Mathematical Definition of Helicopter Manoeuvres. Internal report no. 9225

There is an increasing number of flight mechanics studies where the influence of manoeuvre type has been found to be of importance. A notable example has been the upgrade to the U.S. Mil. Spec, for handling qualities which includes a set of aggressive tasks to be flown as part of the flight test requirements. Another recent development has been the wider use of inverse simulation where a flight path is used to drive a helicopter mathematical model, the aim being to calculate the control actions corresponding to the flight path being flown. Although the evaluation of helicopter performance through the use of standard manoeuvres has become established, there is little information available on the precise form of the manoeuvre, or on how mathematical representations may be constructed. The aim of this paper has been to categorise the various types of manoeuvre commonly used in helicopter military operations, and then to develop algorithms capable of defining them mathematically. Several manoeuvres are fully modelled in the paper, and it becomes apparent that the techniques used may be applied to a variety of different manoeuvres. By way of validation, data from flight tests has been used for comparisons with modelled flight paths and manoeuvre parameters. Methods of grading manoeuvres are also presented along with a discussion on the choice of suitable mathematical functions