The marvelous tricks a helicopter can do are all attributed to its whirling rotor, the large horizontal propeller that spins on top of its body. The blades of the rotor are like its wings. By changing their angle, a pilot can go in any direction or even hover, or stand still.
If the pilot wants to go up or down, or hover in one spot, he keeps all the blades at the same angle. But if he wants to go forward, backward, or turn completely around sideways, he tilts the entire rotor in that direction.
The ancient Chinese made flying toys, a kind of flying top that traveled through the air like a helicopter, with rotors made of feathers!
