Calculating the Benefits of Dynamic Soaring

Abstract

The benefits of dynamic soaring can be very great if turbulence or wind shear is present in the atmosphere. A mixture of updraft and downdraft can be a much stronger source of glider energy than just updraft alone. This is particularly true as the updrafts become stronger. Large g forces can be beneficial in even moderate strength dynamic soaring conditions. To get all the energy from an updraft rising at twice a glider's normal sinking speed, the glider can pull four g's while flying at twice its normal best L:D speed. High g loads and turbulence scale may both limit dynamic soaring possibilities. Atmospheric flow variations are best for dynamic soaring when within a certain size range. If the air blocks are too large the required changes in aircraft path angle become too large and the speed chinges also. The high frequency limit may come from the wing's size and from the rate of lift force change possible on the wing. In dynamic soaring the high g's and aerodynamic forces can extract much more energy from the atmosphere than can a gravity -limited glider flying at one g. If we can find consistent airways containing enough wind shear and can tolerate the high g forces used, then dynamic soaring technique can enable very long and fast flights.