Discovery Science: Technology – Light Aircraft

Physics and Technology – Technology – Light Aircraft

Not every aircraft is as impressively huge as the A380 or Boeing’s 787 Dreamliner.

On the contrary, light aircrafts and gliders can be smaller than a car. They usually carry one or two people and often have no engine.

Gliders, paragliders, and hang gliders can fly for long periods of time without needing an onboard power source. Instead, they are designed to make maximum use of air currents. To gain height, gliders use thermals, which are rising columns of air that occur naturally.

Thermals called slope winds form on the windward side of a mountain, and those known as lee waves form on the downwind side of a mountain. While people using hang gliders can often launch the glider from a high location, such as a cliff top, most other gliders require an external power source to get them off the ground and into the air.

Two commonly used launching power sources are winches with stationary motors and powered airplanes, but some gliders do have their own engines. Gliders of all kinds seek an optimal relationship between the loss of altitude incurred and the distance that is covered.

These aircraft should be light, so they can rise quickly in thermal columns. However, since the weight of a craft allows it to travel faster, they cannot be excessively light. Another design concern involves the ability to turn quickly, since this means that the aircraft can spend longer periods circling in a thermal.

Furthermore, since gliders must sometimes land without an airfield (an “out landing”), they need to be easy to transport. Some gliders have water tanks in the wings that provide extra weight, allowing the pilot to adjust the craft’s center of mass. The water, however, must be jettisoned prior to landing in order to reduce the stress on the frame.

Another category of especially small air vehicles is ultralight or microlight aircraft. In affluent countries, these now account for up to 20 percent of the civil aviation fleet. In the U.S., these small engine-powered machines for one or two people can be flown without any license (although good training is strongly advisable).

They are limited in weight and speed and must not be flown at night or over populated areas. In Europe there are varying degrees of regulations, but some kind of license is always required.


A hang glider only consists of the utterly necessary parts of an airplane wings and something for the pilot to hang on to Today, a few navigation instruments, such as variometers or GPS devices, are also included.

Pilots steer by shifting their weight. Because of this, pilots need physical strength and may suffer back problems.


FUEL SAVINGS of around 25 to 35 percent, longer ranges and higher payloads are cause for flying wings to revolutionize aviation as an alternative to airplanes with tails.

INEXPERIENCE can lead to dangerous accidents. Also, a good general state of health is required, especially for hang gliders and paragliders.