Tag Archives: Sikorsky a Lockheed Martin Company

Igor Ivanovich Sikorsky (25 May 1889–26 October 1972)

Igor Ivanovich Sikorsky, 1914. (Karl Karlovich Bulla)
Igor Ivanovich Sikorsky, 1914. Sikorsky is wearing the cross of the Imperial Order of St. Vladimir. (Karl Karlovich Bulla)

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.

15 year-old Midshipman Igor Ivanovich Sikorksky, at lower right, with his sisters Olga, Lydia and Elena, and brother Sergei, 1904. (Sikorsky, a Lockheed Martin Company)
15 year-old Midshipman Igor Ivanovich Sikorksky, Imperial Naval Academy, at lower right, with his sisters Olga, Lydia and Elena, and brother Sergei, 1904. (Sikorsky, a Lockheed Martin Company)

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.

Airplane pilot Igor Sikorsky with a passenger. (RIA Novosti)
Pilot Igor Ivanovich Sikorsky with a passenger, circa 1914. (RIA Novosti)

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).

Igor I. Sikorsky's FAI pilot's license. (Sikorsky Historical Archives)
Igor I. Sikorsky’s FAI pilot’s license. (Sikorsky Historical Archives)

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 with one of his early biplanes.
Igor Sikorsky with one of his early biplanes.
Sikorsky S-21 in flight
Sikorsky’s S-21 in flight, 1913

Igor Sikorsky married Olga Fyodorovna Simkovich. They had a daughter, Tania. The couple soon divorced, however.

Compagnie Générale Transatlantique liner, SS La Lorraine, 11,146 gross tons.
Compagnie Générale Transatlantique liner, S.S. La Lorraine, 11,146 gross tons.

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.

Sikorsky S-39 amphibian NC54V (Civil Air Patrol)
Sikorsky S-39 amphibian NC54V (Civil Air Patrol)

Beginning in 1934, Sikorsky Aircraft produced the S-42 flying boat for Pan American Airways at a new plant at Stratford, Connecticut.

U.S. Navy RS-1 (Sikorsky S-41) (National Museum of Naval Aviation)
U.S. Navy RS-1 (Sikorsky S-41) (National Museum of Naval Aviation)
A Pan American Airways Sikorsky S-42, NC16742, moored at Honolulu, Territory of the Hawaiian Islands. (hawaii.gov/hawaiiaviation)
Pan American Airways Sikorsky S-42, NC16734, moored at Honolulu, Territory of the Hawaiian Islands. (hawaii.gov/hawaiiaviation)

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 prototype VS-300 helicopter clears the ground for the first time, 14 September 1939. Igor Sikorsky is at the controls. His right foot rests on the anti-torque pedal. (Sikorsky Historical Archives)
The prototype VS-300 helicopter clears the ground for the first time, 14 September 1939. Igor Sikorsky is at the controls. His right foot rests on the anti-torque pedal. (Sikorsky Historical Archives)
Igor Sikorsky hovers the Vought-Sikorsky VS-300. (Sikorsky, a Lockheed Martin Company)
Igor Sikorsky hovers the Vought-Sikorsky VS-300A. (Sikorsky, a Lockheed Martin Company)
On behalf of the Fédération Aéronautique Internationale, the National Aeronautic Association of the United States issued Helicopter Pilot Certificate No. 1 to Igor I. Sikorsky, 10 December 1940. (Sikorsky Historical Archives)
On behalf of the Fédération Aéronautique Internationale, the National Aeronautic Association of the United States issued Helicopter Pilot Certificate No. 1 to Igor I. Sikorsky, 10 December 1940. (Sikorsky Historical Archives)
Igor Sikorsky hovers the VS-300 before presenting it to The Henry Ford, 7 October 1943. (Photograph courtesy of Tom Fisher, The Henry Ford. Object ID: 84.1.1660.P.B.27654)
Igor Sikorsky in the cockpit of a Sikorsky S-48 (R-5) helicopter. (Smithsonian Institution National Air and Space Museum)

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.

Igor Sikorsky piloting his pontoon-equipped VS-300, 17 April 1941. (Sikorsky Historical Archives)
Igor Sikorsky piloting his pontoon-equipped VS-300, 17 April 1941. (Sikorsky Historical Archives)
s-47-4
Les Morris at the controls of the Vought-Sikorsky XR-4, 41-18874 (VS-316A), on its first flight at Stratford, Connecticut, 14 January 1942. (Sikorsky Historical Archives)
Lt. Carter Harman hovering in ground effect with Sikorsky YR-4B Hoverfly 43-28247 at Lalaghat, India, March 1944. This is the helicopter with which he made the first combat rescue, 21-25 April 1944. (U.S. Air Force)
Lt. Carter Harman hovering in ground effect with Sikorsky YR-4B Hoverfly 43-28247 at Lalaghat, India, March 1944. This is the helicopter with which he made the first combat rescue, 21-25 April 1944. (U.S. Air Force)
A Sikorsky R-5 flown by Jimmy Viner with Captain Jack Beighle, lifts a crewman from Texaco Barge No. 397, aground on Penfield Reef, 29 November 1945. (Sikorsky Historical Archive)
U.S. Army R-5 (Sikorsky S-48) flown by Jimmy Viner with Captain Jack Beighle, lifts a crewman from Texaco Barge No. 397, aground on Penfield Reef, 29 November 1945. (Sikorsky Historical Archive)
Sikorsky R-5 medevac, Korean War
U.S. Air Force H-5 (Sikorsky S-51) lifts off during the Korean War. (U.S. Air Force)
U.S. Coast Guard HOS-1 (Sikorsky S-49), with Igor Sikorsky as a passenger, over the Kill Devil Hills, North Carolina, 17 December 1947—the 44th annivesary of teh Wright Brothers first controlled, powered airplane flight. (Sikorsky Historical Archives)
U.S. Coast Guard HOS-1 (Sikorsky S-49), with Igor Sikorsky as a passenger, over the Kill Devil Hills, North Carolina, 17 December 1947—the 44th annivesary of the Wright Brothers first controlled, powered airplane flight. (Sikorsky Historical Archives)
U.S. Army YH-18A 49-2889 (Sikorsky S-52-2) (Ed Coates Collection)
U.S. Army YH-18A 49-2889 (Sikorsky S-52-2) (Ed Coates Collection)
SH-19A Air Rescue Sqd. AR.1999.026
U.S. Air Force SH-19A Chickasaw 51-3850 (Sikorsky S-55), Air Rescue Service. (U.S. Air Force)
Sikorsky H-34A-SI Choctaw (S-58) 57-1743 hovers in ground effect. Later registered as a civilian aircraft, N47246). (U.S. Army)
U.S. Army H-34A-SI Choctaw (Sikorsky S-58) 57-1743 hovers in ground effect. Later registered as a civilian aircraft, N47246). (U.S. Army)
Sikorsky CH-37 Mojave heavy-lift helicopter
U.S. Marine Corps CH-37 Mojave (Sikorsky S-56) heavy-lift helicopter
A U.S. Navy Sikorsky SH-3A Sea King (S-61), Bu. No. 149867, near Oahu, Hawaiian Islands, 5 April 1976. (PH2 (AC) Westhusing, U.S. Navy)
U.S. Navy SH-3A Sea King (Sikorsky S-61), Bu. No. 149867, near Oahu, Hawaiian Islands, 5 April 1976. (PH2 (AC) Westhusing, U.S. Navy)
A U.S. Coast Guard HH-52A Seaguard (Sikorsky Model 62). (United States Coast Guard)
A Sikorsky HH-3E Jolly Green Giant (66-13290) ot the 37th ARRS, hovering in ground effect at Da Nang, 1968. (U.S. Air Force)
U.S. Air Force HH-3E Jolly Green Giant (Sikorsky S-61R), 66-13290, of the 37th ARRS, hovering in ground effect at Da Nang, 1968. (U.S. Air Force)
A U.S. Air Force Sikorsky HH-53C Super Jolly Green Giant hovers to hoist a pararescueman with one downed pilot, while a second waits on the ground, 16 June 1967. The blade tip vortices are visible because of the high humidity. (National Archives at College Park)
Sikorsky CH-54A Tarhe 68-18448, Nevada National Guard, 16 Nober 1989. (Mike Freer/Wikipedia)
U.S. Army CH-54A Tarhe 68-18448 (Sikorsky S-64) heavy-lift helicopter, Nevada National Guard, 16 November 1989. (Mike Freer/Wikipedia)
Sikorsky MH-53M Pave Low IV, 68-8424, prepares for its last combat mission, Iraq, 27 September 2008. (A1C Jason Epley, U.S. Air Force)
U.S. Air Force MH-53M Pave Low IV 68-8424 (Sikorsky S-65), prepares for its last combat mission, Iraq, 27 September 2008. (A1C Jason Epley, U.S. Air Force)
U.S. Army Special Forces soldiers dismount a Sikorsky UH-60 Blackhawk, Zabul Province, Afghanistan, 21 January 2010. (Detail from photograph by Staff Sergeant Aubree Clute, U.S. Army)
Sikorsky HH-60G Pave Hawk 89-26212. (U.S. Air Force)
U.S. Air Force HH-60G Pave Hawk (Sikorsky S-70) 89-26212, Kunar Province, Afghanistan. (Captain Erick Saks, U.S. Air Force)
British Airways' Sikorsky S-61N G-BEON, 1982. ( )
British Airways’ Sikorsky S-61N Sea King G-BEON, 1982.
An Erickson Air-Crane, Inc. Sikorsky S-64 Skycrane drops water on a forest fire. (Sikorsky Archives)
An Erickson Air-Crane, Inc., Sikorsky S-64 Skycrane drops water on a forest fire. (Sikorsky Archives)
1280px-040327-pb-firehawk-17-16
A Los Angeles County Fire Department Sikorsky S-70A Firehawk, N160LA, during a rescue near Palmdale, California, 27 March 2004. (Alan Radecki/Wikipedia)
A Queen's Helicopter Flight Sikorsky S-76C, s/n 760753, G-XXEB (Russell Lee/Wikipedia)
A Queen’s Helicopter Flight Sikorsky S-76C, s/n 760753, G-XXEB (Russell Lee/Wikipedia)
Cougar Helicopters' Sikorsky S-92A C-GKKN landing at Ilulissat Airport, Greenland, 5 August 2010. (Algkalv/Wikipedia)
Cougar Helicopters’ Sikorsky S-92A C-GKKN landing at Ilulissat Airport, Greenland, 5 August 2010. (Algkalv/Wikipedia)
Sikorsky CH-53K King Stallion (Sikorsky, A Lockheed Martin Company)
The prototype Sikorsky CH-53K King Stallion (Sikorsky, A Lockheed Martin Company)

© 2017, Bryan R. Swopes

17 May 1942

Sikorsky XR-4 41-18874 at Wright Field, Ohio, 17 May 1942. (Sikorsky Historical Archives)
Vought-Sikorsky XR-4 41-18874 at Wright Field, Ohio, 17 May 1942. (Sikorsky Historical Archives)
The Sikorsky XR-4 41-18874 at Wright Field, 17 May 1942. Left to right: E. Walsh, A. Planefisch, Igor Sikorsky, Orville Wright, R. Alex, Les Morris, B. Labensky. (Sikorsky Archives)

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.

Sikorsky test pilot Charles Lester (“Les”) Morris in the cockpit of an earlier version of the Vought-Sikorsky VS-300. (Hans Groenhoff Photographic Collection, Smithsonian Institution National Air and Space Museum NASM-HGC-1408)

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.

Vought-Sikorsky XR-4C 41-18874 at the National Air and Space Museum. (NASM)

© 2019, Bryan R. Swopes

9 May 1962

Sikorsky S-64 Skycrane N325Y, s/n 64001. (John Daniel)

9 May 1962: The Sikorsky S-64 Skycrane, N325Y, prototype of a heavy-lift helicopter, made its first flight at Stratford, Connecticut. The Skycrane was a turbine-powered evolution of the piston-engined S-60. The United States Army bought six S-64s for evaluation, and then ordered 54 production aircraft, designated CH-54A Tarhe, and 35 CH-54Bs. Sikorsky produced 12 S-64E and Fs for the commercial helicopter market.

The Bridgeport Post reported:

First Flight Is Made By Sikorsky Skycrane

     STRATFORD — Sikorsky’s twin-turbine S-64 Skycrane, a giant new helicopter which is expected to have wide military and commercial applications, made its first flight May 9, the company said today.

     The S-64 lifted off the flight field here and hovered 50 feet in the air. Short sidewards, forward and backward flights were made, and the aircraft touched down and took off again twice after the original lift off. Engineering test pilots James E. Chudars and John H. Peterson were at the controls during the 20 minutes of flying time. As a result of this successful flight, a public demonstration for press military and commercial observers is planned for early June.

     The big turbocopter is designed to carry external loads as heavy as nine tons. Two S-64s are being built for the West German government, while a third will be used by Sikorsky for demonstrations in the United States.

Bridgeport Sunday Post, Vol. LXXIII, No. 19, 13 May 1962, Page C-18, Column 3

The Sikorsky CH-54A Tarhe is a large single-main-rotor/tail rotor helicopter, specifically designed to carry large external loads. In U.S. Army service, it had a crew of five: pilot, co-pilot, third pilot and two mechanics. The third pilot was in a rear-facing cockpit position and flew the helicopter while it was hovering to pick up or position an external load.

FAI record-setting Sikorsky CH-54A Tarhe (FAI)

The CH-54A is 88 feet, 5.9 inches (26.972 meters) long and 25 feet, 4.7 inches (7.739 meters) high. The main rotor has six blades and turns counter-clockwise, seen from above. (The advancing blade is on the helicopter’s right side.) The main rotor has a diameter of 72 feet (21.946 meters). The main rotor blades have a chord of 1.97 feet (0.601 meters) and incorporate a twist of -13°. The tail rotor has four blades and is placed on the left side of a vertical pylon in a pusher configuration. The tail rotor turns clockwise, as seen from the helicopter’s left side. (The advancing blade is below the axis of rotation.) The diameter of the tail rotor is 16 feet (4.877 meters). The chord of the tail rotor blade is 1.28 feet (0.390 meters).

The helicopter has an empty weight of 19,120 pounds (8,673 kilograms) a design gross weight of 38,000 pounds (17,237 kilograms) and overload gross weight of 42,000 pounds (19,051 kilograms).

The prototype S-64A Skycrane, N325Y, lifts an  M-113 armored personnel carrier during a demonstration at Fort Benning, Georgia. (NASM-84-8161)

The CH-54A is powered by two Pratt & Whitney JFTD12A-4A (T73-P-1) turboshaft engines, each rated at 4,000 shaft horsepower at 9,000 r.p.m. (N2) maximum continuous power at Sea Level, and 4,500 shaft horsepower at 9,500 r.p.m. (N2) for takeoff, 5-minute limit, or 30 minutes, with one engine inoperative (OEI). The maximum gas generator speed (N1) is 16,700 r.p.m. The T73-P-1 is an axial-flow free-turbine turboshaft engine with a 9-stage compressor section, 8 combustion chambers and a 4-stage turbine section (2-stage gas generator and 2-stage free turbine). It is 107.0 inches (2.718 meters) long, 30.0 inches (0.762 meters) in diameter, and weighs 966 pounds (438 kilograms). The helicopter’s main transmission is limited to a maximum 6,600 horsepower.

It has a useful load of 22,880 pounds (10,342 kilograms) and can carry a payload of 20,000 pounds (9,072 kilograms) from a single point cargo hoist.

The CH-54A has a maximum cruise speed of 115 knots (132 miles per hour, 213 kilometers per hour). It’s range is 217 nautical miles (250 miles,  402 kilometers). The CH-54A has a hover ceiling in ground effect (HIGE) of 10,600 feet (3,231 meters) and its service ceiling is 13,000 feet (3,962 meters).

The United States Army has a tradition of using Native American names for its aircraft. Tarhe (pronounced tar-HAY) was a famous chief, or sachem, of the Wyandot People of North America, who lived from 1742–1818. He was very tall and the French settlers called him “The Crane.”

Sikorsky CH-54A Tarhe 68-18448, Nevada National Guard, 16 November 1989. (Mike Freer/Wikipedia)

N325Y, the prototype Sikorsky S-64, was damaged beyond repair in an accident near Arboletes, Columbia, 19 August 1968. The FAA registration was cancelled.

© 2021, Bryan R. Swopes

6 May 1941

Igor Sikorsky with his VS-300A, Stratford, Connecticut, 6 May 1941. (Sikorsky Archives)

6 May 1941: At Stratford, Connecticut, Igor Sikorsky piloted his Vought-Sikorsky VS-300 helicopter to a new world’s record for endurance. He flew for 1 hour, 32 minutes, 26 seconds. ¹ The previous record—1 hour, 20 minutes, 49 seconds—had been set by Ewald Rohlfs with the Focke-Wulf Fw 61 tandem-rotor helicopter, 25 June 1937. ²

During its development, the VS-300 went through at least 18 changes in its rotor configuration. This photograph, taken after the record-setting flight, shows an intermediate version, with one main rotor for lift and three auxiliary rotors for anti-torque and directional control.

Igor Ivanovich Sikorsky 1888–1970. Sikorsky Archives)

In the final configuration, Sikorsky arrived at what we now recognize as a helicopter, with the main rotor providing lift, thrust and roll control through variable collective and cyclic pitch, and a single tail rotor for anti-torque and yaw control.

The VS-300 had a welded tubular steel airframe and used a 28-foot (5.34 meters) diameter, fully-articulated, three-bladed main rotor, which turned clockwise (as seen from above) at 260 r.p.m. (The advancing blade was on the left. This would later be reversed.) The main rotor had collective pitch control for vertical control, but cyclic pitch (Sikorsky referred to this as “sectional control”) for directional control would not be developed for another several months.

The tail “propellers” (what we now consider to be rotors—one vertical and two horizontal) each had two blades with a diameter of 7 feet, 8 inches (2.337 meters) and turned approximately 1,300 r.p.m. The vertical rotor provided “torque compensation” (anti-torque) and the blade pitch was fully reversible. The horizontal rotors were mounted on 10-foot (3.048 meters) outriggers at the aft end of the fuselage. For lateral control, the pitch on one rotor was increased and the other decreased. For longitudinal control, the pitch of both rotors was increased or decreased together.

The VS-300 was originally equipped with an air-cooled, normally-aspirated 144.489-cubic-inch-displacement (2.368 liter) Lycoming O-145C-3 four-cylinder horizontally-opposed engine which was rated at 75 horsepower at 3,100 r.p.m. According to Mr. Sikorsky, “early in 1941,” the Lycoming engine was replaced by an air-cooled, normally-aspirated 198.608 cubic inch (3.255 liter) Franklin 4AC-199-E, a four-cylinder horizontally-opposed overhead valve (OHV) direct-drive engine with a compression ratio of 7:1, rated at 90 horsepower at 2,500 r.p.m. It is not known if this change was made prior to 6 May.

¹ During World War II, only a very few ballooning and gliding world records were certified by the Fédération Aéronautique Internationale. Although Sikorsky’s flight duration exceeded that of Rohlfs, it is not listed as an official world record.

² FAI Record File Number 13147

© 2019, Bryan R. Swopes

17 April 1941

Igor Sikorsky piloting his pontoon-equipped VS-300, 17 April 1941. (Sikorsky Historical Archives)
Igor Sikorsky piloting his pontoon-equipped VS-300, 17 April 1941. (Sikorsky Historical Archives)

17 April 1941: Igor Sikorsky’s Vought-Sikorsky VS-300 helicopter went through various rotor configurations during development as he searched for a combination that would give stability, anti-torque control, as well as lateral and yaw control. By April 1941, the VS-300 was configured with a single main rotor for lift and three smaller tail rotors to provide anti-torque and directional control.

This was not the ultimate solution, but he had the aircraft fitted with three inflatable pontoons and on 17 April, made a successful water landing, demonstrating that the helicopter could be a practical amphibious aircraft. During a lecture to the Rotating Wing Section of the Tenth Annual Meeting of the Institute of Aeronautical Sciences, Igor Sikorsky gave a brief description of the flight:

Igor Ivanovich Sikorsky 1888–1970. Sikorsky Archives)
Igor Ivanovich Sikorsky (Sikorsky Archives)

“On April 17 the helicopter, mounted on rubber floats, was repeatedly taken off from water and landed on water and then landed on ground, demonstrating for the first time a direct lift aircraft with excellent amphibian characteristics on which no adjustments whatsoever are needed when going from water to land and vice versa.”

The VS-300 had a welded tubular steel airframe and used a 28-foot (5.34 meters) diameter, fully-articulated, three-bladed main rotor, which turned clockwise (as seen from above) at 260 r.p.m. (The advancing blade was on the left. This would later be reversed.) The main rotor had collective pitch control for vertical control, but cyclic pitch (Sikorsky referred to this as “sectional control”) for directional control would not be developed for another several months.

The tail “propellers” (what we now consider to be rotors—one vertical and two horizontal) each had two blades with a diameter of 7 feet, 8 inches (2.337 meters) and turned approximately 1,300 r.p.m. The vertical rotor provided “torque compensation” (anti-torque) and the blade pitch was fully reversible. The horizontal rotors were mounted on 10-foot (3.048 meters) outriggers at the aft end of the fuselage. For lateral control, the pitch on one rotor was increased and the other decreased. For longitudinal control, the pitch of both rotors was increased or decreased together.

Igor Sikorsky banks the VS-300 through assymetric pitch of the horizontal tail rotors. (Sikorsky Historical Archives)
Igor Sikorsky banks the VS-300 through assymetric pitch of the horizontal tail rotors. (Sikorsky Historical Archives)

The VS-300 was originally equipped with an air-cooled, normally-aspirated 144.489-cubic-inch-displacement (2.368 liter) Lycoming O-145C-3 four-cylinder horizontally-opposed engine which was rated at 75 horsepower at 3,100 r.p.m. According to Mr. Sikorsky, “early in 1941,” the Lycoming engine was replaced by an air-cooled, normally-aspirated 198.608 cubic inch (3.255 liter) Franklin 4AC-199-E, a four-cylinder horizontally-opposed overhead valve (OHV) direct-drive engine with a compression ratio of 7:1, rated at 90 horsepower at 2,500 r.p.m. It is not known if this change was made prior to 17 April.

© 2019, Bryan R. Swopes