Speed and collective pitch bias of helicopter longitudinal cyclic pitch
AssigneeUnited Technologies Corporation
InventorsGregory P. Wright, Don L. Adams
Life of this patent
Estimating the term…
Abstract
A bias actuator, such as an extensible link, in the longitudinal cyclic pitch channel of a helicopter is provided with inputs as a function of airspeed multiplied inversely with collective pitch, and as a function of the rate of change of collective pitch stick position, so as to enforce positive angle of attack and speed stability and positive static pitch trim gradient and to decouple collective pitch from the longitudinal cyclic pitch channel at cruise airspeeds, the invention compensates, inter alia, adverse control effects of tail stabilizer surfaces at cruise speeds. A pair of indicators display bias commands and actual bias responses.
Claims6
In a helicopter having a longitudinal cyclic pitch control channel and a collective pitch control channel, a pitch bias actuator system comprising:
- airspeed sensing means for sensing airspeed of the helicopter and providing an airspeed signal in response thereto;
- cruise speed means responsive to said airspeed signal for providing a cruise speed signal which is a function of airspeed above a threshold speed;
- means connected to the collective pitch control channel and responsive to the collective pitch command indicated thereby for providing a collective pitch signal indicative thereof;
- means responsive to said collective pitch signal for providing an inverse collective pitch signal which varies inversely with the collective pitch command;
- bias command means for multiplying said cruise speed signal with said inverse collective pitch signal so as to provide a pitch bias command signal as a compound function of airspeed and the inverse of collective pitch;
- and
- bias actuator means responsive to said bias signal for providing a pitch bias input command to said longitudinal cyclic pitch channel.
Dependencies are inferred from the claim text.