Flight fascinates people of all ages. Recent advances in battery technology have extended the capabilities of model airplanes and toy helicopters. For those who have never outgrown a childhood enthusiasm for the wonders of flight, it is possible to buy inexpensive, remotely controlled planes and helicopters. A toy helicopter offers an opportunity to investigate and study some basics of flight.
An airplane is able to fly because of its wings. A helicopter flies by using a spinning rotor blade. Those familiar with the law of conservation of angular momentum immediately recognize one of the problems a successful helicopter has to overcome. Since the rotor is spinning in one direction, once the helicopter lifts off, the body of the helicopter will spin in the opposite direction so that the total angular momentum remains zero. This is not an ideal situation for either the pilot or the passengers in a helicopter. A small rotor mounted on the tail of the helicopter with rotor plane perpendicular to the ground provides a torque to counter the tendency of the helicopter body to rotate. Large helicopters with two rotors overcome the difficulty by the simple expedient of having the rotors spin in opposite directions. 
In 1968 a man named Dieter Schlüter was the first person to master the mechanics for the remote control helicopter. He built his kits from his house and only produced a very limited number of them. The first readily available kit in mass numbers was manufactured just a couple of years on by Dave Grey, named the Du-Bro Whirlybird.
The Whirlybird was a very dangerous toy however and ever since its initial development product designers have been working to make the remote control helicopter a safer toy to play with. They succeeded in doing this thanks to lightweight plastics meaning a metal rotor wasn’t required to generate enough lift for