Control for helicopter having dual rigid rotors

The method of operating dual, counterrotating, rigid rotors comprising coupling lateral cyclic to longitudinal cyclic pitch control through phase angle and varying the phase angle as a function of aircraft forward speed to produce optimal differential cyclic pitch control to the rotors.

The method of operating a helicopter having counterrotating rigid rotors comprising varying the phase angle of each rotor simultaneously as a function of vehicle forward speed to optimize performance and controllability.

The method of operating a helicopter having counterrotating rigid rotors comprising producing selected differential lateral cyclic control to the rotors to achieve optimum performance and controllability by automatically varying the control phase angle of each rotor as a function of vehicle forward flight speed.

The method of optimally positioning the lift vectors of rigid counterrotating helicopter rotors so as to produce maximum rotor lift-to-drag ratio and further so that an aerodynamic moment is generated in each rotor to cancel or minimize the gyroscopic precession moment caused by rotor axis tilting comprising coupling longitudinal cyclic control input to lateral cyclic control input through rotor phase angle and selectively varying rotor phase angle as a function of helicopter forward speed so that the introduction of longitudinal cyclic control input will produce optimum differential lateral cyclic control.

The method of operating a helicopter having counterrotating rigid rotors comprising varying the phase angles of each rotor as a direct function of airspeed so that the coupled longitudinal and lateral cyclic controls introduce differential cyclic inputs during helicopter attitude changes to automatically produce aerodynamic moments in magnitude and direction in each rotor to cancel or minimize the moments created therein by the gyroscopic precession characteristics of the rotors, and to introduce differential lateral cyclic inputs during helicopter steady state operation to automatically produce aerodynamic moments in magnitude and direction in each rotor to produce lift vector of preselected offset to produce optimum lift-to-drag ratio at varying airspeed.

The method of operating a helicopter having counterrotating, rigid rotors comprising varying the phase angles of each rotor as a direct function of airspeed so that the coupled longitudinal and lateral cyclic controls introduce differential cyclic inputs during helicopter steady state operation to automatically produce aerodynamic moments in magnitude and direction in each rotor to produce lift vector of preselected offset to produce optimum lift-to-drag ratio at all airspeeds.

The method of operating a helicopter having counterrotating rigid rotors comprising varying the phase angles of each rotor as a direct function of airspeed so that the coupled longitudinal and lateral cyclic controls introduce differential cyclic inputs during helicopter attitude changes to automatically produce aerodynamic moments in magnitude and direction in each rotor to cancel or minimize the moments created therein by the gyroscopic precession characteristics of the rotors.

A control for a helicopter rotor system utilizing two, rigid, counterrotating rotors including means to selectively vary the phase angle of the rotors as a function of helicopter forward speed to both optimally position the rotor lift vectors so as to produce maximum rotor lift-to-drag ratio performance, and generate an aerodynamic moment in each rotor to cancel or minimize the gyroscopic precession moment created during maneuver.

A control for a rotor system utilizing two, rigid, counterrotating rotors comprising means to couple lateral cyclic to longitudinal cyclic pitch control of each rotor through rotor phase angle so that as rotor phase angle increases as a function of helicopter forward speed, optimum differential cyclic input is imparted to the rotors.

A control for a helicopter rotor system utilizing two, rigid, counterrotating rotors including means for varying the phase angle of each rotor simultaneously as a function of helicopter forward speed to optimize performance and controllability.

A control for a helicopter rotor system utilizing two, rigid, counterrotating rotors comprising means to produce selected differential lateral cyclic control to the rotors to achieve optimum performance and controllability by automatically varying the control phase angle of each rotor as a function of helicopter forward speed.

A control for a helicopter rotor system utilizing two, rigid, counterrotating rotors comprising means to couple longitudinal cyclic control input to lateral cyclic control input through rotor phase angle and selectively varying rotor phase angle as a function of helicopter forward speed thereby optimally positioning the lift vectors of the rotors to produce maximum rotor lift-to-drag ratio performance and to also develop an aerodynamic moment to cancel or minimize gyroscopic precession moments during helicopter maneuver.

A control for a helicopter rotor system utilizing two, rigid, counterrotating rotors including means to vary the phase angles of each rotor as a direct function of airspeed so that the coupled longitudinal and lateral cyclic controls introduce differential cyclic inputs during helicopter attitude changes to automatically produce aerodynamic moments in magnitude and direction in each rotor to cancel or minimize the moments created therein by gyroscopic precession of the rotors, and which also introduce differential lateral cyclic inputs during helicopter steady state operation to automatically produce aerodynamic moments in magnitude and direction in each rotor to produce selected lift vector offset resulting in optimum lift-to-drag ratio rotor performance.

A control for a helicopter rotor system utilizing two, rigid, counterrotating rotors including means to vary the phase angles of each rotor as a direct function of airspeed so that the coupled longitudinal and lateral cyclic controls introduce differential cyclic inputs during helicopter attitude changes to automatically produce aerodynamic moments in magnitude and direction in each rotor to cancel or minimize the moments created therein by gyroscopic precession of the rotors.

A control for a helicopter rotor system utilizing two, rigid, counterrotating rotors including means to vary the phase angles of each rotor as a direct function of airspeed so that the coupled longitudinal and lateral cyclic controls introduce differential cyclic inputs during helicopter steady state operation to automatically produce aerodynamic moments in magnitude and direction in each rotor to produce selected lift vector offset resulting in optimum lift-to-drag ratio rotor performance.