An Analytical Method of Quantifying Helicopter Agility

This paper outlines a method of measuring the Inherent Agility (i.e. the agility of the aircraft alone) of a helicopter configuration. The method is based on Inverse Solutions of the Equations of Motion and standard performance measurement techniques. Inverse solutions can be found for a helicopter performing a family of manoeuvres within specified limits. An Agility Performance Index is given for each manoeuvre forming an agility surface covering this set of limits. An Agility Rating is then calculated as the volume under the surface. This agility rating corresponds to a single configuration over a single class of manoeuvre. Other configurations can then be tested over the same manoeuvres for comparison. The method is illustrated by comparing the agility of three helicopter configurations; transport, battlefield and agile, over a series of standard manoeuvres