Tag Archives: Browning .303 Mark II

23 April 1941

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.)
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.)
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, AG348 and AG354, 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.

© 2019, Bryan R. Swopes

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20 April 1941

Squadron Leader Marmaduke Thomas St. John “Pat” Pattle, Officer Commanding No. 33 Squadron, Royal Air Force, and the Squadron Adjutant, Flight Lieutenant George Rumsey, standing by a Hawker Hurricane at Larissa, Thessaly, Greece, March–April 1941. (IWM)

20 April 1941: Squadron Leader Marmaduke Thomas St. John Pattle, D.F.C. and Bar, Royal Air Force, commanding No. 33 Squadron, was killed in action during the Battle of Athens when his Hawker Hurricane fighter was shot down by two or more Luftwaffe Messerschmitt Bf 110 fighters. Pattle’s airplane crashed into the sea near the Port of Piraeus, southwest of Athens.

Messerschmitt Bf 110 twin-engine heavy fighter, circa 1942. (Deutsches Bundesarchiv)

Squadron Leader Pattle may have been the highest-scoring Allied fighter ace of World War II. The exact number of enemy aircraft destroyed cannot be determined precisely because records were lost or destroyed during the Battle of Greece. The last officially acknowledged score was 23 airplanes shot down, mentioned in The London Gazette with the notice of the award of a Bar to his Distinguished Flying Cross. It is widely acknowledged that he shot down many more, and on at least two occasions, shot down five enemy airplanes in one day. Authors who have researched Pattle’s combat record believe that he shot down at least 50, and possibly as many as 60 aircraft.

For comparison, Air Vice Marshal James Edgar (“Johnnie”) Johnson, C.B., C.B.E., D.S.O. and Two Bars, D.F.C. and Bar, is officially credited by the Royal Air Force with shooting down 34 enemy airplanes. Colonel Francis Stanley (“Gabby”) Gabreski, United States Air Force, was credited with 28 kills during World War II. In the Pacific Theater of Operations, Major Richard Ira Bong is officially credited with 40 enemy airplanes shot down.

Marmaduke Thomas St. John Pattle was born at Butterworth, Cape Province, South Africa, 23 July 1914. He was the son of Sergeant-Major William John Pattle, British Army, and Edith Brailsford Pattle. After failing to be accepted by the South African Air Force, at the age of 21 years, he traveled to Britain to apply to the Royal Air Force. He was offered a short-service commission and sent to flight school.

Pattle was commissioned as an Acting Pilot Officer on probation, effective 24 August 1936. He trained as a fighter pilot in the Gloster Gauntlet, and was rated as exceptional. He was then assigned to No. 80 Squadron, which was equipped with the newer Gloster Gladiator. He was confirmed in the rank of Pilot Officer 29 June 1937.

Prototype Gloster Gladiator in flight, now marked K5200.

No. 80 Squadron was sent to Egypt to protect the Suez Canal. With the United Kingdom’s declaration of war on the Axis powers, Pattle and his unit were soon in combat with the Regia Aeronautica (the Italian Royal Air Force) across North Africa. He shot down his first enemy airplanes, a Breda Ba.65 and a Fiat CR.42, on 4 August 1940. Unfortunaely, Pattle was also shot down and he had to walk across the Libyan desert to friendly lines.

Distinguished Flying Cross

Pattle was promoted to Flight Lieutenant, 3 September 1940. He is credited with having shot down at least 15 Italian airplanes with the Gladiator.

In February 1941, No. 80 Squadron began flying the Hawker Hurricane. This was a huge technological advance over the Gladiator, and the Hurricane’s eight .303-caliber machine guns doubled the firepower of the biplane.  The squadron was sent to Greece, where it would engage the Luftwaffe.

Flight Lieutenant Pattle was awarded the Distinguished Flying Cross, 11 February 1941. The following month, 12 March 1941, Pat Pattle was promoted to Acting Squadron Leader, and given command of No. 33 Squadron at Larissa, Thessaly, Greece.

Squadron Leader Pattle was awarded a Bar to his DFC (a second award), 18 March 1941.

Pilots of No. 33 Squadron, Royal Air Force, with a Hawker Hurricane Mk.I fighter, V7419. Pattle is in the first row, seated, fifth from left. (Imperial War Museum)

Designed by Sydney Camm to meet a Royal Air Force Specification for a high speed monoplane interceptor, the airplane was designed around the Rolls-Royce PV-12 engine. The prototype Hawker Hurricane, K5083, first flew 6 November 1935.

The Hurricane was built in the traditional means of a light but strong framework covered by doped linen fabric. Rather than wood, however, the Hurricane’s framework used high strength steel tubing for the aft fuselage. A girder structure covered in sheet metal made up the forward fuselage. A primary consideration of the fighter’s designer was to provide good visibility for the pilot.

The Hawker Hurricane Mk.I was ordered into production in the summer of 1936. The first production airplane flew on 12 October 1937. The Hurricane Mk. I was 31 feet, 5 inches (9.576 meters) long with a wingspan of 40 feet, 0 inches (12.192 meters), and overall height of 10 feet, 6 inches (3.200 meters). Its empty weight was 5,234 pounds (2,374 kilograms) and maximum gross weight was 6,793 pounds (3,081 kilograms).

The Mk.I’s engine was a liquid-cooled, supercharged, 27.01 liter (1,648.96 cubic inches) Rolls-Royce R.M.1.S. Merlin Mk.III single-overhead-cam 60° V-12, rated at 990 horsepower at 2,600 r.p.m. at 12,250 feet (3,734 meters), and 1,030 horsepower at 3,000 r.p.m., at 10,250 feet (3,124 meters), using 87 octane aviation gasoline. The Merlin III drove the propeller through a 0.477:1 gear reduction ratio. It weighed 1,375 pounds (624 kilograms).

The fixed-pitch propeller was soon replaced with a three-bladed, two-pitch propeller, and then a three-bladed constant-speed propeller. Speed trials of a Mk.I equipped with a 10 foot, 9 inch (3.277 meters) diameter Rotol constant-speed propeller achieved a maximum True Air Speed in level flight of 316 miles per hour (509 kilometers per hour) at 17,500 feet (5,334 meters). The service ceiling was 32,250 feet (9,830 meters). The Mk.I’s range was 600 miles (966 kilometers) at 175 miles per hour (282 kilometers per hour).

The Hurricane Mk.I could climb to 20,000 feet in 9.7 minutes.

The fighter was armed with eight Browning .303 Mark II machine guns mounted in the wings, with 334 rounds of ammunition per gun.

Hawker Hurricane Mk.I at NACA Langley Memorial Aeronautical Laboratory. (NASA)

© 2018, Bryan R. Swopes

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