The manoeuvrability of aircraft in circling flight

Abstract

An investigation is made into the manoeuvre of an aeroplane in the entry into and recovery from a true banked horizontal turn executed without sideslip or loss-of height, and the proper continuous co-ordination of aileron, elevator and rudder is deduced for all stages of the manoeuvre. It is shown that the roiling motion is practically unaffected by the other modes of motion, enabling the kinematics of the rolling.mode to be solved in terms solely of the applied aileron movement or stick force. The aileron is regarded as the prnne initiator of the turn, operated in some pre-chosen manner, and the elevator and rudder loads are expressed as functions of the determinable rolling velocity and acceleration. The loads to trim in the final steady turn are found as a particular case. Several different forms of aileron operation are examined, including a family in which the maximum value of the rolling velocity (or helix-angle in roll) is stipulated beforehand. The co-ordinating elevator load may, in adverse cases, attain peak values considerably in excess of the final load to trim, and the dependence of such peaks on the manner of aileron control operation is examined. It is shown that rapid entries into a turn demanding large rolling velocities at high altitudes are likely to require a large pull back of the stick, followed by a hasty push forward. In order to ensure that the elevator co-ordination should consist of a steady one-way movement of the stick, it is necessary that the aileron be applied in such a way that maximum rolling velocity be obtained when the angle of bank is small. Two manoenvrability criteria are suggested for the entry into the turn, the first relating the final elevator load to the amount of g generated, and the second relating maximum aileron toad to the maximum required rolling velocity and final angle of bank. Extensive information regarding this roiling aspect of the manoeuvre is presented in a set of charts using non-dimensional parameters. The mathematical analysis is contained in appendices.