Tag Archives: NACA

25 April 1956

Aviation, , , , , , , , , , , , , ,
Lieutenant Colonel Frank K. Everest, U.S. Air Force, with a Bell X-2 at Edwards Air Force Base. Colonel Everest is wearing a capstan-type partial pressure suit for protection at very high altitude. (U.S. Air Force)
Lieutenant Colonel Frank K. Everest, U.S. Air Force, with a Bell X-2 at Edwards Air Force Base. Colonel Everest is wearing a David Clark Co. T-1 capstan-type partial-pressure suit for protection at very high altitude. (U.S. Air Force)

25 April 1956: At Edwards Air Force Base, California, test pilot Lieutenant Colonel Frank Kendall (“Pete”) Everest, United States Air Force, was airdropped from a Boeing EB-50D Superfortress in the Bell X-2 supersonic research rocket plane, serial number 46-674. This was the tenth flight of the X-2 program, and only the third powered flight.

For the first time, Everest fired both chambers of the Curtiss-Wright XLR25 rocket engine. On this flight, the X-2 reached Mach 1.40 and 50,000 feet (15,240 meters). It was the first time an X-2 had gone supersonic.

Bell X-2 46-674 in flight over Southern California, circa 1955–56. (NASA Photograph ET–128)
Bell X-2 46-674 in flight over Southern California, circa 1955–56. (NASA Photograph ET–128)

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).

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.

Bell X-2 46-674 on final approach. (NASA)

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.

Two X-2 rocketplanes were built. The second X-2, 46-675, was destroyed during a captive flight, 12 May 1953. The explosion killed Bell test pilot Skip Ziegler and Frank Wolko, an engineer aboard the B-50A mothership. The B-50 made an emergency landing but was so badly damaged that it never flew again.

The X-2 reached a maximum speed of Mach 3.196 (2,094 miles per hour/3,370 kilometers per hour) and maximum altitude of 126,200 feet (38,466 meters).

Boeing EB-50D Superfortress 49-096 with a Bell X-2 (U.S. Air Force)
Boeing EB-50D Superfortress 48-096 with a Bell X-2 (U.S. Air Force)

The EB-50D was a highly modified four-engine Boeing B-50D-95-BO Superfortress long range heavy bomber, engineered to carry research aircraft to high altitudes before releasing them for a test flight. The B-50 was an improved version of the World War II B-29A Superfortress.

Boeing B-50D-95-BO (S/N 48-096) in flight. (U.S. Air Force photo)
Boeing B-50D-95-BO Superfortress 48-096 prior to modification to an EB-50D X-2 carrier. (U.S. Air Force/Bill Pippin Collection, 1000aircraftphotos.com)
Boeing B-50D-90-BO Superfortress 48-096 prior to modification to an EB-50D X-2 carrier. (U.S. Air Force)
Boeing B-50D-95-BO Superfortress 48-096 prior to modification to an EB-50D X-2 carrier. (U.S. Air Force)
Boeing B-50D-95-BO Superfortress 48-096 prior to modification to an EB-50D X-2 carrier. (U.S. Air Force)

Frank Kendall (“Pete”) Everest, Jr., was born 10 Aug 1920, at Fairmont, Marion County, West Virginia. He was the first of two children of Frank Kendall Everest, an electrical contractor, and Phyllis Gail Walker Everest. Attended Fairmont Senior High School, Fairmont, West Virginia, graduating in 1939. He studied at Fairmont State Teachers College, also in Fairmont, West Virginia, and then studied engineering at teh University of Wesst Virginia in Morgantown.

Pete Everest enlisted as an aviation cadet in the United States Army Air Corps at Fort Hayes, Columbus, Ohio, 7 November 1941, shortly before the United States entered World War II. His enlistment records indicate that he was 5 feet, 7 inches (1.703 meters) tall and weighed 132 pounds (59.9 kilograms). He graduated from pilot training and was commissioned as a second lieutenant, Air Reserve, 3 July 1942.

Everest married Miss Avis June Mason in Marion, West Virginia, in 1942.

Pete Everest with his Curtiss-Wright P-40 Warhawk, North Africa, 1943.

He was promoted to 1st Lieutenant, Army of the United States, 11 November 1942. He was assigned as a Curtiss-Wright P-40 Warhawk pilot, flying 94 combat missions in North Africa, Sicily and Italy. He was credited with shooting down two German airplanes and damaging a third. Everest was promoted to the rank of Captain, 17 August 1943.

In 1944, Everest was returned to the United States to serve as a flight instructor. He requested a return to combat and was then sent to the China-Burma-India theater of operations where he flew 67 missions and shot down four Japanese airplanes. He was himself shot down by ground fire in May 1945. Everest was captured by the Japanese and suffered torture and inhumane conditions before being freed at the end of the war. He was promoted to the rank of major, 1 July 1945. He was returned to the United States military 3 October 1945.

After the war, Everest was assigned as a test pilot at Wright-Patterson Air Force Base, Ohio, before going west to the Air Force Flight Test Center at Edwards Air Force Base, California.

Everest was returned to the permanent rank of first lieutenant, Air Corps, 19 June 1947, with date of rank retroactive to 3 July 1945.

Major Frank Kendall Everest, Jr., U.S. Air Force, with a Bell X-1 supersonic research rocketplane, 46-062, circa 1950. (mach-buster.co.uk)

At Edwards, he was involved in nearly every flight test program, flying the F-88, F-92, F-100, F-101, F-102, F-104 and F-105 fighters, the XB-51, YB-52, B-57 and B-66 bombers. He also flew the pure research aircraft, the “X planes:” the X-1, X-1B, X-2, X-3, X-4 and X-5. Pete Everest flew the X-1B to Mach 2.3, and he set a world speed record with the X-2 at Mach 2.9 (1,957 miles per hour, 3,149.5 kilometers per hour) which earned him the title, “The Fastest Man Alive.” He was the test pilot on thirteen of the twenty X-2 flights.

Major Frank Kendall Everest, Jr., U.S. Air Force, with the Bell X-2 supersonic research rocketplane, on Rogers Dry Lake at Edwards AFB, California, 1956. (U.S. Air Force via Jet Pilot Overseas)

Frank Everest returned to operational assignments and commanded a fighter squadron, two combat crew training wings, and was assigned staff positions at the Pentagon. On 20 November 1963, Colonel Everest, commanding the 4453rd Combat Crew Training Squadron, flew one of the first two operational McDonnell F-4C Phantom II fighters from the factory in St. Louis to MacDill Air Force Base.

Brigadier General Gilbert L. Meyers and Colonel Frank Kendall Everest delivered the first production F-4C Phantom IIs to the Tactical Air Command at MacDill Air Force Base, Florida. (U.S. Air Force)

In 1965, Pete Everest was promoted to the rank of brigadier general. He was commander of the Aerospace Rescue and Recovery Service. He retired from the Air Force in 1973 after 33 years of service. He later worked as a test pilot for Sikorsky Aircraft.

During his military career General Everest was awarded the Air Force Distinguished Service Medal; Legion of Merit with two oak leaf clusters (three awards); Distinguished Flying Cross with two oak leaf clusters (three awards); Purple Heart; Air Medal with one silver and two bronze oak leaf clusters (seven awards); Air Force Commendation Medal with one oak leaf cluster (two awards); Presidential Unit Citation with two bronze oak leaf clusters (three awards); Air Force Gallant Unit Citation; Prisoner of War Medal; American Campaign Medal; European-African-Middle Eastern Campaign medal with four bronze stars; Asiatic-Pacific campaign Medal with two bronze stars; World War II Victory Medal; National Defense Service Medal; Armed Forces Expeditionary Medal; Vietnam Service Medal; Air Force Longevity Service Award with one silver and two bronze oak leaf clusters (seven awards); Air Force Small Arms Expert Marksmanship Ribbon; and the Republic of Vietnam Campaign Medal with 1960– device. General Everest was rated as a Command Pilot, and a Basic Parachutist.

Brigadier General Frank Kendall Everest, Jr. United States Air Force (Retired), died at Tucson, Arizona, 1 October 2004 at the age of 84 years.

Brigadier General Frank Kendall Everest, United states Air Force
Brigadier General Frank Kendall Everest, Jr., United States Air Force. (U.s. Air Force)

© 2019, Bryan R. Swopes

24 April 1939

Aviation, , , , , , , , , , ,
The Curtiss XP-40 prototype at Langley Field in the original configuration. (NASA)
The Curtiss-Wright XP-40 prototype, 36-10, at Langley Field in the original configuration. Compare this to the first production P-40 Warhawk in the photograph below. (NASA)
Curtiss P-40 Warhawk 39-156. (U.S. Air Force)
Curtiss-Wright P-40 Warhawk 39-156. (U.S. Air Force)

24 April 1939: Curtiss-Wright’s prototype fighter, the XP-40 (Model 75P), was evaluated by the National Advisory Committee for Aeronautics (NACA) at the Langley Memorial Aeronautical Laboratory, Langley Field, Virginia, in March and April 1939. NACA engineers placed the XP-40 inside the Full-Scale Wind Tunnel, which was capable of accepting airplanes with wing spans of up to 40 feet (12.2 meters).

Compare this production Curtiss-Wright P-36A Hawk to the first production P-40 Warhawk in the photograph below.
Curtiss Model 81, P-40 Warhawk, 39-156. (San Diego Air and Space Museum Archive)

The airplane was a production Curtiss P-36A Hawk, serial number 38-10, which had been modified by replacing its original air-cooled Pratt & Whitney Twin Wasp S1C1-G (R-1830-17) 14-cylinder radial engine with a Harold Caminez-designed, liquid-cooled, supercharged, 1,710.597-cubic-inch-displacement (28.032 liter) Allison Engineering Co. V-1710-C13 (V-1710-19).

This was a single overhead cam (SOHC) 60° V-12 engine with four valves per cylinder and a compression ration of 6.65:1. It had a Normal Power rating of 910 horsepower at 2,600 r.p.m. at Sea Level, and 1,060 horsepower at 2,950 r.p.m. for Takeoff. At 10,000 feet (3,048 meters), the V-1710-19 had Maximum Continuous Power rating of 1,000 horsepower at 2,600 r.p.m., and Military Power rating of 1,150 horsepower at 2,950 r.p.m. The engine required 100/130-octane aviation gasoline. It drove a three-bladed Curtiss Electric constant-speed propeller through a 2:1 gear reduction.

The V-1710-19 was 8 feet, 1.75 inches (2.483 meters) long, 3 feet, 4.75″ (1.035 meters) high and 2 feet, 4.94 inches (0.735 meters) wide. It weighed 1,320 pounds (599 kilograms).

Curtiss XP-40 prototype in the NACA wind tunnel at Langley Field, Virginia, 24 April 1939. The technician at the lower left of the photograph provides scale. (NASA)
Curtiss-Wright XP-40 prototype in the NACA wind tunnel at Langley Field, Virginia, 24 April 1939. The technician at the lower left of the photograph provides scale. (NASA)

The primary benefit of the engine change was the streamlined fuselage that resulted. The new airplane was capable of a speed of 366 miles per hour (589 kilometers per hour), a 53 miles per hour (85 kilometers per hour) increase over the P-36.

Over a two-month period, NACA engineers made a number of improvements. The radiator was moved forward under the engine and the oil coolers utilized the same air scoop. The exhaust manifolds were improved as were the landing gear doors.

When they had finished, Lieutenant Benjamin Scovill Kelsey flew the modified XP-40 back to Curtiss at Buffalo, New York. Its speed had been increased to 354 miles per hour (570 kilometers per hour), a 12% improvement. Other improvements were recommended which may have increased the XP-40’s speed by an additional 18 miles per hour (29 kilometers per hour). By December 1939, the airplane had been further improved and was capable of 366 miles per hour (589 kilometers per hour).

These photographs show the full-size prototype in the NACA wind tunnel at Langley, 24 April 1939. Two days later, the U.S. Army Air Corps ordered 524 airplanes as the P-40 Warhawk. By the time production ended in 1945, 13,738 Warhawks had been built.

Curtiss XP-40 in the NACA full scale wind tunnel, Langley Field, Virginia, April 1939. (NASA)
Curtiss XP-40 in the NACA full scale wind tunnel, Langley Field, Virginia, April 1939. (NASA)

© 2018, Bryan R. Swopes

14 April 1947

Aviation, , , , , , , , , , , ,
Douglas test pilot Gene May with a D-558-I Skystreak research airplane. (Douglas Aircraft Company)

14 April 1947: Douglas Aircraft Company test pilot Eugene Francis (“Gene”) May took the Number 1  U.S. Navy/NACA/Douglas D-558-I Skystreak high-speed research aircraft, Bu. No. 37970, for its first flight at at Muroc Army Airfield. The aircraft had been transported from the Los Angeles factory to Muroc by truck.

Douglas Aircraft Company test pilot Eugene Francis May. (Photograph courtesy of Neil Corbett, Test and Research Pilots, Flight Test Engineers)

The Skystreak was a joint United States Navy/National Advisory Committee for Aeronautics (NACA) research aircraft designed to explore flight at high subsonic speed. The Phase I Skystreak was designed by a team led by Douglas Chief Engineer Edward Henry Heinemann. Flight testing was conducted at the NACA High Speed Flight Station at Muroc Army Airfield (later known as Edwards Air Force Base). Three D-558-Is were built, followed by the Phase II, swept-wing Mach 2 D-558-II Skyrocket rocketplane.

The D-558-I carried extensive flight test instrumentation for its time. The wings had 400 orifices for air pressure sensors. During the test series, aircraft stability in the range of 0.82–0.99 Mach was investigated. One of the Skystreaks may have briefly exceeded Mach 1 as it came out of a dive.

Unlike some of the other experimental high speed aircraft of the time, it took off from the ground under its own power rather than being carried aloft by a mother ship. While those other aircraft could briefly reach much higher speeds, the D-558-I was able to fly for extended periods in the high-subsonic range, providing scientists and engineers with a tremendous amount of data.

The research airplane was a single-place, single-engine, low-wing monoplane with retractable tricycle landing gear. The fuselage of the D-558-I was constructed of an aluminum framework covered with sheet magnesium. It was designed for an ultimate load factor of 18 gs. The wings and tail surfaces were aluminum. The airplane was painted scarlet (not orange, like its contemporary, the Bell X-1) and was known as “the crimson test tube.”

The D-558-I was 35 feet, 1.5 inches (10.706 meters) long with a wingspan of 25 feet, 0 inches (7.620 meters) and overall height of 12 feet, 1.6 inches (3.698 meters). Gross weight 10,105 pounds (4,584 kilograms). It carried 230 gallons (871 liters) of kerosene in its wings.

A Douglas D-558-I Skystreak being inspected by U.S. Navy personnel at the Douglas Aircraft Company plant in Los Angeles, California. [Modelers: Note the GREEN anti-glare panel.] (Getty Images/Bettman)
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).

Bu. No. 37970 made 101 of the 228 Phase I flights. It set a world speed record 1,031.178 kilometers per hour (640.744 miles per hour), flown by Commander Turner F. Caldwell Jr., U.S. Navy,  20 August 1947.¹ (Major Marion E. Carl, U.S. Marine Corps, flew the second Skystreak, Bu. No. 37971, to 1,047.356 kilometers per hour (650.797 miles per hour),² breaking Caldwell’s record.)

After Douglas completed the contractor’s test series, the Number 1 Skystreak was turned over to the NACA High Speed Flight Station and designated NACA 140. It was not as highly instrumented as the Number 2 and Number 3 Skystreaks and was not flown, but was used as a source for spare parts for the other D-558-Is.

Douglas D-558-I Skystreak Bu. No. 37970 is on display at the National Naval Aviation Museum, NAS Pensacola, Florida.

Douglas D-558-I Skystreak, Bu. No. 37970, at the National Naval Aviation Museum, Naval Air Station Pensacola, Florida. (U.S. Navy)

¹ FAI Record File Number 9864

² FAI Record File Number 9865

© 2019, Bryan R. Swopes

6 November 1958

Aviation, , , , , , , , , , , , , , , , , ,
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 14 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

4 November 1941

Aviation, , , , , , , , , , , , , , , , , , , , , , , , ,
Lockheed YP-38 Lightning 39-689, manufacturer's serial number 122-2202. (Lockheed)
Lockheed YP-38 Lightning 39-689, manufacturer’s serial number 122-2202. (Lockheed Martin)
Ralph Burwell. Virden (Los Angeles Times)

4 November 1941: Lockheed test pilot Ralph Burwell Virden was conducting high speed dive tests in the first Lockheed YP-38 Lightning, Air Corps serial number 39-689 (Lockheed’s serial number 122-2202).

As the airplane’s speed increased, it approached what is now known as its Critical Mach Number. Air flowing across the wings accelerated to transonic speeds and began to form shock waves. This interrupted lift and caused a portion of the wing to stall. Air no longer flowed smoothly along the airplane and the tail surfaces became ineffective. The YP-38 pitched down into a steeper dive and its speed increased even more.

Designed by famed aeronautical engineer Clarence L. “Kelly” Johnson, the YP-38 had servo tabs on the elevator that were intended to help the pilot maintain or regain control under these conditions. But they increased the elevator’s effectiveness too well.

The Los Angeles Times described the accident:

     Witnesses said the twin-engined, double-fuselaged ship was booming westward at near maximum speed (unofficially reported to be between 400 and 500 miles an hour) when the duralumin tail assembly “simply floated away.”

     A moment afterward the seven-ton craft seemed to put on a burst of speed, the the high whine of its engines rising.

     It then went into a downward glide to about 1500 feet, then into a flat spin, flipped over on its back and shot earthward.

     Several persons said that they thought they had heard an explosion during the dive, but qualified observers doubted it. . .

     . . . Fellow pilots at Lockheed said, “Ralph was the best we had, especially in power dives.”

      Robert E. Gross, president of Lockheed, said, “Ralph Virden was a great pilot but an even greater man. If anyone ever had national defense at heart it was he, who every day was carrying the science of aviation into new and higher fields.”

     Various witnesses said the ill-fated ship’s tail assembly could be followed easily as its bright surfaces glinted in the sun during its drop to earth. It landed several blocks from the scene of the crash.

     Mrs. Jack Davenport of 1334 Elm Ave., left her ironing board when she heard the unfamiliar roar of the plunging plane’s engines.

     “I ran out and saw it passing over us, very low. It disappeared among the trees and then zoomed back into sight just before crashing in the next block,” she said. “It looked just like a toy airplane. I knew the pilot didn’t have a chance, as the ship was too low and going too fast.”

—Los Angeles Times, Vol. LX, Wednesday, 5 November 1941, Page 1, Column 6, and Page 2, Column 5.

The YP-38 crashed into the kitchen of Jack Jensen’s home at 1147 Elm Street, Glendale, California. Fire erupted. Ralph Virden was killed. The airplane’s tail section was located several blocks away.

Another view of Lockheed YP-38 Lightning 39-689. It's factory serial number, "2202," is stenciled on the nose. (Lockheed Martin)
Another photograph of Lockheed YP-38 Lightning 39-689. The factory serial number, “2202,” is stenciled on the nose. (Lockheed Martin)

39-689 was the first of thirteen YP-38 service test aircraft that had been ordered by the U.S. Army Air Corps shortly after the XP-38 prototype, 37-457, had crashed on a transcontinental speed record attempt, 11 February 1939. 39-689 made its first flight 16 September 1940 with test pilot Marshall Headle at the controls. With hundreds of production P-38s being built, Lockheed continued to use the YP-38 for testing.

Newspaper phototograph of the wreckage of Lockheed YP-38 Lightning 39-689 at 1147 Elm Street, Glendale, California. (Los Angeles Times)
Newspaper photograph of the wreckage of Lockheed YP-38 Lightning 39-689 at 1147 Elm Street, Glendale, California. (Los Angeles Times)

The YP-38s were service test prototypes of a single-place, twin engine long range fighter with a unique configuration. There was not a fuselage in the normal sense. The cockpit, nose landing gear, and armament were contained in a central nacelle mounted to the wing. Two engines and their turbochargers, cooling systems and main landing gear were in two parallel booms. The booms end with vertical fins and rudders, with the horizontal stabilizer and elevator between them. The P-38 was 37 feet, 9–15/16 inches (11.530 meters) long, with a wingspan of 52 feet, 0 inches (15.850 meters) and height of 12 feet, 10 inches (3.952 meters).

The P-38’s wings had a total area of 327.50 square feet (30.43 square meters). Their angle of incidence was 2° and there was 5° 40′ dihedral. The leading edges were swept aft 5° 10′.

The YP-38 had an empty weight 11,171 pounds (5,067 kilograms). The gross weight was 13,500 pounds (6,123 kilograms) and the maximum takeoff weight 14,348 pounds (6,508 kilograms).

The YP-38 was powered by two counter-rotating, liquid-cooled, turbosupercharged 1,710.597-cubic-inch displacement (28.032 liter) Allison V-1710-27 right-hand tractor and V-1710-29 left-hand tractor, single overhead cam (SOHC) 60° V-12 engines (Allison Engineering Co. Models F2R and F2L) with a Normal Power rating of 1,000 horsepower at 2,600 r.p.m., and 1,150 horsepower at 3,000 r.p.m. for takeoff. They drove three-bladed Curtiss Electric constant-speed propellers with a diameter of 11 feet, 6 inches (3.505 meters) through a 2.00:1 gear reduction. In a change from the XP-38, the propellers rotated outboard at the top of their arc. The V-1710-27/-29 engines were 7 feet, 1-5/8 inches (2.175 meters) long, 2 feet, 5-9/32 inches (0.744 meters) wide and 3 feet, 0-17/32 inches (0.928 meters) high. The V-1710-27/-29 weighed 1,305 pounds (592 kilograms)

The YP-38 had a maximum speed of 405 miles per hour (651.8 kilometers per hour) at 10,000 feet (3,048 meters) and it could climb  from the surface to 20,000 feet (6,096 meters) in six minutes. Normal range 650 miles (1,046 kilometers).

Lockheed built one XP-38, thirteen YP-38s, and more than 10,000 production fighter and reconnaissance airplanes. At the end of World War II, orders for nearly 2,000 more P-38 Lightnings were cancelled.

Lockheed YP-38 39-692 in flight.(Hans Groenhoff Photographic Collection, Smithsonian Institution National Air and Space Museum NASM-HGC-967)

Ralph Burwell Virden was born 11 June 1898, at Audobon Township, Illinois. He was the second child of Hiram R. Virden, a farmer, and Nancy Carrie Ivy Virden.

Virden attended Bradley Polytechnic Institute at Peoria, Illinois. At the age of 17, 15 October 1918, Ralph Virden enlisted in the U.S. Army. With the end of World War I less than one month later, he was quickly discharged, 7 December 1918.

In 1919, Ralph Virden married Miss Florence I. McCullers. They would have two children, Kathryn and Ralph, Jr. Kathryn died in 1930 at the age of ten years.

Ralph Burwell Virden with a Boeing Model 40 mail plane, circa late 1920s. As a U.S. Air Mail pilot, Virden is armed with a .45-caliber Colt M1911 semi-automatic pistol. (San Diego Air and Space Museum Archives)
Boeing Airplane Company President Clairmont L. Egvtedt and United Air Lines Captain Ralph B. Virden examine a scale model of the Boeing 247D airliner. (Boeing)

During the mid-1920s, Virden flew as a contract mail pilot. He held Airline Transport Pilot Certificate No. 628, and was employed by Gilmore Aviation and Pacific Air Transport. For thirteen years, Virden was a pilot for United Air Lines. He joined Lockheed Aircraft Company as a test pilot in 1939. He had flown more than 15,000 hours.

Virden lived at 4511 Ben Ave., North Hollywood, California, with his  family. Ralph, Jr., now 19 years of age, was also employed at Lockheed. (Following his father’s death, the younger Virden enlisted in the United States Navy.)

After the accident, Lockheed, the Air Corps and the National Advisory Committee on Aeronautics (NACA) undertook an extensive test program of the P-38.

The Lockheed YP-38 Lightning, 39-690, was sent to the NACA Research Center at Langley Field, Virginia. This photograph is dated 4 February 1942. (NASA)
The second Lockheed YP-38 Lightning, 39-690, was sent to the NACA Langley Research Center at Langley Field, Virginia. This photograph is dated 4 February 1942. (NASA)
Lockheed YP-38 39-690 in the NACA Full Scale Tunnel, December 1944. (NASA)
Lockheed YP-38 39-690 in the NACA Full Scale Tunnel, December 1944. (NASA)
Lockheed YP-38 Lightning 39-690, serial number 122-2203. (NASA)
Lockheed YP-38 Lightning 39-690, serial number 122-2203. (NASA)
Lockheed YP-38 #2 in the NACA full-scale wind tunnel at Langley, Virginia. (NASA)
Lockheed YP-38 Lightning, 39-690 (122-2203), in the NACA Langley Research Center’s full-scale wind tunnel at Langley Field, Virginia, December 1944. (NASA)
Lockheed YP-38 Lightning 39-690. (NASA)
Lockheed YP-38 Lightning 39-690. (NASA)
Lockheed YP-38 Lightning 39-690. (NASA)
Lockheed YP-38 Lightning 39-690. (NASA)
Lockheed YP-38 Lightning 39-690. (NASA)
Lockheed YP-38 Lightning 39-690. (NASA)
Lockheed YP-38 Lightning 39-690, 122-2203. (NASA)
Lockheed YP-38 Lightning 39-690, 122-2203. (NASA)

© 2018, Bryan R. Swopes