Gliding – soar like an eagle

A yearning to be airborne puts you in good company. In 1488 Leonardo da Vinci drew his first impression of a ‘flying machine’ based on the wings of a bat. In fact, modern aviation started with soaring.

By the end of the 1900s, the flight success achieved by aviation pioneers Orville and Wilbur Wright (the Wright Brothers), was based on first refining flight control of their best glider before adding power to the aircraft. Today, this recreational activity and competitive sport has perfected the art of using control-sensitive sailplanes (gliders) to remain airborne using naturally occurring currents of rising air.

The discovery of the three main sources of lift transformed the sailplanes of the early days into soaring machines.

Ridge lift (or slope soaring), discovered in 1890, gave pilots the ability to use the upward movement of air by flying close to a slope. The wind blowing up the slope produces the lift.

Thermal lift (thermals) is made possible by rising columns of warm air (it is also the standard way to learn to glide, and generally the safest).

Wave lift (or lee wave) is based on the phenomenon of air flowing over a mountain and taking on the characteristics of water in a stream. The air forms a wave behind the mountain range, and the wave develops many times higher than the top of the mountain, enabling sailplanes to reach altitudes of over 40 000 feet.

According to Dave Mortimer, past Chairman of the Soaring Society of South Africa (SSSA), one of the least understood qualities of a glider plane is the very precise control that can be had over the machine. “Sailplanes have one additional control that ordinary aircraft do not have. The airbrake or glide path control is used for landing and speed limiting. This control, when used for landing, works almost like a throttle in a conventional aircraft, and allows control of that final glide to landing at an angle of between 2-45 degrees down. This, in turn, enables the pilot to put the machine down at a precise speed and a fairly precise point in total safety.”

Dave also points out that sailplanes are very strong and highly manoeuvrable, and handle extreme wind conditions better than most other aircraft. They can be landed safely in ploughed fields and small spaces.

About 80% of the sailplanes used today are ‘pure’ ‒ using only natural air currents for lift. However, more and more high-tech gliders are manufactured with supplementary engines in three basic formats. Self-launching sailplanes feature motors that emerge on a stalk to launch the plane before completely folding away. Sustainer-motor sailplanes have the same feature, but the units are smaller, and serve only to have enough power to get the glider home if they run out of lift. Motorgliders look like conventional aeroplanes, but with long wings, and can be flown like a sailplane or an aeroplane. They can also be used for touring. These planes end up being a bit of a compromise, but are particularly useful for training glider pilots.

Soaring is quite popular among local gliders, with numerous clubs operating countrywide. According to Dave, the sport requires a reasonable amount of co-ordination and balance, “something akin to being able to ride a bicycle well.” He also suggests doing an introductory flight, bearing in mind that the first flight will produce some rather mixed reactions, as the movement in three planes of motion is not something a human being was designed to do (although one soon becomes accustomed to the motion with a little more exposure).

To take up gliding as a sport or hobby, one of the first requirements is to undergo an aviation Class 4 medical examination, which requires normal health with normal vision, although prescription spectacles are permitted. It is also a legal requirement to join a registered club and obtain a student- or full licence. First-time gliders are also required to go through a coached series of exercises that usually result in about 40 to 50 flights before making their first solo flight. This is followed by mixed and solo flights until reaching the advanced level of flying cross-country. To obtain a licence can take anything between six to twelve months, but pilots may fly solo with a student licence once they have qualified to fly solo.

For more information on soaring in South Africa, visit the Soaring Society of South Africa’s website, www.sssa.org.za.