North American Aviation Mustang Mk.I AG345, c/n 73-3098, prior to camouflage paint. Note the short carburetor air intake compared to the photograph of the camouflaged airplane, below. The RAF serial number, barely visible, is stenciled on the rudder just beneath the trim tab. (North American Aviation Inc. 73-0-6)
23 April 1941: At North American Aviation’s Inglewood, California factory, test pilot Louis Sanford Wait takes the very first production Mustang Mk.I, AG345, (c/n 73-3098) for its first flight.
The Royal Air Force had contracted with NAA to design and build a new fighter with a 1,200 horsepower Allison V-1710 supercharged 12-cylinder engine. The first order from the British Purchasing Commission was for 320 airplanes, and a second order for another 300 soon followed.
Mustang Mk.I AG345. (North American Aviation, Inc. 73-0-5)
The Mustang Mk.I (NAA Model NA-73) was a single-place, single-engine fighter primarily of metal construction with fabric control surfaces. It was 32 feet, 3 inches (9.830 meters) long with a wingspan of 37 feet, 5/16-inches (11.373 meters) and height of 12 feet, 2½ inches (3.721 meters). The airplane’s empty weight was 6,280 pounds (2,849 kilograms) and loaded weight was 8,400 pounds (3,810 kilograms).
North American Aviation Mustang Mk.I AG345 (North American Aviation Inc.)
The Mustang Mk.I was powered by a liquid-cooled, supercharged 1,710.597-cubic-inch-displacement (28.032 liter) Allison Engineering Company V-1710-F3R (V-1710-39) single overhead cam (SOHC) 60° V-12 engine with a compression ratio of 6.65:1. The -F3R had a Maximum Continuous Power rating of 880 horsepower at 2,600 r.p.m. at Sea level, and 1,000 horsepower at 11,000 feet (3,353 meters). It was rated at 1,150 horsepower at 3,000 r.p.m. for Take Off and Military Power. The Allison V-12 drove a 10 foot, 9 inch (3.277 meter) diameter, three-bladed Curtiss Electric constant-speed propeller through a 2.00:1 gear reduction. The V-1710-F3R was 7 feet, 4.38 inches (2.245 meters) long, 3 feet, 0.54 inches (0.928 meters) high, and 2 feet, 5.29 inches (0.734 meters) wide. It weighed 1,310 pounds (594 kilograms).
North American Aviation Mustang Mk.I AG345 (North American Aviation Inc.)
The Mustang Mk.I had a cruise speed of 311 miles per hour (500.5 kilometers per hour) at 75% power, and a maximum speed of 384 miles per hour (618 kilometers per hour) at 19,000 feet (5,791 meters). The airplane could reach 20,000 feet (6,096 meters) in 8.80 minutes. The service ceiling was 32,000 feet (9,754 meters) and its range was 640 miles (1,030 kilometers).
The Mk.I was equipped with four Browning AN-M2 .50-caliber machine guns, with one in each wing and two mounted in the nose under the engine. Four Browning .303 Mk.II machine guns were also installed, with two in each wing.
North American Aviation Mustang Mk.I AG345 (c/n 73-3098), front. (North American Aviation Inc.)
The Mk.I was 30 m.p.h. (48 kilometers per hour) faster than its contemporary, the Curtiss P-40 Warhawk, though both used the same engine. Below 15,000 feet (4,572 meters), the Mustang was also 30–35 m.p.h (48–56 kilometers per hour) faster than a Supermarine Spitfire, which had the more powerful Roll-Royce Merlin V-12.
Two Mustang Mk.Is were taken from the first RAF production order and sent to Wright Field for testing by the U.S. Army Air Force. These airplanes, assigned serial numbers 41-038 and 41-039, were designated XP-51. They would be developed into the legendary P-51 Mustang. In production from 1941 to 1945, a total of 16,766 Mustangs of all variants were built.
The first production Mustang Mk.I, AG345, first flight, 23 April 1941. (North American Aviation, Inc.)
Louis Sanford Wait was born 28 June 1908 at Superior, Nebraska. He was the first of two children of Dr. James Enos Wait, a dentist, and Alice Caroline Harrington Wait.
Wait enlisted in the Air Corps, United States Army, as an aviation cadet, in 1929. He trained as a pilot at March Field, near Riverside, California, and at Kelly Field, Bexar, Texas. Wait graduated 27 June 1930 and received his pilot’s wings and a commission as a second lieutenant, Air Corps Reserve. (O274973) Lieutenant Wait trained as an attack pilot and was assigned to Fort Crockett, Galveston, Texas.
From 1932 to 1935, Wait, having been released from active duty, was employed as a test pilot for the Boeing Airplane Company, Seattle, Washington.
By 1937, Lieutenant Wait was assigned to Headquarters Squadron, 2nd Bombardment Group at Langley Field, Virginia, under the command of Brigadier General Robert Olds. While on 18 days leave, on 3 December 1937, Second Lieutenant Wait married Mrs. Elsie O. Callow (née Elsie Oliver) at Amityville, New York.
Wait married Mrs. Mary Elizabeth Croxen (née Mary Elizabeth Musser), 2 November 1944, in Los Angeles, California.
In August 1946, Louis Wait entered a P-51C Mustang, NX28388, in the Bendix Trophy Race. The airplane had been purchased by Jackie Cochran. She flew it in the race and finished in second place behind Paul Mantz.
In 1951, Wait was appointed general administrator of a new North American Aviation plant at the Fresno Air Terminal, Fresno, California. The plant, which employed about 400 people, manufactured and repaired parts for the T-6/SNJ Texan flight trainers, and performed modifications to F-86 Sabre jet fighters.
Louis Sanford Wait died 3 July 1963, at the age of 55 years.
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, NX19998, left front quarter view. (North American Aviation, Inc.)
20 August 1944: At 16:26 hours, Mustang Mk.I AG346, assigned to No. 168 Squadron,¹ 39 (Reconnaissance) Wing, Second Tactical Air Force, Royal Air Force, took off from a forward airfield, B21, at Sainte-Honorine-des-Pertes, Normandy, France.
AG346 was the very first operational Mustang Mk.I. During this mission, it was hit by intense antiaircraft fire northeast of Gacé. The Mustang’s pilot, Flight Lieutenant Denis Clark, Royal Air Force Volunteer Reserve, bailed out. He was captured and taken to a German prisoner of war camp at Les Hogues, a small community east of Rouen.
Flight Lieutenant Clark, along with four other prisoners of war,² was shot and killed at the camp on the afternoon 25 August 1944. A Court of Enquiry held in August 1945 found that the five men had been murdered by SS-Obersturmfürer Eugen Gutemann. Gutemann had been captured in Italy on 28 April 1945 and was held as a prisoner of war by the American forces. It is not known if he was ever brought to trial.
Denis Clark was born 17 December 1918 at Stockton-on-Tees, County Durham, England. He was the son of Sydney Clark, an electrician in the chemical industry, and Minnie Gertrude Ritchie.
Grave marker of Flight Lieuetenant Denis Clark, RAFVR. (Find-a-Grave)
In 1939, Clark was employed as a civil service clerk. He resided at 3 Crayke Road in Stockton, with his parents and maternal grandmother.
He was married to Beth Ayre of Seaton (possibly July 1942)
Clark was trained as a pilot at the Southern Aviation School, a military contract primary flight school in Camden, South Carolina, United States, beginning in July 1941.
On 7 February 1942 Temporary Flight Sergeant Clark 945260 was promoted to the rank of Pilot Officer on probation (Temporary) 119758.
On 1 October 1942, Pilot Officer (prob.) Clark was promoted to Flying Officer on probation (war substantive).
Flight Lieutenant Clark was buried at Les Hogues Communal Cemetery, along with the other four victims.
On 10 September 1945 a warrant was issued as a gratuity for the representatives of deceased officers in the amount of £172/13/7.
North American Aviation Mustang Mk.I AG346 (s/n 73-3099) at Mines Field, California, Summer 1941. Note the short carburetor intake, and compare to the photograph below. (North American Aviation, Inc.)
The very first operational North American Mustang, AG346 (North American Aviation serial number 73-3099) was the second airplane to come off the assembly line at Inglewood, California. North American test pilot Robert Creed Chilton to it for its first flight 3 July 1941. It was the first Mustang Mk.I to be equipped with its full armament.
During flight testing of the first Mk.I, AG345, Chilton and other test pilots heard a banging sound. This was determined to be a resonance in the carburetor intake tract. Also, at high angles of attack, air flow into the intake was decreased. The intake was lengthened. The resonance stopped and air flow to the carburetor was improved.
After flight testing by North American’s test pilots and Royal Air Force fighter pilots Wing Commander Chris Clarkson and Squadron Leader Michael N. (“Red Knight”) Crossley, AG346 was disassembled and crated, then shipped from the port of Long Beach, California, through the Panama Canal and on to England, arriving at Liverpool, 24 October 1941. It was taken to the Lockheed facility at Speke Aerodrome (now, Liverpool John Lennon Airport, LPL) where it was reassembled and put through additional performance and flight tests. Up to 20,000 feet (6,096 meters), AG346 was faster than any other British fighter then in service. A Mk.II reflector gun sight was installed (the same type used in the Supermarine Spitfire), as well as a British VHF radio.
AG346 was publicly displayed for the British news media at Speke Aerodrome on 5 December 1941.
AG346 was then assigned to an operational RAF fighter squadron. It served with Nos. 225, 63 and 26 Squadrons before being assigned to No. 41 Operations Training Unit. AG346 was returned to operations with No. 16 Squadron, and finally, No. 168 Squadron.
North American Aviation Inc. Mustang Mk.I fighter, AG348, built for the Royal Air Force, at Mines Field, Los Angeles, California, 1941. North American Aviation, Inc., photograph. (Ray Wagner Collection/SDASM)
The Mustang Mk.I was a new fighter built by North American Aviation, Inc., for the Royal Air Force. The British Purchasing Commission asked North American Aviation in Los Angeles, California, to build additional Tomahawks (the RAF variant of the Curtiss-Wright P-40 Warhawk) under license from Curtiss-Wright.
North American countered with a proposal to design a completely new and superior fighter around the P-40’s Allison V-12 engine, and to begin production in no more time than it would take to get a P-40 production line up and running. The Purchasing Commission agreed, and with a letter of understanding, North American began work on the NA-73X on 1 May 1940. They were to produce 320 fighters before 30 September 1941, approximately 50 per month, at a total price of $14,746,964.35.
Edgar Schmued with P-51-NA 41-37322 (Mustang Mk.IA) (San Diego Air and Space Museum Archives Catalog #: 02-S-00192)
Designed by a team led by Edgar Schmued, the prototype North American Aviation Model NA-73X, serial number 73-3097, registered NX19998, was completed 9 September 1940. After a delay waiting for the Allison V-1710 to arrive, the prototype made its first flight 26 October 1940, with free lance test pilot Vance Breese in the cockpit. This was only 179 days since work began on the project.
In a contract amendment dated 9 December 1940, the British Purchasing Commission directed that the NA-73 would be identified by the name, “Mustang.”
The Mustang Mk.I (NAA Model NA-73) was a single-place, single-engine fighter primarily of metal construction with fabric control surfaces. It was 32 feet, 3 inches (9.830 meters) long with a wingspan of 37 feet, 5/16-inches (11.373 meters) and height of 12 feet, 2½ inches (3.721 meters). The airplane’s empty weight was 6,280 pounds (2,849 kilograms) and loaded weight was 8,400 pounds (3,810 kilograms).
Allison V-1710-39 (F3R) V-12 aircraft engine.
The Mustang Mk.I was powered by a liquid-cooled, supercharged 1,710.597-cubic-inch-displacement (28.032 liter) Allison Engineering Company V-1710-F3R (V-1710-39) single overhead camshaft (SOHC) 60° V-12 engine with four valves per cylinder and a compression ratio of 6.65:1. The engine had a takeoff rating of 1,150 horsepower at 3,000 r.p.m. at Sea Level with 45.5 inches of manifold pressure (1.51 Bar), and a war emergency rating of 1,490 horsepower with 56 inches of manifold pressure (1.90 Bar). The Allison drove a 10 foot, 9 inch (3.277 meter) diameter, three-bladed, Curtiss Electric constant-speed propeller through a 2.00:1 gear reduction. The V-1710-39 was 7 feet, 4.38 inches (2.245 meters) long, 3 feet, 0.54 inches (0.928 meters) high, and 2 feet, 5.29 inches (0.744 meters) wide. It weighed 1,310 pounds (594 kilograms).
This engine gave the Mustang Mk.I a maximum speed of 382 miles per hour (615 kilometers per hour) and cruise speed of 300 miles per hour (483 kilometers per hour). The service ceiling was 30,800 feet (9,388 meters) and range was 750 miles (1,207 kilometers).
The Mustang Mk.I was equipped with four Browning .303 Mk.II machine guns, two in each wing, and four Browning AN-M2 .50-caliber machine guns, with one in each wing and two mounted in the nose under the engine. The airplane carried 300 rounds of ammunition for each of the .50-caliber guns. Each inboard .303s were supplied with 932 rounds, each; and the outboard .303s, 814 rounds, each.
The British would recommend that the Allison be replaced by the Rolls Royce Merlin V-12. This became the Mustang Mk.III and the U.S.A.A.F. P-51B. Eventually, over 15,000 Mustangs were built, and it was a highly successful combat aircraft. Today, after 71 years, the Mustang is one of the most recognizable of all airplanes.
Mustang Mk.I of No. 168 Squadron, Royal Air Force. (RAF)
¹ No. 168 Squadron was a reconnaissance unit. Its motto was Rerum cognoscere causas (“To know the cause of things”)
² Warrant Officer Griffin James Young R85855, Royal Canadian Air Force, a Spitfire pilot who had been shot down 13 August 1944; Lead Bombardier Jack Martin 976272, 65th Anti-Tank Unit (The Norfolk Yeomanry), Royal Artillery, captured 21 August; an unidentified Gunner, Royal Artillery; and Private Gordon Lafayette Bryant 6969514, 117th Infantry Regiment, 30th Infantry Division, United States Army.
