Tag Archives: NACA High Speed Flight Station

6 November 1958

Bell X-1E 46-063 on Rogers Dry Lake. (NASA)
Bell X-1E 46-063 on Rogers Dry Lake, 1955. (NASA)

6 November 1958: NASA Research Test Pilot John B. (Jack) McKay made the final flight of the X-1 rocketplane program, which had begun twelve years earlier.

Bell X-1E 46-063 made its 26th and final flight after being dropped from a Boeing B-29 Superfortress over Edwards Air Force Base on a flight to test a new rocket fuel.

John B. McKay, NACA/NASA Research Test Pilot. (NASA)
John B. McKay, NACA/NASA Research Test Pilot. (NASA)

When the aircraft was inspected after the flight, a crack was found in a structural bulkhead. A decision was made to retire the X-1E and the flight test program was ended.

The X-1E had been modified from the third XS-1, 46-063. It used a thinner wing and had an improved fuel system. The most obvious visible difference is the cockpit, which was changed to provide for an ejection seat. Hundreds of sensors were built into the aircraft’s surfaces to measure air pressure and temperature.

The Bell X-1E was 31 feet (9.449 meters) long, with a wingspan of 22 feet, 10 inches (6.960 meters). The rocketplane’s empty weight was 6,850 pounds (3,107 kilograms) and fully loaded, it weighed 14,750 pounds (6,690 kilograms). The rocketplane was powered by a Reaction Motors XLR11-RM-5 rocket engine which produced 6,000 pounds of thrust (26.689 kilonewtons). The engine burned ethyl alcohol and liquid oxygen. The X-1E carried enough propellants for 4 minutes, 45 seconds burn.

The Bell X-1E rocketplane being loaded into a Boeing B-29 Superfortress mothership for another test flight. (NASA)
The Bell X-1E rocketplane being loaded into NACA 800, a Boeing B-29-96-BW Superfortress mothership, 45-21800, for another test flight. (NASA)

The early aircraft, the XS-1 (later redesignated X-1), which U.S. Air Force test pilot Charles E. (“Chuck”) Yeager flew faster than sound on 1 October 1947, were intended to explore flight in the high subsonic and low supersonic range. There were three X-1 rocketplanes. Yeager’s Glamorous Glennis was 46-062. The X-1D (which was destroyed in an accidental explosion after a single glide flight) and the X-1E were built to investigate the effects of frictional aerodynamic heating in the higher supersonic ranges from Mach 1 to Mach 2.

Bell X-1E loaded aboard Boeing B-29 Superfortress, circa 1955. (NASA)
Bell X-1E 46-063 loaded aboard NACA 800, a Boeing B-29-96-BW Superfortress, 45-21800, circa 1955. (NASA)

The X-1E reached its fastest speed with NASA test pilot Joseph Albert Walker, at Mach 2.24 (1,450 miles per hour/2,334 kilometers per hour), 8 October 1957. Walker also flew it to its peak altitude, 70,046 feet (21,350 meters) on 14 May 1958.

NACA test pilot Joseph Albert Walker made 21 of the X-1E's 26 flights. In this photograph, Joe Walker is wearing a David Clark Co. T-1 capstan-type partial-pressure suit with a K-1 helmet for protection at high altitudes. (NASA)
NACA test pilot Joseph Albert Walker made 21 of the X-1E’s 26 flights. In this photograph, Joe Walker is wearing a David Clark Co. T-1 capstan-type partial-pressure suit with a K-1 helmet for protection at high altitudes. (NASA)

There were a total of 236 flights made by the X-1, X-1A, X-1B, X-1D and X-1E. The X-1 program was sponsored by the National Advisory Committee on Aeronautics, NACA, which became the National Aeronautics and Space Administration, NASA, on 29 June 1958.

The X-1E is on display in front of the NASA administration building at the Dryden Flight Research Center, Edwards Air Force Base, California.Bell X-1E 46-063 on display at Dryden Flight Research Center© 2016, 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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12 October 1954

North American Aviation’s Chief Engineering Test Pilot, George S. Welch, with the first prototype YF-100A Super Sabre, 52-5754. (U.S. Air Force)

12 October 1954: North American Aviation Chief Engineering Test Pilot George S. Welch, testing the ninth production F-100A-1-NA Super Sabre, serial number 52-5764, made a planned 7.3 G pullout from a Mach 1.55 dive to verify the aircraft’s design limits.

A Boeing B-47 Stratojet crew flying at 25,000 feet (7,620 meters) reported that Welch’s F-100 winged over and began a rapid descent, passing within four miles (6.4 kilometers) of their position and diving at a very high speed. The aircraft appeared to be under control but then suddenly disintegrated.

The Super Sabre had encountered Inertial Roll Coupling. It went out of control and then disintegrated. Its nose folded over the windshield, crushing Welch in his seat. The vertical fin broke away. The ejection seat fired but because of the supersonic speeds the parachute was shredded.

Welch was still alive when rescue teams arrived. He died while being flown to a hospital by helicopter.

George S. Welch, North American Aviation test pilot, wearing his orange flight helmet. An F-86 Sabre is in the background. (San Diego Air and Space Museum Photo Archives)

Inertial roll coupling led to the death of test pilot Mel Apt when his rocket-powered airplane, the Bell X-2, went out of control at Mach 3.2 It nearly killed Chuck Yeager when he lost control of the Bell X-1B at Mach 2.4. It is a complex phenomenon which I will briefly attempt to explain:

To increase maximum speed of transonic and supersonic airplanes during the late 1940s and early 1950s, their wings and tail surfaces were made smaller in order to decrease aerodynamic drag. At the same time, the fuselage became longer and the placement of engines, armament, landing gear, fuel, etc., within the fuselage concentrated the airplane’s mass near its center. While the gyroscopic effects of the turbojet engine contributed some degree of longitudinal stability, the torque effect made rolls to the left occur more easily, but with a higher rate than a roll to the right. The resistance to a change in attitude—inertia—decreased at the same time that the control surfaces’ ability to control the airplanes’ attitude also decreased. The airplanes became unstable.

This North American Aviation F-100-1-NA Super Sabre, 52-5761, is from the same production black as the aircraft flown by George Welch, 12 October 1954. (U.S. Air Force)
This North American Aviation F-100-1-NA Super Sabre, 52-5761, is from the same production block as the aircraft flown by George Welch, 12 October 1954. This photograph shows FW-761 with the original short vertical fin of the F-100A. (North American Aviation, Inc.)
North American Aviation F-100A-1-NA Super Sabre  52-5763, sister ship of the airplane flown by George Welch, 12 October 1954. (North American Aviation, Inc.)

When George Welch tried to pull the F-100 out of its supersonic dive, the airplane’s speed began to decrease as the angle of attack increased. The wings’ ability to stabilize the natural roll instability of the fuselage’s concentrated mass was lessened, and the ailerons could not provide sufficient control to counteract this rolling tendency. The low vertical fin of the original F-100A did not provide adequate directional stability. The Super Sabre rolled and then yawed, entering a side slip. This caused the Super Sabre to pitch down and it was suddenly out of control in all three axes. The physical forces exceeded the strength of the aircraft structure and it came apart.¹

[Aerodynamicists and Aeronautical Engineers: Your corrective comments are welcome.]

Wreckage of North American Aviation F-100A Super Sabre, 12 October 1954. (U.S. Air Force)
Wreckage of North American Aviation F-100A-1-NA Super Sabre 52-5764, 12 October 1954. (North American Aviation, Inc.)

Following the death of George Welch, NACA High Speed Flight Station research test pilot Albert Scott Crossfield spent three months conducting flight tests of the F-100A, demonstrating its inertial roll coupling characteristics using three different vertical fins. F-100A-5-NA 52-5778 was Crossfield’s test aircraft.

Scott Crossfield flew the F-100A-5-NA, 52-5778, in flight testing at the NACA High Speed Flight Station, October–December 1954. (NASA)
Test Pilot A. Scott Crossfield flew this F-100A-5-NA, 52-5778, in flight testing at the NACA High Speed Flight Station, October–December 1954. (NASA)

The North American Aviation F-100 Super Sabre was designed as a supersonic day fighter. Initially intended as an improved F-86D and F-86E, it soon developed into an almost completely new airplane. The fuselage incorporated the “area rule,” a narrowing in the fuselage width at the wings to increase transonic performance, similar to the Convair F-102A. The Super Sabre had a 49° 2′ sweep to the leading edges of the wings and horizontal stabilizer. The ailerons were placed inboard on the wings and there were no flaps, resulting in a high stall speed in 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 F-100A had a distinctively shorter vertical fin than the YF-100A. The upper segment of the vertical fin was swept 49° 43′.

There were two service test prototypes, designated YF-100A, followed by the production F-100A series. The first ten production aircraft (all of the Block 1 variants) were used in the flight testing program.

The F-100A Super Sabre was 47 feet, 1¼ inches (14.357 meters) long with a wingspan of 36 feet, 6 inches (11.125 meters). With the shorter vertical fin, the initial F-100As had an overall height of 13 feet, 4 inches (4.064 meters), 11 inches (27.9 centimeters) less than the YF-100A.

Following Welch's accident, NACA designed a new vertical fin for the F-100A. Ii was taller but also had a longer chord. This resulted in a 10% increase in area. (NASA E-1573)
Following Welch’s accident, the NACA High Speed Flight Station tested the Super Sabre and designed a new vertical fin for the F-100A. The two F-100As in this photograph are both from the second production block (F-100A-5-NA). 52-5778, on the left, has the new fin, while 52-5773 retains the original short fin. The new fin is taller but also has a longer chord. This resulted in a 10% increase in area. (NASA)

The F-100A had an empty weight of 18,135 pounds (8,226 kilograms), and gross weight of 28,899 pounds (13,108 kilograms). Maximum takeoff weight was 35,600 pounds (16,148 kilograms). It had an internal fuel capacity of 755 gallons (2,858 liters) and could carry two 275 gallon (1,041 liter) external fuel tanks.

The early F-100As were powered by a Pratt & Whitney Turbo Wasp J57-P-7 afterburning turbojet engine. It was rated at  9,700 pounds of thrust (43.148 kilonewtons) for takeoff, and 14,800 pounds (65.834 kilonewtons) with afterburner. Later production aircraft used a J57-P-39 engine. The J57 was a two-spool axial flow turbojet which had a 16-stage compressor, and a 3-stage turbine. (Both had high- and low-pressure stages.) The engine was 15 feet, 3.5 inches (4.661 meters) long, 3 feet, 5.0 inches (1.041 meters) in diameter, and weighed 4,390 pounds (1,991 kilograms).

The Super Sabre was the first U.S. Air Force fighter capable of supersonic speed in level flight. It could reach 760 miles per hour (1,223 kilometers) at Sea Level. (Mach 1 is 761.1 miles per hour, 1,224.9 kilometers per hour, under standard atmospheric conditions.) Its maximum speed was 852 miles per hour (1,371 kilometers per hour) at 35,000 feet (10,668 meters). The service ceiling was 44,900 feet (13,686 meters). Maximum range with external fuel was 1,489 miles (2,396 kilometers).

The F-100 was armed with four M-39 20 mm autocannons, capable of firing at a rate of 1,500 rounds per minute. The ammunition capacity of the F-100 was 200 rounds per gun.

North American Aviation built 199 F-100A Super Sabres at its Inglewood, California, plant before production shifted to the F-100C fighter bomber variant. Approximately 25% of all F-100As were lost in accidents.

his is the fifth production F-100A-1-NA Super Sabre, 52-5760, in flight southeast of San Bernardino, California. This fighter is from the same production block as 52-5764, the fighter being tested by George Welch, 12 October 1954. In this photograph, FW-760 has the taller vertical fin that was designed to improve the Super Sabre's controlability. (U.S. Air Force)
This is the fifth production F-100A-1-NA Super Sabre, 52-5760, in flight southeast of San Bernardino, California, 24 June 1955. This fighter is from the same production block as 52-5764, the fighter being tested by George Welch, 12 October 1954. In this photograph, FW-760 has the taller vertical fin that was designed by NACA to improve the Super Sabre’s stability. (North American Aviation, Inc.)

George Welch was born George Lewis Schwartz, Jr., in Wilmington, Delaware, 10 May 1918. He was the first of two sons of George Lewis Schwartz, a chemist at the Dupont Experimental Station in Wilmington, and Julia Welch Schwartz. 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 University, Indiana, and enlisted in the Army Air Corps in 1939. Welch graduated from pilot training at Kelly Field, Texas, and on 4 October 1940, was commissioned as a second lieutenant, U.S. Army Air Corps.

Second Lieutenant Kenneth M. Taylor and Second Lieutenant George S. Welch, 47th Pursuit Squadron, 15th Pursuit Group, the two Curtiss P-40B Warhawk pilots who shot down 8 Japanese aircraft during the attack on Pearl Harbor, Hawaii, 7 December 1941. Both officers were awarded the Distinguished Service Cross. (U.S. Air Force)

George S. Welch is best remembered as one of the heroes of Pearl Harbor. He, along with Second Lieutenant Kenneth M. Taylor, were the only two fighter pilots to get airborne from Haleiwa Auxiliary Airfield 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. Taylor also shot down four Japanese airplanes. For this action, Lieutenant General Henry H. “Hap” Arnold recommended the Medal of Honor, but because Lieutenants Welch and Taylor had taken off without orders, an officer in their chain of command refused to endorse the nomination. Both fighter pilots were awarded 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. In addition to the Distinguished Service Cross, George Welch was awarded the Silver Star, the Distinguished Flying Cross with two oak leaf clusters (three awards), the Air Medal with one oak leaf cluster (two awards), the Presidential Unit Citation with two oak leaf clusters (three awards), American Defense Service medal with one service star, American Campaign Medal, Asiatic-Pacific Campaign Medal with one silver and one bronze star (six campaigns), and the World War II Victory Medal.

George Welch, circa 1943. (Unattributed)
George Welch, circa 1943. (Unattributed)

Welch received the nickname, “Wheaties,” because he was the first military officer to be featured on a box of Wheaties cereal. (Wheaties, “The Breakfast of Champions,” was a toasted wheat bran cereal produced by General Mills. It normally featured champion athletes on its distinctive orange-colored boxes.)

Suffering from malaria, George Welch was out of combat and recuperating in Australia. There he met Miss Janette Alice Williams and they were soon married. Welch returned to the United States with his new wife. They had a son, Giles, born in October 1947. Their home was in Brentwood, California.

North American Aviation approached General Arnold to recommend a fighter pilot who could bring his combat experience to testing new fighters. Welch was one of two that General Arnold suggested. The general authorized Welch’s release from active duty so that he could join North American. Welch held the rank of major, Air Reserve, from 13 November 1944 to 1 April 1953.

George S. Welch, now a civilian test pilot forNorth American Aviation, Inc., sits on the canopy rail of a P-51H Mustang, circa 1945. (North American Aviation Inc.)
George S. Welch, now a civilian test pilot for North American Aviation, Inc., sits on the canopy rail of a P-51H Mustang, circa 1945. (North American Aviation Inc.)

Welch went on to test fly the North American P-51H Mustang, FJ-1 Fury, F-86 Sabre and F-100 Super Sabre.

George Welch made the first flight of the XP-86 prototype, 1 October 1947. There is some evidence that on that flight, and during a subsequent flight on 14 October, Welch exceeded the speed of sound while in a dive. It has been said that during the Korean War, while teaching U.S. Air Force pilots how to best use the F-86 Sabre, he shot down several enemy MiG-15 jet fighters.

George S. Welch is buried at the Arlington National Cemetery, Section 6, Site 8578-D.

¹ Recommended: Coupling Dynamics in Aircraft: A Historical Perspective, by Richard E. Day, Dryden Flight Research Center, Edwards AFB, California. NASA Special Publications 532, 1997.

© 2016, Bryan R. Swopes

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27 September 1956

Captain Milburn G. Apt, U.S. Air Force, with a Bell X-2. (U.S. Air Force)
Captain Milburn G. Apt, U.S. Air Force, with a Bell X-2. (U.S. Air Force)

27 September 1956: Captain Milburn G. (“Mel”) Apt, United States Air Force, was an experimental test pilot assigned to the Air Force Flight Test Center at Edwards Air Force Base, California. After Frank Everest and Iven Kincheloe had made twelve powered flights in the Bell X-2 supersonic research aircraft, Mel Apt was the next test pilot to fly it.

The X-2 was a joint project of the U.S. Air Force and NACA (the National Advisory Committee on Aeronautics, the predecessor of NASA). The rocketplane was designed and built by Bell Aircraft Corporation of Buffalo, New York, to explore supersonic flight at speeds beyond the capabilities of the earlier Bell X-1 and Douglas D-558-II Skyrocket.

In addition to the aerodynamic effects of speeds in the Mach 2.0–Mach 3.0 range, engineers knew that the high temperatures created by aerodynamic friction would be a problem, so the aircraft was built from stainless steel and K-Monel, a copper-nickel alloy.

The Bell Aircraft Corporation X-2 was 37 feet, 10 inches (11.532 meters) long with a wingspan of 32 feet, 3 inches (9.830 meters) and height of 11 feet, 10 inches (3.607 meters). Its empty weight was 12,375 pounds (5,613 kilograms) and loaded weight was 24,910 pounds (11,299 kilograms).

Bell X-2 46-675 on its transportation dolly at Edwards Air Force Base, California, 1952. (NASA)
The second of two Bell X-2 supersonic research rocketplanes, 46-675, on its transportation dolly at Edwards Air Force Base, California, 1952. On 12 May 1953 this X-2 exploded during a captive test flight, killing Bell’s test pilot Jean L. “Skip” Ziegler. (NASA)

The X-2 was powered by a throttleable two-chamber Curtiss-Wright XLR25-CW-1 rocket engine that produced 2,500–15,000 pounds of thrust (11.12–66.72 kilonewtons)

Rather than use its limited fuel capacity to take off and climb to altitude, the X-2 was dropped from a modified heavy bomber as had been the earlier rocketplanes. A four-engine Boeing B-50D-95-BO Superfortress bomber, serial number 48-096, was modified as the drop ship and redesignated EB-50D.

The launch altitude was 30,000 feet (9,144 meters). After the fuel was exhausted, the X-2 glided to a touchdown on Rogers Dry Lake at Edwards Air Force Base.

Bell X-2 46-674 after drop from Boeing EB-50D Superfortress 48-096. (U.S. Air Force)
Bell X-2 46-674 after drop from Boeing EB-50D Superfortress 48-096. (U.S. Air Force)

With Mel Apt in the cockpit on his first rocketplane flight, the B-50 carried the X-2 to 31,800 feet (9,693 meters). After it was dropped from the bomber, Apt ignited the rocket engine and began to accelerate. He passed Mach 1 at 44,000 feet (13,411 meters) and continued to climb. Apt flew an “extraordinarily precise profile” to reach 72,200 feet (22,007 meters) where he put the X-2 into a dive. The rocket engine burned 12.5 seconds longer than planned, and at 65,589 feet (19,992 meters) the X-2 reached Mach 3.196 (2,094 miles per hour, 3,377 kilometers per hour).

Milburn Apt was the first pilot to exceed Mach 3. He was The Fastest Man Alive.

Bell X-2 46-674 in flight over Southern California, 1955–56. Note the supersonic diamond-shaped shock waves in the rocket engine's exhaust. (Bell aircraft Corporation)
Bell X-2 46-674 in flight over Southern California, 1955–56. Note the supersonic diamond-shaped shock waves in the rocket engine’s exhaust. (Bell Aircraft Corporation)

It was known that the X-2 could be unstable in high speed maneuvers. The flight plan called for Apt to slow to Mach 2.4 before beginning a gradual turn back toward Rogers Dry Lake where he was to land, but he began the turn while still at Mach 3. Twenty seconds after engine burn out, the X-2 began to oscillate in all axes and departed controlled flight. His last radio transmission was, “There she goes.” ¹

Mel Apt was subjected to acceleration forces of ± 6 Gs. It is believed that he was momentarily unconscious. Out of control, the X-2 fell through 40,000 feet (12,192 meters) in an inverted spin. Apt initiated the escape capsule separation, in which the entire nose of the X-2 was released from the airframe. It pitched down violently and Mel Apt was knocked unconscious again. He regained consciousness a second time and tried to parachute from the escape capsule, but was still inside when it hit the desert floor at several hundred miles per hour. Mel Apt was killed instantly.

Since 1950, Milburn G. Apt was the thirteenth test pilot killed at Edwards Air Force Base.

Wreckage of the Bell X-2, 46-674. (U.S. Air Force)
Wreckage of the Bell X-2, 46-674. (U.S. Air Force)

Milburn Grant Apt was born at Buffalo, Kansas, 8 April 1924. He was the third child of Oley Glen Apt, a farmer, and Ada Willoughby Apt.

“Mel” Apt enlisted as a private in the Air Corps Enlisted Reserve, United States Army, 9 November 1942. On 23 June 1943, Private Apt was appointed an Aviation Cadet. After completing flight training, Cadet Apt was commissioned a Second Lieutenant, Army of the United States (A.U.S.). He was promoted to First Lieutenant, A.U.S., 4 September 1945. Apt was released from active duty on 11 August 1946. On 10 October 1947, he was reclassified as a Second Lieutenant, Air Corps, United States Army, with date of rank 8 April 1945.

In February 1950, Lieutenant Apt, then stationed at Williams Air Force Base, Arizona, married Miss Faye Lorrie Baker of Phoenix. They would have two children.

Mel Apt earned a Bachelor of Science degree from the University of Kansas, Lawrence, Kansas, in 1951, and a second bachelor’s degree in aeronautical engineering from the Air Force Institute of Technology, Wright-Patterson Air Force Base, Ohio. He then attended the U.S. Air Force Experimental Test Pilot School at Edwards Air Force Base, California, graduating in September 1954. Apt was assigned to the Fighter Operations Branch, Air Force Flight Test Center, as a test pilot.

On 22 December 1954, Captain Apt was flying a chase plane during a test at Edwards. The test aircraft crash-landed on the dry lake and caught fire with its pilot trapped inside. Mel Apt, with his bare hands, rescued the other test pilot, saving his life. For this courageous act, he was awarded the Soldier’s Medal.

Captain Apt was posthumously awarded the Distinguished Flying Cross for his flight in the X-2. The medal was presented to his widow in a ceremony at Edwards in March 1957.

Captain Milburn Grant Apt, United States Air Force, was 32 years old at the time of his death. His remains were buried at the Buffalo Cemetery, Buffalo, Kansas.

Captain Iven Carl Kincheloe and Captain Milburn Grant Apt (seated in cockpit) with the Bell X-2 at Edwards Air Force Base, 1956. (U,S, Air Force)

¹ Recommended: Coupling Dynamics in Aircraft: A Historical Perspective, by Richard E. Day, Dryden Flight Research Center, Edwards AFB, California NASA Special Publications 532, 1997.

© 2017, Bryan R. Swopes

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8 September 1954

Albert Scott Crossfield, NACA Test Pilot. (LIFE Magazine via Jet Pilot Overseas)
Albert Scott Crossfield, NACA Test Pilot. (Allan Grant/LIFE Magazine via Jet Pilot Overseas)

8 September 1954: Scott Crossfield, a NACA Aeronautical Research Pilot at the High Speed Flight Station, Edwards Air Force Base, California, took the North American Aviation F-100A-5-NA Super Sabre, 52-5778, on its first NACA test flight—and his first flight in an F-100.

Tests of the prototype and early production Super Sabres revealed directional stability problems, a very dangerous inertia coupling characteristic that could cause the aircraft to go violently out of control (and which would result in the death of North American’s chief test pilot, George Welch, in just another three weeks). The highly swept wings could stall at high angles of attack, causing the airplane to pitch up in the deadly “Sabre dance”. NACA wanted to explore the causes of these aerodynamic problems and design solutions.

Scott Crossfield pre-flights a North American Aviation F-100A Super Sabre. Note the extended leading-edge "slats". (LIFE Magazine via Jet Pilot Overseas.)
Scott Crossfield pre-flights a North American Aviation F-100A Super Sabre. Note the extended leading-edge “slats”. (Allan Grant/LIFE Magazine via Jet Pilot Overseas.)

During the flight there was an engine fire warning and Crossfield shut down the Pratt & Whitney J57-P-7 turbojet engine. The F-100A had no flaps and North American’s own test pilots did not think a “dead stick” landing was possible due the very high landing speed required.

Scott Crossfield signs the maintenance forms for an F-100, certifying the airplane ready for flight. (LIFE Magazine via Jet Pilot Overseas)
Scott Crossfield signs the maintenance forms for an F-100, certifying the airplane ready for flight. (Allan Grant/LIFE Magazine via Jet Pilot Overseas)

Scott Crossfield tells the story in his autobiography:

. . . As a matter of fact, North American tests pilots were then flipping coins to see who would bring an F-100 in dead-stick to fulfill a requirement of the Air Force acceptance tests. I was not concerned. Dead-stick landings in low L-over-D [Lift-over-Drag] airplanes were my specialty. Every test pilot develops a strong point. I was certain that my talent lay in dead-stick landings.

With the engine idling and generating no energy to the plane’s systems, I was running out of hydraulic pressure to operate the controls. Following the handbook instructions, I pulled a lever which extended a miniature “windmill” into the slipstream. This “windmill” churned, building up pressure in the hydraulic lines. Unknown to me, there was a major leak in the line. The windmill was not helping, but hurting me. It was pumping hydraulic fluid overboard as fast as it could turn.

Scott Crossfield climbs into the cockpit of a North American Aviation F-100A-5-NA Super Sabre. (LIFE Magazine via Jet Pilot Overseas)
Scott Crossfield climbs into the cockpit of a North American Aviation F-100A-5-NA Super Sabre. (Allan Grant/LIFE Magazine via Jet Pilot Overseas)

I called Edwards tower and declared an emergency. All airborne planes in the vicinity of the base were warned away from the lake area. I held the ailing F-100 on course, dropping swiftly, following the glide path that I used for the dead-stick Skyrocket. [Douglas D-558-II Skyrocket] I flared out and touched down smoothly. It was one of the best landings I have ever made, in fact. Seconds later, while the F-100 was rolling out, the remaining bit of hydraulic pressure in the control lines drained out and the controls froze.

I then proceeded to violate a cardinal rule of aviation: never try tricks with a compromised airplane. The F-100 was still rolling at a fast clip, coming up fast on the NACA ramp, when I made my poor decision. I had already achieved the exceptional, now I would end it with a flourish, a spectacular wind-up. I would snake the stricken F-100 right up the ramp and bring it to a stop immediately in front of the NACA hangar. This trick, which I had performed so often in the Skyrocket, was a fine touch. After the first successful dead-stick landing in an F-100, it would be fitting.

Instrument panel of a North American Aviation F-100 Super Sabre. (U.S. Air Force)
Instrument panel of a North American Aviation F-100 Super Sabre. The fire warning light and hydraulic pressure gauge are at the upper right corner. (U.S. Air Force)

According to the F-100 handbook, the hydraulic brake system—a separate hydraulic system from the controls—was good for three “cycles,” engine out. This means three pumps on the brake, and that proved exactly right. The F-100 was moving at about fifteen miles an hour when I turned up the ramp. I hit the brakes once, twice, three times. The plane slowed, but not quite enough. I was still inching ahead ponderously, like a diesel locomotive. I hit the brakes a fourth time—and my foot went clear to the floorboards. The hydraulic fluid was exhausted. The F-100 rolled on, straight between the yawning hangar doors!

The good Lord was watching over me—partially anyhow. The NACA hangar was then crowded with expensive research tools—the Skyrocket, all the X-1 series, the X-3, X-4 and X-5. Yet somehow, my plane, refusing to halt, squeezed by them all and bored steadily on toward the side wall of the hangar.


The nose of the F-100 crunched through the corrugated aluminum, punching out an eight-inch steel I-beam. I was lucky. Had the nose bopped three feet to the left or right, the results could have been catastrophic. Hitting to the right, I would have set off the hangar fire-deluge system, flooding the hangar with 50,000 barrels of water and ruining all the expensive airplanes. Hitting to the left, I would have dislodged a 25-ton hangar-door counterweight, bringing it down on the F-100 cockpit, and doubtless ruining Crossfield.

Chuck Yeager never let me forget the incident. He drew many laughs at congregations of pilots by opening his talk: “Well, the sonic wall was mine. The hangar wall was Crossfield’s.” That’s the way it was at Edwards. Hero one minute, bum the next. That I was the first pilot to land an F-100 dead-stick successfully, and memorized elaborate and complete instrument data on the engine failure besides, was soon forgotten.

The F-100 is a tough bird. Within a month NACA’s plane was flying again, with Crossfield back at the helm. In the next few weeks I flew forty-five grueling flights in the airplane, pushing it to the limits, precisely defining the roll coupling. (On one flight the coupling was so severe that it cracked a vertebra in my neck.) These data confirmed, in actual flight, the need for a new F-100 tail, which North American was planning to install on later models of the airplane.

Every night after landing, I taxied the F-100 slowly to the NACA ramp. At the bottom, placed there on orders of Walt Williams, there was a large new sign, symbolic of the new atmosphere at Edwards. It said:

PLEASE COME TO A COMPLETE STOP BEFORE TAXIING UP RAMP 

Always Another Dawn, The Story Of A Rocket Test Pilot, by A. Scott Crossfield with Clay Blair, Jr., The World Publishing Company, Cleveland and New York, 1960. Chapter 20 at Pages 196–199.

North American F-100A-5-NA Super Sabre parked on Rogers Dry Lake, 1959. It had been repaired and returned to service after running through the NACA hangar wall at Edwards AFB, 8 September 1954. In 1960, FW-778 was retired to Davis-Monthan AFB, Tucson, AZ. (NASA)
North American Aviation F-100A-5-NA Super Sabre 52-5778 parked on Rogers Dry Lake, 1959. It had been repaired and returned to service after running through the NACA hangar wall at Edwards AFB, 8 September 1954. In 1960, FW-778 was retired to Davis-Monthan AFB, Tucson, AZ. (NASA)
North American Aviation F-100A-5-NA Super Sabre 52-5778. (NASA)
North American Aviation F-100A-5-NA Super Sabre 52-5778. (NASA)
North American Aviation F-100A-5-NA Super Sabre 52-5778. (NASA)
North American Aviation F-100A-5-NA Super Sabre 52-5778. (NASA)
North American Aviation F-100A-5-NA Super Sabre 52-5778 parked on the ramp in front of the NACA hangar, Edwards Air Force Base, California, 1959. (NASA)
North American Aviation F-100A-5-NA Super Sabre 52-5778 parked on the ramp in front of the NACA hangar, Edwards Air Force Base, California, 1959. (NASA)
NACA High Speed Flight Station, 24 August 1954. The Boeing P2B-1S Superfortress is parked at the northeast corner of the ramp. (NASA DFRC
E54-1361)

© 2017, Bryan R. Swopes

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