United Technologies Corporation

Sikorsky Aircraft Corporation

Other

United Technology Corporation

Schmaling, David N.

Byrnes, Francis E.

Francis E Byrnes

David N Schmaling

Edward S Hibyan

David H Hunter

Donald L Ferris

Peter C Ogle

William L Noehren

George J Wehnert

Robert Cunningham

Thomas J Toner

Ryan Thomas Casey

Albert T Krauss

Francis D Federici

Frank Paul D'Anna

Eric G Olsen

Timothy A Krauss

Charles J Isabelle

Frederick J Miner

William P Fallon, Jr

Robert James Milne

Douglas E Tritsch

Lawrence Nicholas Varholak, Jr

I Lawrence Cullen, Iii

Lawrence I Cullen, Iii

Ralph D Costanza

Jacob A Fehrman

Kevin S French

A rotor hub assembly for a helicopter includes a rotor hub operably connectable to a shaft of a helicopter. One or more flex beams extend through the rotor hub, with each end of each flex beam operably connectable to a rotor blade. One or more inner bearings are located at the rotor hub to spherically support the one or more flex beams in the rotor hub. A rotor assembly for a helicopter includes a rotor hub operably connectable to a shaft of a helicopter. One or more flex beams extending through the rotor hub and one or more inner bearings are located at the rotor hub to spherically support the one or more flex beams in the rotor hub. A plurality of rotor blades are operably connected to the ends of the one or more flex beams.

Flexbeam rotor

A composite spar for a helicopter blade includes two or more layers of unidirectional laminate material. One or more upper plies of bi-directional laminate extend from an upper airfoil portion of the spar disposed between adjacent layers of the two or more layers of unidirectional laminate material. One or more lower plies of bi-directional laminate material extend from a lower airfoil portion of the spar disposed between adjacent layers of the two or more layers of unidirectional material. The upper plies and the lower plies overlap defining a crackstopper layer configured to prevent propagation of defects in the spar.

Helicopter composite blade spar and method

A rotor for use in an aircraft includes an inner hub; and a plurality of blades arranged around the inner hub, each of the plurality of blades comprising an inner structural member; an outer blade shell surrounding the inner structural member; and a centering block located at a base of the inner structural member proximal to the inner hub, wherein the centering block is located between a first lateral portion of the inner structural member and a second lateral portion of the inner structural member, wherein the centering block is further connected to the outer blade shell, and wherein the centering block allows the outer blade shell to rotate about an axis approximately corresponding to the inner structural member.

Rotor with blades including outer blade shell and inner structural member

An elastomeric spherical bearing includes a multiple of shims, at least two of which have different thicknesses. In one exemplary embodiment, each of the shims has a different thickness with a generally equivalent stress on each shim.

Spherical elastomeric bearing with improved shim thickness

An elastomeric spherical bearing includes a multiple of elastomeric layers with an essentially equivalent fatigue life.

Uniform fatigue life spherical elastomeric bearing

An elastomeric spherical bearing includes a multiple of shims, at least two of which have different thicknesses. In one exemplary embodiment, each of the shims has a different thickness with an essentially equivalent stress on each shim.

A snubber inner member has a doubly convex outer surface portion having a central longitudinal axis. A shim/spacer stack secured to the outer surface portion couples the snubber inner member to the second member. A retainer having one or more engagement surfaces cooperates with one or more engagement surfaces of the snubber inner member to constrain lateral movement of the snubber inner member relative to the retainer while permitting longitudinal movement of the snubber inner member away from the retainer. An elastomer secures the retainer to the first member.

Snubber

A variable diameter rotor blade assembly includes a rotor hub with multiple rotor blades each having an outboard blade section telescopically mounted to an inboard blade section. A reeling assembly includes a strap drum that extends and retracts a strap attached to each of the outboard blade sections to selectively change the diameter of the rotor blade assembly. The strap includes a body portion extending toward the drum and a termination portion attached to each of the outboard blade sections. The termination portion is made from a rigid fiber reinforced composite that has a higher rigidity than the body portion. A transition region is formed between the body portion and the termination portion and is made from a flexible matrix-fiber composite that has a higher rigidity than the body portion and a lower rigidity than the rigid fiber reinforced composite. The body portion is formed from layers of spanwise fibers and the termination portion is formed from alternating layers of spanwise fibers and angled fibers resulting in the termination portion having a greater thickness than the body portion. The orientation of the fibers in addition to the rigid fiber composite material increases the overall strength of the termination portion.

Method and apparatus for fiber strap termination

A VDR blade lock system includes a set of blade pins that are rigidly mounted into the outboard blade section and a set of mount pins that are rigidly mounted to a rotor mount assembly. A resilient bushing at least partially surrounds each pin to provide high-energy absorption, impact resistance and low compressive modules. Should the outboard rotor blade section become free, centrifugal force will cause the outboard rotor blade section to rapidly telescope radially outward over the inboard blade section. The lock system prevents full extension of the outboard rotor blade section while the bushings act as a series of springs to reduce the deceleration rate of the outboard rotor blade section to minimize an impact force experienced by the VDR system.

Blade lock system for variable diameter rotor systems

A novel apparatus and method are provided to reduce the interlaminar shear loading in the retention area of composite springs used in a vibration isolator for use with a helicopter main rotor. The composite springs, which are made of a graphite laminate, are weakest when subject to inter-laminate shear. The shear forces are highest during bending and twisting about the longitudinal axis of the laminate composite. The invention consists of several techniques to minimize the inter-laminate shear. The first is the use of nylon mounting pads which are attached to the ends of the graphite laminate spring arm at the locations where mounting to the inner and outer hubs is to take place. In particular, it has been found that the nylon spacer must be recessed back from the perimeter edges of the graphite spring arm the same distance which is approximately equal to the width of the graphite spring arm. Next the location of the bolt holes in the spring arm must be critically located so as to avoid that portion of the spring arm which has the highest shear loading.

Inertial vibration isolator spring for helicopter

A structural interlock (40) for inhibiting relative rotation between mating elements (20, 42) characterized by a plurality of grooves (50) being formed in one of the mating elements, and a mechanism (60) for producing a nominal contact pressure on the contact area (A.sub.1 thru A.sub.8) between the mating element, which contact pressure elastically deforms the other of the mating elements into the grooves (50), and is less than the material yield strength of either of the mating elements. In the preferred embodiment, the grooves (50) are radially oriented and an applied compressive load produces a nominal contact pressure which is about 80% of the material yield strength.

Structural interlock for inhibiting relative rotation between mating

A composite rotating swashplate for a helicopter rotor system which includes rotor blades with associated control rods. The control rods control the pitch of the rotor blades. The composite rotating swashplate according to the present invention includes an outer tubular ring with an inner tubular ring located within the outer ring. The outer ring is made from braids of tri-axial graphite fibers interwoven with unidirectional plies. The inner tubular ring is made from braided .+-.45 degree graphite fibers. A support ring is located within the outer ring and external to an inboard periphery of the inner tubular ring. A plurality of apertures are formed through the outer and inner rings. The apertures are adapted to receive the terminal ends of the control rods. Mounting bolts extend through at least one wall of the outer and inner rings and attach the terminal ends of the control rods to the swashplate.

Composite rotating swashplate for a helicopter rotor system

An optimized composite flexbeam (10) having a pitch region (PR) which includes a core laminate (50) of unidirectional fiberglass material (U.sub.F), and face laminates (52) of unidirectional graphite material (U.sub.G) bonded to mating surfaces (50.sub.M) defined by the core laminate (50). The core laminate (50) and face laminates define an aspect ratio which is greater than or equal to 10 and define chamfered edge surfaces (54.sub.S). Each chamfered edge surface (54.sub.S) defines a critical acute angle .alpha. with respect to the flapwise bending neutral axis (X.sub.A) of the pitch region (PR) and defines a lateral edge (54.sub.E) disposed a vertical distance X from the flapwise bending neutral axis (X.sub.A). The critical acute angle .alpha. is between about 14 degrees to about 22 degrees and the vertical distance X is about 12.5% to about 37.5% of the pitch region thickness dimension (T.sub.PR). The optimized composite flexbeam (10) further includes an inboard transition region (ITR) having a first transition subregion (ITR-1) and a second transition subregion (ITR-2). The second transition subregion (ITR-2) defines a width conic and a critical width transition subregion (Cr.sub.wt). Furthermore, the first and second inboard transition regions (ITR-1, ITR-2) are composed of a combination of unidirectional and off-axis composite materials (U, O) wherein the off-axis composite material (O) defines a percentage %O of off-axis composite material (O) and wherein the percentage %O in the critical transition subregion (CR.sub.wt) is defined by an optimized curve (100).

Optimized composite flexbeam for helicopter tail rotors

An axisymmetric elastomeric bearing assembly (30) for an articulated rotor hub assembly (10), which axisymmetric elastomeric bearing assembly (30) is disposed in combination with a rotor assembly yoke (24) and hub retention member (12) of the rotor hub assembly (10) and is operative for accommodating the multi-directional displacement of a rotor blade assembly (14) thereof. The axisymmetric elastomeric bearing assembly (30) includes a central bearing element (32) having a spherical bearing surface (32s) defining a bearing focal point (30f) and spherical elastomeric elements (34) bonded to the spherical bearing surface (32s) on opposing sides of the bearing focal point (30f). Each of the spherical elastomeric elements (34) have a plurality of alternating layers of elastomer and nonresilient shims (36, 38) which have a center of curvature which is coincident with the bearing focal point (30f) and disposed at increasing radii therefrom. Bearing endplates (40) are bonded to the spherical elastomeric elements (34) and are mounted in combination with the yoke (24) and hub retention member (12). In operation, the central bearing element (32) is rotationally self-positioning to effect load and motion sharing between the spherical elastomeric elements (34).

Axisymmetric elastomeric bearing assembly for helicopter rotors

An acoustic isolator is incorporated between a noise generating device and a support structure, such as between a transmission housing and an airframe. The isolator has a first fitting which attaches to the noise generating device, and a second fitting which attaches to the support structure, with an acoustic attenuation member disposed therebetween. Preferably, a first elastomer member is disposed between a pair of vertical walls of the first and second fittings. Optionally, a second elastomer member is disposed between an upper surface of the supporting structure and a lower surface of the second fitting such that horizontal loads are reacted therethrough. Alternatively the first and second elastomers comprise a spherical elastomer member and a cylindrical elastomer member in the form of a spherical bearing. The acoustic isolator thus allows rigid attachment of the adjacent structures yet provides acoustic isolation of complex forces which would normally transmit noise through the structure, particularly those from the vertical, lateral and fore/aft directions. Utilizing the inventive acoustic isolator, noise transmission through the support structure can be substantially reduced.

Growing community of inventors

White Plains, NY, United States of America

Francis E Byrnes