9 January 1941: Test pilot Captain Harry Albert (“Sam”) Brown, O.B.E., (1896–1953) makes the first flight of the Avro Lancaster prototype, BT308, at RAF Ringway, Cheshire, England, south of Manchester.
Throughout World War II, 7,377 of these long range heavy bombers were produced for the Royal Air Force. The majority were powered by Rolls-Royce or Packard Merlin V-12 engines—the same engines that powered the Supermarine Spitfire and North American P-51 Mustang fighters.
The bomber was designed by Roy Chadwick, F.R.S.A., F.R.Ae.S., the Chief Designer and Engineer of A. V. Roe & Company Limited, based on the earlier twin-engine Avro Manchester Mk.I. Because of this, it was originally designated as the Manchester Mk.III, before being re-named Lancaster. Chadwick was appointed Commander of the Most Excellent Order of the British Empire, 2 June 1943, for his work.
The first prototype, BT308, was unarmed and had three small vertical fins.
With the second prototype, DG595, the small center vertical fin was deleted and two larger fins were used at the outboard ends of a longer horizontal tailplane. DG595 was also equipped with power gun turrets at the nose, dorsal and ventral positions, and at the tail.
The first production model, Lancaster Mk.I, was operated by a crew of seven: pilot, flight engineer, navigator/bombardier, radio operator and three gunners. It was a large, all-metal, mid-wing monoplane with retractable landing gear. It was 68 feet, 11 inches (21.001 meters) long with a wingspan of 102 feet, 0 inches (31.090) meters and an overall height of 19 feet, 6 inches (5.944 meters). The Mk.I had an empty weight of 36,900 pounds (16,738 kilograms) and its maximum takeoff weight was 68,000 pounds (30,909 kilograms).
BT308 and early production Lancasters were equipped with four liquid-cooled, supercharged, 1,648.96-cubic-inch-displacement (27.01 liter), Roll-Royce Merlin XX single overhead camshaft (SOHC) 60° V-12 engines, which were rated at 1,480 horsepower at 3,000 r.p.m. to 6,000 feet (1,829 meters). The Merlins drove three-bladed de Havilland Hydromatic quick-feathering, constant-speed airscrews (propellers), which had a diameter of 13 feet, 0 inches (3.962 meters), through a 0.420:1 gear reduction.
DG595 was used for performance testing at the Aeroplane and Armament Experimental Establishment (A&AEE) at Boscombe Down. The Mark I had a maximum economic cruise speed of 267 miles per hour (430 kilometers per hour) at 20,800 feet (6,340 meters), and a maximum speed of 286 miles per hour (460 kilometers per hour) at 20,000 feet (6,096 meters) at a gross weight of 45,300 pounds (20,548 kilograms).¹ Its service ceiling was 20,000 feet (6,096 meters) at 64,500 pounds (29,257 kilograms). It had a range of 2,530 miles (4,072 kilometers) with a 7,000 pound (3,175 kilogram) bomb load.
The Lancaster was designed to carry a 14,000 pound (6,350 kilogram) bomb load, but modified bombers carried the 22,000 pound (9,979 kilogram) Grand Slam bomb. For defense, the standard Lancaster had eight Browning .303-caliber Mark II machine guns in three power-operated turrets, with a total of 14,000 rounds of ammunition.
According to the Royal Air Force, “Almost half all Lancasters delivered during the war (3,345 of 7,373) were lost on operations with the loss of over 21,000 crew members.”
Only two airworthy Avro Lancasters are in existence.
25 November 1940: De Havilland Aircraft Company’s Chief Test Pilot, Geoffrey Raoul de Havilland, Jr., and engineer John Walker, made the first flight of the DH.98 Mosquito prototype, E0234, at Hatfield, Hertfordshire, England. The prototype’s Royal Air Force identification was W4050. The multi-role combat aircraft was constructed primarily of layers of balsa covered with layers of birch, then a layer of doped cotton fabric. It was powered by two Rolls-Royce Merlin V-12 engines.
The construction materials took advantage of plentiful supplies of wood, and also made workers who were not in the standard metal aircraft industry able to take part.
The prototype was rolled out 19 November 1040, painted overall yellow.
The prototype had a wingspan of 54 feet, 2 inches (16.510 meters), and its gross weight was 19,670 pounds (8,922 kilograms). W4050 was powered by two liquid-cooled, supercharged, 1,648.96-cubic-inch-displacement (27.01 liter) Rolls-Royce Merlin Mk.21 single overhead camshaft (SOHC) 60° V-12 engines, producing 1,460 horsepower at 3,000 r.p.m. at 10,000 feet (3028 meters), with 10 pounds (0.69 Bar) of boost, and driving three-bladed de Havilland Hydromatic propellers through a gear reduction.
The DH.98 had been predicted to be 20 miles per hour (32 kilometers per hour) faster than the Supermarine Spitfire, but was actually much faster. In testing, the prototype reached 392 miles per hour (631 kilometers per hour) at 22,000 feet (6,706 meters). Improvements were continuously made, and with 2-stage superchargers, W4050 reached a maximum 437 miles per hour (703 kilometers per hour). The DH.98 prototype had a service ceiling of 34,000 feet (10,363 meters) and range of 2,180 miles (3,500 kilometers).
The production fighter variant, the Mosquito F. Mk.II, was 41 feet, 2 inches (12.548 meters) long with a wingspan of 54 feet, 2 inches (16.510 meters) and height of 15 feet, 3 inches (4.648 meters) in 3-point position. The wings had 1½° incidence with approxmatey 2½° dihedral. The leading edges were swept aft 2½°. The total wing area was 436.7 square feet (40.6 square meters). The fighter’s empty weight was 13,356 pounds (6,058 kilograms) and the maximum takeoff weight was 18,649 pounds (8,459 kilograms). The Mk.II had a total fuel capacity of 553 gallons.
The Mk.II had a cruise speed of 265 miles per hour (426 kilometers per hour) at 15,000 feet (4,572 meters) and maximum speed of 380 miles per hour (612 kilometers per hour) at 21,400 feet (6,523 meters).
Mosquito bomber variants could carry four 500 pound bombs, or two 2,000 pound bombs, but were otherwise unarmed. Fighters were equipped with four Hispano Mk.II 20 mm autocannon and four Browning .303-caliber Mk.II machine guns in the nose.
6,411 DH.98 Mosquitoes were built in England, 1,134 in Canada and 212 in Australia. It was produced in bomber, fighter, night fighter, fighter bomber and photo reconnaissance versions.
W4050’s (the prototype’s Royal Air Force identification) fuselage was damaged while taxiing at Boscombe Down, 24 February 1941, and had to be replaced with one intended for a second prototype, W4051. It remained at de Havilland and was used to test different engines, armaments and versions. After a series of tests conducted in December 1943, the prototype Mosquito was permanently grounded. It was used as an instructional airframe and later placed in storage.
In September 1958, W4050 was turned over to the de Havilland Aircraft Heritage Centre. Today, the restored prototype DH.98 Mosquito is at the museum at London Colney, Hertfordshire, England.
12 November 1944: No. 9 Squadron and No. 617 Squadron (Dambusters), Royal Air Force, sent a force of 32 Avro Lancaster long range heavy bombers to attack the 49,948 metric-ton-displacement Kriegsmarine battleship KMS Tirpitz at Tromsø Fjord, Norway. The attack was filmed by a photo aircraft of No. 463 Squadron, Royal Australian Air Force.
The Lancasters were armed with 12,030 pound (5,457 kilogram) Tallboy bombs. They bombed from altitudes from 12,000 to 16,000 feet (3,658–4,877 meters). Two of the bombs hit the battleship, one was a very near miss and another three also were close enough that they probably contributed to the overall damage. Many other Tallboys landed within the torpedo nets that surrounded the ship and cratered the seabed, removing the sandy bottom which had been built up under Tirpitz‘ hull to prevent her from sinking. Tirpitz immediately began to list and was then rocked by an internal explosion. It capsized and sank to the sea bed. As many as 1,204 sailors were killed.
Tirpitz was a Bismarck-class battleship armed with a main battery of eight 38-centimeter (15-inch/52-caliber) guns in four turrets. These guns had a maximum range of 22.7 miles (36.5 kilometers) when firing a 1,800 pound (816 kilogram) projectile. The German Navy did not use its heavy warships to directly engage the British fleet, but instead to raid the Atlantic convoys. The merchant ships with their destroyer escorts were defenseless against a battleship or battle cruiser. Allied forces expended tremendous effort and resources to contain or destroy Tirpitz throughout the war.
The Avro Lancaster was a four-engine long range heavy bomber. It wasn’t as fast as the American B-17 Flying Fortress, but was capable of flying longer distances with a heavier bomb load. It was operated by a crew of seven: Pilot, flight engineer, navigator, radio operator, bomb aimer/nose gunner, top gunner and tail gunner. The “Lanc” was 69 feet, 4 inches (21.133 meters) long, with a wingspan of 102 feet (31.090 meters) and had an overall height of 20 feet, 6 inches (6.248 meters). It had a maximum takeoff weight (MTOW) of 72,000 pounds (32,657 kilograms) when carrying a 22,000 pound (9,979 kilogram) Grand Slam bomb.
The Lancaster was powered by four liquid-cooled, supercharged, 1,648.96-cubic-inch-displacement (27.01 liter), Rolls Royce Merlin XX or Packard V-1650 single overhead camshaft (SOHC) 60° V-12 engines, which were rated at 1,480 horsepower at 3,000 r.p.m. to 6,000 feet (1,829 meters). They turned three-bladed de Havilland Hydromatic constant-speed propellers which had a diameter of 13 feet (3.962 meters) through a 0.420:1 gear reduction.
These Merlin engines, the same as those powering Supermarine Spitfire, Hawker Hurricane and North American P-51 Mustang fighters, gave the Lancaster a maximum speed of 282 miles per hour (456 kilometers per hour) at 13,000 feet (3,962 meters) at a weight of 63,000 pounds (28,576 kilometers per hour). The service ceiling was 21,400 feet (6,523 meters) and maximum range was 2,530 miles (4,073 kilometers).
Defensive armament for a standard Lancaster consisted of eight Browning Mark II .303-caliber machine guns in three power turrets, nose, dorsal and tail. Modified bombers deleted various combinations of guns to reduce weight.
The Tallboy (Bomb, Medium Capacity, 12,000 lb) was a special demolition bomb designed to be dropped from high altitude, reach supersonic speeds, then penetrate as far as 90 feet (27 meters) into the ground before detonating. It was built of a specially hardened steel casing filled with 5,200 pounds (2,358 kilograms) of Torpex explosive. The bomb was designed by Barnes Wallis, who had also designed the special bomb used by the Dambusters in their famous 1943 attack on the Ruhr Valley hydroelectric dams, as well as the Grand Slam, a 22,000-pound (10,000 kilogram) scaled-up version of the Tallboy. The Tallboy and Grand Slam bombs were very successfully used against U-boat pens and heavily fortified underground rocket facilities.
20 September 1918: While assigned to No. 213 Squadron, Royal Air Force, Lieutenant (junior grade) David Sinton Ingalls, United States Navy, shot down a Fokker D.VII reconnaissance airplane near Vlissegham, Belgium, while flying a Sopwith Camel, serial number D8177. This was Ingalls’ fifth confirmed aerial victory, making him the U.S. Navy’s only fighter ace of World War I.
Lieutenant Ingalls was awarded the Navy Cross for his actions of 15 September 1918, when “he led a flight of five machines on a low bombing raid of an enemy aerodrome. On the homeward journey he shot down a two-seater enemy aeroplane in flames. He further participated in two other low bombing raids and upon still another occasion shot down an enemy kite balloon in flames near Ostend.” He was also awarded the Distinguished Service Medal for exceptionally meritorious service. The Royal Air Force awarded him its Distinguished Flying Cross for the 15 September mission against Uytkerke Aerodrome, and he was Mentioned in Dispatches. France appointed him Chevalier de la légion d’honneur.
The Sopwith Camel F.1 was a British single-place, single-engine biplane fighter, produced by the Sopwith Aviation Co., Ltd., Canbury Park Road, Kingston-on-Thames. The airplane was constructed of a wooden framework, with the forward fuselage being covered with aluminum panels and plywood, while the aft fuselage, wings and tail surfaces were covered with fabric.
The length of the Camel F.I varied from 18 feet, 6 inches (5.639 meters) to 19 feet, 0 inches (5.791 meters), depending on which engine was installed. Both upper and lower wings had a span of 28 feet, 0 inches (8.534 meters) and chord of 4 feet, 6 inches (1.372 meters). They were separated vertically by 5 feet (1.524 meters) at the fuselage. The upper wing had 0° dihedral, while the lower wing had 5° dihedral and was staggered 1 foot, 6 inches (0.457 meters) behind the upper wing. The single-bay wings were braced with airfoil-shaped streamline wires. The overall height of the Camel also varied with the engine, from 8 feet, 6 inches (2.591 meters) to 8 feet, 9 inches (2.667 meters).
The heaviest Camel F.I variant used the Le Rhône 180 h.p. engine. It had an empty weight of 1,048 pounds (475 kilograms). Its gross weight of 1,567 pounds (711 kilograms). The lightest was equipped with the Gnôme Monosoupape 100 horsepower engine, with weights of 882 pounds (400 kilograms) and 1,387 pounds (629 kilograms), respectively.
The first Camel was powered by an air-cooled 15.268 liter (931.72 cubic inches) Société Clerget-Blin et Cie Clerget Type 9 nine-cylinder rotary engine which produced 110 horsepower at 1,200 r.p.m. and drove a wooden two-bladed propeller. Eight different rotary engines ¹ from four manufacturers, ranging from 100 to 180 horsepower, were used in the type.
The best performance came with the Bentley B.R.1 engine (5.7:1 compression ratio). This variant had a maximum speed of 121 miles per hour (195 kilometers per hour) at 10,000 feet (3,048 meters), and 114.5 miles per hour (184 kilometers per hour) at 15,000 feet (4,572 meters). It could climb to 6,500 feet (1,981 meters) in 4 minutes, 35 seconds; to 10,000 feet (3,048 meters) in 8 minutes, 10 seconds; and 15,000 feet (4,572 meters) in 15 minutes, 55 seconds. It had a service ceiling of 22,000 feet (6,706 meters). Two other Camel variants could reach 24,000 feet (7,315 meters).
The Bentley B.R.1 rotary engine was designed by Lieutenant Walter Owen Bentley, Royal Naval Air Service (later, Captain, Royal Air Force), based on the Clerget Type 9, but with major improvements. It used aluminum cylinders shrunk on to steel liners, with aluminum pistons. The Bentley B.R.1 (originally named the Admiralty Rotary, A.R.1, as it was intended for use by the Royal Navy) was an air-cooled, normally-aspirated 17.304 liter (1,055.9 cubic inches) nine-cylinder rotary engine with a compression ratio of 5.7:1. It was rated at 150 horsepower at 1,250 r.p.m. The B.R.1 was 1.110 meters (3 feet, 7.7 inches) long, 1.070 meters (feet, 6.125 inches) in diameter and weighted 184 kilograms (406 pounds.) The engine was manufactured by Humber, Ltd., Coventry, England.
For his work developing this engine, Captain Bentley was appointed a Member of the Military Division of the Most Excellent Order of the British Empire (M.B.E.) in the New Years Honours List, 1 January 1919. He would later found Bentley Motors, Ltd.
The Camel was armed with two fixed, forward-firing .303 Vickers machine guns, synchronized to fire forward through the propeller. These guns were modified for air cooling. Some night fighter variants substituted Lewis machine guns mounted above the upper wing for the Vickers guns. Four 25 pound (11.3 kilogram) bombs could be carried on racks under the fuselage.
The Sopwith Camel was a difficult airplane to fly. Most of its weight was concentrated far forward, making it unstable, but, at the same time making the fighter highly maneuverable. The rotary engine, with so much of its mass in rotation, caused a torque effect that rolled the airplane to the right to a much greater degree than in airplanes equipped with radial or V-type engines. A skilled pilot could use this to his advantage, but many Camels ended upside down while taking off.
Twelve manufacturers ² produced 5,490 Sopwith Camels between 1916 and 1920. By the end of World War I, it was becoming outclassed by newer aircraft, however it was the single most successful fighter of the war, shooting down 1,294 enemy aircraft. One single fighter, flown by Major William Barker, shot down 46 enemy aircraft, more than any other fighter in history.
It is believed that only seven Sopwith Camels still exist.
David Sinton Ingalls was born 28 January 1899 at Cleveland, Ohio. He was the son of Albert Stimson Ingalls, a vice president of the New York Central Railroad, and Jane Ellison Taft Ingalls, niece of President William Howard Taft. He was educated at the University School, a private school for boys in Cleveland. He entered Yale University at New Haven, Connecticut, in 1916. Ingalls was a member of The First Yale Unit, which would become the U.S. Navy’s first aviation unit.
Shortly after the United States entered World War I, David Sinton Ingalls enlisted as a Machinist’s Mate 1st Class, United States Naval Reserve Force, at New London, Connecticut, 26 March 1917. He was sent to the Naval Aviation Detachment at West Palm Beach, Florida, for initial flight training, and then to the Naval Aviation Detachment, Huntington, New York. MM1c Ingalls was discharged 1 September 1917 and appointed an Ensign, 4 September 1917. He was Naval Aviator Number 85.
Ensign Ingalls was sent to France for duty, 12 September 1917. In December 1917, he was detached and sent to the Royal Flying Corps air station at Turnberry, South Ayrshire, Scotland, for training in aerial gunnery. He then underwent squadron formation training at nearby Ayr, Scotland. Following training, Ensign Ingalls was assigned to the Naval Air Detachment at Paris, France, 12 March 1918. On 23 March 1918, Ingalls was promoted to the rank of Lieutenant (junior grade).
On 21 May 1918, Lieutenant (j.g.) Ingalls was assigned to the U.S. Army Bombing School at Clermont-Ferrand, France. On 27 June 1918, Lieutenant (j.g.) Ingalls was assigned to the Naval Air Station Dunkerque. He flew combat missions with No. 213 Squadron, and No. 218 Squadron, both of the Royal Air Force. (While flying with the 218th, he was reported to have shot down an observation balloon and a biplane. The records were lost and these claims are considered unconfirmed.)
While flying with No. 213 Squadron, on 11 August 1918, Lieutenant (j.g.) Ingalls shot down an Albatros C northeast of Diksmuide, West Flanders—his first confirmed victory. His second confirmed victory was a two-place Luftverkehrsgesellschaft m.b.H. (L.V.G.) biplane south of Zevecote, Belgium, on 21 August. He shot down a Rumpler C over Ostend, 15 September. His fourth confirmed victory took place on 18 September when he destroyed an observation balloon at La Barrière. The Fokker D.VII that he shot down on 20 September was his fifth. He shot down his sixth,a Rumpler, on 24 September 1918, over Saint-Pierre-Cappelle, Belgium. Other than the Fokker D.VII, Ingalls shared credit with other pilots for the shoot-downs.
Lieutenant (j.g.) Ingalls flew his final combat mission, his sixty-third, on 3 October 1918.
On 24 September 1919, he was given the provisional rank of Lieutenant, Naval Reserve Flying Corps, with date of rank, 1 April 1919. He was released from active duty 23 December 1919.
Returning to Yale University, he graduated in 1920 with a Bachelor of Arts degree, and in 1923, received a Doctor of Laws (LL.D.) degree from Harvard University, Cambridge, Massachusetts. He practiced law for several years before being elected to the state legislature of Ohio in 1926. Later, he ran for governor and United States senator.
David Sinton Ingalls married Miss Louise Hale Harkness at Locust Valley, New York, 27 June 1922. They would have five children: Edith, Jane, Anne, Louise, and David.
Ingalls was appointed Assistant Secretary of the Navy for Aeronautics by President Herbert Hoover, serving from 16 March 1929 until 1 June 1932, reporting to Secretary of the Navy Charles Francis Adams III.
Secretary Ingalls’ photograph was featured on the cover of TIME Magazine, 2 March 1931.
On 24 December 1931, Ingalls was appointed a Lieutenant Commander, United States Naval Reserve.
Going to work in the business sector, Ingalls became vice president and general manager of Pan American Air Ferries, a commercial transport service from the United States to Egypt, and which also transported newly-built military aircraft from the United States via South America, across the South Atlantic Ocean to Africa, and then on to the Middle East.
Lieutenant Commander Ingalls was promoted to Commander, U.S.N.R., 1 July 1941, and following the United States entry into World War II, he was recalled to active duty, 23 November 1942. Commander Ingalls served as Assistant Operations Officer on the staff of the Commander, Naval Air Forces, Pacific, (COMNAVAIRPAC), for which he was awarded the Legion of Merit. He was promoted to Captain, 10 June 1943. He then served as chief of staff to the Commander Aircraft South Pacific Force, Admiral Aubrey W. Fitch, USN.
Captain Ingalls took command of U.S. Naval Air Station 29 (now, Daniel K. Inouye International Airport—HNL—Honolulu, Hawaii) on 1 April 1944.
Captain Ingalls was released from active duty 8 November 1945, but he remained an officer in the Naval Reserve. Ingalls returned to Pan American World Airways as vice president, and remained in that position until 1949. Later, he was president and publisher of the Cincinnati Times-Star newspaper, and a vice president of Taft Broadcasting Company.
By 1951, Ingalls held the rank of Commodore. On 1 July 1955, Commodore Ingalls was promoted to the rank of Rear Admiral. From 1945 until 1959, Ingalls was Commander, Navy Reserve Forces Command (COMNAVRESFORCOM). He retired from the Naval Reserve in February 1959.
During his Naval career, Rear Admiral Ingalls had been awarded the Navy Cross, the Distinguished Service Medal, the Legion of Merit, the Bronze Star, World War I Victory Medal, American Defense Service Medal, American Campaign Medal, Asiatic-Pacific Campaign Medal with four service stars, the World War II Victory Medal, the National Defense Service Medal, the Naval Reserve Medal, and the Armed Forces Reserve Medal with hourglass device.
Louise Harkness Ingalls died in 1978. David Ingalls married his second wife, Frances W. Wragg, 16 February 1979.
Ingalls is the author of Hero of the Angry Sky: The World War I Diary and Letters of David S. Ingalls, America’s First Naval Ace, Ohio University Press, 2013 (Edited by Geoffrey L. Rossano).
Rear Admiral David Sinton Ingalls died 26 April 1985 at the age of 86 years. He is buried at the Warm Springs Cemetery, Warm Springs, Virginia.
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).
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.