14 September 1939: At Stratford, Connecticut, Igor Sikorsky made the first tethered flight of the Vought-Sikorsky VS-300 prototype helicopter. The duration of the flight was just 10 seconds but demonstrated that the helicopter could be controlled.
The Vought-Sikorsky VS-300 was the first successful single main rotor, single tail rotor helicopter.
The three-bladed main rotor had a diameter of 28 feet (8.534 meters) and turned approximately 255 r.p.m. The rotor turned clockwise as seen from above (the advancing blade is on the left). This would later be reversed. A counter-weighted single blade anti-torque rotor with a length of 3 feet, 4 inches (1.016 meters) is mounted on the left side of the monocoque beam tail boom in a pusher configuration and turns counter-clockwise as seen from the helicopter’s left (the advancing blade is above the axis of rotation).
In the initial configuration, the VS-300 was powered by an air-cooled, normally-aspirated, 144.489-cubic-inch-displacement (2.368 liter) Lycoming O-145-C3 horizontally-opposed, four-cylinder, direct-drive engine with a compression ratio of 6.5:1. It was rated at 75 horsepower at 3,100 r.p.m., using 73-octane gasoline. It was equipped with a single Stromberg carburetor and dual Scintilla magnetos. The dry weight of the O-145-C3 was 167 pounds (75.75 kilograms). Later in the VS-300’s development, the Lycoming was replaced by a 90-horsepower Franklin 4AC-199 engine.
On 19 December 1939, the VS-300 was rolled over by a gust of wind and damaged. It was rebuilt, however, and developed through a series of configurations. It made its first free (untethered) flight 13 May 1940.
Test flights continued for several years. After 102 hours, 32 minutes, 26 seconds of flight, the VS-300 was donated to the Henry Ford Museum, Dearborn, Michigan.
18 August 1943: At Bridgeport, Connecticut, Sikorsky chief test pilot Charles Lester (“Les”) Morris made the first flight of the Vought-Sikorsky VS-327, c/n 33. Also known as the Sikorsky Model S-48, the U.S. Army Air Corps designated the helicopter XR-5 and assigned the serial number 43-28236.
The XR-5 was a significant improvement over the earlier R-4. Its narrow fuselage was streamlined and the cockpit had excellent visibility. The R-4’s box-like fuselage interfered with the downward flow of air from the main rotor, and this was a consideration in the shape of the new helicopter.
The Sikorsky XR-5 (Model S-48) was a single-engine, two-place helicopter. The cabin was built of aluminum with plexiglas windows. The fuselage was built of plastic-impregnated plywood and the tail boom was wood monocoque construction. The main rotor consisted of three fully-articulated blades built of wood spars and ribs and covered with fabric. The three bladed semi-articulated tail rotor was built of laminated wood. The main rotor turned counter-clockwise as seen from above. (The advancing blade is on the helicopter’s right.) The tail rotor was mounted on the helicopter’s left side in a pusher configuration. It turned clockwise as seen from the helicopter’s left.
There were five XR-5 helicopters, followed by twenty-six YR-5A service test helicopters built between November 1944 and July 1945. There were slight changes from the earlier five XR-5A prototypes. The R-5A went into production in July 1945 and more than 300 had been built by the time production ended in 1951.
The helicopter’s fuselage was 41 feet, 7½ inches (12.687 meters) long. The main rotor had a diameter of 48 feet (14.630 meters) and tail rotor diameter was 8 feet, 5 inches (2.2.565 meters), giving the helicopter an overall length of 57 feet, 1 inch (17.399 meters) with rotors turning. It was 13 feet, 1½ inches (4.001 meters) high. The landing gear tread was 12 feet (3.7 meters). The R-5A had an empty weight of 3,780 pounds (1,714.6 kilograms) and maximum takeoff weight of 4,900 pounds (2,222.6 kilograms). Fuel capacity was 100 gallons (378.5 liters).
The helicopter was powered by an air-cooled, supercharged, 986.749-cubic-inch-displacement (16.170 liter) Pratt & Whitney Wasp Jr. T1B4 (R-985 AN-5) direct-drive, nine-cylinder radial engine which was placed vertically in the fuselage behind the crew compartment. This engine was rated at 450 horsepower at 2,300 r.p.m., Standard Day at Sea Level. The R-985 AN-5 was 48.00 inches (1.219 meters) long, 46.25 inches (1.175 meters) in diameter and weighed 684 pounds (310.3 kilograms) with a magnesium crankcase.
The R-5 had a maximum speed (Vne) of 107 knots (123.1 miles per hour/198.2 kilometers per hour). Range was 275 miles (442.6 kilometers). The service ceiling was 14,800 feet (4,511 meters). The absolute hover ceiling was 3,000 feet (914.4 meters).
On 13 September 1943, Dimitry D. (“Jimmy”) Viner was hovering out of ground effect at 75 feet (23 meters) when 43-28236 suffered a tail rotor failure. The helicopter made a hard landing and was dignificantly damaged. Neither Viner nor his passenger were injured.
In 1944, while flying to a war bond rally in Nebraska, XR-5 43-28236 suffered an engine failure and crash landed. The helicopter was damaged beyond repair and was stripped for parts.
Thanks to regular This Day in Aviation reader Mike for suggesting this subject.
24 June 1942: The first production Vought-Sikorsky F4U-1 Corsair, Bu. No. 02155, made its first flight at Stratford, Connecticut. (Some sources state 25 June.)
The Corsair was designed by Rex Buren Beisel, and is best known for its distinctive inverted “gull wing,” which allowed sufficient ground clearance for its 13 foot, 4 inch (4.064 meter) diameter propeller, without using excessively long landing gear struts. The prototype XF4U-1, Bu. No. 1443, had first flown 29 May 1940, with test pilot Lyman A. Bullard in the cockpit.
The F4U-1 was had a length of 33 feet, 4.125 inches (10.163 meters), wingspan of 40 feet, 11.726 inches (12.490 meters) and overall height (to top of propeller arc) of 15 feet, 0.21 inches (4.577 meters). The wings’ angle of incidence was 2°. The outer wing had 8.5° dihedral and the leading edges were swept back 4°10′. With its wings folded, the width of the F4U-1 was 17 feet, 0.61 inches (5.197 meters), and gave it a maximum height of 16 feet, 2.3 inches (4.935 meters). When parked, the Corsair’s 13 foot, 4 inch (4.064 meter) propeller had 2 feet, 1.93 inches (65.862 centimeters) ground clearance, but with the fighter’s thrust line level, this decreased to just 9.1 inches (23.1 centimeters). The F4U-1 had an empty weight of 8,982 pounds (4,074.2 kilograms) and gross weight of 12,162 pounds (5,516.6 kilograms).
The F4U-1 variant of the Corsair was powered by an air-cooled, supercharged, 2,804.4-cubic-inch-displacement (45.956 liter) Pratt & Whitney Double Wasp SSB2-G (R-2800-8) two-row, 18-cylinder radial engine, with a compression ratio of 6.65:1. The R-2800-8 had a normal power rating of 1,675 horsepower at 2,550 r.p.m. and 44.0 inches of manifold pressure (1.490 bar) at 5,500 feet (1,676 meters); 1,550 horsepower at 21,500 feet (6,553 meters); and 2,000 horsepower at 2,700 r.p.m. with 54.0 inches of manifold pressure (1.829 bar) for takeoff. The engine turned a three-bladed Hamilton Standard Hydromatic constant-speed propeller with a diameter of 13 feet, 4 inches (4.064 meters) through a 2:1 gear reduction. The R-2800-8 was 7 feet, 4.47 inches (2.247 meters) long, 4 feet, 4.50 inches (1.334 meters) in diameter and weighed 2,480 pounds (1,125 kilograms).
The F4U-1 had a cruise speed of 186 miles per hour (299 kilometers per hour) at Sea Level. Its maximum speed at Sea Level was 365 miles per hour (587 kilometers per hour). During flight testing, an F4U-1 reached 431 miles per hour (694 kilometers per hour) at 20,300 feet (6,187 meters) with War Emergency Power. The service ceiling was 38,200 feet (11,643 meters) and its maximum range was 1,510 miles (2,430 kilometers) with full main and outer wing tanks.
The Corsair was armed with six air-cooled Browning AN-M2 .50-caliber machine guns, three in each wing, with 400 rounds of ammunition per gun.
A total of 12,571 Corsairs were manufactured by the Vought-Sikorsky Aircraft Division (F4U-1), Goodyear Aircraft Corporation (FG-1D) and Brewster Aeronautical Corporation (F3A-1). The Corsair served the U.S. Navy and Marine Corps in World War II and the Korean War. Corsairs also served in other countries’ armed forces. Its last known use in combat was in Central America in 1969.
29 May 1940: Vought-Sikorsky Aircraft Division test pilot Lyman A. Bullard, Jr. took the U.S. Navy’s new prototype fighter, the XF4U-1, Bu. No. 1443, for its first flight at the Bridgeport Municipal Airport, Bridgeport, Connecticut. Designed by Rex Buren Beisel, the prototype would be developed into the famous F4U Corsair.¹
The F4U Corsair is a single-place, single-engine fighter, designed for operation from the U.S. Navy’s aircraft carriers. The XF4U-1 prototype was 30 feet (9.144 meters) long with a wing span of 41 feet (12.497 meters) and overall height of 15 feet, 7 inches (4.750 meters). It had an empty weight of 7,576 pounds (3,436 kilograms) and gross weight of 9,374 pounds (4,252 kilograms).
The XF4U-1 was first powered by an experimental air-cooled, supercharged, 2,804.4-cubic-inch-displacement (45.956 liters) Pratt & Whitney R-2800 X-2 (Double Wasp A2-G), and then an R-2800 X-4 (Double Wasp SSA5-G), both two-row 18-cylinder radial engines. The R-2800 X-4 was an X-2 with an A5-G supercharger. The R-2800 X-2 had a compression ratio of 6.65:1 and was rated at 1,500 horsepower at 2,400 r.p.m. at 7,500 feet (2,286 meters). The X-4 was rated at 1,600 horsepower at 2,400 r.p.m. at 3,500 feet (1,067 meters); 1,540 horsepower at 2,400 r.p.m. at 13,500 feet (4,115 meters); 1,460 horsepower at 2,400 r.p.m. at 21,500 feet (6,553 meters); and 1,850 horsepower at 2,600 r.p.m for takeoff. The engine drove a 13 foot, 4 inch (4.064 meter) diameter, three-bladed, Hamilton Standard Hydromatic constant-speed propeller through a 2:1 gear reduction. The X-4 had a compression ratio of 6.66:1 and used a two-speed, two-stage supercharger. This was the most powerful engine and largest propeller used on any single engine fighter up to that time. The R-2800 X-4 was 4 feet, 4.50 inches (1.334 meters) in diameter and 7 feet, 4.81 inches (2.256 meters) long. It weighed 2,500 pounds (1,134 kilograms).
The size of the propeller was responsible for the Corsair’s most distinctive feature: the inverted gull wing. The width of the wing (chord) limited the length of the main landing gear struts. By placing the gear at the bend, the necessary propeller clearance was gained. The angle at which the wing met the fuselage was also aerodynamically cleaner.
The XF4U-1 prototype had a maximum speed of 378 miles per hour (608 kilometers per hour) at 23,500 feet (7,163 meters). Although it has been widely reported that it was the first U.S. single-engine fighter to exceed 400 miles per hour (643.7 kilometers per hour) in level flight, this is actually not the case. During a flight between Stratford and Hartford, Connecticut, the prototype averaged a ground speed 405 miles per hour (652 kilometers per hour). This was not a record flight, and did not meet the requirements of any official speed record.
Several changes were made before the design was finalized for production. Fuel tanks were removed from the wings to make room for six Browning AN-M2 .50-caliber machine guns and ammunition. A new tank was placed in the fuselage ahead of the cockpit. This moved the cockpit rearward and lengthened the nose.
On 11 July 1940, the XF4U-1 was low on fuel. Rather than returning to Bridgeport, test pilot Boone Tarleton Guyton made a precautionary landing on a golf course at Norwich, Connecticut. The grass was wet from rain and the prototype ran into the surrounding trees. Guyton was not injured, but 1443 was seriously damaged. Vought-Sikorsky repaired it and it returned to flight testing about two months later.
The production F4U-1 Corsair had a length of 33 feet, 4.125 inches (10.163 meters), wingspan of 40 feet, 11.726 inches (12.490 meters) and overall height (to top of propeller arc) of 15 feet, 0.21 inches (4.577 meters). The wing had 2° incidence at the root. The outer wing had a dihedral of 8.5°, and the leading edges were swept back 4°10′. With its wings folded, the width of the F4U-1 was 17 feet, 0.61 inches (5.197 meters), and gave it a maximum height of 16 feet, 2.3 inches (4.935 meters). When parked, the Corsair’s 13 foot, 4 inch (4.064 meter) propeller had 2 feet, 1.93 inches (65.862 centimeters) ground clearance, but with the fighter’s thrust line level, this decreased to just 9.1 inches (23.1 centimeters).
During fight testing of a production F4U-1 Corsair with a Pratt & Whitney R-2800-8 (Double Wasp SSB2-G) engine installed, armed with machine guns with 360 rounds of ammunition per gun, the fighter reached a maximum speed of 395 miles per hour (635.7 kilometers per hour) in level flight at 22,800 feet (6,949 meters), using Military Power. The service ceiling was 38,400 feet (11,704 meters).
A total of 12,571 Corsairs were manufactured the Vought-Sikorsky Aircraft Division (F4U-1), Goodyear Aircraft Corporation (FG-1D) and Brewster Aeronautical Corporation (F3A-1). The Corsair served the U.S. Navy and Marine Corps in World War II and the Korean War. Corsairs also served in other countries’ armed forces. Its last known use in combat was in Central America in 1969.
¹ corsair: noun, cor-sair. A pirate, or privateer (especially along the Barbary Coast of the Mediterranean Sea); a fast ship used for piracy.
25 May 1889: Ігор Іванович Сікорський (Igor Ivanovich Sikorsky) was born at Kiev, Ukraine, Russian Empire, the fifth of five children of Professor Ivan Alexeevich Sikorsky and Doctor Mariya Stefanovich Sikorskaya.
He studied at the Imperial Naval Academy, St. Petersburg, from 1903 until 1906, when he left to study engineering, first in Paris, and then at the Kiev Polytechnic Institute.
Flying an airplane of his own design, the S-5, on 18 April 1911, he received a Fédération Aéronautique Internationale pilot’s license from L’Aéro-Club Imperial de Russie (Imperial Russian Aero Club).
He was chief aircraft engineer for Russko-Baltiisky Vagonny Zavod at St. Petersburg and continued to develop airplanes. In 1913, he flew the twin engine S-21 Le Grand, to which he added two more engines, and it became the Russky Vityaz.
Igor Sikorsky married Olga Fyodorovna Simkovich. They had a daughter, Tania. The couple soon divorced, however.
Following the October Revolution, Sikorsky emigrated to the United States. Departing Le Havre, France, aboard S.S. La Lorraine, he arrived at New York on 31 March 1919. With financial backing from composer and conductor Sergei Vasilievich Rachmaninoff, he founded the Sikorsky Aero Engineering Company at Long Island, New York, in 1924, and continued designing and building airplanes.
In 1924, Sikorsky married Elisabeth Semion, who was also born in Russia, in 1903. They would have four children. In 1928, he became a citizen of the United States of America.
Beginning in 1934, Sikorsky Aircraft produced the S-42 flying boat for Pan American Airways at a new plant at Stratford, Connecticut.
Interested in helicopters since the age of 9, he directed his creative effort toward the development of a practical “direct-lift” aircraft. The first successful design was the Vought-Sikorsky VS-300. Using a single main rotor, the VS-300 went through a series of configurations before arriving at the single anti-torque tail rotor design, the VS-316A. This was put into production for the U.S. military as the Sikorsky R-4.
The company which Igor Sikorsky founded has continued as one of the world’s biggest helicopter manufacturers. Recently acquired by Lockheed Martin, Sikorsky continues to produce the UH-60-series of Blackhawk medium helicopters, the large CH-53K King Stallion, and the civil S-76D and S-92. A variant of the S-92 has been selected as the next helicopter for the U.S. presidential air fleet, the VH-92A. This helicopter is planned to be operational by 2020.
Igor Ivanovich Sikorsky died at Easton, Connecticut, 26 October 1972 at the age of 83 years.