Autogiro

An autogiro is a type of aircraft that looks like a helicopter but works in a different way. Autogiros are rotorcraft, or rotary wing craft. Like a helicopter, an autogiro has a rotor (a set of long thin blades) on top. Unlike a helicopter, an autogiro’s rotor is not powered by an engine-it freewheels, or autorotates. An autogiro is moved forward by an engine-driven propeller, like an airplane.

Just before an autogiro takes off, the pilot starts the overhead rotor spinning. The simplest way to do this is for the
pilot to reach up, take hold of one of the rotor blades, and push it around. Some autogiros use their engine to start the rotor spinning, and then the engine is disconnected from the rotor to let it spin freely on its own.

As the autogiro moves forward, the pressure of air pushing up against the bottom of the blades makes the rotor spin faster. As the blades spin, they gen­erate lift. They quickly generate enough lift for the craft to take off. An autogiro can take off in a much shorter distance than a fixed-wing plane.

In the same way as a helicopter, an autogiro is steered by tilting the rotor.

When the whole rotor tilts, its down – wash (or the air blown downward by the rotor) is tilted to the front, back, or one side. This action pushes the autogiro in the opposite direction. A rudder at the back turns the craft’s nose to the left or right.

A rudder works by deflecting air to one side, so it needs a fast flow of air blowing across it to work. When an autogiro flies slowly, the air flows around it too slowly for the rudder to work well. A modern autogiro’s rudder, therefore, is placed behind its rear – mounted propeller. In this position, it gains a fast airflow from the propeller.

An autogiro has the same basic flight controls as a fixed-wing plane, but autogiros are much more maneuverable. A control stick steers the aircraft. Moving the stick to the front, back, or side moves the craft in that direction by tilting the rotor. Pedals operate the rud­der, and a throttle control adjusts the engine speed.

Spanish engineer Juan de la Cierva invented the autogiro in 1923. The first autogiros had short wings with ailerons for steering. In 1932 the wings were dis­carded, and a tilting rotor was used for steering instead. During the 1930s the development of helicopters overtook autogiros. Interest in commercial and military autogiros died away. A few autogiros were towed behind ships and submarines during World War II to act as spotter craft. They were used to look for enemy ships or submarine periscopes breaking the water’s surface.

AUTOGIRO TIME LINE