The system comprises a grip (20) of composite material having belts, filament windings, unidirectional material and fillers of off axis bias ply material for directing the CF exerted on the grip by the blade rotation to the clevis throat (30) of the grip. The force is further directed through a CF fitting (38), a CF bearing (48) and an OPCBA (56) to the yoke (18), thereby maintaining the yoke in tension. Should this load path fail, the CF will be transmitted through the length of the grip to the IPCBA (80) that will in turn load the yoke with the CF.

Rotor redundant force retention system for vtol and vstol aircraft

Apparatus and methods for fabricating a helicopter main rotor blade (100) include a compaction fixture (10) for assembling and compacting blade subassembly components and a sheath spreading/insertion apparatus (50) for spreading and inserting a leading-edge sheath (120) onto the blade subassembly during the compaction process. The compaction fixture includes a lower assembly (12) having a contoured upper airfoil nest (14) mounted in combination with a support structure and an upper assembly (30) having a pressure bag (32) affixed in sealed combination to a contoured backplate affixed in combination to a structural support truss (36). With the upper and lower assemblies in locked combination, the pressure bag is pressurized to compact the assembled blade subassembly components. The sheath spreading/insertion apparatus (50) includes a movable stanchion (52), upper (60U) and lower (60L) elongate carriage members mounted in synchronized movable combination with the stanchion, and a row of suction cups (66) mounted in combination with each carriage member. A vacuum source (68) is pneumatically interconnected to the suction cups (66) to generate suction forces to cause the leading-edge sheath to be spread apart. Movement of the movable stanchion causes the spread-apart leading-edge sheath to be inserted onto the blade subassembly during compaction thereof.

Apparatus and methods for fabricating a helicopter main rotor blade

A flexbeam for rotor blades of a helicopter comprises a flapping flexible structure forming a mast mounting and flapping part, a flexible structure forming a feathering and lead-lag motion part coupled with the flapping flexible structure, and a rotor blade mounting part located at the free end of the flexible structure and adapted to be coupled with a rotor blade The feathering and lead-lag motion part comprises an elongated central member made of a composite fiber material, and a pair of elongated frame members disposed along the longitudinal sides of the central member The frame members are each made of loops of unidirectional composite fiber material and has a Y-shaped cross section The feathering and lead-lag motion part is fabricated by integrally joining the central member and the frame members along the longitudinal sides of the latter The Y-shaped cross section has a pair of parallel ribs extending away from the central member The above construction enables easy fabrication and reduction of weight of the flexbeam

Flexbeam for rotor blades of helicopter and method for fabrication thereof

A damper has a piston having an axis, an outer surface, and opposing ends. Elastomeric seals are in sealing contact with the outer surface of the piston, the seals being coaxial with the piston and limiting movement of the piston to a path along the axis of the piston. The seals also define fluid chambers adjacent the ends of the piston. A primary passage communicates the fluid chambers, and a selectively switchable valve for controls a flow of fluid from one of the chambers to another of the chambers through the primary passage. When the flow of fluid through the primary passage is permitted, movement of the piston is resisted by a first spring rate due to a shear force required to cause shear deflection of the seals. When the flow of fluid through the primary passage is restricted, movement of the piston is resisted by a second spring rate due to a fluid force required to cause bulging deflection of the seals.

Dual spring rate damper

A method for fabricating a helicopter main rotor blade includes a compaction fixture for assembling and compacting blade subassembly components and a sheath spreading/insertion apparatus for spreading and inserting a leading-edge sheath onto the blade subassembly during the compaction process. The compaction fixture includes a lower assembly having a contoured upper airfoil nest mounted in combination with a support structure and an upper assembly having a pressure bag affixed in sealed combination to a contoured backplate affixed in combination to a structural support truss. The contoured upper airfoil nest includes a plurality of tooling pins for locating an upper composite skin in aligned combination on the contoured upper airfoil nest and a plurality of pusher pins for chordwise alignment of a spar assembly in the contoured upper airfoil nest. Spar stanchions affixed to the support structure provide spanwise alignment of the spar assembly in the contoured upper airfoil nest. With the upper and lower assemblies in locked combination, the pressure bag is pressurized to compact the assembled blade subassembly components.

Methods for fabricating a helicopter main rotor blade

A rotor hub system for a helicopter is fabricated predominately of composite material. The flap hinge, pitch hinge and lead-lag hinge contain elastomeric bearings and one step blade folding in either the forward or aft direction using the same drive system is employed. The rotor hub includes closed loop straps which define generally opposed lugs of the flap hinge, and the pitch housing includes a pair of closed loop straps which define the lugs of the lead-lag hinge and a lug of the flap hinge. The use of composite materials as the predominant material of the rotor hub and the pitch housing results in a highly load redundant structure permitting a reduction in size and number of parts, a reduction in drag, and an increase in reliability and safety.

Method of fabricating a helicopter rotor system

A rotor hub system for a helicopter in which the rotor hub and pitch housing are fabricated predominately of composite material, the flap hinge, pitch hinge and lead-lag hinge contain elastomeric bearings and one step blade folding in either the forward or aft direction using the same drive system. The rotor hub includes closed loop straps which define generally opposed lugs of the flap hinge, and the pitch housing includes a pair of closed loop straps which define the lugs of the lead-lag hinge and a lug of the flap hinge. The use of composite materials as the predominant material of the rotor hub and the pitch housing results in a highly load redundant structure permitting a reduction in size and number of parts, a reduction in drag, and an increase in reliability and safety.

Helicopter rotor system and method

Method of fabricating a helicopter rotor hub

PURPOSE: To reduce weight in a rotor unit, to decrease number in components and to improve durability by providing an endless loop-like strap partly made of a composite material at a pitch housing for mounting a rotor blade at a rotor hub CONSTITUTION: The rotor unit for a helicopter comprises a rotor hub 12 having a plurality of lug 12a pairs, and rotor blades of the same number as the lug pairs The blades are freely oscillatably mounted at the lug pairs by a blade mounting means In this case, the blade mounting means constituting a flap hinge 22 in cooperation with the lug pairs has a pitch shaft 92 made of a composite material mounted at ends at a pitch bearing 28 made of an elastomer supported to a pitch housing 14 having the two straps, and a locking means 94 made of a composite material supported by the housing 14 for locking flapping

Earl Schneider

Papers

Method of fabricating a helicopter rotor system

Helicopter rotor system and method

Method of fabricating a helicopter rotor hub

Rotor device for helicopter

Rotor device for helicopter and its manufacture