10 May 1972: Chief test pilot Howard W. (“Sam”) Nelson made the first flight of the prototype Fairchild Republic YA-10A Thunderbolt II, 71-1369, at Edwards Air Force Base in the high desert of southern California.
The production A-10A Thunderbolt II is a single-place, twin engine low-wing monoplane with retractable tricycle landing gear. The airplane is 52 feet, 7 inches (16.027 meters) long with a wing span of 57 feet, 6 inches (17.526 meters), and overall height of 14 feet, 8 inches (4.470 meters). Its operating weight is 24,513 pounds (11,119 kilograms) and the maximum takeoff weight is 50,000 pounds (22,680 kilograms). This includes the operating weight plus full internal fuel, 1,350 rounds of ammunition and 18 Mk.82 bombs.
The A-10 is powered by two General Electric TF34–GE-100 engines. These are two-spool axial flow turbofans with a single stage fan section, 14-stage compressor, and 6-stage turbine. The engines produce a maximum 8,900 pounds of thrust ( kilonewtons).
The A-10 was designed and built around its hydraulically-operated General Electric GAU-8 Avenger 30 mm Gatling-type autocannon. The gun has 7 rotating barrels and is capable of firing at a rate of 4,300 rounds per minute. The Thunderbolt II can carry a maximum of 1,350 rounds of high explosive-incendiary or armor piercing-incendiary ammunition.
Howard Verner Nelson was born on New Year’s Eve, 31 December 1924, at Hartford Connecticut. He was the second son of Gustaf B. Nelson, a clerk, and Signe Ottilia Nelson.
Nelson entered the United States Army Air Forces on 20 November 1944, and remained on active duty in the U.S. Air Force until 28 May 1957, when he transferred to the Air Force Reserve. He rose to the rank of lieutenant colonel. He flew 105 combat missions during the Korean War.
“Sam” Nelson joined the Republic Aviation Corporation in 1960. He was assigned Republic’s chief test pilot for the F-105 Thunderchief supersonic fighter bomber. In October 1976, Nelson was promoted to Director of Flight Operations.
Nelson was killed at the Paris Air Show 3 June 1977 while demonstrating an A-10A Thunderbolt II.
Lieutenant Colonel Nelson’s remains were buried at the Arlington National Cemetery.
6 May 1941: Just eight months after a prototype for a new single-engine fighter was ordered by the U.S. Army Air Forces, test pilot Lowery Lawson Brabham took off from the Republic Aviation Corporation factory airfield at Farmingdale, New York, and flew the prototype XP-47B Thunderbolt, serial number 40-3051, to Mitchel Field, New York.
During the flight, oil which had collected in the exhaust duct began burning. There was so much smoke that Brabham considered bailing out. He stayed with the prototype, though, and when he arrived at Mitchel Field, he exclaimed, “I think we’ve hit the jackpot!”
The prototype was designed by Alexander Kartveli, a Georgian immigrant and former chief engineer for the Seversky Aircraft Corporation, which became the Republic Aviation Corporation in 1939.
Alexander Kartveli (née Kartvelishvili, ალექსანდრე ქართველი) was born in Tbilisi, in the Kutais Governorate of the Russian Empire, (what is now, Georgia). After World War I, during which he was wounded, Kartvelishvili was sent to study at the Paris Aviation Higher College of Engineering in France by the government of the Democratic Republic of Georgia. He graduated in 1922. Kartvelishvili did not return to his country, which had fallen to the Red Army in the Soviet-Georgian War. He worked for Blériot Aéronautique S.A. until 1928, when he was employed by the Fokker American Company (also known as Atlantic Aircraft, or Atlantic-Fokker) which was headquartered at Passaic, New Jersey, in the United States. In 1931, he became chief engineer for the Seversky Aircraft Company in Farmingdale.
The XP-47B was the largest single-engine fighter that had yet been built. The production P-47B was 34 feet, 10 inches (10.617 meters) long with a wingspan of 40 feet, 9-5/16 inches (12.429 meters), and height of 12 feet, 8 inches (3.861 meters).¹ The wing area was 300 square feet (27.9 square meters). At a gross weight of 12,086 pounds (5,482 kilograms), it was nearly twice as heavy as any of its contemporaries.
The XP-47B was powered by an air-cooled, supercharged and turbocharged, 2,804.4-cubic-inch-displacement (45.956 liter) Pratt & Whitney R-2800-21 (Double Wasp TSB1-G) two-row, 18-cylinder radial with a compression ratio of 6.65:1 had a normal power rating of 1,625 horsepower at 2,550 r.p.m., to an altitude of 25,000 feet (7,620 meters), and a takeoff/military power rating of 2,000 horsepower at 2,700 r.p.m. at 25,000 feet (7,620 meters). The engine drove a 12-foot, 2 inch (3.708 meter) diameter, four-bladed Curtiss Electric constant-speed propeller through a 2:1 gear reduction. The R-2800-21 was 4 feet, 4.50 inches (1.340 meters) in diameter and 6 feet, 3.72 inches (1.923 meters) long. The engine weighed 2,265 pounds (1,027 kilograms). Approximately 80% of these engines were produced by the Ford Motor Company. It was also used as a commercial aircraft engine, with optional propeller gear reduction ratios.
A large General Electric turbosupercharger was mounted in the rear of the fuselage. Internal ducts carried exhaust gases from the engine to drive the turbocharger. This supercharged air was then carried forward through an intercooler and then on to the carburetor to supply the engine. The engine’s mechanical supercharger further pressurized the air-fuel charge.
During flight testing, the XP-47B Thunderbolt demonstrated speeds of 344.5 miles per hour (554.4 kilometers per hour) at 5,425 feet (1,654 meters), and 382 miles per hour (615 kilometers per hour) at 15,600 feet (4,745 meters). Its maximum speed was 412 miles per hour (663 kilometers per hour) at 25,800 feet (7,864 meters). The test pilot reported that the engine was unable to produce full power during these tests. It was determined that it had a cracked cylinder head, resulting in a loss of 2.5–4% of its maximum rated power. Also, the XP-47B was painted in camouflage, resulting in a slight loss of speed.
It could climb to 15,000 feet (4,572 meters) in just five minutes.
The Thunderbolt was armed with eight Browning AN-M2 .50-caliber machine guns, four in each wing, with 3,400 rounds of ammunition. It could also carry external fuel tanks, rockets and bombs. The structure of the P-47 could be described as “robust” and it was heavily armored. The amount of damage that the airplane could absorb and still return was remarkable.
During a test flight, 4 August 1942, the XP-47B’s tail wheel was left down. The extreme heat of the turbocharger’s exhaust set fire to the tire, which then spread to the airplane’s fabric-covered control surfaces. Unable to control the airplane, test pilot Filmore L. Gilmer bailed out. The prototype Thunderbolt crashed into Long Island Sound and was destroyed.
A total of 15,683 Thunderbolts were built; more than any other Allied fighter type. In aerial combat, it had a kill-to-loss ratio of 4.6:1. The P-47, though, really made its name as a ground attack fighter, destroying aircraft, locomotives, rail cars, and tanks by the many thousands. It was one of the most successful aircraft of World War II.
¹ Data from Pilot’s Flight Operating Instructions, Technical Order No. 01-65BC-1, 20 January 1943
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.
2 May 1925: At Santa Monica, California, the Douglas Aircraft Company C-1, A.S. 25-425, made its first flight. The new aircraft was requested by the U.S. Army Air Service to fill the role of a cargo transport. The single-engine, two-bay biplane had a crew of two in an open cockpit and could carry 6–8 passengers in an enclosed compartment, or 2,500 pounds (1,134 kilograms) of cargo. A trapdoor in the floor allowed heavy cargo to be lifted directly into the airplane.
The Douglas C-1 was 35 feet, 4 inches (10.770 meters) long with a wingspan of 56 feet, 7 inches (17.247 meters) and height of 14 feet (4.267 meters). The transport’s empty weight was 3,836 pounds (1,740 kilograms) and its loaded weight was 6,443 pounds (2,922 kilograms).
The C-1 was powered by a water-cooled, normally-aspirated, 1,649.336-cubic-inch-displacement (27.028 liter) Liberty L-12 single overhead cam (SOHC) 45° V-12 engine with a compression ratio of 5.4:1. The Liberty produced 408 horsepower at 1,800 r.p.m. The L-12 as a right-hand tractor, direct-drive engine. It turned turned a two-bladed fixed-pitch wooden propeller. The Liberty 12 was 5 feet, 7.375 inches (1.711 meters) long, 2 feet, 3.0 inches (0.686 meters) wide, and 3 feet, 5.5 inches (1.054 meters) high. It weighed 844 pounds (383 kilograms).
The Liberty L12 aircraft engine was designed by Jesse G. Vincent of the Packard Motor Car Company and Elbert J. Hall of the Hall-Scott Motor Company. This engine was produced by Ford Motor Company, as well as the Buick and Cadillac Divisions of General Motors, The Lincoln Motor Company (which was formed by Henry Leland, the former manager of Cadillac, specifically to manufacture these aircraft engines), Marmon Motor Car Company and Packard. Hall-Scott was too small to produce engines in the numbers required.
The C-1 had a maximum speed of 116 miles per hour (187 kilometers per hour), though its cruising speed was 85 miles per hour (137 kilometers per hour). The service ceiling was 14,850 feet (4,526 meters) and its range was 385 miles (620 kilometers)
In addition to a passenger and cargo transport, the Douglas C-1 was used experimentally as a medical evacuation aircraft and as an aerial refueling tanker. Nine C-1 and C-1A transports were built, and seventeen slightly larger C-1Cs.
The C-1 was the first U.S. Air Force airplane to use the designation “C-” to indicate a cargo transport. That designator is still in use today.
30 April 1962: Though it had been airborne briefly just a few days earlier, “Article 121”, the first Lockheed A-12, serial number 60-6924, took off from a Top Secret facility at Groom Lake, Nevada, on its “official” first flight. Lockheed test pilot Louis Wellington (“Lou”) Schalk, Jr. was in the cockpit.
The 72,000-pound (32,659 kilogram) airplane lifted off the 8,000-foot (2,438 meters) runway at 170 knots (196 miles per hour, 315 kilometers per hour).
During the 59-minute test flight, Schalk kept the airspeed to just 340 knots (391 miles per hour, 630 kilometers per hour), but climbed to 30,000 feet (9.144 meters) while he tested systems and handling characteristics. He described the airplane as very stable and extremely responsive.
The A-12 was a top secret reconnaissance airplane built for the Central Intelligence Agency under the code name “Oxcart.” It was the replacement for the Agency’s high-flying but subsonic U-2 spy plane which had become vulnerable to radar-guided surface-to-air missiles. (A U-2 piloted by Francis Gary Powers had been shot down with an SA-2 Guideline missile while over Russia exactly one year before.)
The A-12 could fly faster than Mach 3 and higher than 80,000 feet—so fast and so high that no missile could reach it. By the time missile site radar locked on to an A-12 and a missile was prepared to fire, the Oxcart had already flown beyond the missile’s range.
The Lockheed A-12 was a single-place, twin-engine hypersonic reconnaisance aircraft. It was 101.6 feet (30.97 meters) long, with a wingspan of 55.62 feet (16.95 meters) and overall height of 18.45 feet (5.62 meters). It had an empty weight of 54,600 pounds (24,766 kilograms) and maximum gross weight of 124,600 pounds (57,878 kilograms).
The A-12 was powered by two Pratt & Whitney JT11D-20 (J58-P-4) turbo-ramjet engines, rated at 25,000 pounds of thrust (111.21 kilonewtons) and 34,000 pounds of thrust (151.24 kilonewtons) with afterburner. The exhaust gas temperature is approximately 3,400 °F. (1,870 °C.). The J58 is a single-spool, axial-flow engine which uses a 9-stage compressor section and 2-stage turbine. The J58 is 17 feet, 10 inches (7.436 meters) long and 4 feet, 9 inches (1.448 meters) in diameter. It weighs approximately 6,000 pounds (2,722 kilograms).
The A-12’s speed was Mach 3.2 (2,125 miles per hour/3,118 kilometers per hour) at 75,000 feet(22,860 meters). Its cruise altitude was 84,500–97,600 feet (25,756–29,748 meters). The range was 4,210 nautical miles (4,845 miles/7,797 kilometers)
Article 121 was the first of thirteen A-12s built by Lockheed’s “Skunk Works.” They were operational from 1964–1968, when they were phased out in favor of the U.S. Air Force two-man SR-71A “Blackbird.”
Today, the first Lockheed A-12 is on display at Blackbird Airpark, an annex of the Air Force Flight Test Museum, Edwards Air Force Base, California. It has made 322 flight and accumulated a total of 418.2 flight hours.