How paragliders fly: lift, thermals, ridge soaring, launching and landing
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A paraglider has no engine and no rigid frame, yet pilots stay up for hours and cover long distances. The trick is that the wing always glides downward through the air, and the pilot looks for air that is rising faster than the wing sinks. Here is how that works.
The wing
A paraglider is a fabric wing made of cells, open at the front. Air flows in as you move forward, inflating the cells into an aerofoil shape. Lines connect the wing to risers and then to the pilot's harness. Brake lines pull down the trailing edge to slow and steer the wing. A speed bar, pushed with the feet, lets the wing fly faster.
How it makes lift
As the wing moves through the air, its curved aerofoil shape and its angle produce lift, just like an aeroplane wing. Gravity pulls the pilot forward and down, and the wing converts that into a long, shallow glide. In still air a paraglider always sinks slowly; to climb, you need rising air.
Sources of rising air
- Ridge lift: when wind blows against a hill or cliff, it is pushed upward. Pilots fly back and forth along the slope in the band of rising air, which is called ridge soaring. It works best with a steady wind blowing roughly straight onto the slope.
- Thermals: the sun warms the ground unevenly; patches of warmer air rise in bubbles or columns. Pilots circle inside them to climb, often to the base of a cumulus cloud that forms on top. Thermals are what make cross-country flights possible.
- Wave: in some conditions, air flowing over mountains forms waves downwind. Wave flying is advanced and less common in paragliding.
Air that rises somewhere sinks somewhere else, so pilots also learn to avoid sinking air and to move quickly through it.
Launching
- Forward launch: used in light wind. The pilot faces downhill, runs, and the wing rises overhead as it fills.
- Reverse launch: used in stronger wind. The pilot faces the wing, inflates it, checks it overhead, then turns round and takes off. It gives a better view of the wing before committing.
Launch sites face into the prevailing wind. A good launch is calm and deliberate: check the wing is fully open and overhead before committing to run. Abort if it is not.
Turning and controlling speed
Pulling one brake slows that side of the wing and the glider turns, helped by shifting weight in the harness. Pulling both brakes gently slows the wing; pulling them too far causes a stall. Pilots learn to keep the wing above them in turbulence, called active flying.
Glide and wind
A paraglider's glide is measured as distance forward for each unit of height lost. Wind changes the result: flying into a headwind, you cover less ground; with a tailwind, much more. That is why pilots plan landings into the wind, and why strong wind is dangerous for paragliders, which fly relatively slowly.
Landing
- Choose a landing field early, away from obstacles, power lines and trees.
- Assess wind direction using windsocks, flags, smoke or water.
- Lose height in a planned circuit downwind of the field, not overhead the landing spot.
- Make the final approach into the wind, with the wing flying at normal speed.
- Just before touching down, flare by pulling both brakes smoothly to slow the wing, and land on your feet ready to run.
A missed landing field is far less dangerous than one chosen too late. Experienced pilots keep a landing option within reach all the time.
What limits a flight
- Wind too strong or too weak.
- Thermals stopping in the evening or under overcast.
- Airspace restrictions.
- The pilot's skill and the wing's limits.
Want to know more about thermals, glide or a specific site? Share your questions or flying stories in the comments.