The blades of the three-bladed main rotor were attached to the rotor head with lightweight interleaving steel plates while tie-rods carried the centrifugal tension loads. The blade levers were connected using ball joints to the arms of a control spider, the cone of which was actuated up and down by the collective pitch lever which changed the pitch of all the blades; an irreversible mechanism was used to prevent blade loads being transferred back to the control stick. The blades were supported when stationary or turning slowly by droop stops, which maintained a minimum clearance between the blade tips and the tailboom even in high winds; these stops were withdrawn above 100 rpm so that full freedom of movement for effective flight was possible.Flight 1958, pp. 369–370.
