Glide Speed and Distance

Gliding performance is critical information for a pilot who needs to estimate how far the aircraft can fly when engine power is lost. Due to the tradeoff between induced drag and parasitic drag with airspeed, there is an optimal airspeed associated with maximum lift‐to‐drag ratio where the glide performance is optimized. This chapter describes the theory of gliding performance, beginning with a force balance applied to the aircraft in steady flight. Following the discussion of the theoretical optimal conditions, methods for flight testing are described in detail. Correction factors for non‐standard weight, altitude, and temperature are derived and applied, culminating in a presentation of sample flight test data.