by Morgan Johnson

Created on: May 14, 2008   Last Updated: September 21, 2009

Modern Rotary Wing aircraft are the fulfillment of the second oldest vision of flight. The first was to fly like a bird with straight, flapping wings.

The second vision was to "corkscrew" into the air kind of like a propeller in water. In fact some early designs were derived from water movers. But it soon became obvious that air and water are very different things.

Many believe Leonardo DaVinci invented the concept in the early 15th century. However, this ignores an earlier independent working Chinese toy created 1,100 years earlier.

The concept of the rotary wing is actually simple in theory. You create lift by moving the wing through the air. Lift was balanced by having equal wings on opposite sides of the drive shaft.

Two problems became apparent when the theory became practice:

- Torque created by the energy of the blades as soon as the vehicle lifted off, and,
- Balancing lift and thrust to create stable flight.

A semi functional craft called an autogiro appeared around 1904 in France. It had an unpowered main rotor that created lift by converting gravity into motion.

Confusing yes, but permit me to explain: The autogiro body doesn't create enough lift to stay in the air. As it moves forward and tries to fall at the same time, wind flows over the rotor blades. The air moving over the airfoil shape of the rotor blades create lift.

The blades begin to move around their shaft and their momentum creates and maintains lift for the duration of the flight.

A Russian immigrant to the United States, Igor Sikorsky created the first safe and practical rotary wing aircraft. He worked on the idea of using a tail rotor to cancel out the tendency to for the body to counter-rotate.

His prototype, the VS-300 first flew in 1940.

The incredible flexibility of the rotary wing has permitted flying feats impossible with any other class of airship.

A balloon can hover over a stationary spot as long as it is tethered to that spot. A helicopter can hover freely for as long as the pilot chooses then move on to another location.

This feature has permitted emergency rescue in places previously beyond the reach of aid. A helicopter can reach a capsized ship faster than a rescue boat. And it can pick up the survivors unlike an aircraft.

This feature was first discovered by the military. Helicopters were being used as observation platforms at first. Them it was noticed that they could be used to quickly get the wounded to medical treatment directly from the battlefield.

Civilians eventually

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