FLYING IN THERMALS

FLYING IN THERMALS

RULES:

1. Clear your turns before you start turning.
2. First pilot in the thermal determines the direction of the turn. Don't switch directions if other pilots are in the thermal.
3. All other pilots entering the thermal must turn the same direction.
4. Lower pilot has right of way.

Hang gliders are different than paragliders. If you were flying a hang glider and encountered a thermal under your left wing tip, the most efficient way of entering the thermal would be to turn to the right, away from the thermal, complete a 270 degree turn and straighten out, entering the thermal straight on. This is because it is more efficient to use the lift under the left wing, created by the thermal, and the sink under the right wing, created by the boundary layer, to produce a very quick turn back into the thermal. Turning the hang glider left, into the thermal, produces a slow wide turn. This takes more effort and often results in the pilot flying past the thermal.

Because paragliders have non-rigid wings, movable control surfaces combined with weight shift, slower flying speeds, and tighter turning capabilities, it is safer to use the opposite technique from the hang gliders. Let's assume the conditions mentioned earlier; encountering a thermal on your left side. With lift under your left wing and sink at your right wing, there is potential for an asymmetrical collapse to form on your right wing. Going back to basic flying techniques, the proper way to correct the asymmetrical would be to apply left brake to maintain directional control, shift your weight to the left wing, and pump the right brake to re-inflate the right wing.

What if a paraglider used the hang gliders 270-degree turn technique? Same conditions as before… only this time you shift your weight to the right wing and apply a little right brake to turn right. Suddenly, pressure is lost on the right side of the canopy and an asymmetric collapse occurs. The left side of the canopy accelerates forward and the right side stalls, going backwards. You are now spinning in a negative.

If we had entered the thermal from the left we probably would have had fewer problems. The right side of the canopy may start to depressurize, while you are initiating your first turn. But you are weight shifting to the left and applying left brake, which is turning you 90 degrees into the thermal. This maneuver in itself will usually re-inflate the collapsed portion of the canopy. But if it doesn't we are still weight shifting and steering ready to pump out the collapsed wing.