Igor Sikorsky VS-300
1930s, the French Louis Bréguet and
German Heinrich Focke had made major
advances in helicopter design in Europe. A Russian who had emigrated to
the United States, Igor Sikorsky,
eventually made the most significant advances. Although Sikorsky is not
generally credited with inventing any new solutions to the problems of
controlling a helicopter in flight, he is widely regarded as the person
who improved existing technology and made the helicopter practical and
successful. Sikorsky Aircraft remains
the oldest helicopter firm in the world.
1930s, Sikorsky was building transport aircraft and flying boats for Pan
American Airways. His company, the Sikorsky Aviation Corporation in
Bridgeport, Connecticut, became a subsidiary of the giant United Aircraft
and Transport Corporation. Sikorsky and his aides occasionally sneaked
helicopter models into the company wind tunnel. In 1931, he applied for a
patent for a novel helicopter design that used a
single main lifting rotor and a small vertical
tail rotor to counteract torque. He later visited Europe to
witness the flights of both Focke's Fa-61 and Bréguet's experimental
as United Aircraft was closing down Sikorsky's company to cut costs,
Sikorsky received permission to expand his helicopter research and to
begin work on an experimental vehicle. In spring 1939, he designed the
VS-300, which was built that summer. The VS-300 was constructed of an open
welded tubular steel frame with three-wheel main landing gear. A
three-bladed rotor with a diameter of 28 feet (8.5 meters) was mounted at
the top. A single two-bladed vertical rotor was mounted at the tail. Both
rotors were powered by a four-cylinder 75-horsepower (56-kilowatt)
Lycoming air-cooled engine connected to the rotors through a truck
transmission and a series of pulleys and belts. The main rotor could
increase the pitch of the three blades
collectively to change lift. Sikorsky
also adopted cyclic control from Cierva's
Igor Sikorsky at the controls, the VS-300 hovers during an early public
First flown in September 1939, the VS-300 brought the world record for
helicopter endurance to the United States
in 1941 when it stayed aloft for one hour thirty-two minutes.
All Sikorsky production helicopters have been refined versions of this
first successful single main rotor, torque-compensating tail rotor
a topcoat and fedora to protect himself from the cold, Sikorsky piloted
the VS-300 himself during its first flight on September 14. The craft
vibrated excessively, until Sikorsky was a blur at the controls of the
skeletal craft. He lifted the helicopter off the ground and set it down
several times. The VS-300 remained tethered to weights on the ground by
wires during these early flights.
made constant modifications to the craft in an attempt to reduce vibration
and increase control. His mechanics began calling it "Igor's nightmare."
By November 1939, the craft was making hops lasting a minute or two, but
it was heavily damaged in December when a gust of wind toppled the machine
and the rotor blades smashed against the ground.
cutaway of the XR-4
machine made its first free flight on May 13, 1940. By this time, Sikorsky
had added outriggers at the tail end and two additional tail rotors, and
had switched to a more powerful 90-horsepower (67-kilowatt) Franklin
engine. By mid-1940, the VS-300 was flying for 15 minutes at a time. In
July, Captain Franklin Gregory, the project officer for the budding U.S.
Army helicopter program, took the VS-300 for a test flight. He described
the craft as having poor handling capabilities, saying that it flew like a
bucking bronco. Gregory was an
unaccustomed to the helicopter's unusual flight control system, which
often required delicate hand movements. The U.S. Army Air Corps was very
impressed, however, and awarded a contract to Sikorsky in December 1940 to
build an experimental helicopter known as the XR-4, which was to be larger
than the VS-300.
Sikorsky XR-4 was first flown on January 14, 1942.
It was the test version of the popular R-4 used extensively in World War
next year, Sikorsky continued to refine his craft. It ultimately went
through eighteen visibly different configurations. On May 6, 1941, the
VS-300 broke the world helicopter endurance record held by the
Focke-Achgelis Fa-61, remaining airborne for 1 hour, 32 minutes and 26.1
soon decided to eliminate the horizontal outriggers holding the tail
rotors and mount the vertical tail rotor on a pylon added to the tail
boom. This dramatically improved performance and soon the craft was flying
forward stably at 70 miles per hour (113 kilometres per hour).
January 14, 1942, the XR-4 was wheeled out and performed several short
hops. By May, the craft was ready for delivery to Wright Field in Ohio.
Sikorsky's test pilot flew the unusual aircraft on a series of short hops
over five days from Connecticut to Ohio, and Sikorsky himself finished the
trip. His test pilot navigated by reading highway signs or asking
directions from surprised motorists.
soon contracted for production to begin and also ordered a new, larger
model. In April 1943, it requested another version. More than 400 Sikorsky
helicopters were produced for the U.S. Army by the end of World War II.
The R-4 saw service with the 1st Air Commando unit in the
China-Burma-India Theatre, where it performed some of the missions that
would be later expanded during the Korean War and become common during the
Vietnam War. Although they had no impact on the war, they clearly offered
Sikorsky R-4 was first used in combat in May 1944.
Sikorsky's VS-300 was significant because it was the first working
helicopter that did not require two counter-rotating rotors to cancel out
torque, instead using a tail rotor that provided thrust in the opposite
direction of the torque. This made the craft less complicated, lighter,
and easier to control. But perhaps more importantly, the VS-300 served as
the forerunner for the modern
more like helicopters in use decades later than any of its predecessors.
Unlike either Heinrich Focke or Louis Bréguet, Sikorsky continued building
helicopters and ultimately became the most famous helicopter manufacturer
in the world.