Propellors are on airplanes. Helicopters call them rotors. The small rotor on the back of the helicopter is used to counteract the torque created from the engine driving the main rotors.
Generally speaking there are 4 propellers. Two of them are crossed over each other that form the main propellers, and the other two are at the rear.
300 Pounds
to move the helicopter left and right
black hawk
The Helicopter with the long propellers creates more list and has to do less rotations, and use less power than the one with short proplellers. Therefore Helicopter with the long propellers will hover and stay in air longer than the one with short propellers.
it depends on the engine and the shape of the blade.
To counter the rotation induced by the lift rotor(s)
Aircraft do have propellers , unless they are jets.
Standing next to a helicopter while the propellers are spinning is 110-115dB.
It wouldn't, the propellers are designed to propel the helicopter off of the ground, thus the word propeller, not to make the helicopter glide. The wings are too thin to hold up a helicopter and that is why they spin to gain ground as well as using kinetic energy to lift up. The propellers would eventually bend or snap if the helicopter would be to fall, the speed of the wind would break or damage the propellers.
12.5 ft. to 19 ft. :-)
They do not have propellors for kids. The propellors make the helicopter fly straight