Some answers for those unfamiliar with gliding ......
How do gliders stay up - with no engine?
Easily. Gliders stay up in the same way as any other winged aircraft. As they move forward, air flowing over the wings makes them lift upwards. It's that "lift" that keeps gliders up. Gliders are pulled forward through the air by gravity. Just like anything on wheels will roll forward down a slope, a glider flies down a slope in the air - although it is a very shallow slope. 1 in 40 is typical.
How can gliders climb on their own?
The air lifts them. Gliders climb on their own by flying in air that is going up faster than the glider is coming down. That is called soaring. There are three kinds of soaring - they are described below.
What is hill soaring?
It's how flying started. Hill soaring is the art of keeping a glider airborne using the up-currents caused by the wind blowing onto a hill side, slope or ridge where it is deflected upwards before continuing horizontally. On a breezy day, gliders can soar up to heights more than twice the height of the hill.
What is thermal soaring?
It's soaring using big bubbles and currents of warm air that float upwards like an invisible hot air balloon. If conditions are right, the bubbles are so big and their rate of rise is so high that gliders flying in circles within them are lifted up.
You can't see thermals, but you can often see where they are - because birds circle in them and climb without flapping their wings. And the tops of thermals are also often marked by puffy, cotton wool like, clouds in a blue sky. As the thermal air rises it cools. If it cools enough, the water vapour contained in it condenses, forming a cloud.
What is wave soaring?
It's the best. You have probably seen stationery ripples or undulations on the surface of a flowing river - just downstream of a submerged rock. If conditions are right, the atmosphere also undulates up and down in the wind "downstream" of hills and mountains. These undulations are called "lee waves" - because they occur in the lee of hills and mountains.
Just like the ripples on the river surface, the lee waves remain in the same position above the ground. If a glider is flown in the part of the wave where the air is rising towards the crest of the wave it can soar. By wave soaring the glider pilot can get the chance to fly to great heights - above the clouds, higher than any other type of soaring.
Do gliders have to go where the wind takes them?
No they don't - they can go in any direction. A glider normally flies through the air much faster than the wind is blowing. So like powered planes, gliders can make headway over the ground against the wind direction. Of course, also like powered planes, if going with the wind, a glider makes faster progress across the ground than if going against the direction of the wind.
How far can gliders fly?
Further than you think. As long as they can keep soaring they can go for hundreds of miles. The world distance record (in a straight line) is 2,123 Kms and the UK distance record is 1,108 Kms.
How high can gliders fly?
Much higher than Mt. Everest. Gliders can fly higher than the top of the highest mountains in the world, higher than commercial airliners fly. The limit is set by not having enough air pressure to survive even when breathing 100% oxygen. The world record is 15,460 metres (c. 50,000 feet) and the UK record is 11,570 metres (c. 37,950 feet) above sea level.
How fast do gliders fly?
Surprisingly fast. The minimum speed for most gliders is about 40kts (about 74 km/hr). The maximum speed depends on the model but modern gliders designs can fly at 146kts (about 270 km/hr). Average cross country speed attained depends on the soaring conditions - i.e. the weather. The world record for a 300 km flight is 225 km/hr and the UK record is 127km/hr..
Is gliding expensive?
No. Compared with power flying it is much less expensive. You can attain a gliding equivalent of a private pilots license (called the Bronze C certificate) for about one third of the cost.
Do glider pilots have a pilots licence?
Not in the UK. Unlike power pilots, glider pilots do not at present get a licence from the Civil Aviation Authority. Fixed wing (sailplane) gliding is controlled by the British Gliding Association who issue a qualification certificate which is an approximate equivalent to a power private pilots licence (PPL). This allows glider pilots to fly cross country. A further qualification (as an instructor) allows a glider pilot to carry others for trial lessons and instruction. .
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