14 October 1938: At Buffalo, New York, test pilot Everett Edward Elliot made the first flight in the new Curtiss-Wright Corporation’s Model 75P, a prototype for a single-engine pursuit plane which had been designated XP-40 by the U.S. Army Air Corps.
Curtiss-Wright’s Chief Engineer, Donovan Reese Berlin, had taken the tenth production P-36A Hawk, Air Corps serial number 38-10, and had its air-cooled radial engine replaced with the Harold Caminez-designed, liquid-cooled, supercharged, 1,710.597-cubic-inch-displacement (28.032 liter) Allison Engineering Co. V-1710-C13 (V-1710-19).
The V-1710-19 was a single overhead cam (SOHC) 60° V-12 engine with four valves per cylinder and a compression ration of 6.65:1. It had a Normal Power rating of 910 horsepower at 2,600 r.p.m. at Sea Level, and 1,060 horsepower at 2,950 r.p.m. for Takeoff. At 10,000 feet (3,048 meters), the V-1710-19 had Maximum Continuous Power rating of 1,000 horsepower at 2,600 r.p.m., and Military Power rating of 1,150 horsepower at 2,950 r.p.m. The engine required 100/130-octane aviation gasoline. It drove a three-bladed Curtiss Electric constant-speed propeller through a 2:1 gear reduction. The V-1710-19 was 8 feet, 1.75 inches (2.483 meters) long, 3 feet, 4.75 inches (1.035 meters) high and 2 feet, 4.94 inches (0.735 meters) wide. It weighed 1,320 pounds (599 kilograms).
At 1,829.39-cubic-inches (29.978 liters), the original Pratt & Whitney Twin Wasp S1C1-G (R-1830-17) 14-cylinder radial engine had greater displacement and produced 80 horsepower more for takeoff than the Allison V-12. The long, narrow V-12, though, allowed for a much more streamlined engine cowling for higher speed and greater efficiency.
In the early testing, the XP-40 was much slower than expected, reaching only 315 miles per hour (507 kilometers per hour). (The P-36A Hawk had a maximum speed of 313 miles per hour). Engineers experimented with different placement for the coolant radiator, oil coolers and the engine air intake. The Air Corps project officer, Lieutenant Benjamin Scovill Kelsey, had the prototype sent to the National Advisory Committee for Aeronautics (NACA) Research Center at Langley Field, Virginia, where the full-size airplane was placed inside a wind tunnel.
Over a two-month period, NACA engineers made a number of improvements. The radiator was moved forward under the engine and the oil coolers utilized the same air scoop. The exhaust manifolds were improved as were the landing gear doors.
When they had finished, Lieutenant Kelsey flew the modified XP-40 back to Curtiss. Its speed had been increased to 354 miles per hour (570 kilometers per hour), a 12% improvement.
By December 1939 the airplane had been further improved and was capable of 366 miles per hour (589 kilometers per hour).
The Curtiss Hawk 75P, XP-40 38-10, was 31 feet, 1 inch (9.574 meters) long with a wingspan of 37 feet, 4 inches (11.354 meters) and overall height of 12 feet, 4 inches (3.734 meters). It had an empty weight of 5,417 pounds (2,457.1 kilograms) and maximum gross weight of 6,870 pounds (3,116.2 kilograms).
The prototype had a maximum speed of 342 miles per hour (550 kilometers per hour) at 12,200 feet (3,719 meters) with a gross weight of 6,260 pounds (2,839.5 kilograms). Its range was 460 miles (740 kilometers) flying at 299 miles per hour (481 kilometers per hour) with 100 gallons (378.5 liters) of fuel. With 159 gallons (601.9 liters) and with speed reduced to 200 miles per hour (322 kilometers per hour), the XP-40 had a maximum range of 1,180 miles (1,899 kilometers).
The prototype was armed with two air-cooled Browning AN-M2 .50-caliber machine guns mounted above the engine and synchronized to fire forward through the propeller arc.
The Air Corps placed an initial order for 524 P-40s. This was the largest single order for airplanes by the U.S. military up to that time. The first production model was the P-40 Warhawk, armed with two .50-caliber machine guns. There was only one P-40A variant which was a P-40 modified as a camera aircraft. The definitive pursuit model was the P-40B Warhawk, which retained the two .50-caliber guns of the P-40 and added two Browning M2 .30-caliber machine guns to each of the wings.
The P-40B was best known as the airplane flown by the American Volunteer Group fighting for China against the Japanese. They were called the “Flying Tigers”. Between 1939 and 1945, Curtiss built 13,738 P-40s in many configurations. They flew in combat in every theater of operations during World War II.
6 May 1935: At Buffalo, New York, the prototype Curtiss-Wright Model 75, NX17Y, serial number 11923, made its first flight.
Designed by Donovan Reese Berlin, the airplane was a modern design of all metal construction, with fabric covered control surfaces. The Model 75 was a single-seat, single-engine low wing monoplane with retractable landing gear.
In its original configuration, the Model 75 was powered by an air-cooled, supercharged 1,666.860 cubic inch displacement (27.315 liter) Wright Aeronautical Division GR1670A1 two-row 14-cylinder radial engine. The GR1670A1 was a developmental engine with a compression ratio of 6.75:1. It was rated at 775 horsepower at 2,400 r.p.m. at Sea Level, and 830 horsepower at 2,600 horsepower for takeoff, burning 87-octane gasoline. The engine was 3 feet, 9 inches (1.143 meters) in diameter, 4 feet, 4–25/32 inches (1.341 meters) long, and weighed 1,160 pounds (526 kilograms). The GR1670A1 drove a three-bladed Curtiss Electric constant-speed propeller through a 16:11 gear reduction.
The GR1670A1 was also used in the Seversky SEV-S1, NR18Y, a record-setting experimental variant of the rival Seversky P-35.
Registration issued 1 June 1936, cancelled 26 April 1937.
The Curtiss-Wright Model 75 would be developed into the P-36 Hawk fighter for the U.S. Army Air Corps. France ordered it as the H75A-1, and in British service, it was known as the Mohawk Mk.I.
The tenth production P-36 was modified with a liquid-cooled Allison V-1710 V-12 engine to become the prototype XP-40.
26 April 1939: The United States Army Air Corps placed an order for 524 Curtiss-Wright P-40 Warhawks. This was the largest production order for any U.S.-built fighter since World War I. The total cost was $12,872,398.¹
The order was authorized by the Air Corps Expansion Act, approved by Congress 3 April, and signed by President Roosevelt on 26 April 1939.
The Curtiss-Wright Corporation Hawk 81 (P-40 Warhawk) was a single-seat, single-engine pursuit, designed by Chief Engineer Donovan Reese Berlin. It was developed from Berlin’s radial-engine P-36 Hawk. The P-40 was a low-wing monoplane of all-metal construction and used flush riveting to reduce aerodynamic drag. It had an enclosed cockpit and retractable landing gear (including the tail wheel). Extensive wind tunnel testing at the NACA Langley laboratories refined the airplane’s design, significantly increasing the top speed.
The new fighter was 31 feet, 8-9/16 inches (9.666 meters) long with a wingspan of 37 feet, 3½ inches (11.366 meters) and overall height of 9 feet, 7 inches (2.921 meters). The P-40’s empty weight was 5,376 pounds (2,438.5 kilograms) and gross weight was 6,787 pounds (3,078.5 kilograms).
The P-40 was powered by a liquid-cooled, supercharged, 1,710.597-cubic-inch-displacement (28.032 liter) Allison Engineering Co. V-1710-C15 (V-1710-33). This was a single overhead cam (SOHC) 60° V-12 engine designed by Harold Caminez, Allison’s chief engineer. The V-1710-33 had a compression ratio of 6.65:1. It was rated at 930 horsepower at 2,600 r.p.m. at 12,800 feet (3,901 meters), and 1,040 horsepower at 2,800 r.p.m. for takeoff, burning 100-octane gasoline. The engine turned a three-bladed Curtiss Electric constant-speed propeller through a 2:1 gear reduction. The V-1710-33 was 8 feet, 2.54 inches (2.503 meters) long, 3 feet, 5.88 inches (1.064 meters) high, and 2 feet, 5.29 inches (0.744 meters) wide. It weighed 1,340 pounds (607.8 kilograms).
The cruising speed of the P-40 was 272 miles per hour (438 kilometers per hour) and the maximum speed was 357 miles per hour (575 kilometers per hour) at 15,000 feet (4,572 meters). The Warhawk had a service ceiling of 30,600 feet (9,327 meters) and the absolute ceiling was 31,600 feet (9,632 meters). The range was 950 miles (1,529 kilometers) at 250 miles per hour (402 kilometers per hour).
The fighter (at the time, the Air Corps designated this type as a “pursuit”) was armed with two air-cooled Browning AN-M2 .50-caliber machine guns on the engine cowl, synchronized to fire through the propeller, with 380 rounds of ammunition per gun. Provisions were included for one Browning M2 .30-caliber aircraft machine gun, with 500 rounds of ammunition, in each wing.
The first production P-40 Warhawk, 39-156, made its first flight 4 April 1940. The 8th Pursuit Group at Langley Field, Virginia, was the first Army Air Corps unit to be equipped with the P-40.
After 200 P-40s were produced for the Air Corps, production was interrupted to allow Curtiss-Wright to build 100 Hawk 85A-1 export variants for the French Armée de l’air, then engaged with the invading forces of Nazi Germany. When France surrendered 22 June 1940, none of these airplanes had been delivered. The order was then assumed by the British Royal Air Force as the Tomahawk I.
U.S. Warhawk production resumed as the improved P-40B, and the remainder of the P-40 order was cancelled.
Buffalo, N.Y., January 24—(AP)—A Curtiss Hawk 75A pursuit plane, one of 100 being constructed for the French Government, has “substantially exceeded all known speed records” with a free dive of more than 575 miles an hour, it was announced today.
The speed mark was established yesterday while the ship was undergoing acceptance tests, officials of the Curtiss Aeroplane Division of the Curtiss Wright Corporation said.
The tests were made by H. Lloyd Child, chief test pilot of the Buffalo Curtiss plant, who said he “felt no ill effects and did not realize” that the speed was presumably the fastest man has ever traveled.”
National Aeronautic Association officials said that no Federation Aeronautique Internationale records “even approached this speed.”
The speed of the dive was so great that the marker on the recording airspeed indicator exceeded the instrument’s range and moved off the paper on which the graph of the dive was recorded.
Aviation experts, who declined to be quoted directly, estimated that the speed might have exceeded 600 miles per hour, compared with the normal falling rate for a 170-pound man of 150 miles an hour.
The dive was begun at an altitude of 22,000 feet, and the record speed was attained during a 9,000 foot dive.
At no time during the dive, Child said, did the engine exceed 2,550 revolutions a minute, its normal rated speed in level flight. Hence, he explained, the strain on the motor during the dive was not increased, but was held to the speed of normal operation by the Curtiss electric propeller, with its unlimited blade pitch range.
Since the motor’s speed was kept at normal during the dive, it was a “free,” rather than a “power” dive as when the motor throttle is opened wide, aviation experts explained.
Previously, company officials explained, a limiting factor in the speed at which an airplane could dive was the engine’s revolutions each minute, since overspeeding would result to serious damage to the motor.
The Curtis Hawk 75A pursuit plane is similar to the Curtiss P-36A, the standard pursuit airplane of the United States Army Air Corps.
It carried two machine guns and is equipped to carry bombs under each wing when on a fighting mission.
The greatest previously registered speed was 440.681 miles an hour, made by Francesco Agello of Italy over a three-kilometer course in level flight October 23, 1934.
The world’s land speed record is held by George E. T. Eyston of England at 357.5 miles an hour, established September 16, 1938.
—The Cincinnati Enquirer, Vol. XCVIII, No. 291, Wednesday, January 25, 1939, at Page 1, Columns 1 and 2
The Oakland Tribune reported:
‘Faster Than Any Man Alive,’ Flier Says After Diving 575 M.P.H.
BUFFALO, N.Y., Jan. 25.—(AP)—A test pilot who free-power dived a heavily armed pursuit airplane at more than 575 miles per hour claimed today the distinction of having traveled “faster than any other human being.”
Chief test pilot H. Lloyd Child dropped a Curtiss Hawk 75A through the clouds above Buffalo Airport yesterday at almost 1000 feet a second to exceed “all known speed records,” the Curtiss aeroplane division of the Curtiss-Wright Corporation announced.
Child was testing the plane for the French Army, which has purchased 100 of the ships. The terrific speed was recorded on instruments installed by the French Government’s representatives, who witnessed the flight.
The velocity was so great the marker on the indicator exceeded the instrument’s range and moved off the paper roll. Aviation experts said Child probably exceeded 600 miles per hour.
“I didn’t feel anything,” the test pilot commented, “it was all over too quickly.”
Child said the dive was part of a day’s work.
“No danger at all, I would say,” he commented.
His spare time hobby, skiing, however, “is awful dangerous,” Child asserted.
“I wouldn’t be surprised if someone would exceed my speed soon. A diving speed of 700 miles per hour is within the realm of possibility,” he added.
—Oakland Tribune, VOL. CXXX—NO. 25, Wednesday, January 25, 1939, Page 3, Columns 2 and 3
The Curtiss-Wright Model 75 was a single-seat, single-engine, low wing monoplane with retractable landing gear. The airplane was designed by Donovan Reese Berlin. Curtiss-Wright intended to offer it as a pursuit for the U.S. Army Air Corps. H. Lloyd Child took the prototype, NX17Y, for its first flight 6 May 1935.
After evaluation by the Air Corps at Wright Field, the rival Seversky Aircraft Corporation SEV-1XP was selected by the Air Corps and 77 P-35s were ordered. Don Berlin worked on improving the Model 75, and in 1937, the Air Corps ordered 210 Curtiss P-36As.
Curtiss-Wright also offered versions of the Hawk 75 to foreign governments. Variants were available with fixed or retractable gear, a choice of Pratt & Whitney Twin Wasp or Wright Cyclone engines, and various combinations of machine gun and cannon armament.
The Curtiss Hawk 75 A was 28.8 feet (8.78 meters) long with wingspan of 37.3 feet (11.37 meters) and height of 9.25 feet (2.82 meters). The total wing area was 236.0 square feet (21.93 square meters). With a Pratt & Whitney engine, the airplane had an empty weight of 4,713 pounds (2,127.3 kilograms), and gross weight of 5,922 pounds (2,675.7 kilograms).
The Armée de l’air initially ordered 100 Hawk 75A-1s, designated H75-C1 in French service. Pratt & Whitney Twin Wasp engines (including spares) were ordered separately. They were delivered to France for final assembly, and were unpainted. These airplanes had minor differences from U.S. Army Air Corps P-36As. For example, the instrument markings were metric. It was French custom to have the throttle off when pushed full forward, and wide open when pulled rearward. The pilot’s seat was different in order to fit the standard French parachute.
The French H75-A1 was powered by an air-cooled, supercharged, 1,829.39-cubic-inch-displacement (29.97 liter) Pratt & Whitney Twin Wasp SC-G [Specification Number PW-5028-C]. This was a two-row 14-cylinder radial engine with a compression ratio of 6.7:1. The SC-G was rated at 900 horsepower at 2,550 r.p.m. at 11,000′ (3,353 meters), and 1,050 horsepower at 2,700 r.p.m. for take off. The engine drove a three bladed, 10 foot, 1½ inch (3.086 meters) diameter Curtiss Electric constant-speed propeller through a 16:9 gear reduction. The SC-G was 48.00 inches (1.219 meters) in diameter, 59.90 inches (1.521 meters) long, and weighed 1,423 pounds (645 kilograms).
The Hawk 75A-1 had a maximum cruise speed of 260 miles per hour (418 kilometers per hour) at 19,000 feet (5,790 meters). Its maximum speed was 258 miles per hour (413 kilometers per hour) at Sea Level, 290 miles per hour at 8,200 feet (2,500 meters), and 303 miles per hour (488 kilometers per hour) at 19,000 feet (5,790 meters). Although Child demonstrated a dive at over 575 miles per hour, in service, the Hawk was restricted to a maximum dive speed of 455 miles per hour (732 kilometers per hour). The airplane had a service ceiling of 32,800 feet (9,997 meters), and absolute ceiling of 33,700 feet (10,272 meters).
The Armée de l’air H75A-1 was armed with four FN-Browning de Belgique mle 1938 7.5 mm. × 54 mm MAS (.295-caliber) machine guns, with two mounted on the engine cowl, synchronized to fire through the propeller arc, and one in each wing. 2,200 rounds of ammunition were carried. The 7.5 mm was a shorter, less powerful cartridge than the .303 British (7.7 × 56 mm) or U.S. standard .30-06 Springfield (7.62 × 63 mm) cartridges.
France followed with orders for Hawk 75A-2, 75A-3 and 75A-4 fighters. These had different combinations of guns and engine variants.
After the surrender of France to invaders from Nazi Germany, many Curtiss Hawks made their way to England. In service with the Royal Air Force, these airplanes were called the Mohawk.
Henry Lloyd Child was born at Philadelphia, Pennsylvania, 25 May 1904, the second of two children of Edward Taggart Child, a consulting engineer in shipbuilding, and Lillian Rushmore Cornell Child. He was baptized at the Church of the Good Shepherd, Rosemont, Pennsylvania, 22 December 1913. Child graduated from Flushing High School in Flushing, New York, then attended the Haverford School in Philadelphia.
“Skipper” Child majored in mechanical engineering at the University of Pennsylvania where he was a member of the Hexagon Senior Engineering Society and the Phi Sigma Kappa (ΦΣΚ) and Sigma Tau (ΣΤ) fraternities. He was a member of the varsity and all-state soccer team, and also played football and tennis. Child graduated with a bachelor of science degree, 15 June 1926.
After graduation from college, Child went to work for the Curtiss-Wright Corporation as an engineer.
Child joined the United States Navy, 23 November 1927. He was trained as a pilot at Naval Air Station Hampton Roads, Norfolk, Virginia, and was commissioned as an Ensign. He was promoted to lieutenant (junior grade), 7 November 1932, and to lieutenant, 11 November 1935.
While maintaining his commission in the Navy, Child returned to Curtiss-Wright as a test pilot.
Henry Lloyd Child married Miss Allene Ann Gausby of Hamilton, Ontario, Canada, 28 October 1939. They had met in July 1938, while playing in a tennis tournament at Muskoka, Northern Ontario. They would have a daughter, Beverley L. Child.
H. Lloyd Child worked for Lockheed from 1958 to 1968, when he retired. He died at Palmdale, California 5 August 1970 at the age of 66 years.