Assessing Control Qualities: The Hystero‐Differential Method applied to Elevator Characteristics

IN so far as the behaviour of an aeroplane in flight depends upon the behaviour of its pilot, it is relatively unpredictable, and for practical purposes seems likely to remain so, except from a statistical point of view. It is, however, reasonable to suppose that by making certain simplifying assumptions it will be feasable to regard the pilot as a machine which responds to given situations in definite ways; in other words, to regard him as a form of servo mechanism with characteristics which may be adjusted to fit the average behaviour, though necessarily differing more or less from that of any given individual.