Helicopters are amazing machines. They literally seem to be able to defy gravity when they hover in place. Being able to perform this maneuver for prolonged periods of time have made helicopters invaluable in search and rescue, medical transport, and as a weapons platform for military uses.

Watch an Amazing Helicopter Rescue

Helicopters are great but if the engine stops running they don’t have wings like an airplane to glide to the ground. So how does a helicopter that loses power from its engine land safely? Autorotation.

The definition of ‘autorotation’ according to dictionary.com is “the condition of flight occurring when lift is derived solely from the action of air upon the unpowered rotor of a moving helicopter.”

The term autorotation dates to a period of early helicopter development between 1915 and 1920, and refers to the rotors turning without the engine. It is analogous to the gliding flight of a fixed-wing aircraft.

In normal powered helicopter flight, air is drawn into the main rotor system from above and exhausted downward, but during autorotation, air moves up into the rotor system from below as the helicopter descends. Autorotation is permitted mechanically because of both a freewheeling unit, which allows the main rotor to continue turning even if the engine is not running, as well as aerodynamic forces of relative wind maintaining rotor speed. – Wikipedia

This simply means a helicopter can easily land safely in the event of total engine failure.

Watch Autorotation Explained

If you watched the video above you now know that performing a successful and safe autorotation should not be a problem for a well trained helicopter pilot.

Watch a Bell Jet Ranger 206B Perform an Amazing Autorotation

Featured Image by Wikimedia Commons