In this part of the paper the theoretical considerations underlying the design of an autopilot system for helicopters are discussed, in particular, the system investigated has three modes of operation, viz —

1. (i) Stabiliser

   In this mode, whilst the pilot still exercises overall control, the autopilot introduces artificial stabilisation so that the helicopter becomes more easy to fly

2. (ii) Cruising

   Here the pilot establishes a desired attitude and heading in straight-line flight, on selection the autopilot maintains this mode of flight automatically

3. (iii) Automatic Hover

   Assuming that signals are available defining the plan-position of the helicopter with respect to the point on the ground over which the pilot wishes to hover, on selection the autopilot maintains this hover condition automatically

In the first part of this paper the theoretical considerations underlying the design of an automatic control system for helicopters have been discussed This second part describes some flight experiments carried out at R A E , Farnborough In addition to demonstrating the validity of the theory presented, there has emerged from the flying a clear conception of the design features needed in a practical system for every day use by the average helicopter pilot

One of the more interesting aspects of the experimental programme has been in the fact that the results were achieved almost entirely from flight tests At the time when this work was commenced, aerodynamic information of the test aircraft was scanty Thus whilst the theoretical form of the control law was known, the optimum values of the control parameters could only be roughly forecasted and the actual values were obtained in flight

The CHAIRMAN, in introducing the Author, said that Mr VENNING had spent from 1941 to 1946 in the Royal Signals on mobile communications and from 1946 to 1949 at the City and Guilds Engineering College From 1949 to 1952 he had been in the Royal Naval Scientific Service, working on underwater acoustics From 1952 to 1955 Mr Venning had been at the College of Technology, University of Manchester, as a Lecturer in Electrical Engineering In 1955 he joined the University of Southampton in the Department of Electronics where, in addition to lecturing in electronics he was undertaking a research contract for the Ministry of Supply basically on the subject of his present paper