Counterrotating rotor transmission for helicoptors

Claim 2

In a helicopter having an airframe, a drive shaft rotatably mounted by the airframe about a fixed axis, a pair of rotor blades producing a vertical downdraft, transmission means drivingly connecting said drive shaft to the rotor blades for rotation in opposite directions about a common rotor axis intersecting the fixed axis, means mounting said transmission means on the airframe for angular displacement about a pivotal axis extending through the intersection of said rotor axis and the fixed axis of the drive shaft, airflow responsive stabilizing means movably mounted by the airframe in the downdraft of the rotor blades for overcoming gyroscopic forces generated by rotation of said rotor blades during horizontal movement of the airframe, and control means operatively connected to the transmission means and the stabilizing means for synchronized displacement of the transmission means and the stabilizing means to directionally control said horizontal movement of the airframe, said stabilizing means including at least two airfoil members, means pivotally mounting the airfoil members on the airframe for displacement by the control means from positions substantially parallel to said downdraft of the rotor blades and transverse to the direction of movement of the airframe, said control means including a control member displaceable in different planes relative to the airframe, linkage means connecting said control member to the transmission means and the airfoil members for simultaneously tilting the rotor blades and airfoil members in the same direction in response to displacement of the control member in one of the planes or tilting the airfoil member in opposite directions without tilting the transmission means in response to displacement of the control member in the other of the planes.

Claim 3

The combination of claim 1 wherein the control means further includes attitude trimmer means for tilting the transmission means independently of the control member.

Claim 4

In a helicopter having an airframe, a drive shaft rotatably mounted by the airframe about a fixed axis, a pair of rotor blades producing a vertical downdraft, transmission means drivingly connecting said drive shaft to the rotor blades for rotation in opposite directions about a common rotor axis intersecting the fixed axis, means mounting said transmission means on the airframe for angular displacement about a pivotal axis extending through the intersection of said rotor axis and the fixed axis of the drive shaft, airflow responsive stabilizing means movably mounted by the airframe in the downdraft of the rotor blades for overcoming gyroscopic forces generated by rotation of said rotor blades during horizontal movement of the airframe, and control means operatively connected to the transmission means and the stabilizing means for synchronized displacement of the transmission means and the stabilizing means to directionally control said horizontal movement of the airframe, said transmission means comprising a gear housing pivotally mounted on the airframe, an inner shaft journaled by said housing and connected to an upper one of said pair of rotor blades, pivotal coupling means connecting said inner shaft to the other of said pair of rotor blades and journaled by the housing in coaxial relation to the inner shaft, and positive gearing drivingly connecting said inner and outer shafts within the housing for rotation at the same speed in opposite directions, said stabilizing means including at least two airfoil members, means pivotally mounting the airfoil members on the airframe for displacement by the control means from positions substantially parallel to said downdraft of the rotor blades and transverse to the direction of movement of the airframe, said control means including a flight control lever, means operatively connecting the gear housing and the airfoil members to the control lever for simultaneously tilting the gear housing and pivotally displacing the airfoil members in the same direction in response to movement of the control lever from a neutral position, a steering control member, and means operatively connecting the gear housing and airfoil members to the steering control member for simultaneously tilting the gear housing and pivotally displacing the airfoil members in opposite directions in response to movement of the steering control member from a neutral position.

Claim 5

In a helicopter having an airframe, a drive shaft rotatably mounted by the airframe about a fixed axis, a pair of rotor blades producing a vertical downdraft, transmission means drivingly connecting said drive shaft to the rotor blades for rotation in opposite directions about a common rotor axis intersecting the fixed axis, means mounting said transmission means on the airframe for angular displacement about a pivotal axis extending through the intersection of said rotor axis and the fixed axis of the drive shaft, airflow responsive stabilizing means movably mounted by the airframe in the downdraft of the rotor blades for overcoming gyroscopic forces generated by rotation of said rotor blades during horizontal movement of the airframe, and control means operatively connected to the transmission means and the stabilizing means for synchronized displacement of the transmission means and the stabilizing means to directionally control said horizontal movement of the airframe, said transmission means comprising a gear housing pivotally mounted on the airframe, an inner shaft journaled by said housing and connected to an upper one of said pair of rotor blades, pivotal coupling means connecting said inner shaft to the other of said pair of rotor blades and journaled by the housing in coaxial relation to the inner shaft, and positive gearing drivingly connecting said inner and outer shafts within the housing for rotation at the same speed in opposite directions, said stabilizing means including at least two airfoil members, means pivotally mounting the airfoil members on the airframe for displacement by the control means from positions substantially parallel to said downdraft of the rotor blades and transverse to the direction of movement of the airframe, said control means including a flight control lever, means operatively connecting the gear housing and the airfoil members to the control lever for simultaneously tilting the gear housing and pivotally displacing the airfoil members in the same direction in response to movement of the control lever from a neutral position, a steering control member, and means operatively connecting the gear housing and airfoil members to the steering control member for simultaneously tilting the gear housing and pivotally displacing the airfoil members in opposite directions in response to movement of the steering control member from a neutral position.

Claim 6

The combination of claim 3 wherein the control means further includes attitude trimmer means for tilting the gear housing independently of the control member.