Abstract: A method for laying a sheet of material having a sticky texture on to a surface comprises applying pressure by way of a flexible diaphragm to force the sheet of material on to the surface and adjusting the diaphragm so that its surface assumes a varying curved convex shape whereby the diaphragm is peeled gradually from the surface of the sheet of material inwardly from an edge region. The invention is described with particular reference to the laying of sheets of pre impregnated fibre-reinforced material in a mould tool in the automated manufacture of a helicopter rotor blade and several embodiments are disclosed.

Abstract: In a helicopter, signals representative of the rotor disc attitude of a main sustaining rotor (11) are fed into a flight control system (24) to modify an actuator demand signal (31) controlling a rotor blade actuation system (32) of the main sustaining rotor.

Abstract: A helicopter rotor control system includes a plurality of control rods (31) extending downwardly from pitch control means (24) through a hollow rotor drive shaft (12) and gearbox (14) for connection directly to individual actuators (36) located generally concentrically of an axis of rotation (15).

Abstract: A helicopter has two engines adapted to drive a main sustaining rotor and a plurality of auxiliary propulsion means through a transmission system that is selectively operable to vary the relative speeds of rotation of the sustaining rotor and the auxiliary propulsion means depending upon operating conditions.