Aircraft

From ArticleWorld

There are two main types of aircraft:

1. Heavier than air, or aerodyne
2. Lighter than air, or aerostat

Heavier than air

Heavier than air vehicles are the most common forms of aircraft. They include:

• fixed-wing aircraft, such as jets, and gliders
• rotary-wing aircraft, such as helicopters, and autogyros

Fixed-wing aircraft tend to have some form of internal-combustion engine, either as a piston engine with a propeller, or a turbine engine. This engine provides the thrust that moves the aircraft forward through the air. The lift effect is produced by the movement of air over the airfoil shape of the wings. Turbine engines are used by pressurized aircraft, as they are naturally efficient at higher altitudes and able to operate above 40,000 ft. Rockets have also been experimented with as a method of aircraft propulsion, but this tends to be for space flight as there is no oxygen available for the combustion that a regular jet engine requires. Gliders do not have any form of engine to produce this initial thrust, but use ground-based winches, or tug aircraft, to lift them until they are able to fly independently by utilizing thermal currents, and gravity.

Rotary-wing aircraft, such as helicopters, and autogyros, gain their lift, and thrust from a spinning rotor.

Lighter than air

Lighter than air craft include:

• hot air balloons
• airships, or dirigibles

These aircraft float in the air using buoyancy in a similar manner to ships floating on the water. The air around these lighter than air craft is displaced by the lower density gas that is being used, either helium, hydrogen, or heated air. Balloons do not have any means of steering, and have to rely on the direction of the wind for their travel. The pilot is able to control the altitude by increasing the heat of the air, or by releasing ballast. Airships, and dirigibles have controls to enable them to steer.