Tag Archives: Rogers Dry Lake

1 December 1984

NASA 833, a remotely-piloted Boeing 720 airliner, pulls up after a practice approach to the impact point on Rogers Dry Lake. The "X" is the planned touchdown point. The "rhino" barriers are at the runway threshold. (NASA)
NASA 833, a remotely-piloted Boeing 720 airliner, pulls up after a practice approach to the impact point on Rogers Dry Lake. The “X” is the planned touchdown point. The “rhino” barriers are at the runway threshold. (NASA)

After four years of planning and preparation, the National Aeronautics and Space Administration (NASA) and the Federal Aviation Administration (FAA) intentionally crashed a Boeing 720 airliner to test an experimental fuel additive intended to reduce post-crash fires, and to assess passenger survivability. An anti-misting agent was added to standard commercial JP-5 jet fuel to create AMK, or “Anti-Misting Kerosene.” The airliner’s fuel tanks were filled with the AMK mixture, totaling 16,060 gallons (10,794 liters). Instrumented crash test dummies were placed in the passengers seats.

Passengers relaxing before a flight aboard NASA’s Boeing 720, N833NA. (NASA ECN-28307)

NASA 833, the Boeing 720-027 airliner, FAA registration N833NA, was a remotely-piloted aircraft. NASA test pilot Fitzhugh Lee (“Fitz”) Fulton, Jr., flew NASA 833 from a ground station, the NASA Dryden Remotely Controlled Vehicle Facility. More than 60 flights had been made prior to the actual test.

Fitz Fulton in the CID.
Fitz Fulton in the NASA Dryden Remotely Controlled Vehicle Facility

The test was planned so that the airliner would make a shallow 3.8° approach to a prepared runway on the east side of Rogers Dry Lake at Edwards Air Force Base. It was to land on its belly in a wings-level attitude, then slide into a group of barriers, called “rhinos,” which would slice open the wing tanks. The fuselage and passenger cabin would remain intact. NASA and the FAA estimated that this would be “survivable” for all occupants.

Just before touchdown, the Boeing 720 entered a "Dutch roll." The airliner's nose yawed to the left and the left wing dipped, striking the ground sooner than was planned. All four engines are still at full throttle. NASA 833 is to the right of the runway center line. (NASA)
Just before touchdown, the Boeing 720 entered a “Dutch roll.” The airliner’s nose yawed to the left and the left wing dipped, striking the ground sooner than was planned. All four engines are still at full throttle. NASA 833 is to the right of the runway center line. (NASA)

As the Boeing 720 descended on its Final Approach, its nose yawed to the right and the airplane went to the right of the runway center line. It then yawed back to the left and entered an out-of-phase oscillation called a “Dutch roll.” The decision height to initiate a “go-around” was 150 feet (45.7 meters) above the surface of the lake bed. Fitz Fulton thought he had enough time to get NASA 833 back on the center line and committed to the test landing. However, the Dutch roll resulted in the airliner’s left wing impacting the ground with the inboard engine on the left wing (Number Two) just to the right of the center line.

NASA 833 slews left as it approaches the test apparatus. The Boeing 720 has reached the intended touchdown point but is out of position, still to the right of center line and misaligned. (NASA)
NASA 833 slews left as it approaches the test apparatus. The Boeing 720 has reached the intended touchdown point but is out of position, still to the right of center line and misaligned. (NASA)

According to the test plan, all four of the airliner’s engines should have been brought to idle, but they remained at full throttle. The left wing’s impact yawed the airliner to the left and, rather than the fuselage passing through the rhino barriers undamaged, the passenger compartment was torn open. Another rhino sliced into the Number Three engine (inboard, right wing), opening its combustion chamber. With the fuel tanks in the wings ruptured, raw fuel was sprayed into the engine’s open combustion chamber which was still at full throttle.

 As the airliner slides through the "rhino" barriers, they rip open the fuel tanks, the Number Three engine and the passenger compartment. The raw fuel immediately ignited. (NASA)
As the airliner slides through the “rhino” barriers, they rip open the fuel tanks, the Number Three engine and the passenger compartment. The raw fuel immediately ignited. (NASA)

The raw fuel ignited and exploded into a fireball. Flames immediately entered the passenger compartment. As the 720 slid on the runway it continued to rotate left and the right wing broke off though the fuselage remained upright.

NASA 833's right wing breaks off, rupturing the fuel tanks. Nearly 8,000 gallons (30,000 liters) of jet fuel pours out into the fireball. (NASA)
NASA 833’s right wing breaks off, rupturing the fuel tanks. Nearly 8,000 gallons (30,000 liters) of jet fuel pours out into the fireball. (NASA)

As the right wing came off the ruptured fuel tanks emptied most of the raw fuel directly into the fireball.

The flaming wreckage of NASA 833 slides to a stop on Rogers Dry Lake. Fire fighters needed more than one hour to extinguish the fire. (NASA)
The flaming wreckage of NASA 833 slides to a stop on Rogers Dry Lake. Fire fighters needed more than one hour to extinguish the fire. (NASA)

Over an hour was required to extinguish the flames. The test of the flame-reducing fuel additive was a complete failure. Test engineers estimated that 25% of the occupants might have survived the crash, however, it was “highly speculative” that any could have escaped from the burning, smoke-filled passenger compartment.

Fithugh L. "Fitz" Fulton, Jr. (NASA)
Fitzhugh Lee “Fitz” Fulton, Jr., with NASA 905, a Shuttle Carrier Aircraft, and Enterprise (OV-101). (NASA)
Fitz Fulton, 1942 (The Cohiscan)

Fitzhugh Lee Fulton, Jr., was born at Blakely, Georgia, 6 June 1925, the first of two sons of Fitzhugh Lee Fulton, a merchant seaman, and Manila Fulton. He attended Columbus High School, Columbus Georgia, graduating in 1942. He entered College at Alabama Polytechnic Institute (now known as Auburn University) and the University of Oklahoma. He was awarded a bachelor of arts degree from Golden Gate University, San Francisco, California.

Fulton entered the U.S. Army Air Corps in 1943, and was trained as a pilot. He married Miss Erma I. Beck at Tucson, Arizona, 16 December 1945. They would have three children.

Following World War II, participated in Operation Crossroads, the atomic bomb tests at Bikini Atoll, July 1946. Lieutenant Fulton flew the Douglas C-54 Skymaster four-engine transport during the Berlin Airlift, making 225 sorties, and then the Douglas B-26 Invader light attack bomber during the Korean War.

Captain Fitz Fulton, U.S. Air Force, in teh cockpit of a Douglas B-26 Invader, circa 1952. (Air & Space Magazine)
Captain Fitz Fulton, U.S. Air Force, in the cockpit of a Douglas B-26 Invader, circa 1952. (Air & Space Magazine)

Fulton graduated from the Air Force Test Pilot School in 1952. He served as project test pilot for the Convair B-58 Hustler supersonic bomber and flew the B-58 to a World Record Altitude of 26,017.93 meters (85,360.66 feet) on 14 September 1962.¹

Major Fitz Fulton in the cockpit of a Convair B-58. (Jet Pilot Overseas)
Major Fitz Fulton in the cockpit of a Convair B-58. (Jet Pilot Overseas)

At Edwards Air Force Base, he flew the B-52 “mother ships” for the X-15 Program. He flew the North American XB-70A Valkyrie faster than Mach 3. When Fulton retired from the Air Force in 1966, he was a lieutenant colonel assigned as Chief of Bomber and Transport Test Operations.

Fitz Fulton continued as a research test pilot for NASA, flying as project pilot for the YF-12A and YF-12C research program. He flew all the early test flights of the NASA/Boeing 747 Shuttle Carrier Aircraft and carried the space shuttle prototype, Enterprise. By the time he had retired from NASA, Fulton had flown more than 16,000 hours in 235 aircraft types.

Fitzhugh L. Fulton, Jr., died at Thousand Oaks, California, 4 February 2015, at the age of 89 years..

Lieutenant Colonel Fitzhugh Lee Fulton, Jr., with a North American Aviation XB-70A Valkyrie.
Colonel Joseph Frederick Cotton and Lieutenant Colonel Fitzhugh Lee Fulton, Jr., with a North American Aviation XB-70A Valkyrie.

NASA 833 (c/n 18066) was ordered by Braniff Airways, Inc., as N7078, but the sale was not completed. The airplane first flew 5 May 1961 and it was delivered to the Federal Aviation Administration as a test aircraft one week later, 12 May 1961, registered N113. A few years later the identification was changed to N23, then back to N113, and then once again to N23. In 1982, the Boeing 720 was transferred to NASA to be used in the Controlled Impact Demonstration. At this time it was registered as N2697V. A final registration change was made to N833NA.

NASA 833 at Edwards Air Force Base, prior to the Controlled Impact Demonstration. (Paul)

The Boeing 720 was a variant of the Model 707, intended for short to medium range flights. It had 100 inches (2.54 meters) removed from the fuselage length and improvements were made to the wing, decreasing aerodynamic drag, though it retained the span of the 707.

The Boeing 720 was powered by four Pratt & Whitney Turbo Wasp JT3C-7 turbojet engines, a civil variant of the military J57 series. The 720B was equipped with the more efficient P&W JT3D-1 turbofan engines. The JT3C-7 was a “two-spool” axial-flow engine with a 16-stage compressor (9 low- and 7 high-pressure stages), 8 combustion tubes, and a 3-stage turbine (1 high- and 2 low-pressure stages). It was rated at 12,030 pounds of thrust (53.512 kilonewtons) for takeoff. The JT3D-1 was a dual axial-flow turbofan engine, with a 2-stage fan section 13-stage compressor (6 low- and 7 high pressure stages), 8 combustion chambers and a 4-stage turbine (1 high- and 3 low-pressure stages). This engine was rated at 14,500 pounds of static thrust (64.499 kilonewtons) at Sea Level, and 17,000 pounds (75.620 kilonewtons), with water injection, for takeoff (2½ minute limit). Almost half of the engine’s thrust was produced by the fans. Maximum engine speed was 6,800 r.p.m. (N1) and 10,200 r.p.m. (N2). It was 11 feet, 4.64 inches (3.471 meters) long, 4 feet, 5.00 inches (1.346 meters) wide and 4 feet, 10.00 inches (1.422 meters) high. It weighed 4,165 pounds (1,889 kilograms). The JT3C could be converted to the JT3D configuration during overhaul.

The maximum cruise speed of the Boeing 720 was 611 miles per hour (983 kilometers per hour) and maximum speed was 620 miles per hour (1,009 kilometers per hour). The range at at maximum payload was 4,370 miles (7,033 kilometers).

Boeing built 154 720 and 720B airliners from 1959 to 1967.

The Federal Aviation Administration's Boeing 720-027 N113. (FAA)
The Federal Aviation Administration’s Boeing 720-027 N113. (FAA)

¹ FAI Record File Numbers 14652 and 14656

© 2018, Bryan R. Swopes

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9 November 1961

Major Robert M. White was the first pilot to exceed Mach 4, Mach 5, and on 9 November 1961, he flew to Mach 6.04. (NASA)
Major Robert M. White was the first pilot to exceed Mach 4, Mach 5, and on 9 November 1961, he flew to Mach 6.04. (U.S. Air Force)

9 November 1961: Major Robert M. White, U.S. Air Force, became the first pilot to fly faster than Mach 6 when he flew the number two North American Aviation X-15 hypersonic research rocketplane, 56-6671, to Mach 6.04.

This was the 45th flight of the X-15 program, and Bob White’s 11th flight. The purpose of this test flight was to accelerate 56-6671 to its maximum velocity, to gather data about aerodynamic heating at hypersonic speeds, and to evaluate the rocketplane’s stability and handling.

Boeing NB-52A Stratofortress 52-003 carries a North American Aviation X-15 piloted by Major Bob White. (NASA)
Boeing NB-52A Stratofortress 52-003 carries a North American Aviation X-15 piloted by Major Bob White. (NASA)

The X-15 was carried to approximately 45,000 feet (13,716 meters) while mounted to a pylon under the right wing of the “mothership,” a Boeing NB-52B Stratofortress, 52-008, nicknamed Balls 8. White was dropped over Mud Lake, Nevada, approximately 200 miles (322 kilometers) north of Edwards Air Force Base. Once clear of the B-52, he ignited the Reaction Motors XLR99-RM-1 rocket engine, and with it producing 57,000 pounds of thrust (253.549 kilonewtons) at full throttle, the X-15 accelerated for 86.9 seconds. The rocketplane reached a peak altitude of 101,600 feet (30,968 meters). Its speed was Mach 6.04 (4,094 miles per hour/6,589 kilometers per hour).

White stated in his post-flight report, “When I leveled off at about 101,000 feet, I made a little downward pressure [on the control stick], because I didn’t want to be climbing. I remember . . . going along watching that [Mach] meter reading roughly 6,000 feet per second, [and] saying to myself, ‘Go, go, go, go!’ We did just crack it, because we knew that bringing all the proper things together, we could or should get just about Mach 6.”

In order to achieve the goal, the flight plan called for pushing the LR-99 to the point of exhaustion instead of manually shutting down the engine at an arbitrary point. White said, “The shutdown seemed to be a little bit different this time, compared with a shutdown by closing the throttle. It seemed to occur over a longer time interval.” 

The X-15 Rocket Plane: Flying the First Wings into Space, by Michelle Evans, University of Nebraska Press, Lincoln and London, 2013, Chapter 3 at Page 87.

The number two North American Aviation X-15, 56-6671, is dropped from the Boeing NB-52A Stratofortress, 52-003. The XLR99 rocket engine is just igniting. Frost from the cryogenic fuels coats the fuselage. (NASA)
The number two North American Aviation X-15, 56-6671, is dropped from the Boeing NB-52A Stratofortress, 52-003. The XLR99 rocket engine is just igniting. Frost from the cryogenic fuels coats the fuselage. (NASA)

“The airplane really did get hot on those flights. Temperatures in excess of 1,300 °F. were recorded. Parts of the airplane glowed cherry red and softened up a bit during those flights. The airplane got so damned hot that it popped and banged like an old iron stove. It spewed smoke out of its bowels and it twitched like frog legs in a skillet. But it survived.”

At the Edge of Space: The X-15 Flight Program, by Milton O. Thompson, Smithsonian Institution Press, Washington, 1992, at Page 98.

North American Aviation X-15 56-6671 accelerates after the XLR99 engine is ignited. (NASA)
North American Aviation X-15 56-6671 accelerates after the XLR99 engine is ignited. (NASA)

As the X-15 decelerated through Mach 2.4, the right side windshield shattered, leaving it completely opaque. On Bob White’s previous flight, the left windshield had also broken. Fortunately, in both cases, only the outer layer of the dual pane glass broke. The reduced visibility made the approach difficult to judge, but White made a successful landing, touching down on Rogers Dry Lake after a flight of 9 minutes, 31.2 seconds duration.

The number three North American Aviation X-15 rocketplane, 56-6672, just before touchdown on Rogers Dry Lake. A Lockheed F-104 Starfighter chase plane escorts it. The green smoke helps the pilots judge wind direction and speed. Frost on the X-15's belly shows residual propellants in the tanks. (NASA)
The number three North American Aviation X-15 rocketplane, 56-6672, just before touchdown on Rogers Dry Lake. A Lockheed F-104 Starfighter chase plane escorts it. The green smoke helps the pilots judge wind direction and speed. Frost on the X-15’s belly shows residual propellants in the tanks. (NASA)
NASA ET62-0270
The shattered windshield of X-15 56-6671, 9 November 1961. (NASA)

A P-51 Mustang fighter pilot in World War II, Robert M. White was shot down on his 52nd combat mission in February 1945 and captured. He was held as a prisoner of war until the war in Europe came to an end in April 1945. White was recalled to active duty during the Korean War. He was a graduate of the Air Force Experimental Test Pilot School and flew tests of many aircraft at Edwards before entering the X-15 program.

Major White had been the first pilot to fly faster than Mach 4, Mach 5 and Mach 6. He was the first to fly over 200,000 feet, then over 300,000 feet. He made at total of sixteen X-15 flights.

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 one of the three North American Aviation X-15s on Rogers Dry Lake, 1961. (NASA)

After leaving the X-15 program, Bob White returned to operational duties. Later, he flew 70 combat missions over North Vietnam in the Republic F-105 Thunderchief supersonic fighter bomber, including leading the attack against the Paul Doumer Bridge at Hanoi, 11 August 1967, for which he was awarded the Air Force Cross. He next went to Wright-Patterson AFB where he was director of the F-15 Eagle systems program. He returned to Edwards AFB as commander of the Air Force Flight Test Center. White was promoted to Major General in 1975.

General White retired from the U.S. Air Force in 1981. He died 10 March 2010.

A North American Aviation support crew deactivates X-15 56-6671 on Rogers Dry Lake after a flight, while the mothership, NB-52A Stratofortress 52-003 flies overhead. (NASA)
A North American Aviation support crew deactivates X-15 56-6671 on Rogers Dry Lake after a flight, while the mothership, NB-52A Stratofortress 52-003 flies overhead. (NASA)

© 2016, Bryan R. Swopes

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3 November 1965

North American Aviation X-15A-2 56-6671 on Rogers Dry Lake. In addition to the lengthened fuselage and external tanks, the nose wheel strut is longer and the windshields have been changed to an oval shape. A wheeled dolly supports the aft end of the rocketplane. (NASA)
North American Aviation X-15A-2 56-6671 on Rogers Dry Lake. In addition to the lengthened fuselage and external tanks, the nose wheel strut is longer and the windshields have been changed to an oval shape. A wheeled dolly supports the aft end of the rocketplane. (NASA)

3 November 1965: Major Robert A. Rushworth made the first flight of the modified X-15A-2 rocketplane, Air Force serial number 56-6671. After a landing accident which caused significant damage to the Number 2 X-15, it was rebuilt by North American Aviation. A 28-inch (0.71 meter) “plug” was installed in the fuselage forward of the wings to create space for a liquid hydrogen fuel tank which would be used for an experimental “scramjet” engine that would be mounted on the the ventral fin. The modified aircraft was also able to carry two external fuel tanks. It was hoped that additional propellant would allow the X-15A-2 to reach much higher speeds.

The first flight with the new configuration was an “envelope expansion” flight, intended to test the handling characteristics of the X-15A-2, and to jettison the tanks (which were empty on this flight) to evaluate the separation and trajectory as they fell away from the rocketplane in supersonic flight.

Boeing NB-52A Stratofortress 52-003, The High and Mighty One, with North American Aviation X-15A-2 56-6671 mounted to the pylon under its right wing. The external propellant tanks have been brightly painted to aid tracking after they are jettisoned. (U.S. Air Force)
Boeing NB-52A Stratofortress 52-003, The High and Mighty One, with North American Aviation X-15A-2 56-6671 mounted to the pylon under its right wing. The external propellant tanks have been brightly painted to aid tracking after they are jettisoned. (U.S. Air Force)

The X-15A-2 was dropped from the Boeing NB-52A Stratofortress 52-003, over Cuddeback Lake, 37 miles (60 kilometers) northeast of Edwards Air Force Base in the Mojave Desert of southern California. This was the only time during the 199-flight X-15 Program that this lake was used as a launch point.

The X-15 was released at 09:09:10.7 a.m., PST. Bob Rushworth ignited the Reaction Motors XLR99-RM-1 rocket engine and it ran for 84.1 seconds before its fuel supply was exhausted. This engine was rated at 57,000 pounds of thrust (253.549 kilonewtons).

The X-15 climbed to 70,600 feet (21,519 meters) and reached Mach 2.31 (1,514 miles per hour/2,437 kilometers per hour.)

The test flight went well. The external tanks jettisoned cleanly and fell away. The recovery parachute for the liquid oxygen tank did not deploy, however, and the tank was damaged beyond repair.

Rushworth and the X-15A-2 touched down on Rogers Dry Lake after a flight of 5 minutes, 1.6 seconds.

© 2016, Bryan R. Swopes

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27 October 1954

NACA's chief project test pilot for the Douglas X-3, in the cockpit of the research aircraft, circa 1954-1956. (LIFE Magazine via Jet Pilot Overseas)
NACA’s chief project test pilot for the Douglas X-3, Joe Walker, in the cockpit of the research aircraft, circa 1954-1956. (LIFE Magazine via Jet Pilot Overseas)

October 27, 1954: between August 1954 and May 1956, Joseph A. Walker, the National Advisory Committee for Aeronautics’ chief project test pilot for the Douglas X-3 supersonic research aircraft, made twenty research flights in the “Stiletto.”

On the tenth flight, 27 October, Walker took the X-3 to an altitude of 30,000 feet (9,144 meters). With the rudder centered, he put the X-3 into abrupt left aileron rolls, first at 0.92 Mach and then at Mach 1.05. Both times, the aircraft violently yawed to the right and then pitched down. Walker was able to recover before the X-3 was completely out of control.

Screen Shot 2015-10-20 at 12.08.52
The Douglas X-3 during NACA flight testing, 1954-1956. (LIFE Magazine via Jet Pilot Overseas)

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 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 airplane was grounded for the next 11 months.

Unlike its predecessors, the Bell Aircraft Corporation's X1 and and X-2 rocketplanes, teh turbojet-powered Douglas X-3 took off under its own power. here, its two Westinghouse J37 engines are stirring up teh sand on Runway 35 at Rogers Dry Lake. (LIFE Magazine via jet Pilot Overseas)
Unlike its predecessors, the Bell Aircraft Corporation’s X1 and and X-2 rocketplanes, the turbojet-powered Douglas X-3 took off under its own power. Here, its two Westinghouse J37 engines are stirring up the sand on Runway 35 at Rogers Dry Lake. (LIFE Magazine via jet Pilot Overseas)

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

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).

The X-3 was very underpowered with the J37 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. Because of its design characteristics, though, it 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.

In addition to Douglas Aircraft test pilot Bill Bridgeman, the Douglas X-3 was flown by Air Force test pilots Lieutenant Colonel Frank Everest and Major Chuck Yeager and  NACA pilot Joe Walker.

Joe Walker resumed flight testing the X-3 in 1955. Its final 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.

NACA test pilot Joe Walker with the Douglas X-3. (LIFE Magazine via Jet Pilot Overseas)
NACA test pilot Joe Walker with the Douglas X-3. (LIFE Magazine via Jet Pilot Overseas)

© 2018, 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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