27 October 2015: The first flight of the Sikorsky CH-53K King Stallion Engineering Development Model–1, Bu. No. 169019, at West Palm Beach, Florida. In the cockpit was Stephen McCulley, Chief Experimental Test Pilot for Sikorsky. During the 30 minute flight, the new helicopter demonstrated sideward, rearward and forward flight while remaining in in-ground-effect hover.
Up to this point, the helicopter had completed about 200 hours of “turn-time,” or ground testing, with engines running..
Three more aircraft will join the test fleet for a planned 2,000 hour flight test program.
The fuselage of the CH-53K King Stallion is 73 feet, 1.5 inches (22.289 meters) long and its width is 9 feet, 10 inches (2.997 meters). The maximum width, across the sponsons, is 17 feet, 6 inches (5.334 meters). The seven-bladed main rotor has a diameter of 79 feet (24.079 meters). The four-blade tail rotor is 20 feet (6.096 meters) in diameter. The tail rotor is tilted 20° to the left. With rotors turning, the helicopter has an overall length of 99 feet (30.175 meters), and height of 28 feet, 4.9 inches (8.659 meters). The helicopter’s maximum gross weight is 88,000 pounds (39,916 kilograms).
Power is supplied by three General Electric T408-GE-400 engines which produce 7,500 shaft horsepower, each. The engine has digital electronic controls. The T408 has a 6-stage compressor section (5 axial-flow stages, 1 centrifugal-flow stage) and – stage turbine section (2 high- and 3 low-pressure stages). The engine is 57.5 inches (1.461 meters) long and 27 inches (0.686 meters) in diameters.
At Sea Level with maximum continuous power, the CH-53K cruises at 158 knots (182 miles per hour/293 kilometers per hour). It can hover out of ground effect at Sea Level at its maximum gross weight. The helicopter’s service ceiling is 16,000 feet (4,877 meters).
The first production CH-53K was delivered to the U.S. Marine Corps on 16 May 2018, at West Palm Beach, Florida.
17 October 1974: Sikorsky Chief Pilot James R. (Dick) Wright and test pilot John Dixson made the first flight of the prototype YUH-60A, 73-21650, at the company’s Stratford, Connecticut, facility. This was the first of three prototypes.
After eight months of testing, the U.S. Army selected the YUH-60A for production over its competitor, the Boeing Vertol YUH-61A. In keeping with the Army’s tradition of naming helicopters after Native Americans, the new helicopter was named Black Hawk, who was a 17th Century leader of the Sauk (or Sac) people.
The Sikorsky Model S-70 (YUH-60A) was designed to meet the requirements of the U.S. Army Utility Tactical Transport Aircraft System (UTTAS). It had a 3-man crew and could carry an 11-man rifle squad. It could be transported by a Lockheed C-141 Starlifter.
The YUH-60A had an empty weight of 11,182 pounds (5,072 kilograms) and gross weight of 16,750 pounds (7,598 kilograms). The helicopter had a structural load factor of 3.5 Gs. With 1,829 pounds (830 kilograms) of fuel, it had an endurance of 2 hours, 18 minutes.
The YUH-60A had a four-blade fully-articulated main rotor with a diameter of 53 feet, 8 inches (16.358 meters). The blades had 18° negative twist and turned counterclockwise, as seen from above (the advancing blade is on the right) at 258 r.p.m. The blade tip speed was 725 feet per second (221 meters per second).
The four-bladed tail rotor was positioned on the right side of the tail rotor pylon in a tractor configuration. The tail rotor diameter was 11 feet (3.353 meters), and turned 1,214 r.p.m., rotating clockwise as seen from the helicopter’s left (the advancing was blade below the axis of rotation). The blade tip speed was 699 feet per second (213 meters per second). The tail rotor blades had -18° of twist. Because the Black Hawk’s engines are behind the transmission, the aircraft’s center of gravity (c.g.) is also aft. The tail rotor plane is inclined 20° to the left to provide approximately 400 pounds of lift (1.78 kilonewtons) to offset the rearward c.g.
Power was supplied by two General Electric T700-GE-700 modular turboshaft engines, rated at 1,622 shaft horsepower at 20,900 r.p.m. Np, at Sea Level under standard atmospheric conditions. The T700 has a 5-stage axial-flow, 1-stage centrifugal-flow compressor, with a 2-stage axial-flow gas producer and 2-stage axial-flow power turbine. The T700 is 3 feet, 11 inches (1.194 meters) long, 2 feet, 1 inch (0.635 meters) in diameter and weighs 437 pounds (198 kilograms). The helicopter’s main transmission was designed for 2,828 horsepower. The engines are derated to the transmission limit.
The YUH-60A had a cruise speed of 147 knots (169 miles per hour/272 kilometers per hour) at 4,000 feet (1,219 meters) and 95 °F. (35 °C.). It could climb at 450 feet per minute (2.29 meters per second) at the same altitude and air temperature.
73-21650 crashed into the Housatonic River near the Stratford plant at 9:10 a.m., Friday, 19 May 1978, killing all three Sikorsky employees on board, pilots Albert M. King, Jr., John J. Pasquarello, and flight engineer John Marshall.
During routine maintenance an airspeed sensor for the all-flying tailplane had been disconnected. As the Black Hawk transitioned from hover to forward flight, the all-flying tailplane remained in the hover position and forced the helicopter’s nose to pitch down to the point that recovery was impossible.
The Black Hawk has been in production since 1978. More than 4,000 of the helicopters have been built and the type has been continuously improved. The current production model is the UH-60M.
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.
25 May 1889: И́горь Ива́нович Сико́рский (Igor Ivanovich Sikorsky) was born at Kiev, 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 SS 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.
17 May 1942: After a 761 mile (1,224.7 kilometer) flight over five days, test pilot Charles Lester (“Les”) Morris and Igor Sikorsky arrived at Wright Field, Dayton, Ohio, to deliver the U.S. Army’s first helicopter, the Vought-Sikorsky XR-4. Morris hovered directly up to the base administration building and landed there. He and Sikorsky were greeted by a large group of people which included Lieutenant Colonel Hollingsworth Franklin (“Frank”) Gregory, the Army’s designated rotorcraft expert, and pioneer aviator Orville Wright.
From the Sikorsky factory at Stratford, Connecticut, to Wright Field, Ohio, was 761 miles (1,224.7 kilometers), direct. Because of the XR-4’s low speed and short range (weight limitations restricted the quantity of gasoline it could carry) the distance was covered in sixteen separate flights with a total flight time of 16 hours, 10 minutes. The longest single flight lasted 1 hour, 50 minutes, a new world’s record for helicopter flight endurance. Igor Sikorsky joined Les Morris for the final leg of the flight.
The Vought-Sikorsky VS-316A (which was designated XR-4 by the U.S. Army Air Corps and assigned serial number 41-18874), established the single main rotor/anti-torque tail rotor configuration. It was a two-place helicopter with side-by-side seating and dual flight controls. The fabric-covered three-blade main rotor was 38 feet (11.582 meters) in diameter and turned counter-clockwise as seen from above. (The advancing blade is on the helicopter’s right). The three-blade tail rotor was mounted to the right of the tail boom in a tractor configuration, and rotated clockwise when seen from the helicopter’s left side. (The advancing blade was below the axis of rotation.)
The XR-4 was 33 feet, 11.5 inches (10.351 meters) long and 12 feet, 5 inches (3.785 meters) high. It weighed 2,010 pounds (911.7 kilograms) empty and the maximum gross weight was 2,540 pounds (1,152.1 kilograms).
The VS-316A had originally been powered by a 499.8-cubic-inch-displacement (8.19 liter) air-cooled Warner Aircraft Corporation Scarab SS-50 (R-500-1) seven-cylinder radial engine, rated at 145 horsepower at 2,050 r.p.m. In the XR-4 configuration, the engine was upgraded to an air-cooled, direct-drive 555.298-cubic-inch-displacement (9.100 liter) Warner Super Scarab SS185 (R-550-3) seven-cylinder radial engine with a compression ration of 6.20:1. The R-550-3 was rated at 185 horsepower at 2,175 r.p.m. at Sea Level, and 200 horsepower at 2,475 r.p.m (five minute limit) for takeoff. The engine was placed backwards in the aircraft with the propeller shaft driving a short driveshaft through a clutch to a 90° gear box and the transmission. The R-550-3 weighed 344 pounds (156 kilograms).
The XR-4 was redesignated XR-4C. This would be the world’s first production helicopter. It is at the Steven F. Udvar-Hazy Center of the Smithsonian National Air and Space Museum.