88.

The Lonely Sky, William Bridgeman, Castle and Company LTD, London, 1956, Chapter XXII at Page 260.

NACA 144, a Douglas D-558-II Skyrocket, Bu. No. 37974, parked on Muroc Dry Lake. (NACA E-1441)

Bill Bridgeman had been a Naval Aviator during World War II, flying the Consolidated PBY Catalina and PB4Y (B-24) Liberator long range bombers with Bombing Squadron 109 (VB-109), “The Reluctant Raiders.” Bridgeman stayed in the Navy for two years after the end of the war, then he flew for Trans-Pacific Air Lines in the Hawaiian Islands and Southwest Airlines in San Francisco, before joining the Douglas Aircraft Company as a production test pilot. He flew new AD Skyraiders as they came off the assembly line at El Segundo, California. Bridgeman soon was asked to take over test flying the D-558-2 Skyrocket test program at Muroc Air Force Base.

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The D-558-II Skyrocket was Phase II of a planned three phase experimental flight program. It was designed to investigate flight in the transonic and supersonic range. It was 46 feet, 9 inches (14.249 meters) long with a 25 foot (7.62 meter) wing span. The wings were swept back to a 35° angle. The Skyrocket was powered by a Westinghouse J34-WE-40 11-stage axial-flow turbojet engine, producing 3,000 pounds of thrust, and a Reaction Motors LR8-RM-6 four-chamber rocket engine, which produced 6,000 pounds of thrust. The rocket engine burned alcohol and liquid oxygen.

There were three D-558-2 Skyrockets. Between 4 February 1948 and 28 August 1956, they made a total of 313 flights. The Skyrocket flown by Bill Bridgeman to Mach 1.88 is in the collection of the Smithsonian Institution National Air and Space Museum.

NACA 144, a Douglas D-558-II Skyrocket, on display at the National Mall Building, Smithsonian Institution. (NASM)
NACA 144, a Douglas D-558-II Skyrocket, on display at the National Mall Building, Smithsonian Institution. (NASM)

© 2017, Bryan R. Swopes

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20 October 1952

Douglas X-3 (NASA)
Douglas X-3 49-2892. Rogers Dry Lake is in the background. (NASA)

20 October 1952: At Edwards Air Force Base, California, Douglas Aircraft Company test pilot William Barton (“Bill”) Bridgeman made the first test flight of the X-3 twin-engine supersonic research airplane. During a high-speed taxi test five days earlier, Bridgeman and the X-3 had briefly been airborne for approximately one mile over the dry lake bed, but on this flight he spent approximately 20 minutes familiarizing himself with the new airplane.

William Barton “Bill” Bridgeman, 1916–1968. (LIFE Magazine)

Bill Bridgeman had been a Naval Aviator during World War II, flying the Consolidated PBY Catalina and PB4Y (B-24) Liberator long range bombers with Bombing Squadron 109 (VB-109), “The Reluctant Raiders.”

Bridgeman stayed in the Navy for two years after the war, then he flew for Trans-Pacific Air Lines in the Hawaiian Islands and Southwest Airlines in San Francisco, before joining Douglas Aircraft Co. as a production test pilot. He checked out new AD Skyraiders as they came off the assembly line at El Segundo, California. He soon was asked to take over test flying the D-558-2 Skyrocket test program at Muroc Air Force Base (now, Edwards AFB.) With the Skyrocket, he flew higher—79,494 feet (24,230 meters)—and faster—Mach 1.88—than any pilot had up to that time.

Douglas X-3 parked on Rogers Dry Lake, 1956 (NASA)
Douglas X-3 parked on Rogers Dry Lake, 1956 (NASA)

The Douglas X-3, serial number 49-2892, was built for the Air Force and NACA to explore flight in the Mach 1 to Mach 2 range. It was radically shaped, with a needle-sharp nose, very long thin fuselage and small straight wings. The X-3 was 66 feet, 9 inches (20.345 meters) long, with a wing span of just 22 feet, 8.25 inches (6.915 meters). The overall height was 12 feet, 6.3 inches (3.818 meters). The X-3 had an empty weight of 16,120 pounds (7,312 kilograms) and maximum takeoff weight of 23,840 pounds (10,814 kilograms).

It was to have been powered by two Westinghouse J46 engines, but when those were unsatisfactory, two Westinghouse XJ34-WE-17 engines were substituted. This was an axial flow turbojet with an 11-stage compressor and 2-stage turbine. It was rated at 3,370 pounds (14.99 kilonewtons) of thrust, and 4,900 pounds (21.80 kilonewtons) with afterburner. The XJ34-WE-17 was 14 feet, 9.0 inches (4.496 meters) long, 2 feet, 1.0 inch (0.635 meters) in diameter and weighed 1,698 pounds (770 kilograms).

The X-3 had a maximum speed of 706 miles per hour (1,136 kilometers per hour) and a service ceiling of 38,000 feet (11,582 meters).

This view of the Douglas X-3 shows its very small wings and tail surfaces. (NASA)
This view of the Douglas X-3 shows its very small wings and tail surfaces. (NASA)

The X-3 was very underpowered with the J34 engines and could just reach Mach 1 in a shallow dive. Its highest speed, Mach 1.208, required a 30° dive. The research airplane was therefore never able to be used in flight testing in the supersonic speed range for which it was designed. Because of its design characteristics, though, it became useful in exploring stability and control problems encountered in the transonic range.

Two X-3 aircraft had been ordered from Douglas, but only one completed.

In addition to Bill Bridgeman, the Douglas X-3 was flown by Air Force test pilots Major Chuck Yeager and Lieutenant Colonel Frank Everest, and NACA High Speed Flight Station research pilot Joseph A. Walker.

NACA flight testing began in August 1954. On the tenth flight, 27 October, Joe Walker put the X-3 into abrupt left aileron rolls at 30,000 feet (9,144 meters), first at 0.92 Mach and then at Mach 1.05. Both times, the aircraft violently yawed to the right and then pitched down.

This was a new and little understood condition called inertial roll coupling. It was a result of the aircraft’s mass being concentrated within its fuselage, the torque reactions and gyroscopic effect of the turbojet engines and the inability of the wings and control surfaces to stabilize the airplane and overcome its rolling tendency. (Just two weeks earlier, North American Aviation’s Chief Test Pilot George S. Welch had been killed when the F-100A Super Sabre that he was testing also encountered inertial roll coupling and disintegrated.) A post-flight inspection found that the X-3 had reached its maximum design load. The X-3 was grounded for the next 11 months.

Joe Walker resumed flight testing the X-3 in 1955. It’s last flight was 23 May 1956. After the flight test program came to an end, the X-3 was turned over to the National Museum of the United States Air Force, Wright-Patterson Air Force Base, Ohio.

Douglas X-3 49-2892 at the National Museum of the United States Air Force. (NASM)

© 2016, Bryan R. Swopes

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15 October 1952

William Barton Bridgeman
William Barton Bridgeman. (Photograph courtesy of Neil Corbett, Test and Research Pilots, Flight Test Engineers)

15 October 1952: At Edwards Air Force Base, California, Douglas Aircraft Company test pilot William Barton (“Bill”) Bridgeman, while conducting high speed taxi tests, took a short flight in the new Douglas X-3. The experimental airplane flew about one mile (1.6 kilometers) over the dry lake bed before touching down. The official first flight would come five days later on 20 October.

In his biography, The Lonely Sky, Bill Bridgeman discussed his concerns about taking on the new project:

Then one morning Johnny called me to his office. "Bill, we would like you to take a look at the X-3. Maybe you would like to test her. She's in the final stages over in Hangar Three. Go over and take a look at the mock-up. See what you think. . ." On the ground floor in front of a door marked KEEP OUT. SECRET PROJECT MX656. . . . — The Lonely Sky, by William Bridgeman and Jacqueline Hazard, Cassell and Company Limited, London, 1956, Chapter XXIII at Page 276.
Mock-up of the Douglas X-3 (U.S. Air Force)
William B. Bridgeman with the Douglas X-3.
William B. Bridgeman with the Douglas X-3.

“Then one morning Johnny called me to his office. ‘Bill, we would like you to take a look at the X-3. Maybe you would like to test her. She’s in the final stages over in Hangar Three. Go over and take a look at the mock-up. See what you think. . . ‘ On the ground floor in front of a door marked KEEP OUT. SECRET PROJECT MX656. . .

“I climbed aboard. In order to get into the cockpit, the seat was mechanically lowered to the ground. There was a button to raise the elevator. It buzzed ominously as it very slowly lifted me into the nose. Visibility was extremely poor from her windows, they were faired-in exaggerations of the Skyrocket slits. It was impossible to see the ground. The thin, insecure looking wings were so far behind me that they were out of sight. It would take some weighing to decide whether or not I wanted to bet my life on the integrity of this ship. . .

“I was afraid to take on this airplane. I was also afraid someone else would accept the challenge. And I was afraid that I would decide to accept it.”

The Lonely Sky, William Bridgeman with Jacqueline Hazard, Cassell and Company Limited, London, 1956, Chapter XXIII at Page 276–278.

Douglas X-3 Stilleto

The Douglas X-3, serial number 49-2892, was built for the Air Force and the National Advisory Committee for Aeronautics (NACA) to explore flight in the Mach 1 to Mach 2 range. It was radically shaped, with a needle-sharp nose, very long thin fuselage and small straight wings. The X-3 was 66 feet, 9 inches (20.345 meters) long, with a wing span of just 22 feet, 8.25 inches (6.915 meters). The overall height was 12 feet, 6.3 inches (3.818 meters). The X-3 had an empty weight of 16,120 pounds (7,312 kilograms) and maximum takeoff weight of 23,840 pounds (10,814 kilograms).

It was to have been powered by two Westinghouse J46 engines, but when those were unsatisfactory, two Westinghouse XJ34-WE-17 engines were substituted. This was an axial flow turbojet with an 11-stage compressor and 2-stage turbine. It was rated at 3,370 pounds (14.99 kilonewtons) of thrust, and 4,900 pounds (21.80 kilonewtons) with afterburner. The XJ34-WE-17 was 14 feet, 9.0 inches (4.496 meters) long, 2 feet, 1.0 inch (0.635 meters) in diameter and weighed 1,698 pounds (770 kilograms).

The X-3 had a maximum speed of 706 miles per hour (1,136 kilometers per hour) and a service ceiling of 38,000 feet (11,582 meters).

Three-view drawing of the Douglas X-3. (NASA)
Three-view drawing of the Douglas X-3. (NASA)

The X-3 was very underpowered with the J34 engines, and could just reach Mach 1 in a shallow dive. The X-3′s highest speed, Mach 1.208, required a 30° dive. It was therefore never able to be used in flight testing the supersonic speed range for which it was designed.

The X-3 was prone to Inertial Roll Coupling, a newly discovered and very dangerous situation in which an aircraft goes out of control in all three axes. Because of its design characteristics—a very long, thin, fuselage, small wings and tail surfaces, and concentrated mass—the X-3 was very useful in exploring stability and control in the transonic range.

At one point, replacing the X-3’s turbojet engines with two Reaction Motors XLR-11 rocket engines was considered. Predictions were that a rocket-powered X-3 could reach Mach 4.2. However, with Mach 2 Lockheed F-104 becoming operational and North American Aviation’s X-15 hypersonic research rocketplane under construction, the idea was dropped. Technology had passed the X-3 by.

Two X-3 aircraft had been ordered from Douglas, but only one completed. In addition to Bill Bridgeman, the Douglas X-3 was flown by Air Force test pilots Major Chuck Yeager and Lieutenant Colonel Frank Everest, and NACA test pilot Joseph A. Walker.

After the flight test program came to an end in May 1956, the X-3 was turned over to the National Museum of the United States Air Force, Wright-Patterson Air Force Base, Ohio.

The Douglas X-3 in flight, just a few feet above the dry lake bed at Edwards AFB, California. (Cropped from a LIFE Magazine image at Jet Pilot Overseas)
The Douglas X-3 in flight, just a few feet above the dry lake bed at Edwards AFB, California. (Cropped detail from a LIFE Magazine image at Jet Pilot Overseas)

© 2016, Bryan R. Swopes

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