Autogiro Principle Adapted to Helicopter (Oct, 1931)
Autogiro Principle Adapted to Helicopter
HARRY T. NELSON, a war-time aviator now living in Dallas, Texas, has recently developed a helicopter which has proved very successful in the model stage and which he believes to be a solution of the problem of vertical flight.
One outstanding feature of the machine is the means of rotating the large horizontal propeller at the top. This is done by the slipstream of the powered propellers situated directly below it and turning in opposite directions. This big propeller, which rotates freely; in much the same manner as the rotor blades of an autogiro, not only assists in lift
and getting a “toe-hold” on the air, but acts as a vertical stabilizer and as a parachute in landing.
The lower propeller takes hold similar to the clutch on a bicycle, and coasts when the motors are dead. The speed of the large propeller may be built up gradually just before taking off vertically, thereby giving elasticity to the contact between the motors and the large propeller. As soon as the speed is built up a vertical drop is impossible.
As soon as the desired altitude is reached, horizontal travel is attained by tilting the machine slightly in the desired direction.