Collective detent system for vertical takeoff flight operations

Abstract

A collective detent system is incorporated in combination with the flight control system of a helicopter to enhance vertical takeoff flight operations of the helicopter. One embodiment of the collective detent system includes a collective control stick that is pivotable through a range of operating positions from a full-down collective position to a full-up collective position with one of the operating positions of the range defining a vertical takeoff operating position that provides the vertical takeoff power level required for the vertical takeoff flight profile of the helicopter, a trim switch for a conventional collective trim system that is operative to implement a trim mode function wherein the collective control stick can be trimmed in any selected operating position, a vertical takeoff (VTO) detent switch that is operative to generate a detent signal when activated, an adjustable sensor that is operative to generate a stick-position signal when the collective control stick is pivoted into the vertical takeoff operating position, a restraint force generating (RFG) device, and a modified trim system circuit that functionally interconnects the trim switch, the VTO detent switch, the adjustable sensor, and the RFG device in interactive combination. Prior to pivoting the collective control stick into the vertical takeoff operating position, the VTO detent switch is activated to generate the detent signal. During the vertical takeoff profile, the adjustable sensor detects the pivotal movement of the collective control stick into the vertical takeoff operating positions and generates the stick-position detent signal in response thereto. The RFG device is automatically operative in response to the detent signal and the stick-position signal to generate a restraint force against the collective control stick to electro-mechanically 'detain' the collective control stick in the vertical takeoff operating position and to impede manual movement of the collective control stick out of the vertical takeoff operating position.