Tag Archives: Prototype

10 April 1959

Aviation, , , , , , , , , , , ,
Prototype Northrop YT-38-5-NO Talon 58-1191 takes off for the first time at Edwards AFB, 10 April 1959. (U.S. Air Force)
Prototype Northrop YT-38-5-NO Talon 58-1191 at Edwards AFB, 10 April 1959. (U.S. Air Force)

10 April 1959: Northrop test pilot Lewis A. Nelson made the first takeoff of the prototype YT-38-5-NO Talon, serial number 58-1191, at Edwards Air Force Base, California.

A private venture by Northrop, the Talon was designed by a team led by Edgar Schmued, famous for his work on the North American Aviation P-51 Mustang, F-86 Sabre and the F-100 Super Sabre. The Talon is a twin-engine advanced trainer capable of supersonic speeds. More than 5,500 hours of wind tunnel testing was performed before the airplane’s final configuration was determined.

After testing, the two YT-38s were modified to the YT-38A configuration. The modified aircraft was accepted by the United States Air Force and ordered into production as the T-38A Talon.

The T-38 was the world’s first supersonic flight trainer. The Northrop T-38A Talon is a pressurized, two-place, twin-engine, jet trainer. Its fuselage is very aerodynamically clean and uses the “area-rule” (“coked”) to improve its supersonic capability. It is 46 feet, 4.5 inches (14.135 meters) long with a wingspan of 25 feet, 3 inches (7.696 meters) and overall height of 12 feet, 10.5 inches (3.924 meters). The one-piece wing has an area of 170 square feet (15.79 square meters). The leading edge is swept 32º. The airplane’s empty weight is 7,200 pounds (3,266 kilograms) and maximum takeoff weight is approximately 12,700 pounds (5,761 kilograms).

Northrop YT-38-5-NO 58-1191 in flight over Edwards AFB, 10 April 1959. (U.S. Air Force)
Northrop YT-38-5-NO 58-1191 in flight over Edwards AFB, 10 April 1959. (U.S. Air Force)

The T-38A is powered by two General Electric J85-GE-5 turbojet engines. The J85 is a single-shaft axial-flow turbojet engine with an 8-stage compressor section and 2-stage turbine. The J85-GE-5 is rated at 2,680 pounds of thrust (11.921 kilonewtons), and 3,850 pounds (17.126 kilonewtons) with afterburner. It is 108.1 inches (2.746 meters) long, 22.0 inches (0.559 meters) in diameter and weighs 584 pounds (265 kilograms).

The T-38A has a maximum speed of Mach 1.08 (822 miles per hour/1,323 kilometers per hour) at Sea Level, and Mach 1.3 (882 miles per hour/1,419 kilometers per hour) at 30,000 feet (9,144 meters). It has a rate of climb of 33,600 feet per minute (171 meters per second) and a service ceiling of 55,000 feet (16,764 meters). Its range is 1,140 miles (1,835 kilometers).

Northrop YT-38-5-NO Talon 58-1191. (Northrop)
Northrop YT-38-5-NO Talon 58-1191. (Northrop)

Between 1959 and 1972, 1,187 T-38s were built at Northrop’s Hawthorne, California factory. As of 2014, 546 T-38s remained in the U.S. Air Force active inventory. The U.S. Navy has 10, and NASA operates 15.

Northrop YT-38-5-NO Talon 58-1191. (Northrop)
Northrop YT-38-5-NO Talon 58-1191. (Northrop)
58-1191 and sister ship 58-1192 were converted to YT-38As. (Northrop)
Lewis A. Nelson. (Photograph courtesy of Neil Corbett, Test and Research Pilots, Flight Test Engineers)

Lewis Albert Nelson was born 13 September 1920 at San Diego, California, the second of three children of George Walter Nelson, an electrician, and Edith Clarissa Merrill Nelson. He grew up in Santa Cruz, California.

Nelson first flew in a Piper J-3 Cub as a teenager. While attending a junior college in 1939, he was accepted into the Civilian Pilot Training Program and continued while at San Jose State College, San Jose, California.

Nelson enlisted as an aviation cadet in the U.S. Army Air Corps at Moffett Field, California, 12 January 1942. He was 5 feet, 7 inches (1.702 meters) tall and weighed 154 pounds (69.9 kilograms). He served until 1947. He was twice awarded the Distinguished Flying Cross.

After leaving the Air Corps, Nelson studied aeronautical engineering at the University of Southern California (USC) in Los Angeles, graduating in 1949. He later earned a master’s degree from the University of California, Los Angeles (UCLA).

Lew Nelson worked as an aeronautical engineer for the National Advisory Commission on Aeronautics (NACA), and joined the Northrop Corporation as a test pilot in 1950. In 1952 he was promoted to Chief Experimental Test Pilot. Nelson made the first flights of a number of Northrop aircraft, such as the F-89 Scorpion, N-156 and F-5. Nelson retired from Northrop in 1986.

He married Elaine M. Miller, Clark County, Nevada, 28 April 1979.

Lewis Albert Nelson died at Menifee, California, 15 January 2015, at the age of 94 years. His remains were buried at sea.

© 2019, Bryan R. Swopes

9 April 1969

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Brian Trubshaw and John Cochrane, aboard Concorde 002, 9 April 1969. (Photograph courtesy of Neil Corbett, Test and Research Pilots, Flight Test Engineers)
Brian Trubshaw and John Cochrane, aboard Concorde 002, 9 April 1969. (Photograph courtesy of Neil Corbett, Test and Research Pilots, Flight Test Engineers)

9 April 1969: Concorde 002, G-BSST, the first British-built prototype of the supersonic airliner, made its first flight from Filton Airport, Fairfield, England, with British Aerospace Corporation’s Chief Test Pilot, Ernest Brian Trubshaw CBO MVO, as pilot, John Cochrane as co-pilot and Flight Engineer Brian Watts. Also on board, monitoring a range of instruments in the forward cabin, were three other Test Flight Engineers, Mike Addley, John Allan and Peter Holding.

"Concorde 002 on April 9th 1969 ready for a test flight. The flight crew pose before take-off. From left to right, John Allan and Mike Addley (Flight test Observers) John Cochrane, co-pilot, Brian Trubshaw, pilot; Brian Watts, engineer and Peter Holding (Flight Test Observer)." (Stan Sims/Filton Library)
“Concorde 002 on April 9th 1969 ready for a test flight. The flight crew pose before take-off. From left to right, John Allan and Mike Addley (Flight test Observers) John Cochrane, co-pilot, Brian Trubshaw, pilot; Brian Watts, engineer and Peter Holding (Flight Test Observer).” (Stan Sims/Filton Library)

After a preliminary test flight, they landed the new prototype at RAF Fairford, 50 miles northeast, where the flight test program would continue. This flight was just five weeks after the French-built Concorde 001 had made its first flight.

The two prototypes were used to establish the airliner’s flight characteristics and performance envelope, and to develop flight procedures. Follow-on pre-production Concordes were constructed to go through government certification as a commercial airliner.

G-BSST’s career ended with 836 hours, 9 minutes total flight time, of which 173 hours, 26 minutes were supersonic. Concorde 002 is preserved at Royal Naval Air Station, Yeovilton, Somerset, England.

BAC Concorde 002, G-BSST, makes its first takeoff at Bristol Filton Airport, 9 April 1969. (BAC)
BAC Concorde 002, G-BSST, makes its first takeoff at Bristol Filton Airport, 9 April 1969. (BAC)

© 2017, Bryan R. Swopes

9 April 1967

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The prototype Boeing 737-130, PA-099, N73700, first flight 9 April 1967. (Boeing)
The prototype Boeing 737-130, PA-099, N73700, first flight 9 April 1967. (Boeing)

At 1:15 p.m., 9 April 1967, the prototype Boeing 737-130, N73700, (internal number PA-099) took off from Boeing Field, Seattle, Washington, with test pilots Brien Singleton Wygle and Samuel Lewis (“Lew”) Wallick, Jr., in the cockpit. After a 2 hour, 30 minute flight, the new airliner landed at Paine Field, Everett, Washington.

When asked by a reporter what he thought about the new airplane, Boeing’s president, Bill Allen, replied, “I think they’ll be building this airplane when Bill Allen is in an old man’s home.”

Boeing test pilots Brien Wygle and Lew Wallick with the prototype 737 airliner, N73700. (Boeing)
Boeing test pilots Brien Wygle and Lew Wallick with the prototype 737 airliner, N73700. (Boeing)

He was right. In production since 1968, the Boeing 737 is the most popular airliner ever made and it is still in production. On 13 March 2018, the 10,000th 737 was delivered.

The first Boeing 737 under assembly. (Boeing)

Boeing 737-130 N73700 was a twin engine, medium-range airliner, operated by a pilot and co-pilot. It was designed to carry up to 124 passengers. The airplane is 97 feet (28.57 meters) long with a wingspan of 87 feet (26.52 meters) and overall height of 37 feet (11.3 meters). It has an empty weight of 56,893 pounds (25,807 kilograms) and gross weight of 111,000 pounds (50,350 kilograms).

N73700 is powered by two Pratt & Whitney JT8D-7 turbofan engines rated at 14,000 pounds of thrust, each. The JT8D is a two-spool engine with a 2-stage fan section, 13-stage compressor (6 low- and 7 high-pressure stages), nine combustion chambers and a 4-stage turbine (1 high- and 3 low-pressure stages). The JT8D-7 is 42.5 inches (1.080 meters) in diameter, 123.5 inches (3.137 meters) long, and weighs 3,096 pounds (1,404 kilograms).

The airliner’s cruise speed is 575 miles per hour (925 kilometers per hour) and its range is 1,150 miles (1,850 kilometers).

After the flight test and certification program was complete, Boeing handed N73700 over to the National Aeronautics and Space Administration at Langley Field, Virginia, 12 June 1973, where it became NASA 515 (N515NA).  The airliner was used for research in cockpit design, engine controls, high lift devices, etc. Because of it’s short and stubby appearance, NASA named it “Fat Albert.”

NASA 515, the first Boeing 737, photographed 29 November 1989. (NASA)

The prototype Boeing 737 ended its NASA career and was returned to Boeing, landing for the last time at Boeing Field’s Runway 31L, 3:11 p.m., PDT, 21 September 2003. Today, PA-099 is on display at the Museum of Flight, Seattle, Washington.

NASA 515, the prototype Boeing 737 airliner, rolling out on Runway 31L, Boeing Field, 3:11 p.m. PDT, 21 September 2003.
NASA 515, the prototype Boeing 737 airliner, rolling out on Runway 31L, Boeing Field, 3:11 p.m. PDT, 21 September 2003. (Robert A. Bogash)

© 2019, Bryan R. Swopes

6 April 1939

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The Bell XP-39 prototype in the original turbosupercharged configuration. The intercooler and waste gates created significant aerodynamic drag. (Bell Aircraft Corporation)
The Bell XP-39 prototype, 38-326, in the original turbosupercharged configuration. The intercooler and waste gates created significant aerodynamic drag. (U.S. Air Force)

6 April 1939: ¹ After being shipped by truck from the Bell Aircraft Company factory at Buffalo, New York, the XP-39 prototype, 38-326, (Bell Model 4) made its first flight at Wright Field, Ohio, with test pilot James Taylor in the cockpit. During the test flight, Taylor flew the XP-39 to 390 miles per hour (628 kilometers per hour) at 20,000 feet (6,096 meters). The service ceiling was 32,000 feet (9,754 meters).

The XP-39 was designed by Bell’s chief engineer, Robert J. Woods, to meet a U.S. Army Air Corps requirement, X-609, issued in March 1937, for a high altitude interceptor. A contract for the prototype was issued 7 October 1937. On 15 April 1939, Assistant Secretary of War Louis Johnson announced that the U.S. Army had purchased the experimental Bell XP-39 and the Seversky XP-41.

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.

Bell XP-39 Airacobra 38-326. (U.S. Air Force)

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 Bell XP-39 Aircobra in original configuration. (Allison Engine Historical Society)
The Bell XP-39 Aircobra in original configuration. (U. S. Air Force)

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).² 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.

Bell P-39 Airacobra center fuselage detail with maintenance panels open. (U.S. Air Force photo)

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).

Allison V-1710 E19 (V-1710-85) with extension drive shaft and remote propeller drive gear unit. (Allison Division of General Motors)

On 6 June 1939 the XP-39 was flown to the National Advisory Committee for Aeronautics (NACA) Langley Memorial Aeronautical Laboratory at Hampton, Virginia, by Lieutenant Mark E. Bradley, Jr. The prototype was tested in the Full-Scale Wind Tunnel. Improvements in aerodynamics were recommended and Bell rebuilt the airplane as the XP-39B with an Allison V-1710-E5 (V-1710-37) engine.

Bell XP-39 Airacobra 38-326 in the NACA Langley Memorial Aeronautical Laboratory Full-Scale Wind Tunnel, Langley Field, Virginia. (NASA)
Bell XP-39 Airacobra 38-326 in the NACA Langley Memorial Aeronautical Laboratory Full-Scale Wind Tunnel, Langley Field, Hampton, Virginia, 9 August 1939. The fuselage has had all protrusions removed. (NASA)
Bell XP-39 Airacobra 38-326 in the NACA Langley Memorial Aeronautical Laboratory Full-Scale Wind Tunnel, Langley Field, Hampton, Virginia. (NASA)

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.

The XP-39B, with test pilot George Price in the cockpit, was damaged when when its landing gear did not fully extend, 6 January 1940. It was repaired and test flights resumed. On 6 August 1940, Captain Ernest K. Warburton stalled the prototype on landing. The impact resulted in significant structural damage, beyond economic repair. The airplane was later scrapped.

Bell Model 12 (XP-39) prototype 38-326, at Bell Aircraft Co., Buffalo, New York
Bell XP-39B Airacobra prototype, 38-326, at the Bell Aircraft Corporation airfield, Buffalo, New York, 1940. (Bell Aircraft Corporation)

On 27 April 1939, the U.S. Army announced that a contract to Bell Aircraft had been issued in the amount of $1,073,445 for delivery of thirteen YP-39s. 9,584 Bell P-39 Airacobras were built during World War II. More than half were sent to the Soviet Union.

Bell XP-39 prototype, serial number 38-326. (Bell Aircraft Corporation)
Bell XP-39B prototype, serial number 38-326. (Bell Aircraft Corporation)

¹ Reliable sources indicate the date of the first flight as both 6 April 1938 and 6 April 1939. The Bell Helicopter Company web site, “The History of Bell Helicopter: 1935–1949” states 1938. However, contemporary newspaper articles strongly suggest that the date was 1939. The first newspaper references to the XP-39 located by TDiA are dated 16 April 1939.

² The 37-mm Aircraft Gun Matériel M4 is a recoil-operated aircraft weapon designed by John M. Browning. It has an overall length of 7 feet, 5 inches (2.26 meters). The barrel, or “tube,” is 5 feet, 5 inches (1.65 meters) long with a caliber of 1.457 inches (37.0 millimeters) and weighs 55 pounds (25 kilograms). The barrel is part of the recoiling section of the gun and moves rearward 9-5/8 inches (245 millimeters). The weight of the gun with a loaded 30-round magazine is 306.4 pounds (138.98 kilograms). The M4 fires a high-explosive tracer round with a muzzle velocity of 2,000 feet per second (607 meters per second). Each M54 shell is 9.75 inches (248 millimeters) long and weighs 1.93 pounds, of which the projectile makes up 1.34 pounds (0.608 kilograms). The cannon has a cyclic rate of fire of 125–150 rounds per minute.

© 2023, Bryan R. Swopes

3 April 1941

Aviation, , , , , , , , ,
Test pilot Robert C. Chilton with the North American Aviation prototype NA-73X, NX19998. (North American Aviation, Inc.)
Test pilot Robert C. Chilton with the North American Aviation prototype NA-73X, NX19998. (North American Aviation, Inc.)

3 April 1941: North American Aviation test pilot Robert Creed Chilton takes his first flight—a one hour familiarization—in the company’s prototype of a new fighter for the Royal Air Force, the NA-73X, NX19998, at Mines Field. (Mines would later become Los Angeles International Airport, LAX.)

The airplane had first been flown by free-lance test pilot Vance Breese, 26 October 1940,  and he had flown it several times. North American’s Chief Test Pilot, Paul Baird Balfour, on his first flight in NX19998, ran out of fuel and crash landed in a plowed field 150 yards (137 meters) west of the airfield, 20 November 1940. The prototype had flown just 3 hours, 20 minutes.

The NA-73X was repaired and Bob Chilton was assigned to complete the testing program. The airplane would become the legendary P-51 Mustang, and Chilton would continue to conduct the majority of flight testing on its improvements and modifications.

Test pilot Robert C. Chilton stand on the wing of a North American Aviation P-51B Mustang. (North American Aviation)
Test pilot Robert C. Chilton stands on the wing of a North American Aviation P-51B Mustang. (North American Aviation, Inc.)

Robert Creed Chilton was born 6 February 1912 at Eugene, Oregon, the third of five children of Leo Wesley Chilton, a physician, and Edith Gertrude Gray. He attended Boise High School in Idaho, graduating in 1931. Chilton participated in football, track and basketball, and also competed in the state music contest. After high school, Chilton attended the University of Oregon where he was a member of the Sigma Chi fraternity (ΣΧ). He was also a member of the Reserve Officers Training Corps (ROTC).

Bob Chilton enlisted as an Aviation Cadet in the U.S. Army Air Corps, 25 June 1937. He was trained as a fighter pilot at Randolph Field and Kelly Field in Texas, and was commissioned as a Second Lieutenant in 1938. Lieutenant Chilton was assigned to fly the Curtiss P-36 Hawk with the 79th Pursuit Squadron, 20th Pursuit Group, at Barksdale Field, Louisiana. Because of a medical condition, he was released from active duty, 1 April 1939.

At some time prior to 1940, Bob Chilton, married his first wife, Catherine. They lived in Santa Maria, California, where he worked as a pilot at the local airport.

In January 1941, Chilton went to work as a production test pilot for North American Aviation, Inc., Inglewood, California. After just a few months, he was assigned to the NA-73X.

Chilton married his second wife, Betty W. Shoemaker, 15 November 1951.

On 10 April 1952, Bob Chilton returned to active duty with the U.S. Air Force, with the rank of lieutenant colonel. He served as Chief of the Repulic F-84 and F-105 Weapons System Project Office, Air Material Command, at Wright-Patterson Air Force Base, Dayton, Ohio, until 9 March 1957.

From 1958, Chilton was a vice president for Horkey-Moore Associates, an engineering research and development company in Torrance, California, founded by former North American aerodynamacist Edward J. Horkey. In 1961, he followed Horkey to the Space Equipment Corporation, parent company of Thompson Industries and Kerr Products, also located in Torrance. Chilton served as corporate secretary and contracts administrator.

Chilton married his third wife, Wilhelmina E. Redding (Billie E. Johnson) at Los Angeles, 26 July 1964. They divorced in 1972.

In 1965, Bob Chilton returned to North American Aviation as a flight test program manager. He retired in 1977.

Robert Creed Chilton died at Eugene, Oregon, 31 December 1994, at the age of 82 years.

© 2017, Bryan R. Swopes