Tag Archives: Allison Engineering Co.

8 December 1945

The second prototype Douglas XB-42, 43-50225, In this photograph, the dual bubble canopies have been replaced with a single canopy to improve flight crew communication. (U.S. Air Force)
The second prototype Douglas XB-42, 43-50225, In this photograph, the dual bubble canopies have been replaced with a single canopy to improve flight crew communication. (U.S. Air Force)

8 December 1945: Lieutenant Colonel Henry E. Warden and Captain Glen W. Edwards, U.S. Army Air Corps, flew the second prototype Douglas XB-42, serial number 43-50225, from Long Beach, California to Washington, D.C., in 5 hours, 17 minutes, 34 seconds, averaging 433.6 miles per hour (697.8 kilometers per hour).

The XB-42 (originally designated as an attack aircraft, XA-42) was as unusual design. It used two engines inside the fuselage to drive counter-rotating three-bladed propellers in a pusher configuration at the tail. This created a very low-drag aircraft that was much faster than similar sized and powered aircraft.

Douglas XB-42 43-50225, the second prototype. (U.S. Air Force)
Douglas XB-42 43-50225, the second prototype. (U.S. Air Force)

A pilot and co-pilot sat side-by-side under separate bubble canopies. (This was later changed to improve communication between the crew.) The third crewman, a navigator/bombardier, occupied the nose. The co-pilot also served as a gunner and could operate four remotely-controlled .50-caliber machine guns located in two retractable power turrets inside the trailing edge of the wings. Another two .50-caliber machine guns were fixed, aimed forward. The bomber was designed to carry a 8,000 pound (3,629 kilogram) bomb load.

Douglas XB-42 43-50224 takes off from Palm Springs, California. (U.S. Air Force)

The XB-42 was powered several variants of the Allison Engineering Company E-series V-1710 engines, confiured as combined power assembles, and driving a remote propeller gear box through five Bell P-39 Airacobra driveshafts. The starboard engine turned counter-clockwise and drove the rear propeller. The port engine turned clockwise and drove the forward propeller. These engines were the V-1710-E23 (V-1710-103), V-1710-E24 (V -1710-125) and V-1710-E23B (V-1710-129). The V-1710 was a liquid-cooled, supercharged 1,710.60-cubic-inch-displacement (28.032 liter) single-overhead-camshaft (SOHC) 60° V-12 aircraft engine with four valves per cylinder. The engines used in the XB-42 had two-stage superchargers and turbosuperchargers.

The V-1710-129 was an experimental turbocompound engine, in which an exhaust-driven turbocharger is coupled to the drive shaft to provide a direct power input. It had a compression ratio of 6.65:1 and required 100/130 octane aviation gasoline. The V-1710-129 had a continuous power rating of 1,050 horsepower at 2,600 r.p.m., at Sea Level, and takeoff/military power rating of 1,675 horsepower at 3,200 r.p.m. (1,100 horsepower at 3,000 r.p.m. at 25,000 feet (7,620 meters) ). The engines turned three-bladed, counter-rotating, Curtiss Electric propellers through a 2.773:1 gear reduction. The forward propeller had a diameter of 13 feet, 2 inches (4.013 meters) and the rear diameter was 13 feet (3.962 meters). The difference was to prevent interference of the blade tip vortices.

Douglas XB-42 43-50224. (U.S. Air Force)
Douglas XB-42 43-50224. (U.S. Air Force)

The airplane was 53 feet, 8 inches long (16.358 meters), with a wingspan of 70 feet, 6 inches (21.488 meters). Empty weight was 20,888 pounds (9,475 kilograms), with a maximum gross weight of 35,702 pounds (16,194 kilograms). The prototype’s cruising speed was 310 miles per hour (499 kilometers per hour) and its maximum speed was 410 miles per hour (660 kilometers per hour) at 23,500 feet (7,163 meters). The service ceiling was 29,400 feet (8,961 meters). The XB-42’s normal range was 1,840 miles (2,961 kilometers).

Captain Glen W. Edwards, U.S. Air Force (1918–1948)
Captain Glen W. Edwards, U.S. Air Force (1918–1948)

Glen W. Edwards graduated from the University of California, Berkeley and soon after enlisted in the U.S. Army Air Corps. He was commissioned as a second lieutenant in February 1942 after completing flight training. Edwards flew 50 combat missions in the Douglas A-20 Havoc attack bomber during the North Africa and Sicily campaigns of World War II. He 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. He tested the Northrop XB-35 flying wing and the Convair XB-46. He 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.

Captain Edwards was killed along with four others while test flying the Northrop YB-49 “Flying Wing” in 1948. In 1949, Muroc Air Force Base, California, was renamed Edwards Air Force Base in his honor.

General Reuben C. Hood congratulates Captain Glen Edwards and Lieutenant Colonel Harold E. Warden after their record-setting transcontinental flight, 8 December 1945. ( © Bettman/CORBIS.)
(Left to right) Brigadier General Reuben C. Hood, Jr., congratulates Captain Glen W. Edwards and Lieutenant Colonel Harold E. Warden after their record-setting transcontinental flight, 8 December 1945. ( © Bettman/CORBIS.)

Colonel Henry E. (“Pete”) Warden (1915–2007) flew Curtiss P-40 Warhawks with the 20th Pursuit Squadron in the Philippine Islands at the beginning of World War II. He  was evacuated from Bataan to Australia, where he set up and ran the air logistics system for several years, before being sent to Wright Field.

After World War II, Warden was responsible for the development of the Convair B-36, Boeing B-47 and the Boeing B-52. He was called the “Father of the B-52.” After retiring from the Air Force, Colonel Warden went to work for North American Aviation on the B-70 Valkyrie program.

XB-42 43-50224 flew for the first time 1 August 1944. On 16 December 1945, it was on a routine flight from Bolling Field, Washington, D.C., with Lieutenant Colonel Fred J. Ascani in command, when a series of failures caused the crew to bail out. The XB-42 crashed at Oxon Hill, Maryland and was destroyed.

The second prototype, 43-50225, is in storage at the National Museum of the United States Air Force, Wright Patterson AFB, Ohio.

The first prototype XB-42, 43-50224, at Palm Springs, California, 1945. (U.S. Air Force)
The first prototype XB-42, 43-50224, at Palm Springs, California, 1945. (U.S. Air Force)

© 2016, Bryan R. Swopes

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4 November 1941

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

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