Tag Archives: Edgar Schmued

10 April 1959

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

20 November 1940

North American Aviation's NA-73X fighter prototype, engine idling, with Vance Breese in the cockpit at Mines Field, Los Angeles, 26 October 1941. (North American Aviation Inc.)
North American Aviation’s NA-73X fighter prototype, engine idling, with Vance Breese in the cockpit at Mines Field, Los Angeles, 26 October 1940. (North American Aviation Inc.)

20 November 1940: North American Aviation’s Chief Test Pilot, Paul Baird Balfour, made his first flight in the NA-73X, NX19998, prototype for a Royal Air Force fighter, the Mustang Mk.I.

Vance Breese was the free-lance test pilot who made the first seven flights in the new airplane. Breese claimed to have made a bet with North American executives that Balfour would crash the prototype on his first flight.

Paul B. Balfour (1908–1951). This is Balfour’s NAA employee file card. (North American Aviation Inc.)

This flight was scheduled to be a high speed test. Edgar Schmued, the designer, offered to show Balfour around the airplane. “Before this flight, I asked Balfour to get into the airplane and go through the routine of a takeoff and flight. He responded that one airplane is like another and he would not need the routine checkout.”

The ground crew started the NA-73X’s 1,150 horsepower Allison V-1710-39 liquid-cooled V-12 engine at 5:40 a.m. and let it warm up to normal operating temperature. When it was restarted just prior to Paul Balfour’s flight, “it was a little hard to start,” according to Olaf Anderson, the airplane’s mechanic.

The prototype Mustang, NA-73X, lies upside down in a plowed field, 20 November 1941. (North American Aviation Inc.)
The prototype Mustang, NA-73X, lies upside down in a plowed field, 20 November 1940. (North American Aviation Inc.)

Balfour took off from Mines Field at about 7:10 a.m. After about twelve minutes of flight, the Allison stopped running. Balfour was too far from Mines Field to make it back to the runway. He landed in a plowed field west of Lincoln Boulevard. When the tires hit the soft surface, the prototype flipped over. Balfour was not hurt and was able to crawl out of the upside-down wreck.

The Civil Aeronautics Board report described the damage as “engine housing broken, both wingtips damaged, tail surfaces damaged, top of fuselage damaged, and other miscellaneous damage.” The NA-73X had accumulated just 3 hours, 20 minutes of flight.

Vance Breese won his bet.

Paul Balfour was not injured in the crash landing, but the NA-73X prototype was significantly damaged. (North American Aviation Inc.)
Paul Balfour was not injured in the crash landing, but the NA-73X prototype was significantly damaged. (North American Aviation Inc.)

According to the C.A.B. investigation, the engine had stopped due to fuel starvation when Balfour neglected to select another tank.

The prototype was taken back to the factory and rebuilt. It would become the famous Mustang, one of the most significant aircraft of World War II.

Damage to the wingtips, tail surfaces, fuselage. (North American Aviation Inc.)
Damage to the wingtips, tail surfaces, fuselage. (North American Aviation Inc.)

Robert C. Chilton was hired as the new Chief Test Pilot. He would continue testing the Mustang developments throughout the war. Chilton made his first flight in NA-73X on 3 April 1941.

The Mustang prototype was hoisted out of the plowed field and taken back to the factory where it was rebuilt. (North American Aviation Inc.)
The Mustang prototype was hoisted out of the plowed field and taken back to the factory where it was rebuilt. (North American Aviation Inc.)

Paul Balfour continued to work for North American Aviation, testing the NA-40 and NA-40B prototypes and the B-25 Mitchell medium bomber. He later served in the United States Air Force.

Paul Baird Balfour was born 5 July 1908 in Washington State. He was the son of Fred Patrick Balfour and Edna May Baird Balfour. Balfour attended two years of college.

Paul Balfour entered the U.S. Army Air Corps (prior to 1930). He was stationed at Rockwell Field, San Diego, California.

Balfour married Martha Lillette Cushman of Coronado, California, at Yuma, Arizona, 6 June 1930.

Balfour began working as a test pilot for North American Aviation, Inc., 1 March 1936.

On 2 July 1938, he married Lois Tresa Watchman at Kingman, Arizona. They would have two children.

Paul B. Balfour, center, with a North American Aviation B-25 Mitchell medium bomber. (Photograph courtesy of Neil Corbett, Test and Research Pilots, Flight Test Engineers)
Paul B. Balfour, center, with a North American Aviation B-25 Mitchell medium bomber. (Photograph courtesy of Neil Corbett, Test and Research Pilots, Flight Test Engineers)

On 9 November 1951, Major Paul B. Balfour, U.S. Air Force, attached to the 1002nd Inspector General Group at Norton Air Force Base, California, was flying a North American VB-25J, 44-30955, a transport conversion of a B-25J-30-NC Mitchell medium bomber.

Shortly after takeoff, at about 10:00 a.m., the airplane developed engine trouble. Unable to return to Norton, Balfour attempted a belly landing at a small private airfield. Witness saw that the airplane’s left engine was idling, and its propeller was feathered. As he approached, the airplane was blocked by a windbreak of eucalyptus trees bordering U.S. Route 66. Balfour banked away from the trees but the B-25 crashed in an orange grove along Bloomington Avenue in Rialto, approximately 7 miles (11 kilometers) north of Norton.

Balfour, still buckled in his seat, was thrown clear of the burning wreck and landed in the street. One man on board was killed and two others seriously injured. Balfour died in a hospital three hours later. He was 41 years old. Major Balfour was buried at the Inglewood Park Cemetery, Inglewood, California.

Burning wing of North American VB-25J 44-30955, near Rialto, California, 9 November 1951.
Burning wing of North American VB-25J 44-30955, near Rialto, California, 9 November 1951.

© 2016, Bryan R. Swopes

15 September 1948

Major Richard L. Johnson, United States Air Force.
Major Richard Lowe Johnson, United States Air Force. (Unattributed)
Major Richard L. Johnson with the record-setting North American Aviation F-86A Sabre.
Major Richard L. Johnson with the record-setting North American Aviation F-86A Sabre. (Unattributed)

15 September 1948: Major Richard L. Johnson, U.S. Air Force, Air Materiel Command, set a new Fédération Aéronautique Internationale (FAI) World Record Speed Over a 3 Kilometer Course,¹ flying the sixth production North American Aviation F-86A-1-NA Sabre, serial number 47-611, at Muroc Air Force Base, California (renamed Edwards AFB in 1949).

The air temperature was 70° F. (21° C.) with very little wind. Making four consecutive passes at an altitude of 75–125 feet (23 to 38 meters), the Sabre averaged 1,079.84 kilometers per hour (670.98 miles per hour) — 0.889 Mach. The slowest pass was 669.830 miles per hour and the fastest was 672.762 miles per hour (1,077.987 and 1,082.705 kilometers per hour, respectively) — 0.8875–0.8914 Mach.

This was Major Lowe’s second attempt for the speed record. At the National Air Races in Cleveland, Ohio, on 5 September, official timers clocked the wrong airplane, and then on a repeat pass, a timing camera jammed. During that attempt, Major Johnson flew under a light airplane which had wandered onto the course, missing it by about ten feet (3 meters).

Major Richard L Johnson, USAF with F-86A-1-NA 47-611 and others at Muroc AFB, 15 September 1948. Note the gun port doors on this early production aircraft. They opened in 1/20 second as the trigger was pressed. Proper adjustment was complex and they were soon eliminated. (Image from F-86 SABRE, by Maurice Allward, Charles Scribner’s Sons, New York, 1978, Chapter 3 at Page 24.)
Major Richard L. Johnson, USAF with F-86A-1-NA Sabre 47-611 and others at Muroc AFB, 15 September 1948. Note the gun port doors on this early production aircraft. They opened in 1/20 second as the trigger was pressed. Proper adjustment was complex and they were soon eliminated. (Image from F-86 Sabre, by Maurice Allward, Charles Scribner’s Sons, New York, 1978, Chapter 3 at Page 24.)
The De la Vaulx Medal.

Major Johnson was awarded the De la Vaulx Medal by the Fédération Aéronautique Internationale.

North American Aviation claimed that any F-86 coming off the assembly line could beat this world record speed. This record stood until 1952 when it was broken by an F-86D Sabre.

The Associated Press reported:

Air Force Tells Of New Speed

     NEW YORK(AP) — The Air Force announced Saturday a new world speed record of 670.981 miles an hour, made with a fully armed standard jet fighter, the North American F-86.

     The mark was set Wednesday. It is 20 miles an hour faster than the record set in August, 1947, by a Navy research plane, the Douglas D-558.

     It was the first world speed mark in history for a production model aircraft ready to fight.

     The pilot was Maj. Richard L. Johnson, slender quiet-spoken test flier for the Air Material Command at Wright-Patterson Airbase near Dayton Ohio. He flew the course at Muroc Lake, Calif., where the record was raised three times last year.

     Gen. Hoyt S. Vandenberg, Air Force chief of staff, announced the new mark at Mitchel Field, Long Island, where he participated in one of the numerous shows being held in observance of the first anniversary of the Air Force.

Eugene Register-Guard, Saturday, 18 September 1948, Page 1, Column 7.

Major Johnson had made a previous speed record attempt flying a different Sabre, but due to a technical problem with the timing equipment, that attempt was disqualified.

47-605 was the first production F-86A-1-NA Sabre. (U.S. Air Force)
F-86A-1-NA 47-605 was the first production Sabre. It first flew on 20 May 1948. (U.S. Air Force)

47-611 was from the first production block of thirty-three F-86A-1-NA Sabres (originally designated P-86A) and was built at North American Aviation’s Inglewood, California, plant. Its NAA serial number was 151-38438. The airplane was withdrawn from service 16 November 1955 and assigned as a ground trainer for the California Air National Guard at Van Nuys, California.

The F-86A was a single-seat, single-engine, swept-wing day fighter, powered by a turbojet engine. The airplane’s design team was headed by Edgar Schmued, who was also responsible for North American’s legendary P-51 Mustang of World War II.

The F-86A had the same dimensions as the prototype XP-86 which had first flown almost two years earlier. The F-86A was 37 feet, 6.6 inches (11.445 meters) long with a wingspan of 37 feet, 1.4 inches (11.313 meters) and overall height of 14 feet, 8.9 inches (4.493 meters). It had an empty weight of 10,093 pounds (4,578 kilograms) and the maximum takeoff weight was 15,876 pounds (7,201 kilograms).

North American Aviation F-86A-1-NA Sabre 47-605, the first production aircraft. (U.S. Air Force)
North American Aviation F-86A-1-NA Sabre 47-605, the first production aircraft. (U.S. Air Force)

The F-86 wings’ leading edges were swept to 35° and included leading edge slats, which automatically extended at low speed to provide an increase in lift.

The F-86A was initially powered by a General Electric TG-190A (J47-GE-1) turbojet engine. This was a major improvement over the Chevrolet-built J35-C-3 that had powered the prototype, and it produced almost 25% greater thrust. The J47-GE-1 was rated at 4,850 pounds of thrust (21.57 kilonewtons), or 5,820 pounds (25.89 kilonewtons) with water injection. The J47 was an axial-flow turbojet with a 12-stage compressor, eight combustion chambers, and single-stage turbine. The engine was 12 feet, 0.0 inches (3.658 meters) long, 3 feet, 3.0 inches (0.991 meters) in diameter and weighed 2,475 pounds (1,123 kilograms).

Early in F-86A production, the engine was standardized with the J47-GE-13, which was rated at 5,200 pounds of thrust (23.13 kilonewtons) and 6,000 pounds (26.69 kilonewtons) “wet.” The -13 had the same exterior dimensions as the -1 engine, but weighed 50 pounds (23 kilograms) more.

North American Aviation F-86-A-NA Sabre 47-630. (North American Aviation, Inc./Chicago Tribune)
North American Aviation F-86A-1-NA Sabre 47-630. (North American Aviation, Inc.)

The F-86A had a maximum speed of 679 miles per hour (1,093 kilometers per hour) at Sea Level, and 601 miles per hour (967 kilometers per hour) at 35,000 feet (10,668 meters). The service ceiling as 48,000 feet (14,630 meters) and it could climb to 40,000 feet (12,192 meters) in 10 minutes, 24 seconds. It had a range of 1,200 miles (1,931 kilometers).

This photograph of a Canadair CL-13 Sabre, a license-built F-86E, shows the firepower of the six .50-caliber machine guns placed close together in the airplane's nose. The smoke trails show the spin of the bullets caused by the gun barrels' rifling. (Royal Canadian Air Force)
This photograph of a Canadair CL-13 Sabre (a license-built F-86E) test-firing its guns shows the firepower of the six .50-caliber machine guns placed close together in the airplane’s nose. The smoke trails show the spin of the bullets caused by the gun barrels’ rifling. The total rate of fire is approximately 7,200 rounds per minute. (Royal Canadian Air Force)

Designed as a day fighter, the F-86 Sabre was armed with six air-cooled Browning AN-M3 .50-caliber aircraft machine guns with 267 rounds of ammunition per gun. These guns had a rate of fire of 1,200 rounds per minute. The F-86A-1-NA had electrically-actuated doors covering the gun ports to maintain the aerodynamically clean surface. Because of their complexity, these doors were deleted beginning with the F-86A-5-NA aircraft.

The fighter could also carry bombs or rockets.

In this photograph, the record-settining North American Aviation F-86A Sabre, 47-611, is seen suspended from a crane while it conducts armament tests. It has just launched a 5-inch High Velocity Aerial Rocket. (U.S. Air Force)

Richard Lowe Johnson ² was born at Cooperstown, North Dakota, 21 September 1917. He was the eighth of nine children of Swedish immigrants, John N. Johnson, a farmer, and Elna Kristina Helgesten Johnson, a seamstress.

Dick Johnson attended Oregon State College at Corvallis, Oregon, as a member of the Class of 1943. He was a member of the Sigma Alpha Epsilon (ΣΑΕ) fraternity.

Dick Johnson was a pitcher for the college baseball team, and later, played for the Boston Red Sox “farm” (minor league) system.

On 18 June 1942, Johnson enlisted as a private in the Air Corps, United States Army. On 5 November, he was appointed an aviation cadet and assigned to flight training.

Aviation Cadet Johnson married Miss Juanita Blanche Carter, 17 April 1943, at Ocala, Florida. The civil ceremony was officiated by Judge D. R. Smith.

After completing  flight training, on 1 October 1943, Richard L. Johnson was commissioned as a second lieutenant, Army of the United States (A.U.S.).

Lieutenant Johnson was assigned to the 66th Fighter Squadron, 57th Fighter Group, Twelfth Air Force, in North Africa, Corsica, and Italy, flying the Republic P-47 Thunderbolt. He was promoted to first lieutenant, A.U.S., 9 August 1944, and just over three months later, 26 November 1944, to the rank of captain, A.U.S. On 14 May 1945, Captain Johnson was promoted to the rank of major, A.U.S. (Major Johnson was assigned a permanent rank of first lieutenant, Air Corps, United States Army, on 5 July 1946, with a date of rank retroactive to 21 September 1945.)

Republic P-47D-25-RE Thunderbolt 42-26421, assigned to the 66th Fighter Squadron, 57th Fighter group, Twelfth Air Force. This airplane was purchased by the employees of Republic Aviation. (American Air Museum in Britain UPL 25505)

During World War II, Major Johnson flew 180 combat missions with the 66th Fighter Squadron. He is officially credited with one air-to-air victory, 1 July 1944. Johnson was awarded the Silver Star, the Distinguished Flying Cross with two oak leaf clusters (3 awards), and the Air Medal with twelve oak leaf clusters (thirteen awards).

In 1946, was assigned to the Air Materiel Command Engineering Test Pilot School at the Army Air Forces Technical Base, Dayton, Ohio (Wright-Patterson Air Force Base). He was the second U.S. Air Force pilot to be publicly acknowledged for breaking the “sound barrier.”

A few weeks after arriving at Dayton, Major Johnson met Miss Alvina Conway Huester, the daughter of an officer in the U.S. Navy. Dick Johnson and his wife Juanita were divorced 8 January 1947, and he married Miss Huester in a ceremony in Henry County, Indiana, 10 January 1947. They would have three children, Kristie, Lisa and Richard.

During the Korean War, Major Johnson was sent to the war zone to supervise field installations of improvements to the F-86 Sabre. He was “caught” flying “unauthorized” combat missions and was sent home.

Lieutenant Colonel Johnson resigned from the Air Force in 1953 to become the Chief Test Pilot for the Convair Division of General Dynamics. He made the first flights of the YF-102 on 24 October 1953, the F-106A Delta Dart, 26 December 1956. He made the first flight of the F-111 on 21 December 1964.

Chief Test Pilot Dick Johnson in the cockpit of a Convair B-58A Hustler, a Mach 2 strategic bomber. (Courtesy if Neil Corbett, Test and Research Pilots, Flight Test Engineers)

in 1955, Johnson was one of the six founding members of the Society of Experimental test Pilots.

Dick Johnson was Chief Engineering Test Pilot for the General Dynamics F-111 “Aardvark.” In 1967, the Society of Experimental Test Pilots awarded Johnson its Iven C. Kincheloe Award for his work on the F-111 program. In 1977, Dick Johnson, now the Director of Flight and Quality Assurance at General Dynamics, retired.

In 1998, Dick Johnson was inducted into the Aerospace Walk of Honor at Lancaster, California. His commemorative monument is located in front of the Lancaster Public Library on W. Lancaster Boulevard, just West of Cedar Avenue. ³

Lieutenant Colonel Richard Lowe Johnson, United States Air Force, (Retired), died 9 November 2002 at Fort Worth, Texas. He was buried at Arlington National Cemetery, Arlington, Virginia, on 7 January 2003.

Richard L. Johnson waves from the cockpit of the record-setting North American Aviation F-86A-1-NA Sabre, 47-611.

¹ FAI Record File Number 9866

² Several sources spell Johnson’s middle name as “Loe.”

³ Various Internet sources repeat the statement that “Richard Johnson has been honored with. . . the Thompson Trophy, Mackay Trophy, Flying Tiger Trophy, Federation Aeronautique Internationale Gold Medal and Golden Plate Award of the American Academy of Achievement. . . .” TDiA has checked the lists of awardees of each of the appropriate organizations and has not found any support for the statement.

© 2018, Bryan R. Swopes

9 September 1940

North American Aviation NA-73X prototype, NX19998, at Mines Field, California, 9 September 1940. (North American Aviation, Inc.)

9 September 1940: North American Aviation completed assembly of the NA-73X, the first prototype of the new Mustang Mk.I fighter for the Royal Air Force. This was just 117 days after the British Purchasing Commission had authorized the construction of the prototype. The airplane was designed by a team led by Edgar Schmued. The 1,150-horsepower Allison V-12 engine had not yet arrived, so the NA-73X was photographed with dummy exhaust stacks. The prototype’s company serial number was 73-3097. It had been assigned a civil experimental registration number, NX19998.

The NA-73X was a single-seat, single-engine, low wing monoplane with retractable landing gear. It was primarily of metal construction, though the flight control surfaces were fabric covered. The airplane was designed for the maximum reduction in aerodynamic drag.  The Mustang was the first airplane to use a laminar-flow wing. The fuselage panels were precisely designed and very smooth. Flush riveting was used. The coolant radiator with its intake and exhaust ducts was located behind and below the cockpit. As cooling air passed through the radiator it was heated and expanded, so that as it exited, it actually produced some thrust.

The prototype was 32 feet, 2⅝ inches (9.820 meters) long, with a wing span of 37 feet, 5/16 inch (11.286 meters). Empty weight of the NA-73X was 6,278 pounds (2,848 kilograms) and normal takeoff weight was 7,965 pounds (3,613 kilograms).

Aeronautical Engineer Edgar Schmued with a North American P-51-2-NA (Mustang Mk.IA), 41-37322. (San Diego Air and Space Museum Archives)

The NA-73X was powered by a liquid-cooled, supercharged, 1,710.60-cubic-inch-displacement (28.032 liter) Allison Engineering Company V-1710-F3R (V-1710-39) single overhead cam 60° V-12 engine, with four valves per cylinder and a compression ratio of 6.65:1. It used a single-stage, single-speed supercharger. This was a right-hand tractor engine (the V-1710 was built in both right-hand and left-hand configurations) which drove a 10 foot, 6 inch (3.200 meter) diameter, three-bladed, Curtiss Electric constant-speed propeller through a 2.00:1 gear reduction.

The V-1710-39 had a Normal Power rating of 880 horsepower at 2,600 r.p.m. at Sea Level; Take Off Power rating of 1,150 horsepower at 3,000 r.p.m. at Sea Level, with 44.5 inches of manifold pressure (1.51 Bar), 5 minute limit; and a War Emergency Power rating of 1,490 horsepower at 3,000 r.p.m., with 56 inches of manifold pressure (1.90 Bar). The V-1710-F3R was 7 feet, 4.38 inches (2.245 meters) long, 3 feet, 0.64 inches (0.931 meters) high, and 2 feet, 5.29 inches (0.744 meters) wide. It had a dry weight of 1,310 pounds (594 kilograms).

U.S. Army Air Corps flight tests of the fully-armed production Mustang Mk.I (XP-51 41-038), equipped with the V-1710-39 and a 10 foot, 9-inch (3.277 meters) diameter Curtiss Electric propeller, resulted in a maximum speed of 382.0 miles per hour (614.8 kilometers per hour) at 13,000 feet (3,962 meters). The service ceiling was 30,800 feet (9,388 meters) and the absolute ceiling was 31,900 feet (9,723 meters).

The Curtiss P-40D Warhawk used the same Allison V-1710-39 engine as the XP-51, as well as a three-bladed Curtiss Electric propeller. During performance testing at Wright Field, a P-40D, Air Corps serial number 40-362, weighing 7,740 pounds (3,511 kilograms), reached a maximum speed of 354 miles per hour (570 kilometers per hour) at 15,175 feet (4,625 meters). Although the Mustang’s test weight was 194 pounds (88 kilograms) heavier, at 7,934 pounds (3,599 kilograms), the Mustang was 28 miles per hour (45 kilometers per hour) faster than the Warhawk. This demonstrates the effectiveness of the Mustang’s exceptionally clean design.

Only one NA-73X was built. It made its first flight 26 October 1940 with test pilot Vance Breese. The prototype suffered significant damage when it overturned during a forced landing, 20 November 1941. NX19998 was repaired and flight testing resumed. The prototype’s final disposition is not known.

Originally ordered by Great Britain, the Mustang became the legendary U.S. Army Air Corps P-51 Mustang. A total of 15,486 Mustangs were built by North American Aviation at Inglewood, California and Dallas, Texas. Another 200 were built in Australia by the Commonwealth Aircraft Corporation.

The P-51 remained in service with the U.S. Air Force until 27 January 1957 when the last one, F-51D-30-NA 44-74936, was retired from the 167th Fighter Squadron, West Virginia Air National Guard. It was then transferred to the National Museum of the United States Air Force at Wright-Patterson Air Force Base, where it is on display.

North American Aviation NA-73X prototype, left front quarter view. (North American Aviation, Inc.)
North American Aviation NA-73X prototype, NX19998, left front quarter view. (North American Aviation, Inc.)

© 2017, Bryan R. Swopes