Tag Archives: Bell P-39 Airacobra

13 February 1923

Brigadier General Charles E. Yeager, U.S. Air Force (Retired), at Edwards AFB, 14 October 1997, the fiftieth anniversary of his Mach 1 flight. (Photograph © 2017 by Tim Bradley Imaging. Used with permission.)

13 February 1923: Brigadier General Charles Elwood Yeager, United States Air Force (Retired), was born at Myra, West Virginia.

Who is the greatest pilot I ever saw? Well, uh. . . Well, let me tell you. . . .

The following is from the official U.S. Air Force biography: (Photographs from various sources)

“The world’s first man-made sonic boom told the story. On Oct. 14, 1947, over dry Rogers Lake in California, Chuck Yeager rode the X-1, attached to the belly of a B-29 bomber, to an altitude of 25,000 feet. After releasing from the B-29, he rocketed to an altitude of 40,000 feet. Moments later he became the first person to break the sound barrier, safely taking the X-1 he called Glamorous Glennis to a speed of 662 mph, faster than the speed of sound at that altitude. His first words after the flight were, ‘I’m still wearing my ears and nothing else fell off neither.’

Captain Chuck Yeager on Rogers Dry Lake with the Bell X-1, 1948.
Captain Charles E. (“Chuck”) Yeager, USAF, at Rogers Dry Lake with the Bell X-1, 1948.

“Yeager was born in February 1923 in Myra, W. V. In September 1941, he enlisted as a private in the Army Air Corps. He was soon accepted for pilot training under the flying sergeant program and received his pilot wings and appointment as a flight officer in March 1943 at Luke Field, Ariz.

Aviation Cadet Charles E. Yeager, U.S. Army Air Corps. (U.S. Air Force)

“His first assignment was as a P-39 pilot with the 363rd Fighter Squadron, Tonopah, Nev. He went to England in November 1943 and flew P-51s in combat against the Germans, shooting down one ME-109 and an HE-111K before being shot down on his eighth combat mission over German-occupied France on March 5, 1944. He evaded capture by the enemy when elements of the French Maquis helped him to reach the safety of the Spanish border. That summer, he was released to the British at Gibraltar and returned to England. He returned to his squadron and flew 56 more combat missions, shooting down 11 more enemy aircraft.

Second Lieutenant Charles E. (“Chuck”) Yeager, U.S. Army Air Forces, standing on the wing of his North American Aviation P-51D-5-NA Mustang, 44-13897, Glamorous Glenn II, at Air Station 373, 12 October 1944. (U.S. Air Force)
First Lieutenant Charles E. (“Chuck”) Yeager, U.S. Army Air Corps, standing on the wing of his North American Aviation P-51D-5-NA Mustang, 44-13897, Glamorous Glenn II, at Air Station 373, 12 October 1944. (U.S. Air Force)

“Returning to stateside, Yeager participated in various test projects, including the P-80 Shooting Star and P-84 Thunderjet. He also evaluated all the German and Japanese fighter aircraft brought back to the United States after the war. This assignment led to his selection as pilot of the nation’s first research rocket aircraft, the Bell X-1, at Muroc Army Air Field (now Edwards Air Force Base, Calif.). After breaking the sound barrier in 1947, Yeager flew the X-1 more than 40 times in the next two years, exceeding 1,000 mph and 70,000 feet. He was the first American to make a ground takeoff in a rocket-powered aircraft. In December 1953 he flew the Bell X-1A 1,650 mph, becoming the first man to fly two and one-half times the speed of sound.

Captain Charles E. Yeager, USAF with a North American Aviation F-86A Sabre, Los Angeles, 21 January 1949. (© Bettman/CORBIS)
Captain Charles E. Yeager, USAF with a North American Aviation F-86A Sabre, Los Angeles, 21 January 1949. (Bettman/CORBIS)
Major Charles E. Yeager, U.S. Air Force, in the cockpit of the Bell X-1A rocketplane. (U.S. Air Force)
Major Charles E. Yeager, U.S. Air Force, in the cockpit of the Bell X-1A rocketplane. (U.S. Air Force)
Major Charles E. Yeager, USAF, Ramstein Air Base, Germany, 1958. (Stars and Stripes)
Lieutenant Colonel Charles E. Yeager, USAF, 1st Fighter Day Squadron, with North American Aviation F-100F-15-NA Super Sabre, 56-3950, George Air Force Base, California, 1958. (U.S. Air Force)
Lieutenant Colonel Charles E. Yeager, USAF, 1st Fighter Day Squadron, 413th Fighter Day Wing, with North American Aviation F-100F-15-NA Super Sabre, 56-3950, George Air Force Base, California, 1958. (Jet Pilot Overseas)
Colonel Charles E. (“Chuck”) Yeager, United States Air Force, 306th Tactical Fighter Squadron, 31st Tactical Fighter Wing, 1958. (U.S. Air Force)
Colonel Yeager became Commandant of the U.S. Air Force Aerospace Research Pilot School at Edwards Air Force Base, 23 July 1962. (U.S. Air Force)
Colonel Charles E. (“Chuck”) Yeager, USAF, commanding the 405th Fighter Wing, with crew chief TSGT Rodney Sirois, before a combat mission with a Martin B-57 Canberra during the Vietnam War. (Stars and Stripes)

“After a succession of command jobs, Yeager became commandant of the Aerospace Research Pilot School (now the U.S. Air Force Test Pilot School), where all military astronauts were trained.

Colonel Charles E. Yeager, USAF, in the cockpit of a Lockheed NF-104A Aerospace Trainer, 4 December 1963. (U.S. Air Force)
Colonel Charles E. Yeager, USAF, in the cockpit of a Lockheed NF-104A Aerospace Trainer, 4 December 1963. (U.S. Air Force)

“On Dec. 10, 1963, he narrowly escaped death while testing an NF-104 rocket-augmented aerospace trainer. His aircraft went out of control at 108,700 feet (nearly 21 miles up) and crashed. He parachuted to safety at 8,500 feet after battling to gain control of the powerless aircraft. He thus became the first pilot to make an emergency ejection in the full pressure suit needed for high altitude flights. Yeager has flown more than 200 types of military aircraft and has more than 14,000 hours, with more than 13,000 of them in fighter aircraft.

Brigadier General Charles E. Yeager, United States Air Force, July 1969. (Stars and Stripes)

“Yeager retired from active duty in the U. S. Air Force in March 1975, after serving as the United States defense representative to Pakistan and director of the Air Force Inspection and Safety Center, Norton AFB, Calif.

Brigadier General Charles E. Yeager, U.S. Air Force, made his final flight as an active duty officer aboard A McDonnell F-4C Phantom II at Edwards AFB, 25 February 1975. (U.S. Air Force)
Brigadier General Charles E. Yeager, U.S. Air Force, made his final flight as an active duty officer aboard a McDonnell Douglas F-4E Phantom II at Edwards AFB, 25 February 1975. (U.S. Air Force)

“Retirement was never part of his plans. He remains an active aviation enthusiast, acting as adviser for various films, programs and documentaries on aviation. He has published two books, entitled Yeager, An Autobiography and Press On: Further Adventures in the Good Life.”

Brigadier General Charles E. Yeager, United States Air Force

© 2017, Bryan R. Swopes

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9 August 1939

Bell XP-39 Airacobra 38-326 in the NACA Full Scale Wind Tunnel at Langley Field, Virginia, 9 August 1939. The man at the base of the supports shows scale. (NASA)

9 August 1939: After General Henry H. Arnold had ordered that the prototype Bell Aircraft Corporation XP-39 Airacobra be evaluated in the National Advisory Committee for Aeronautics (NACA) Full-Scale Tunnel at the Langley Memorial Aeronautics Laboratory, Langley Field, Virginia, it was flown there from Wright Field. It was hoped that aerodynamic improvements would allow the prototype to exceed 400 miles per hour (644 kilometers per hour).

NACA engineers placed the full-size airplane inside the large wind tunnel for testing. A number of specific areas for aerodynamic improvement were found. After those changes were made by Bell, the XP-39’s top speed had improved by 16%.

Bell XP-39 in the NACA wind tunnel at Langley Field. (NASA)
Bell XP-39 Airacobra 38-326 in the NACA wind tunnel at Langley Field. The man at the base of the supports shows scale. (NASA)

The Bell XP-39 Airacobra was a single-place, single-engine prototype fighter with a low wing and retractable tricycle landing gears. The airplane was primarily built of aluminum, though control surfaces were fabric covered.

As originally built, the XP-39 was 28 feet, 8 inches (8.738 meters) long with a wingspan of 35 feet, 10 inches (10.922 meters). The prototype had an empty weight of 3,995 pounds (1,812 kilograms) and gross weight of 5,550 pounds (2,517 kilograms).

The XP-39 was unarmed, but it had been designed around the American Armament Corporation T9 37 mm autocannon, later designated Gun, Automatic, 37 mm, M4 (Aircraft). The cannon and ammunition were in the forward fuselage, above the engine driveshaft. The gun fired through the reduction gear box and propeller hub.

The XP-39 was originally powered by a liquid-cooled, turbosupercharged and supercharged 1,710.597-cubic-inch-displacement (28.032 liter) Allison Engineering Co. V-1710-E2 (V-1710-17), a single overhead cam (SOHC) 60° V-12 engine with a compression ratio of 6.65:1. The V-1710-17 had a Maximum Continuous Power rating of 1,000 horsepower at 2,600 r.p.m. at 25,000 feet (7,620 meters), and Takeoff/Military Power rating of 1,150 horsepower at 3,000 r.p.m. at 25,000 feet, burning 91 octane gasoline. The engine was installed in an unusual configuration behind the cockpit, with a two-piece drive shaft passing under the cockpit and turning the three-bladed Curtiss Electric constant-speed propeller through a remotely-mounted 1.8:1 gear reduction gear box. The V-1710-17 was 16 feet, 1.79 inches (4.922 meters) long, including the drive shaft and remote gear box. It was 2 feet, 11.45 inches (0.900 meters) high, 2 feet, 5.28 inches (0.744 meters) wide and weighed 1,350 pounds (612 kilograms).

After initial flight testing, the XP-39 was sent to NACA at Langley Field, Virginia for wind tunnel tests. Improvements in aerodynamics were recommended and the airplane was rebuilt as the XP-39B with an Allison V-1710-E5 (V-1710-37) engine. The turbosupercharger had been removed, which reduced the airplane’s power at altitudes above 15,000 feet (4,572 meters). The V-1710-37 had a maximum power of 1,090 horsepower at 3,000 r.p.m. at 13,300 feet (4,054 meters). This resulted in the P-39 being used primarily as a ground-attack weapon.

A Bell P-39 Airacobra fires all of its guns at night. (U.S. Air Force)

© 2017, Bryan R. Swopes

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