Tag Archives: Muroc Air Force Base

5 June 1948

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Northrop YB-49 42-102368. (U.S. Air Force)

5 June 1948: Flying at 40,000 feet (12,192 meters), north of Muroc Air Force Base, California, the second Northrop YB-49 “flying wing,” serial number 42-102368, was undergoing stall recovery performance testing with a crew of five aboard. The pilot was Major Daniel A. Forbes, Jr., United States Air Force, and the co-pilot was Captain Glen W. Edwards.

The aircraft suffered a catastrophic structural failure with the outer wing panels tearing off. The experimental airplane crashed approximately 10 miles (16 kilometers) east of the small desert town of Mojave. The entire crew, which included 1st Lieutenant Edward L. Swindell, flight engineer, and civilian engineers Charles H. LaFountain and Clare C. Lesser, were killed.

Northrop YRB-49A 42-102369, the sole six-engine reconnaissance prototype. Note the engine mounted in a pod below the wing’s leading edge. (U.S. Air Force)

The YB-49 was an experimental jet engine-powered bomber, modified from a propeller-driven Northrop XB-35. It was hoped that the all-wing design would result in a highly efficient airplane because of its very low drag characteristics. However, the design could be unstable under various flight conditions.

A few months after the crash, the first YB-49 was destroyed in a taxiing accident and the project cancelled. It would be 41 years before the concept would be successful with the Northrop B-2 Spirit.

Northrop YB-49 42-102367. (U.S. Air Force)

42-102367 had been converted from the second YB-35 pre-production test aircraft. The original Flying Wing’s four Pratt & Whitney Wasp Major (R-4360-21) radial engines were replaced by eight Allison J35-A-15 turbojet engines and several aerodynamic improvements were made. The change to jet power  increased the airplane’s speed by about 100 miles per hour (161 kilometers per hour) and significantly reduced the vibrations caused by the reciprocating engines, drive shafts and counter-rotating propellers.

The YB-49 was a very unusual configuration for an aircraft of that time. There was no fuselage or tail control surfaces. The crew compartment, engines, fuel, landing gear and armament was contained within the wing. Air intakes for the turbojet engines were placed in the leading edge of the wing. The exhaust nozzles were at the trailing edge. Four small vertical fins for improved yaw stability were also at the trailing edge.

The fins were likely too small. Test pilots complained about the airplane’s instability, which made it difficult to maintain course or altitude. A stability augmentation system was required.

Northrop YB-49 (U. S. Air Force)

The YB-49 had a length of 53 feet, 1 inch (16.180 meters), wingspan of 172 feet, 0 inches (52.426 meters) and overall height of 15 feet, 2 inches (4.623 meters). It weighed 88,442 pounds (40,117 kilograms) empty, and its maximum takeoff weight was 193,938 pounds (87,969 kilograms).

The Wing defined the airplane. It had an aspect ratio of 7.4:1. The wing’s root chord was 37 feet, 6 inches (11.430 meters). The wing was 7 feet, 1.5 inches (2.172 meters) thick at the root. The tip chord was 9 feet, 4 inches (2.844 meters). There was 0° angle of incidence at the root, -4° at the wing tips, and 0° 53′ dihedral. The leading edge was swept aft 26° 57′ 48″, and the trailing edge, 10° 15′ 22″. The wing’s total area was 4,000 square feet (371.6 square meters).

Northrop YB-49

The YB-49 was powered by eight General Electric-designed, Allison Engine Company-built J35-A-15 engines. The J35 was a single-spool, axial-flow turbojet engine with an 11-stage compressor section and single-stage turbine. The J35-A-15 was rated at 3,270 pounds of thrust (14.55 kilonewtons) at 7,400 r.p.m., Normal Power, and a Maximum (Military Power) rating of 3,750 pounds of thrust (16.68 kilonewtons) at 7,700 r.p.m. The engine was 14 feet, 0.0 inches (4.267 meters) long, 3 feet, 4.0 inches (1.016 meters) in diameter and weighed 2,400 pounds (1,089 kilograms).

Cruise speed for the YB-49 was 429 miles per hour (690 kilometers per hour). Its maximum speed 499 miles per hour (802 kilometers per hour) at 18,000 feet (5,486 meters) was restricted by Mach number. The airplane could climb from Sea Level to 30,000 feet (9,144 meters) in 21.0 minutes. It had a service ceiling of 49,700 feet (15,149 meters). The YB-49 had a combat radius of 1,611 miles (2,593 kilometers) at 420 miles per hour (676 kilometers per hour), carrying a 10,000 pound (4,536 kilogram) bomb load.

The YB-49 had no defensive armament. It could carry a maximum bomb load of 16,000 pounds (7,257 kilogram) in its internal bomb bay. (Turbulence resulting from open bomb bays significantly decreased bombing accuracy.)

Only two Northrop YB-49s were built. They were tested by Northrop and the Air Force for nearly two years. A third XB-35, 42-102369, was converted to a reconnaissance variant with an additional two engines mounted in pods below the leading edge of the wing, and designated YEB-49A.Although an additional nine YB-35s were ordered converted, the B-49 was not placed into production.

Northrop YB-49.
Daniel H, Forbes, Jr., 1940

Daniel Hugh Forbes, Jr., was born at Carbondale, Kansas, 20 June 1920. He was the son of Daniel Hugh Forbes, a farmer, and Hattie Rundle Forbes. He attended North High School in Wichita Kansas, and then the Kansas State College at Manhattan, Kansas,

Maj. Daniel Forbes, Jr., USAF

Daniel Forbes enlisted in the United States Army as an aviation cadet at Fort Riley, Kansas, 23 May 1941. On 9 January 1942, he was commissioned a second lieutenant, Air Reserve. Forbes was promoted to the rank of 1st lieutenant, Army of the United States, 25 August 1942, and to captain, A.U.S., 15 August 1944. On 4 October 1945, he was promoted to major, A.U.S.

Major Forbes married Mrs. Edward C. Winkle (née Hazel Marie Moog), 11 March 1948. Her first husband, a 1st lieutenant assigned to the 314th Infantry Regiment, 79th Infantry Division, was killed in action in France, 1 October 1944. Less than three years later, Mrs. Hughes was a widow again.

Major Daniel Hugh Forbes, Jr., Air Corps, United States Army.

Glen Walter Edwards was born at Medicine Hat, Alberta, Canada, 5 March 1916, the second son of Claude Gustin Edwards, a real estate salesman, and Mary Elizabeth Briggeman Edwards. The family immigrated to the United States in August 1923 and settled near Lincoln, California. He attended Lincoln High School, where he was a member of the Spanish Club and worked on the school newspaper, “El Eco.” He graduated in 1936.

Lt. Glen W. Edwards

Edwards attended Placer Junior College, Auburn, California, before transferring to the University of California, Berkeley. He graduated in 1941 with a Bachelor of Arts (A.B.) degree, and then enlisted in the United States Army as an aviation cadet, 16 July 1941.

Following pilot training, Edwards was commissioned as a second lieutenant, Air Reserve, 6 February 1942. He was promoted to 1st lieutenant, Army of the United States, 16 September 1942. Lieutenant Edwards flew 50 combat missions in the Douglas A-20 Havoc light bomber with the 86th Bombardment Squadron (Light), 47th Bomb Group, in North Africa and fought at the Battle of the Kasserine Pass, 19–24 February 1943. He was next promoted to captain, 28 April 1943. He also flew during the invasion of Sicily, in late 1943.

Two U.S. Army Air Force Douglas A-20B-DL Havoc light bombers, 41-3014 and 41-3134, in Tunisia, 1943. (U.S. Air Force)

Edwards returned to the United States and was assigned to the Pilot Standardization Board, but was then sent to train as a test pilot at Wright Field. Captain Edwards was assigned as a test pilot in 1944 and tested the Northrop XB-35 and Convair XB-36. After World War II came to an end the U.S. Army and Air Corps were demobilized to 1/16 of their peak levels (from 8,200,000 to 554,000). Edwards was retained but reverted to the rank of 1st lieutenant. He had been awarded the Distinguished Flying Cross and the Air Medal with three oak leaf clusters (four awards). He was transferred to the United States Air Force after it was established as a separate service, 18 September 1947.

Glen Edwards was recommended to fly the Bell X-1 rocket plane, but when that assignment went to Chuck Yeager, Edwards was sent to Princeton University, Princeton, New Jersey, to study aeronautical engineering. He earned a masters degree in engineering (M.S.E.) in 1947.

Captain Glen Walter Edwards, Air Corps, United States Army.

Following the crash of the YB-49, Topeka Air Force Base in Kansas was renamed Forbes Air Force Base. Muroc Air Force Base was renamed Edwards Air Force Base in honor of Captain Edwards.

Captains Edwards’ remains were buried at the Lincoln Cemetery, Lincoln, California.

Edwards Air Force Base, California, looking northeast, photographed in 2007. (U.S. Air Force)

Edward Lee Swindell was born at Currituck, North Carolina, 22 April 1916. He was the son of Rudolph Bridgman Swindell, a machinist’s helper at the Portsmouth Navy Yard, and Eula Belle Williams Swindell.

Edward L. Swindell married Miss Edna Irene Hayman, 2 January 1942 at South Mills, North Carolina.

Swindell enlisted in the U.S. Army at Camp Lee, Virginia, 17 March 1942. He was 5 feet, 9 inches (1.75 meters) tall and weighed 156 pounds (70.7 kilograms).

Lieutenant Swindell’s remains were buried at the Forest Lawn Cemetery, Norfolk, Virginia.

Charles H. LaFountain was born 12 June 1925 in New York. He was the son of Leo L. LaFountain and Gladys Ethel Taylor LaFountain. He had served in the United States Navy and was a civilian employee of the Air Force. His remains were buried at the Lake Luzerne Cemetery, Lake Luzerne, New York.

Clare C. Lesser was born 27 June 1925 at Joliet, Illinois. He was the fifth of five children of Henry J. Leser, a worker at a wire mile, and Alvina Leser. Leser served as an ensign in the United States Naval Reserve. Like LaFountain, he was also a civilian employee of the Air Force. His remains were buried at St. John’s Cemetery, Joliet, Illinois.

© 2018, Bryan R. Swopes

3 May 1948

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One of the three Douglas D-558-I Skystreaks. (Smithsonian Institution National Air and Space Museum, NASM A4958D)

3 May 1948: At Muroc Air Force Base in the high desert of southern California (after 1949, known as Edwards AFB), NACA 141, the second of three Douglas D-558-I Skystreak research aircraft, took off on a test flight to study stability at transonic speeds. In the cockpit was National Advisory Committee for Aeronautics Engineering Test Pilot Howard Clifton (“Tick”) Lilly. It was his twentieth flight in the Skystreak.

As Lilly climbed through 200 feet (61 meters), the Skystreak’s J35 turbojet engine suffered a catastrophic compressor failure. Fragments of the compressor cut through the airplane’s flight controls. With Lilly unable to control the airplane, it yawed to the left, then rolled over, and at 3:04 p.m., Pacific Daylight Saving Time (22:04 UTC), crashed onto Rogers Dry Lake. Lilly was decapitated in the crash.

Howard C. Lilly was the first NACA test pilot to be killed during a test flight since the commission had been established in 1915.

NACA Engineering Test Pilot Howard Clifton Lilly. (National Aeronautics and Space Administration )
Howard C. Lilly

Howard Clifton Lilly was born 27 August 1916 at Crow, West Virginia. He was the fourth of five children of Ova Ashton Lilly, a locomotive engineer, and Amanda Elmira Bragg Lilly.

Lilly was given the nickname, “Tickie,” by a friend who, as a child, had been unable to pronounce his middle name, Clifton.

Lilly attended Beaver Elementary School. He graduated from Shady Spring High School, and then attended Beckley College (now, the West Virginia University Institute of Technology), both in Beckley, West Virginia. He also studied at the Concord State Teachers College at Athens, WV (now, Concord University).

Lilly began flying at Mount Hope Airport in Beckley as a member of the Civilian Pilot Training Program. His flight instructor was Karl Williams.

Howard C. Lilly registered for Selective Service (conscription) on 16 October 1940. He was described as having a ruddy complexion with brown hair and blue eyes. Lilly was 5 feet, 10½ inches (179.1 centimeters) tall and weighed 150 pounds (68 kilograms). He was employed as a pressman for the Beckley Newspaper Corporation, and later in the stereotyping department of the Charleston Gazette.

Aviation Cadet Howard C. Lilly, USNR. (Tooley-Myron Studios)

Howard C. Lilly enlisted in the United States Navy as a seaman second class, 11 September 1941, at Washington, D.C. As part of the Navy’s V-5 Program, Seaman Lilly was assigned to U.S. Naval Reserve Aviation Base at Anacostia, D.C., for Elimination Flight Training. He was then transferred to the Naval Reserve Air Base, New Orleans, Louisiana. Although Lilly had hoped to fly fighters, he was assigned to fly seaplanes.

Aviation Cadet Lilly requested to be discharged from the Navy. His request was approved and he was discharged 18 September 1942.

Lilly joined the National Advisory Committee for Aeronautics (NACA) as a test pilot at the Langley Memorial Aeronautical Laboratory, Hampton, Virginia, in October 1942. He was then assigned to the Lewis Flight Propulsion Laboratory, Cleveland, Ohio, in May 1943.

Mrs. H. Clifton Lilly (Raleigh Register)

Howard C. Lilly married Miss Arline Eveyn Grentzer, 20 July 1945, at the St. James Rectory in Cleveland. The ceremony was officiated by Rev. George R. Betting. Following their wedding, the couple resided at the Westlake Hotel in Cleveland. They divorced in 1947.

On 1 September 1946, Lilly flew a Bell P-63A Kingcobra, 42-69063, in the Thompson Trophy Race at Cleveland. His airplane, with civil registration NX69901 and carrying race number 64, had qualified for the race in eighth place with an average speed of 346.155 miles per hour (557.083 kilometers per hour). He finished in ninth place at an average speed of 328.154 miles per hour (528.113 kilometers per hour). Bell Aircraft test pilot Tex Johnston won the race in his Bell P-39Q Airacobra with an average speed of 373.908 mph (601.746 kilometers per hour).

Howard Clifton Lilly, NACA engineering test pilot, with his 1946 Thompson Trophy racer, Bell P-63A NX69901. (NASA E-49-0091)

In August 1947, Lilly was assigned to NACA’s Muroc Flight Test Unit at Muroc Air Force Base as the commission’s first permanently assigned engineering test pilot there. He first flew the Bell XS-1 rocketplane on 9 January 1948. On 31 March 1948, Lilly flew the XS-1 to Mach 1.10, becoming just the third pilot to break sound barrier. Lilly made six test flight in the XS-1, all in the number two aircraft, 46-063.

Bell X-1 46-063. (NASA E49-001)

On 29 April 1948, Lilly flew the D-558-I to 0.88 Mach at 36,000 feet (10,973 meters). This was the highest speed that a Skystreak had reached up to that time.

Howard Clifton Lilly’s remains were interred at the Arlington National Cemetery. Lilly Avenue at Edwards AFB was named in his honor.

In May 1950, Lilly was posthumously awarded the Air Medal.

One the the three Douglas D-558-I Skystreaks in flight near Muroc Air Force Base. (Naval Aviation Museum)

NACA 141 (U.S. Navy Bureau of Aeronautics serial number 37971) was the second of three Douglas D-558-I Skystreak transonic research aircraft.

The D-558 Program was intended as a three-phase test program for the U.S. Navy and the National Advisory Committee on Aeronautics (NACA) to investigate transonic and supersonic flight using straight and swept wing aircraft powered by turbojet and/or rocket engines.

The Douglas Aircraft Company designed and built three D-558-I Skystreaks and three D-558-II Skyrockets. The Phase I aircraft were flown by Douglas test pilot Gene May and the Navy’s project officer, Commander Turner Caldwell.

Cutaway illustration of the Douglas D-558-I Skystreak. (U.S. Navy)

The D-558-I Skystreak was a single-engine, turbojet-powered airplane. It was built of magnesium and aluminum for light weight, but was designed to withstand very high acceleration loads. It was 35 feet, 8 inches (10.871 meters) long with a wingspan of 25 feet (7.62 meters) and overall height of 12 feet, 1¾ inches (3.702 meters). The airplane had retractable tricycle landing gear. Its empty weight was approximately 7,500 pounds (3,400 kilograms), landing weight at the conclusion of a flight test was 7,711 pounds (3,498 kilograms). The maximum takeoff weight was 10,105 pounds (4,583.6 kilograms). The aircraft fuel load was 230 gallons (870.7 liters) of kerosene.

The D-558-I was powered by a single Allison J35-A-11 turbojet engine. The J35 was a single-spool, axial-flow turbojet with an 11-stage compressor section, 8 combustion chambers and single-stage turbine. The J35-A-11 was rated at 5,000 pounds of thrust (22.24 kilonewtons). The engine was 12 feet, 1.0 inches (3.683 meters) long, 3 feet, 4.0 inches (1.016 meters) in diameter and weighed 2,455 pounds (1,114 kilograms). The J35-A-11 was a production version of the General Electric TG-180, initially produced by Chevrolet as the J35-C-3. It was the first widely-used American jet engine.

Cutaway illustration of J35 turbojet engine. (General Electric)

The D-558-I had a designed service ceiling of 45,700 feet (13,930 meters). Intended for experimental flights of short duration, it had a very short range and took off and landed from Rogers Dry Lake at Muroc. The experimental airplane was not as fast as the more widely known Bell X-1 rocketplane, but rendered valuable research time in the high transonic range.

The three D-558-I Skystreaks made a total of 229 flights.

Douglas test pilot Gene May (left) and Howard C. Lilly with the number two Douglas D-558-I Skystreak, Bu. No. 37971, at Muroc, circa 1948. (NASA E95-43116-8)

© 2023, Bryan R. Swopes

14 October 1947

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Captain Charles Elwood (“Chuck”) Yeager, U.S. Air Force, with “Glamorous Glennis,” the Bell XS-1. (U.S. Air Force/National Air and Space Museum)

14 October 1947: At approximately 10:00 a.m., a four-engine Boeing B-29 Superfortress heavy bomber, piloted by Major Robert L. Cardenas, took off from Muroc Air Force Base (now known as Edwards Air Force Base) in the high desert north of Los Angeles, California. The B-29’s bomb bay had been modified to carry the Bell XS-1, a rocket-powered airplane designed to investigate flight at speeds near the Speed of Sound (Mach 1).

A Bell XS-1 rocketplane carried aloft in the bomb bay of a modified Boeing B-29-96-BW Superfortress, serial number 45-21800. (NASA)
Captain Chuck Yeager with the Bell XS-1 on Muroc Dry Lake, 1947. (Chuck Yeager collection)

Air Force test pilot Captain Charles Elwood (“Chuck”) Yeager, a World War II fighter ace, was the U.S. Air Force pilot for this project. The X-1 airplane had been previously flown by company test pilots Jack Woolams and Chalmers Goodlin. Two more X-1 aircraft were built by Bell, and the second, 46-063, had already begun its flight testing.

Captain Yeager had made three glide flights and this was to be his ninth powered flight. Like his P-51 Mustang fighters, he had named this airplane after his wife, Glamorous Glennis.

Bob Cardenas climbed to 20,000 feet (6,096 meters) and then put the B-29 into a shallow dive to gain speed. In his autobiography, Yeager wrote:

“One minute to drop. [Jack] Ridley flashed the word from the copilot’s seat in the mother ship. . . Major Cardenas, the driver, starts counting backwards from ten. C-r-r-ack. The bomb shackle release jolts you up from your seat, and as you sail out of the dark bomb bay the sun explodes in brightness. You’re looking at the sky. Wrong! You should have dropped level. The dive speed was too slow, and they dropped you in a nose-up stall. . .

Cockpit of Bell X-1, 46-062, Glamorous Glennis, on display at the National Air and Space Museum. (Photo by Eric Long, National Air and Space Museum, Smithsonian Institution)

“I fought it with the control wheel for about five hundred feet, and finally got her nose down. The moment we picked up speed I fired all four rocket chambers in rapid sequence. We climbed at .88 Mach. . . I turned off two rocket chambers. At 40,000 feet, we were still climbing at .92 Mach. Leveling off at 42,000 feet, I had thirty percent of my fuel, so I turned on rocket chamber three and immediately reached .96 Mach. . . the faster I got, the smoother the ride.

“Suddenly the Mach needle began to fluctuate. It went up to .965 Mach—then tipped right off the scale. . . .”

—Brigadier General Charles E. Yeager, U.S. Air Force (Retired), Yeager, An Autobiography, by Chuck Yeager and Leo Janos, Bantam Books, New York, 1985, Pages 120, 129–130.

In his official report of the flight, Yeager wrote:

Date: 14 October 1947

Pilot: Captain Charles E. Yeager

Time: 14 Minutes

       9th Powered Flight

1. After normal pilot entry and subsequent climb, the XS-1 was dropped from the B-29 at 20,000′and at 250 MPH ISA. This was slower than desired.

2. Immediately after drop, all four cylinders were turned on in rapid sequence, their operation stabilizing at the chamber and line pressure reported in the last flight. The ensuing climb was made at .85–.88 Mach, and, as usual, it was necessary to change the stabilizer setting to 2 degrees nose down from its pre-drop setting of 1 degree nose down. Two cylinders were turned off between 35,000′ and 40,000′,  but speed had increased to .92 Mach as the airplane was leveled off at 42,000′. Incidentally, during the slight push-over at this altitude, the lox line pressure dropped perhaps 40 psi and the resultant rich mixture caused chamber pressures to decrease slightly. The effect was only momentary, occurring at .6 G’s, and all pressures returned to normal at 1 G.

3. In anticipation of the decrease in elevator effectiveness at speeds above .93 Mach, longitudinal control by means of the stabilizer was tried during the climb at .83, .88, and .92 Mach. The stabilizer was moved in increments of 1/4–1/3 degree and proved to be very effective; also, no change in effectiveness was noticed at the different speeds.

4. At 42,000′ in approximately level flight, a third cylinder was turned on. Acceleration was rapid and speed increased to .98 mach. The needle of the machmeter fluctuated at this reading momentarily, then passed off the scale. Assuming that the offscale reading remained linear, it is estimated that 1.05 Mach was attained at this time. Approximately 30% of fuel and lox remained when this speed was reached and the meter was turned off.

5. While the usual light buffet and instability characteristics were encountered in the .88–.90 Mach range and elevator effectiveness was very greatly decreased at .94 Mach, stability about all three axes was good as speed increased and elevator effectiveness was regained above .97 Mach. As speed decreased after turning off the motor, the various phenomena occurred n reverse sequence at the usual speed, and in addition, a slight longitudinal porpoising was noticed from .98–.96 Mach which controllable by the elevators alone. Incidentally, the stability setting was not changed from its 2 degree nose down position after trial at .92 Mach.

6. After jettisoning the remaining fuel and lox a 1 G stall was performed at 45,000′. The flight was concluded by the subsequent glide and a normal landing on the lake bed.

CHARLES E. YEAGER
Capt., Air Corps

Chuck Yeager had flown the XS-1 through “the sound barrier,” something many experts had believed might not be possible. His maximum speed during this flight was Mach 1.06 (699.4 miles per hour/1,125.7 kilometers per hour).

Bell X-1 46-062 in flight. Note the “shock diamonds” visible in the rocket engine’s exhaust. (Photograph by Lieutenant Robert A. Hoover, U.S. Air Force)

The Bell XS-1, later re-designated X-1, was the first of a series of rocket powered research airplanes which included the Douglas D-558-II Skyrocket, the Bell X-2, and the North American Aviation X-15, which were flown by the U.S. Air Force, U.S. Navy, NACA and its successor, NASA, at Edwards Air Force Base to explore supersonic and hypersonic flight and at altitudes to and beyond the limits of Earth’s atmosphere.

The X-1 is shaped like a bullet and has straight wings and tail surfaces. It is 30 feet, 10.98 inches (9.423 meters) long with a wing span of 28.00 feet (8.534 meters) and overall height of 10 feet, 10.20 inches (3.307 meters). Total wing area is 102.5 square feet ( 9.5 square meters). At its widest point, the diameter of the X-1 fuselage is 4 feet, 7 inches (1.397 meters). The empty weight is 6,784.9 pounds (3,077.6 kilograms), but loaded with propellant, oxidizer and its pilot with his equipment, the weight increased to 13,034 pounds (5,912 kilograms). The X-1 was designed to withstand an ultimate structural load of 18g.

The X-1 is powered by a four-chamber Reaction Motors, Inc., XLR11-RM-3 rocket engine which produced 6,000 pounds of thrust (26,689 Newtons). This engine burns a mixture of ethyl alcohol and water with liquid oxygen. Fuel capacity is 293 gallons (1,109 liters) of water/alcohol and 311 gallons (1,177 liters) of liquid oxygen. The fuel system is pressurized by nitrogen at 1,500 pounds per square inch (10,342 kilopascals).

The X-1 was usually dropped from a B-29 flying at 30,000 feet (9,144 meters) and 345 miles per hour (555 kilometers per hour). It fell as much as 1,000 feet (305 meters) before beginning to climb under its own power.

The X-1’s performance was limited by its fuel capacity. Flying at 50,000 feet (15,240 meters), it could reach 916 miles per hour (1,474 kilometers per hour), but at 70,000 feet (21,336 meters) the maximum speed that could be reached was 898 miles per hour (1,445 kilometers per hour). During a maximum climb, fuel would be exhausted as the X-1 reached 74,800 feet (2,799 meters). The absolute ceiling is 87,750 feet (26,746 meters).

The X-1 had a minimum landing speed of 135 miles per hour (217 kilometers per hour) using 60% flaps.

Bell X-1 46-063 with its Boeing B-29 Superfortress carrier aircraft, 45-21800. (Flight Test Historical Foundation)

The three X-1 rocketplanes made a total of 157 flights with the three X-1. The number one ship, Glamorous Glennis, made 78 flights. On 26 March 1948, with Chuck Yeager again in the cockpit, it reached reached Mach 1.45 (957 miles per hour/1,540 kilometers per hour) at 71,900 feet (21,915 meters).

The third X-1, 46-064, made just one glide flight before it was destroyed 9 November 1951 in an accidental explosion.

The second X-1, 46-063, was later modified to the X-1E. It is on display at the NASA Dryden Research Center at Edwards Air Force Base.

Glamorous Glennis is on display at the Smithsonian Institution National Air and Space Museum, next to Charles A. Lindbergh’s Spirit of St. Louis.

Bell X-1, 46-062, Glamorous Glennis, on display in the Milestones of Flight gallery at the National Air and Space Museum, Washington, D.C. (Photo by Eric Long, National Air and Space Museum, Smithsonian Institution)

© 2017, Bryan R. Swopes

1 October 1947

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North American Aviation test pilot George S. Welch, flying the first of three XP-86 prototypes, serial number 45-59597. (North American Aviation, Inc.)

1 October 1947: After three years development in which 801,386 engineering hours and 340,594 drafting hours had been expended, the first prototype North American Aviation XP-86 (company designation NA-140), serial number 45-59597, was ready for its first flight at Muroc Dry Lake in the high desert, north of Los Angeles, California.

Completed at North American’s Inglewood plant on 8 August 1947, it was trucked to Muroc in mid-September. It was reassembled, everything was checked out, and after a few taxi tests, company test pilot George S. Welch took off for a initial familiarization flight. Chief Test Pilot Bob Chilton flew chase in an XP-82 Twin Mustang with a company photographer on board. The duration of the first flight was 1 hour, 18 minutes.

Recently completed, the first prototype XP-86, 45-59597, waits inside the North American Aviation plant at Inglewood, California, 14 August 1947. (North American Aviation, Inc.)

During this first flight, George Welch climbed to 35,000 feet (10,668 meters):

“In a little more than ten minutes he had reached 35,000 feet. Leveling out, the test pilot smiled as he watched the indicated airspeed accelerate to 320 knots. He estimated that should be 0.90 Mach number. . . Rolling into a 40 degree dive, he turned west. . . The airspeed indicator seemed to be stuck at about 350 knots. The Sabre was behaving just fine. Then at 29,000 feet, there was a little wing roll. Correcting the roll, George pushed into a steeper dive. The airspeed indicator suddenly jumped to 410 knots and continued to rise. At 25,000 feet, he pulled the Sabre into level flight and reduced power. The wing rocked again and the airspeed jumped back to 390.”

—Aces Wild: The Race for Mach 1, by Al Blackburn, Scholarly Resources Inc., Wilmington, Delaware, 1998, at Chapter 5, Pages 144–145.

George Welch was the first to report instrument readings that would be referred to as “Mach jump.” It has been argued that George Welch flew the XP-86 beyond Mach 1 during this flight, breaking the “sound barrier” two weeks before Chuck Yeager did with the Bell X-1 rocketplane. During flight testing, it was firmly established that the XP-86 could reach Mach 1.02–1.04 in a dive, so it is certainly possible that he did so on the Sabre’s first flight.

North American Aviation Model NA-140, the first XP-86 prototype, 45-59597, at Muroc AAF, 1947. (U.S. Air Force)
North American Aviation Model NA-140, the first XP-86 prototype, 45-59597, at Muroc AAF, 1947. (U.S. Air Force)

The XP-86 was unlike any airplane before it. It was the first airplane with a swept wing. After analyzing test data from the Messerschmitt Me 262, North American’s engineers designed a wing with a 35° degree sweepback to its leading edge. The wing tapered toward the tips, and its thickness also decreased from the root to the tip. In order to create a very strong but very thin wing, it was built with a two-layered aluminum skin, instead of ribs and spars, with each layer separated by “hat” sections. The wing sweep allowed high speed shock waves to form without stalling the entire wing.

Cutaway illustration of the XP-86. The speed brake configuation was not used for production aircraft. (North American Aviation, Inc.)

The wing also incorporated leading edge “slats” which were airfoil sections that automatically extended below 290 knots, smoothing the air flow over the wing’s upper surface and creating more lift at slow speeds. Above that speed, aerodynamic forces closed the slats, decreasing drag and allowing for higher speeds. Effectively, the wing could change its shape in flight.

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)
This photograph of the XP-86 shows the 35° wing sweep. Test pilot George S. Welch, wearing his distinctive orange helmet, in the cockpit of the prototype XP-86. (North American Aviation, Inc.)

The XP-86 prototypes were 37 feet, 6½ inches (11.443 meters) long with a wingspan of 37 feet, 1–7/16 inches (11.314 meters) and overall height of 14 feet, 9 inches (4.496 meters). The empty weight was 9,730 pounds (4,413.5 kilograms), gross weight, 13,395 pounds (6,075.9 kilograms) and maximum takeoff weight was 16,438 pounds (7,456.2 kilograms).

North American Aviation XP-86 45-59597. (Ray Wagner Collection, San Diego Air & Space Museum Archives, Catalog #: 16_002950)

The XP-86 was initially powered by a General Electric-designed, Chevrolet-built J35-C-3 turbojet which produced 4,000 pounds of thrust. This was soon changed to an Allison J35-A-5. Performance testing was conducted with the Allison engine installed. The J35 was a single-spool, axial-flow turbojet engine with an 11-stage compressor and single-stage turbine. The J35-A-5 was rated at 4,000 pounds of thrust (17.79 kilonewtons) at 7,700 r.p.m. (static thrust, Sea Level). The engine was 14 feet, 0.0 inches (4.267 meters) long, 3 feet, 4.0 inches (1.016 meters) in diameter and weighed 2,400 pounds (1,089 kilograms).

The three North American Aviation XP-86 prototypes. Front to back, 45-59598, 45-59597 and 45-59599. (National Archives and Records Administration)

The maximum speed of the XP-86 at Sea Level was 0.787 Mach (599 miles per hour, 964 kilometers per hour), 0.854 Mach (618 miles per hour, 995 kilometers per hour) at 14,000 feet (4,267 meters) and 575 miles per hour (925 kilometers per hour) at 35,000 feet (10,668 meters)—0.875 Mach.

The prototype fighter was able to take off at 125 miles per hour (201 kilometers per hour) in just 3,020 feet (920.5 meters) of runway. It could climb to 30,000 feet (9,144 meters) in 12.1 minutes and had a service ceiling of 41,300 feet (12,588 meters).

The end of XP-86 45-59597 at Frenchman Flats, 1953.

XP-86 45-59597 was expended as a target during nuclear weapons tests. On 25 May 1953, it was 1,850 feet from ground zero of Upshot Knothole Grable. The only part still intact was the engine, which was thrown 500 feet.

Upshot Knothole Grable (National Nuclear Security Administration CIC 0315864)
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)

George Welch was born George Lewis Schwartz, in Wilmington, Delaware, 10 May 1918. 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, and enlisted in the Army Air Corps in 1939.

George S. Welch is best remembered as one of the heroes of Pearl Harbor. He was one of only two fighter pilots to get airborne 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. For this action, Lieutenant General H.H. “Hap” Arnold recommended the Medal of Honor, but because Lieutenant Welch had taken off without orders, an officer in his chain of command refused to endorse the nomination. He received the Distinguished Service Cross.

During World War II, George 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.

Suffering from malaria, George Welch was out of combat, and when North American Aviation approached him to test the new P-51H Mustang, General Arnold authorized his resignation. Welch test flew the P-51, FJ-1 Fury, F-86 Sabre and F-100 Super Sabre. He was killed 12 October 1954 when his F-100A Super Sabre came apart in a 7 G pull up from a Mach 1.5 dive.

North American Aviation F-86-A-NA Sabre 47-630. (North American Aviation, Inc./Chicago Tribune)
An early production aircraft, North American Aviation P-86A-1-NA Sabre 47-630 (s/n 151-38457). (North American Aviation, Inc./Chicago Tribune)

After testing, the North American Aviation XP-86 was approved for production as the F-86A. It became operational in 1949. The first squadron to fly the F-86 held a naming contest and from 78 suggestions, the name “Sabre” was chosen. The F-86 Sabre was in production until 1955 at North American’s Inglewood, California, and Columbus, Ohio, plants. It was also built under license by Canadair, Ltd., Sain-Laurent, Quebec, Canada; the Commonwealth Aircraft Corporation, Port Melbourne, Victoria, Australia; and Mitsubishi Heavy  Industries at Nagoya, Aichi Prefecture, Japan. A total of 9,860 Sabres were built. They served with the United States Air Force until 1970.

XP-86 45-59597 was expended in nuclear weapons tests, Operation Snapper Easy and Snapper Fox, at the Nevada Test Site, Frenchman’s Flat, Nevada, in May 1952. The second and third prototypes, 45-59598 and 45-59599, met similar fates.

© 2017, Bryan R. Swopes

18 September 1948

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Lieutenant Ellis Dent Shannon, Air Corps, United States Army

18 September 1948: The first delta-winged aircraft took flight for the first time when Consolidated-Vultee Aircraft Corporation test pilot Ellis D. “Sam” Shannon lifted off from Muroc Dry Lake with the prototype delta-wing XF-92A, serial number 46-682. For the next 18 minutes he familiarized himself with the new aircraft type, before landing back on the lake bed.

The Convair XF-92 on Rogers Dry lake. (U.S. Air Force)
The Convair XF-92A on Muroc Dry Lake. (U.S. Air Force)

Later, with Captain Chuck Yeager flying, the XF-92A reached Mach 1.05. Yeager found that the airplane’s delta wing made it nearly impossible to stall, even with a 45° angle of attack. He was able to land the airplane at nearly 100 miles per hour slower than the designers had predicted.

The XF-92A was a difficult airplane to fly. NACA test pilot Scott Crossfield commented, “Nobody wanted to fly the XF-92. There was no lineup of pilots for the airplane. It was a miserable flying beast.” Scotty made 25 flights in the experimental delta-winged aircraft. On its last flight, 14 October 1953, the airplane’s nose gear collapsed after landing. The XF-92A was damaged and never flew again.

Convair XF-92A 46-682 on Muroc Dry Lake, 1948. (U.S. Air Force)
Convair XF-92A 46-682 on Muroc Dry Lake, 1948. (U.S. Air Force)

The XF-92A (Consolidated-Vultee Model 7-002) was a single-place, single-engine prototype fighter. The airplane was 42 feet, 6 inches (12.954 meters) long with a wingspan of 31 feet, 4 inches (9.550 meters) and overall height of 17 feet, 9 inches (5.410 meters). It had an empty weight of 9,078 pounds (4,118 kilograms) and gross weight of 14,608 pounds (6,626 kilograms).

The prototype was originally powered by an Allison J33-A-21 turbojet engine with a single-stage centrifugal flow compressor and single-stage turbine. It produced 4,250 pounds of thrust at 11,500 r.p.m. at Sea Level. The engine was 8 feet, 6.9 inches (2.614 meters) long, 4 feet, 2.5 inches (1.283 meters) in diameter, and weighed 1,850 pounds (839 kilograms). This was later replaced by a more powerful J33-A-29 (7,500 pounds thrust).

The XF-92A touches down on Muroc Dry Lake, 1948. (San Diego Air and Space Museum Archives)
The XF-92A touches down on Muroc Dry Lake, 1948. (San Diego Air and Space Museum Archives)

The XF-92A had a maximum speed of 718 miles per hour (1,156 kilometers per hour) and a service ceiling of 50,750 feet (15,469 meters).

The XF-92A was not put into production. It did appear in several motion pictures, including “Toward The Unknown” (one of my favorites) and “Jet Pilot.” It is in the collection of the National Museum of the United States Air Force. This was the first of several Convair delta-winged aircraft, including the F2Y Sea Dart, F-102A Delta Dagger and F-106A Delta Dart supersonic interceptors, and the B-58A Hustler four-engine Mach 2+ strategic bomber.

Convair XF-92A. (NACA High Speed Flight Station)

Consolidated-Vultee XF-92A 46-682 is displayed at the National Museum of the United States Air Force, Wright-Patterson Air Force Base, Ohio.

The flight test program of the XF-92A came to an ignonimous colclusion
The flight test program of the XF-92A came to an ignominious conclusion on 14 October 1953. (San Diego Air and Space Museum Archives)

Ellis Dent Shannon was born at Andalusia, Alabama, 7 February 1908. He was the third of five children of John William and Lucy Ellen Barnes Shannon.

He was commissioned as a second lieutenant the Alabama National Guard (Troop C, 55th Machine Gun Squadron, Cavalry) 21 May 1926. He transferred to the U.S. Army Air Corps in 1929. In 1930, he was stationed at Brooks Army Airfield, Texas.

In 1932 Shannon was employed was assigned as a flight instructor and an advisor to the government of China.

On 24 December 1932, Shannon married Miss Martha Elizabeth Reid at Shanghai, China. They had son, Ellis Reid Shannon, born at Shanghai, 24 August 1934, and a daughter, Ann N. Shannon, born at Baltimore, Maryland, in 1940.

Shannon and his family returned to the United States in 1935 aboard SS Bremen, arriving at New York.

He was employed by the Glenn L. Martin Co., at Baltimore, Maryland, in 1936 as a test and demonstration pilot. He travel throughout Latin America for the company, demonstrating the company’s aircraft. As a test pilot he flew the Martin Model 187 Baltimore, the B-26 Marauder, PBM Mariner and the Martin JRM Mars.

In February 1943, Shannon started working as a Chief of Flight Research for the Consolidated Aircraft Company at San Diego, California. While there, made the first flights of the Consolidated XB-24K, a variant of the Liberator bomber with a single vertical tail fin; the XR2Y-1, a prototype commercial airliner based on the B-24 Liberator bomber; the XB-46 jet-powered medium bomber; the XP5Y-1 Tradewind, a large flying boat powered by four-turboprop-engines; the Convair 340 Metropolitan airliner; and the XF2Y Sea Dart, a delta-winged seaplane powered by two turbojet engines. Shannon also participated in the flight test program of the YF-102A Delta Dart.

After retiring from Convair in 1956, Ellis and Martha Shannon remained in the San Diego area. Ellis Dent Shannon died at San Diego, California, 8 April 1982 at the age of 74 years.

Ellis Dent Shannon, Convair test pilot (Photograph courtesy of Neil Corbett, Test and Research Pilots, Flight Test Engineers)
Ellis Dent Shannon, Convair test pilot, circa 1953. (Photograph courtesy of Neil Corbett, Test and Research Pilots, Flight Test Engineers)

© 2017, Bryan R. Swopes