LOAD VARIATION FLIGHT STYLE AND ITS IMPLICATIONS TO THE THEORY OF SOARING

Abstract

A strict, generally applicable formula is derived which describes the total energy compensated climb rate of the glider dependent on the load factor vedtor, the wind vector and the polar sink rate. The well-known flight technique of speed variation proves useful when smooth and widely extended lift or sink areas have to be crossed during straight flight. Load variation techniques are better suited to exploit short range lift or sink regions. A combined flight style is proposed which takes advantage of both speed and load variation. It is characterized by adjusting the average speed according to the appropriate speed command which is continuously derived using the actual value of the average climb/sink rate. At the same time, load variation is performed. For mechanical reasons, the climb rate during steady circling in a thermal is greatly influenced by an energy gain which results from the confluent air motion and which can be increased by increasing the bank ang1e. Possible consequences for optimiztion of sailplane design are disscussed.