The first manned helicopter
flight was achieved by the Frenchman paul Cornu who lifted his twin-rotor craft
off the ground for twenty seconds in 1907, his machine unfortunately broke up
on landing. In1909 Igor Sikorsky
(1889-1972) build two helecopters but these could lift very little more than
their own weight. The first practical
helicopter was the German Focke-Wulf FW61, which flew in 1936. By 1939 the British had built the two-seater
Weir W.6, which was powered by a pair of rotors mounted independently, one of
each side of the fuselage. The Weir W6’s
prototype was the first helicopter in the world to carry three occupants.
Many control problems had to be
solved, the main ones being unsymmetrical lift, which caused the craft to flip
over on takeoff and the fact that the body’s natural tendency was to spin in
the opposite direction to the rotors.
However one big advance was the realization that changing the angle at which
the rotor blades were set was much more effective for stabilizing the
helicopter in flight than trying to change the rate at which the rotors
rotated.
The real breakthrough came when
Sikorsky’s VS-300 in 1939. As well as
horizontal main rotor the prototype had two smaller tail rotors, one ensuring
horizontal stability and the other acting like a rudder and controlling
direction of the flight. This was
followed in the United States in 1945 by the highly successful mass-produced
Bell 47.
Today there are more helicopters
in military service than civilian operations.
The vision of city-center ‘vertiports’ speeding passengers to local
airports and between nearby airports is still to be realized.
“The VS-300 has only one tail
rotor, but the prototype had a second, horizontal rotor mounted above it.”
