eonardo da Vinci
was not the only great inventor who was fascinated with vertical
flight. Thomas A. Edison, convinced that airplanes required too much
engine power and takeoff room to ever be practical, also dabbled in
helicopter research.
"If I were to build a flying machine," Edison told a reporter in 1909, "I would plan to sustain it by means of a number of rapidly revolving inclined planes, the effect of which would be to raise the machine by compressing the air between the planes and the earth."
Two years previously, the first man- carrying vertical flight was achieved by Frenchman Louis Breguet, whose four-rotor machine lifted two feet off the ground. A few months later, another Frenchman, Paul Cornu, piloted a rotorcraft for several minutes at a height of one foot, and a forward speed of six miles per hour.
But problems with stability and control were extremely complex, and most powered-flight investigators turned their attention to airplanes.
Research into vertical flight was continued by a handful of enthusiasts around the world, and by the eve of World War II, most of the problems with helicopter flight--rotor systems, torque control and engine power--had been resolved.
It was Russian inventor Igor Sikorsky who brought all the developments together and "invented" the first practical and useful helicopter. In 1941, his VS-300 craft achieved 92 minutes of fully controlled flight, and the modern helicopter was born. More than 400 helicopters were built to serve the Allied war effort.
In 1947, aeronautical entrepreneur Larry Bell developed the Bell Model 47--the worlds first helicopter certified for civil use. With its distinctive plexiglass bubble cockpit, the Bell 47 became everyone's idea of how a helicopter should look. Bell 47s ferried wounded American soldiers in the Korean conflict, and also starred in the 1950s television show "Whirlybirds."
The development of turbine engines in the early '60s greatly increased helicopters' efficiency and expanded their range of military and civilian applications.
Helicopter development is far from complete. New technology and research will enhance the viability of vertical flight and encourage greater public acceptance of it. As helicopters become faster and more reliable, they may yet assume the pre-eminent role that Edison envisioned for them more than 80 years ago.