Sikorsky Aircraft Corporation

United Technologies Corporation

David A Kovalsky

Corey D Jones

Kevin P Leahy

William C Reinfelder

Kevin P Viola

Richard Joseph Simkulak

Leon M Meyer

Ashish Bagai

Jeffry C Purse

Peter B Leoni

Allen E Trudeau

Christopher J Damon

William Degnan

Nicholas Iszczyszyn

Bruce F Kay

Kevin Viola

A main rotor blade assembly includes a main spar with an integral cuff. The main spar is directly to a rotor hub assembly through the integral cuff.

Main rotor blade with integral cuff

A rotor blade includes a removable blade tip section which is mounted to an outboard rotor blade section by mechanically mounting a tip spar to a main blade spar with a spar interface section which bridges a butt joint between the blade spar and the tip spar. The spar interface section is mounted within the blade spar and the tip spar with a multiple of threaded fasteners which are under shear load during rotor blade rotation.

Mission replaceable rotor blade tip section

A braided rotor blade spar includes a tri-axle braid in which braided bias angled fibers are located non-parallel to a longitudinal axis of the spar. Zero degree fibers are located parallel to the axis and are positioned to be on the upper and lower surfaces of the spar. The bias angle fibers are braided around the zero degree fibers. In a method of manufacture of the braided spar, a braided sleeve is formed dry over a mandrel by a multi-axial braiding machine. Once the braided sleeve is formed upon the mandrel, the mandrel is located within a matched metal mold, resin impregnated, and cured. The mandrel is then removed from the finished braided spar.

Braided spar for a rotor blade and method of manufacture thereof

A main rotor blade includes a tip section having a splice cap, a structural tip spar, a core and an upper and lower tip skin. The tip section is mounted to a central blade section by mounting the tip spar to a main blade spar. The tip spar includes a first surface substantially parallel to a second surface. The first and second surfaces each extend from a shear web therebetween to define the generally C-shape in cross section. The shear web generally carries rotor blade torsional loads and eliminates the heretofore required structural core. A section of the tip spar overlaps a section of the main blade spar. The tip section thereby transfers the loads carried thereby through interaction between the overlapped spar sections. The tip section core and skins need not be structural members as the tip spar carries rotor blade tip section torsional loads.

Rotor blade tip section

A method for manufacture of a fiber reinforced composite spar for a helicopter rotor blade including upper and lower sidewall regions and forward and aft conic regions. Constant width crossplies and unidirectional plies are stacked and arranged to form crossply and unidirectional laminates. The composite spar is manufactured via a vacuum forming technique which includes forming the composite laminates directly over an inflatable mandrel assembly. Regarding the latter method, a spar forming apparatus is used to position and manipulate the mandrel assembly as composite laminates are laid. The spar forming apparatus includes first and second pedestal supports being suitably configured so as to facilitate formation of the butt joints in the conic regions of the composite spar. The pedestal supports are movable from a first orientation to facilitate lay-up of composite laminates over the mandrel assembly, to a second orientation to facilitate transfer of the mandrel assembly from one to the other of the pedestal supports. The spar forming apparatus further includes an electromagnetic coil system comprising at least one electrically activated coil and a controllable power source. The electrically activated coils are disposed in combination with each of the pedestal supports and the controllable power source selectively energizes the electrically activated coils to effect a magnetic clamping force between the mandrel assembly and one of the pedestal supports. Such electromagnetic coil system accurately positions the inflatable mandrel assembly during lay-up of the composite laminates and effects transfer of the mandrel assembly.

Method for manufacture of a fiber reinforced composite spar for rotary

A composite tip cap assembly for a helicopter main rotor blade includes a composite main fairing, a unitary composite rib detail internally integrated in combination with the composite main fairing, a composite closure fairing bonded in combination with the composite main fairing, and an abrasion strip bonded in combination with the composite main fairing and the composite closure fairing.

Composite tip cap assembly for a helicopter main rotor blade

An apparatus for installing a leading-edge sheath onto a helicopter main rotor blade subassembly, including a lower assembly having a leading-edge sheath contour nest configured for supporting the leading-edge sheath, opposed carriage members connected to a base, wherein each of the opposed carriage members supports a plurality of suction cups and is capable of synchronized translational movement relative to the leading-edge sheath contour nest between an engaged position wherein the plurality of suction cups are in abutting engagement with the leading-edge sheath, and a disengaged position where the plurality of suction cups are disengaged from the leading-edge sheath. A vacuum system is connected in fluid communication with the plurality of suction cups and is capable of providing vacuum pressure to the plurality of suction cups, whereby the vacuum pressure generates suction forces between the plurality of suction cups and the leading-edge sheath when the opposed carriage members are in the engaged position. An upper assembly is disposed in combination with the lower assembly, and comprises a plurality of stanchions connected to the base of the lower assembly, and a contour clamp connected to each of the stanchions capable of translational movement relative to the leading-edge sheath contour nest. The contour clamps are configured for supporting the helicopter main rotor blade subassembly and function to facilitate insertion of the helicopter main rotor blade subassembly into the leading-edge sheath.

Apparatus for installing a leading-edge sheath onto a helicopter main

An apparatus for assembling a helicopter main rotor blade subassembly which includes a lower airfoil skin, a core, an upper airfoil skin, and a spar assembly having a tip end and a root end, the apparatus including a lower assembly including a base having a contoured upper airfoil nest, wherein the contoured upper airfoil nest has a root end and a tip end, at least two guide ramps disposed proximal to the contoured upper airfoil nest, wherein at least one of the guide ramps is disposed proximal to the root end and at least one of the guide ramps is disposed proximal to the tip end, and a plurality of leading-edge pusher cams disposed proximal to the contoured upper airfoil nest. An upper assembly configured for mating with the lower assembly is provided, and includes a support structure and a flexible impervious membrane supported by the support structure, wherein the flexible impervious membrane and the contoured upper airfoil nest define a molding cavity therebetween upon mating of the upper assembly to the lower assembly.

Apparatus for assembling a helicopter main rotor blade subassembly

A method for fabricating a helicopter blade subassembly includes the steps of providing a blade compaction apparatus having a lower assembly configured for mating with an upper assembly. The lower assembly includes a base having a contoured upper airfoil nest with at least two guide ramps and a plurality of leading-edge pusher cams disposed proximal thereto. The upper assembly includes a support structure supporting a flexible impervious membrane, wherein the flexible impervious membrane and the contoured upper airfoil nest define a molding cavity therebetween upon mating of the upper assembly to the lower assembly. The method further includes disposing the upper airfoil skin and the core in combination with the contoured upper airfoil nest, and then connecting a tip end support insert and a root end support insert in combination with the spar assembly, wherein each of the support inserts include guide members. The spar assembly is located in chordwise alignment in the contoured upper airfoil nest by driving the guide members into conics in the guide ramps and driving the spar assembly into a core conic with the leading-edge pusher cams. The lower airfoil skin is then disposed in combination with the core and the spar to form the helicopter blade subassembly, and then the upper assembly is mated to the lower assembly. The air within the molding cavity is then evacuated such that evacuating the air causes the flexible impervious membrane to apply compaction forces to the helicopter blade subassembly.

Methods for fabricating a helicopter main rotor blade

Fiber reinforced composite spar for a rotary wing aircraft and method of

A fiberglass or other material skin is applied to a composite airfoil structure in a mold assembly having a partially compliant caul plate component which defines the shape of the lower surface of the airfoil. The caul plate component includes a first portion which is essentially rigid and which covers the leading edge of the airfoil. The rigid portion of the caul plate component provides improved conformation of the airfoil skin to the leading edge of the airfoil. The caul plate component also includes a compliant portion which covers and defines the shape of the trailing edge of the lower surface of the airfoil. The stiffness of the caul plate component also has a variable stiffness zone which interconnects the rigid and compliant portions thereof. The use of rigid and compliant portions on the caul plate provides for a controlled conformance of the skin to the leading edge of the airfoil, while allowing the skin to accurately conform to the remainder of the airfoil in spite of variations in the dimensions of internal operating components of the airfoil.

Method for applying a skin layer to an airfoil structure

Molding assembly for forming airfoil structures

The rotor blades of a helicopter are balanced both in the chordal direction and in the spanwise direction in a static balancing assembly. The assembly includes a support surface on which there are four weighing scales. The scales are positioned in close proximity with the four corners of the rotor blade. The scales provide four cooperating pairs of blade spanwise and chordwise balancing reference data. The scales are operably connected to a microprocessor which is preprogrammed with desired balance data for the blades being tested. Deviations from the desired balance data detected by the scales and the microprocessor are corrected by selectively adding or subtracting weight on the blades at appropriate locations of the surfaces thereof.

Method and apparatus for balancing helicopter rotor blades

The method of fabricating selectively shaped dog-leg plies of composite material comprising unidirectionally extending high tensile strength fibers or filaments extending for the full length of the ply and embedded in a resin matrix comprising winding high tensile strength filament onto a mandrel of generally cylindrical shape but having circumferentially extending frustoconical projections extending radially therefrom so that the filament wound onto the cylindrical portion of the mandrel forms the straight legs of the dog-leg ply and so that the filament wound on the frustoconical projection of the mandrel form the arcuate central portion of the dog-leg ply.

Growing community of inventors

Shelton, CT, United States of America

David A Kovalsky