Dynamic Soaring - Basic Mechanism

Basic Mechanism

While different flight patterns can be employed in dynamic soaring, the simplest example to explain the energy extraction mechanism is a closed loop across the boundary layer between two airmasses in relative movement. The gain in speed can be explained in terms of airspeed or groundspeed:

• The glider gains airspeed twice during the loop, when it pierces the boundary layer at an acute angle. Since the 180°-turns retain most of the airspeed the glider completes the loop within the initial airmass at a higher airspeed.
• The gain in groundspeed occurs when the glider performs a 180°-downwind-turn within the moving airmass. Since the opposite 180°-turn is done within the stationary airmass the groundspeed gain is not reversed.

The energy is extracted by reducing the velocity difference between the two airmasses during the 180°-turns which accelerate air in opposite directions.