Tag Archives: Bell XS-1

25 January 1946

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Jack Valentine Woolams, Chief Experimental Test Pilot, Bell Aircraft Corporation. (John Trudell/Ancestry)

25 January 1946:¹ Near Pinecastle Army Airfield in central Florida, Bell Aircraft Corporation Senior Experimental Test Pilot Jack Woolams made the first unpowered glide flight of the XS-1 supersonic research rocketplane, 46-062.

46-062 was the first of three XS-1 rocketplanes built by Bell for the U.S. Army Air Corps and the National Advisory Committee for Aeronautics (NACA) to explore flight at speeds at and beyond Mach 1, the speed of sound. The airplane had been rolled out of Bell’s plant at Buffalo, New York, on 27 December 1945. The rocket engine, which was being developed by Reaction Motors, Inc., at Franklin Lakes, New Jersey, was not ready, so the experimental aircraft was carrying ballast in its place for the initial flight tests.

Jack Woolams with the second Bell XS-1, 46-063. (Niagara Aerospace Museum)

The XS-1 was to be air-dropped from altitude by a modified heavy bomber so that its fuel could be used for acceleration to high speeds at altitude, rather than expended climbing from the surface. Bell manufactured B-29B Superfortresses at its Atlanta, Georgia, plant and was therefore very familiar with its capabilities. A B-29, 45-21800, was selected as the drop ship and modified to carry the rocketplane in its bomb bay.

Boeing B-29-96-BW Superfortress 45-21800 carries a Bell XS-1 rocketplane. (Bell Aircraft Museum)

Pinecastle Army Airfield was chosen as the site of the first flight tests because it had a 10,000 foot (3,048 meter) runway and was fairly remote. There was an adjacent bombing range and the base was a proving ground for such aircraft as the Consolidated B-32 Dominator. (Today, Pinecastle A.A.F. is known as Orlando International Airport, MCO.)

Bell XS-1 46-062 was placed in a pit at Pinecastle A.A.F. so that the B-29 drop ship in the background could be positioned over it. (NASA)
Bell XS-1 46-062 was placed in a pit at Pinecastle A.A.F. so that the B-29 drop ship in the background could be positioned over it. (NASA)

The B-29 carrying the XS-1 took off from Pinecastle at 11:15 a.m., and began its climb to altitude. Woolams was in the forward crew compartment. As the bomber reached approximately 10,000 feet (3,048 meters), he entered the bomb bay and climbed down into the cockpit of the research aircraft. At the drop altitude, the B-29 was flying at 180 miles per hour (290 kilometers per hour) with the inboard propellers feathered and flaps lowered to 20°.

The XS-1 dropped away smoothly. Woolams flew the rocketplane to a maximum 275 miles per hour (443 kilometers per hour), indicated air speed, during this first glide test. He described the rocketplane as, “solid as a rock, experiencing absolutely no vibration or noise. At the same time, it felt as light as a feather during maneuvers due to the lightness, effectiveness and nice balance between the controls.” Woolams described the visibility from the cockpit as “not good, but adequate.”

The duration of the first glide flight was about ten minutes. Woolams misjudged his approach to Pinecastle and landed slightly short of the runway, on the grass shoulder, but the XS-1 was not damaged.

The conclusion of Woolams’ flight report is highly complementary of the experimental airplane:

11.  Of all the airplanes the writer has flown, only the XP-77 and the Heinkel 162 compare with the XS-1 for maneuverability, control relationship, response to control movements, and lightness of control forces. Although these impressions were rather hastily gained during a flight which lasted only 10 minutes, it is the writer’s opinion that due to these factors and adding to them the security which the pilot feels due to the ruggedness, noiselessness, and smoothness of response of this airplane, it is the most delightful to fly of them all.

—PILOT’S REPORT, Flight 1, by Jack Woolams

Jack Woolams made ten glide flights with 46-062, evaluating its handling characteristics and stability. The aircraft was returned to Bell to have the rocket engine installed, and it was then sent to Muroc Army Airfield in the high desert of southern California for powered flight tests. (Muroc A.A.F. was renamed Edwards Air Force Base in 1949.)

Bell XS-1 46-062 was later named Glamorous Glennis by its military test pilot, Captain Charles E. Yeager, U.S. Army Air Corps. On 14 October 1947, Chuck Yeager flew it to Mach 1.06 at 13,115 meters (43,030 feet). Today the experimental aircraft is on display at the Smithsonian Institution National Air and Space Museum.

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.

An X-1 under construction at teh Bell Aircraft Corporation plant, Buffalo, New York. (Bell Aircraft Corporation)
An X-1 under construction at the Bell Aircraft Corporation plant, Buffalo, New York. (Bell Aircraft Corporation)

The X-1 has an ogive nose, similar to the shape of a .50-caliber machine gun 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).

46-062 was built with a thin 8% aspect ratio wing, while 46-063 had a 10% thick wing. The wings were tapered, having a root chord of 6 feet, 2.2 inches (1.885 meters) and tip chord of 3 feet, 1.1 inches (0.942 meters), resulting in a total area of 130 square feet (12.1 square meters). The wings have an angle of incidence of 2.5° with -1.0° twist and 0° dihedral. The leading edges are swept aft 5.05°.

The horizontal stabilizer has a span of 11.4 feet (3.475 meters) and an area of 26.0 square feet (2.42 square meters). 062’s stabilizer has an aspect ratio of 6%, and 063’s, 5%.

The fuselage cross section is circular. At its widest point, the diameter of the X-1 fuselage is 4 feet, 7 inches (1.397 meters).

46-062 had an 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.

Front view of a Bell XS-1 supersonic research rocketplane at the Bell Aircraft plant, Buffalo, New York. (Bell Aircraft Museum)

The X-1 was powered by a four-chamber Reaction Motors, Inc., 6000C4 (XLR11-RM-3 ) rocket engine which produced 6,000 pounds of thrust (26,689 Newtons). This engine burned a 75/25 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 was pressurized by nitrogen at 1,500 pounds per square inch (103.4 Bar).

The X-1 was usually dropped from the 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).

Bell X-1 46-062 on the dry lake bed at Muroc Army Airfield, circa 1947. (NASM)

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

There were 157 flights with the three X-1 rocket planes. The number one ship, 46-062, 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 at the National Air and Space Museum, Washington, D.C. (NASM)
Bell X-1 46-062, Glamorous Glennis, on display at the National Air and Space Museum, Washington, D.C. (NASM)

Jack Valentine Woolams was born on Valentine’s Day, 14 February 1917, at San Francisco, California. He was the second of three children of Leonard Alfred Woolams, a corporate comptroller, and Elsa Mathilda Cellarius Woolams. He grew up in San Rafael, California, and graduated from Tamalpais School in 1935.

Jack Woolams, 1941

After two years of study at The University of Chicago, in 1937 Woolams entered the Air Corps, U.S. Army, as an aviation cadet. He trained as a pilot at Kelly Field, San Antonio, Texas. On graduation, 16 June 1938, he was discharged as an aviation cadet and commissioned as a second lieutenant, Air Reserve. He was assigned to Barksdale Army Air Field, Louisiana, where he flew the Boeing P-26 and Curtiss P-36 Hawk.

On 10 February 1939, Lieutenant Woolams was one of three Air Corps officers thrown into the waters of Cross Lake, near Shreveport, Louisiana, when the boat, owned by Woolams, capsized in 4 foot (1.2 meters) waves. Woolams and Lieutenant J.E. Bowen were rescued after 4 hours in the water, but the third man, Lieutenant Wilbur D. Camp, died of exposure.

Lieutenant Woolams transferred from active duty to inactive reserve status in September 1939 in order to pursue his college education at The University of Chicago, where he was a member of the Alpha Delta Phi (ΑΔΦ) fraternity. While at U. of C., he played on the university’s football and baseball teams, and was a member of the dramatic society. Woolams graduated 18 July 1941 with a Bachelor of Arts (A.B.) degree in Economics.

Mr. and Mrs. Jack V. Woolams, 16 June1941. (Unattributed)

Jack Woolams married Miss Mary Margaret Mayer at the bride’s home in Riverside, Illinois, 16 June 1941. They would have three children. Miss Mayer was also a 1941 graduate from the University of Chicago. She had been Woolams’ student in the Civilian Pilot Training Program.

Woolams became a production test pilot for the Bell Aircraft Corporation at Buffalo, New York. He tested newly-built Bell P-39 Airacobra fighters. As he became more experienced, he transitioned to experimental testing with the P-39, P-63 King Cobra, and the jet-powered P-59 Airacomet.

Jack Valentine Woolams, Chief Experimental Test Pilot, Bell Aircraft Corporation, circa 1946. (Niagara Aerospace Museum)

On 28 September 1942, Jack Woolams flew a highly-modified Bell P-39D-1-BE Airacobra, 41-38287, from March Field, near Riverside, California, to Bolling Field, Washington, D.C., non-stop. The duration of the flight was approximately 11 hours. The modifications were intended to allow P-39s to be flown across the Pacific Ocean to Hawaii and on to the Soviet Union for delivery under Lend Lease.

During the summer of 1943, Woolams flew the first Bell YP-59A Airacomet, 42-108771, to an altitude of 47,600 feet (14,508 meters) near Muroc Army Air Field in California.

On 5 January 1945, Woolams was forced to bail out of a Bell P-59A-1-BE, 44-22616. He suffered a deep laceration to his head as he left the airplane. He lost his flight boots when the parachute opened, and on landing, had to walk barefoot through knee-deep snow for several miles to reach a farm house. The deep snow prevented the company’s ambulance from getting to Woolams. Bell Aircraft president Lawrence D. Bell sent the company’s second prototype Bell Model 30 helicopter, NX41868, flown by test pilot Floyd Carlson, to transport a doctor, J.A. Marriott, M.D., to the location. Another Bell test pilot, Joe Mashman, circled overhead in a P-63 King Cobra to provide a communications link. Later in the day, an ambulance was able to get through the snow to take Woolams to a hospital.

Wreckage of Bell P-59A-1-BE Airacomet 44-22616. Jack Woolams bailed out of this airplane 5 January 1945. (Niagara Aerospace Museum)

Woolams was scheduled to make the first powered flight of the XS-1 during October 1946.

Jack Woolams was killed Friday, 30 August 1946, when his red Thompson Trophy racer, Cobra I, a modified 2,000-horsepower Bell P-39Q Airacobra, crashed into Lake Ontario at over 400 miles per hour. His body was recovered by the U.S. Coast Guard four days later.

Bell Aircraft Corporation experimental test pilots Jack Woolams and Tex Johnston with their modified Bell P-39Q Airacobras, Cobra I and Cobra II. (Niagara Aerospace Museum)

¹ This article was originally dated 19 January 1946. There were known discrepancies as to the date of the first flight from various reliable sources. Recently discovered test flight reports, provided to TDiA by Mr. Roy T. Lindberg, Historian of the Niagara Aerospace Museum, Niagara Falls, New York, have confirmed that the date of the first flight was actually 25 January 1946. The article has been been revised accordingly, as well as to incorporate new information from these reports.

TDiA is indebted to Mr. Lindberg for providing this and other documentation.

© 2019, 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 and 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

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.
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