Daniel Stanish Jr., age 13, of Youngstown, Ohio, for his question:
WHAT MAKES A HELICOPTER FLY?
Chopper, egg beatert flying windmill and whirlybird are a few of the affectionate nicknames given to the noble helicopter. It can do so many flying tricks that you would almost think there is something magical about it: it can fly forward, sideways, backward, stay airborne in one spot and also turn completely around in the air.
It isn’t magic that makes the helicopter perform so well in the air. A large horizontal propeller that spins above the helicopter’s body is called the rotor. The rotor’s long blades actually lift the aircraft and move it.
A helicopter’s rotor blades are in reality its wings. Technically they are called rotor wings because of their circular motion. The pilot controls the helicopter by changing the pitch or angle of the rotor blades. In order to make the craft hover over the same spot or to go straight up or down, the pilot simply keeps all blades at the same pitch. To move forward, backward or sideways, he tilts the rotor in the direction he wants to go.
A helicopter’s tail rotor pedals control the pitch of the tail rotor blades and are used to turn the craft right or left. For straight flight, the pitch of the tail rotor is set to prevent the helicopter’s body from turning to the right as the main rotor turns to the left. The pilot pushes the left pedal to increase the pitch of the tail rotor and turn the body to the left. He pushes the right pedal to decrease the pitch of the tail rotor and turn the body to the right.
The collective pitch stick controls the main rotor blades. To fly upward, the pilot pulls the stick up to increase the pitch of all the blades. To fly downward, he pushes the stick down to decrease the pitch of the blades.
The helicopter’s cyclic pitch stick controls the main rotor blades to make the craft fly forward, backward or sideways. When the pilot pushes the stick in the direction he wants to fly, the craft goes that way. The cyclic pitch stick continuously changes the pitch of each blade to make it rise highest at a spot directly opposite the direction of flight. To drive the helicopter forward, the blades rise highest at the rear. The blades get their greatest pitch one fourth of a revolution ahead of the spot where they rise highest.
Nonstop distance record for a helicopter is held by Robert Ferry who in 1966 traveled a distance of 2,213 miles from Culver City, Calif. to Daytona Beach, Fla. The helicopter altitude record of 40,814 was set in 1972 by French pilot Jean Boulet. The chopper’s speed record was set by Byron Graham of the United States in 1970 when he covered a 1.9 mile straight course at 216.8 miles per hour.