United Technologies Corporation

Sikorsky Aircraft Corporation

The United States of America As Represented by the Department of Health

Leonard J Doolin

Stephen V Poulin

Frank Paul D'Anna

Thomas J Toner

Eric G Olsen

William L Noehren

William C Reinfelder

Lance Halcom

Kevin A White

Kenneth L Lauck

Robert J Milne

Joseph Panalone, Iii

Dave H Hunter

William Cermignani

George Capowich

A rotor assembly includes a rotor hub which rotates about a hub rotation axis and a blade connected to the rotor hub. The blade rotates with the rotor hub around the hub rotation axis, and the blade is configured to rotate around a pitch rotation axis of the blade to adjust a pitch of the blade. The rotor assembly includes a pitch horn having a first end rotatably connected to the blade. The pitch horn is configured to rotate with the blade around the pitch rotation axis of the blade to adjust the pitch of the blade, and the pitch horn is configured to rotate relative to the blade around a pitch horn pivot axis arranged at a non-parallel angle relative to the pitch rotation axis of the blade.

Rotor blade pitch horn assembly

A structural dielectrically tailored prepreg panel includes structural materials having desired electrical qualities in one or more desired areas without loss of structural integrity or the addition of parasitic weight. In one method of manufacture an applicator such as a spray nozzle applies a first dielectric material to a first area not covered by a mask. In another method, the dielectric material includes a dry material, which is sprinkled upon a tacky impregnating resin in a controlled volume percentage to provide a dielectric gradient. In yet another embodiment an applicator arrangement includes a plurality of applicators arranged to form a multiple of applicator sets which communicates with a controller to selectively activate a particular applicator and dispense a desired dielectric resin in a desired location.

Composite pre-preg ply having tailored dielectrical properties and method of fabrication thereof

A helicopter rotor has two or more blades which extend from a hub and has an adjustment mechanism for adjusting the lead/lag variation of the blades which typically occur due to manufacturing tolerance variations or to changes which occur through operation such as softening of the supporting elastomer dampers. One embodiment of the invention incorporates an end plate on an upper damper with a lug positioned adjacent to a lug on the torque tube such that the end plate of the damper can be changed relative to the longitudinal axis of the blade. For example, a .+-.1/2 degree adjustment can be made in the blade angle relative to the hub to insure that lead/lag errors are reduced. In another embodiment, the damper set includes extended metal shims adjacent to the end most laminate plys of the upper and lower dampers such that these shims can be bolted to the end plates of the snubber assemblies for step increasing the stiffness of the assemblies. Utilizing the apparatus of the invention, each blade of the rotor can be adjusted to balance the rotor assembly to minimize vibration.

Apparatus and method for adjusting rotor blade tracking

One embodiment of a main rotor pitch control rod subassembly includes an upper rod end segment having a bearing subassembly, a lower rod end segment having a bearing subassembly, an eccentric bushing disposed in rotatable combination with the upper rod end segment bearing subassembly for varying the axial length of the pitch control rod subassembly, a composite central body structure interposed between the upper and lower end segments, a composite strap member wrapped around and secured in combination with the lower end segment bearing subassembly, the composite central body structure, and the upper end segment bearing subassembly, eccentric bushing combination, a composite overwrap overlayed in combination with the composite strap member, a locking key member and a clamp-up bolt for clamping the composite strap member in tensioned combination with the locking key member, and a locking bolt. The eccentric bushing has a plurality of spaced apart bushing apertures formed therethrough, and the locking key member includes a clevis configuration having a plurality of spaced key apertures formed therethrough, interaction between the bushing and key apertures providing a fine, vernier-type adjustment capability. To vary the axial length of the pitch control rod subassembly, the eccentric bushing is rotated about the upper rod end segment bearing subassembly to a predetermined position wherein one of the bushing apertures aligns with one pair of the key apertures. The locking bolt is inserted through the aligned apertures to lock the eccentric bushing in the predetermined position.

Main rotor pitch control rod subassembly

An advanced composite blade construction for a helicopter rotor blade using for the most part fiber reinforced plastic materials in which the major assembly of blade elements is a single step co-cure operation and in which an integral spar/skin carries centrifugal, flapwise and chordwise loads and also incorporates redundant means to carry torsional loads and a honeycomb core carries shear and aerodynamic pressures loads.

Advanced composite rotor blade

A mid-beam jointed reconfigurable bearingless main rotor (BMR) assembly that includes reconfiguration joints that facilitate BMR assembly reconfiguration by main rotor blade removal or folding to reduce the structural envelope of a helicopter for rapid deployment, routine transport, and/or storage. The BMR assembly comprises a rotor hub structure that includes a plurality of radially extending flexbeams, combinations of torsion flexure members and main rotor blades disposed in combination with corresponding flexbeams, and torque tube subassemblies disposed in combination with corresponding flexbeams and torsion flexure member, main rotor blade combinations. Each reconfiguration joint is formed by a combination of an outboard joint segment of a flexbeam and an inboard joint segment of the corresponding torsion flexure member. The rotor hub structure is fabricated so that the configuration joints are purposefully located at radial stations that are subjected to minimal flapwise loading, which for aerodynamic efficiency and manufacturing considerations should not exceed about fifteen percent of the overall span of the BMR assembly. The torque tube subassemblies are fabricated to provide access to the respective reconfiguration joints. For reconfiguration by the removal technique, each torque tube subassembly includes one or more access panels. For reconfiguration by the folding technique, each torque tube subassembly includes a removable splice tube.

Mid-beam jointed reconfigurable bearingless main rotor assembly

A helicopter with a retractable rotor for transport wherein the rotor and its blades, the swashplate, the pitch change rods and support mast are lowered or raised in unison by the hydraulic flight control servos as commanded by the helicopter computerized flight control when being commanded by special rotor retraction/extension software.

Helicopter with retractable rotor for transport

Main rotor pitch control rod assemblies on helicopters constitute means for ranslating an aviator's control impulses in the cockpit to the main rotor blades. Pitch control rod assemblies typically include means for locking the assembly into a predetermined attitude setting. The setting may be held by locking nuts. This invention provides a passive locking means using spring tension to maintain the desired setting if the locking nuts loosen due to stress loads or improper torquing during maintenance. The invention also provides passive means for maintaining expansive stress within the control rod to prevent distortion of the assembly under compressive loads.

Main rotor pitch control rod assembly with passive locking feature

A swashplate configuration for a helicopter which eliminates the need for a uniball centering bearing and either a stationary or rotating scissors linkage through the use of elastomeric bearing assemblies consisting of a first stack of flat laminates oriented both vertically and radially with respect to the axis of the main rotor shaft and a second stack of spherical laminates having a center axis oriented radially with respect to the main rotor shaft axis and which reacts centering and torque loads through compression of the laminate stacks.

Elastomeric swashplate configuration for helicopters

A flexible composite scissor assembly is disclosed which utilizes one or more composite straps disposed either in a radial or non-radial relationship between a hub attached to a rotor and an inner or outer ring of a helicopter swashplate. The composite material has sufficient edge-wise stiffness to allow effective torque transmission between the rotor shaft and the swashplate yet has sufficient flexibility to allow for a vertical and angular displacement of the swashplate relative to the rotor shaft. Utilizing a flexible composite scissor assembly eliminates the need for mechanical linkages having pins and bearings which are a frequent source for wear, increasing the reliability of the rotor assembly, while reducing weight.

Composite scissors for a swashplate

A helicopter rotor hub including a main retention plate that comprises triaxial braided tubular composite material having a fiber orientation that withstands forces both in the plane and normal to the plane of the retention plate. The retension plate comprises a plurality of fiber reinforced resin braided tubular rings that are spaced about in a plane normal to a central axis. The rings form a circumferential ring structure having arm means extending inwardly. A flattened braided tubular ring strap surrounds the circumferential ring structure. Fiber reinforced plates are disposed above and below the ring structure providing additional in-plane strength. The braided tubular rings and braided tubular ring strap comprises substantially circumferential fibers interwoven with angled fibers oriented at a predetermined angle to the circumferential fibers.

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Southbury, CT, United States of America

Leonard J Doolin