United Technologies Corporation

Rotating Composite Technologies, LLC

Aero Composites, Inc.

John A Violette

David P Nagle

Sean Auyeung

Eric Stephen Loos

Charles E Carlson

Thomas Mashey

Thomas G Corley

John M Graff

Matthew C Soule

Eugene J Delgrosso

Edward A Rothman

Marcia A Fecto

Coleman D Shattuck

Peter D Ventura

A support structure for a propulsor blade includes at least one sleeve configured to support a root portion of the propulsor blade, the at least one sleeve fixedly attached to a surface of the root portion. The support structure also includes a preloading component configured to apply a residual compressive force to the at least one sleeve and the root portion of the propulsor blade, the residual compressive force configured to maintain an attachment of the at least one sleeve to the root portion. The propulsor blade and root portion may incorporate composite structural materials. The support structure and/or the preloading component increases the high cycle fatigue strength and bending capacity of blade retention assemblies (including, e.g., composite-to-metal joints) when subjected to high cycle bending loads under reduced centrifugal load conditions, thereby making further reductions in the size and weight of blade retention assemblies feasible.

Composite propulsor blade support structure and system

A system for providing variable pitch to a rotor blade of an aircraft engine includes a rotatable hub; at least one blade mounted on the rotatable hub; a gear mechanism operably connected to the rotatable hub; a timing ring rotatably and operably connected to the gear mechanism; and a pitch arm operably connecting the timing ring and the at least one blade mounted on the rotatable hub. In the operation of the system, the gear mechanism facilitates the rotation of the timing ring to vary the pitch of the at least one blade mounted on the rotatable hub.

Fan blade retention and variable pitch system

A propulsive thrust device for an engine includes a rotor blade and a hub assembly on which the rotor blade is mounted. The rotor blade comprises an airfoil and at least two support members. A propeller thrust device includes a rotor blade, a central hub at which the rotor blade centrifugal load is supported, and an outer hub supporting a control mechanism mechanically connected to the rotor blade and controllable to vary the pitch of the rotor blade on the central hub. A rotor blade for an aircraft engine or in a separate ducted fan housing driven by a powered shaft or gearbox output shaft includes an airfoil and first and second support members attached to the airfoil. An extended arm or portion of the structure at the root of the airfoil of each blade is attached to a controllable mechanism that can vary the pitch of all blades simultaneously.

Variable pitch rotor blade with double flexible retention elements

A composite blade assembly comprises a root portion and blade portion that is connected to the root portion. The root portion comprises inner and outer rings and the blade portion comprises at least one layer of composite material that is folded to form a loop. The inner ring is disposed in the loop and the outer ring is disposed outside the loop such that a portion of the loop is positioned between the inner and outer rings. In this manner, the loop portion is held in compression between the inner and outer rings at least when the composite blade assembly is subject to centrifugal force to thereby prevent separation of the root portion and blade portion.

Composite airfoil assembly

A propeller blade for attachment to a receiving member of a hub of a propeller, is disclosed. The blade comprises a composite spar having an elongated portion formed in the shape of an airfoil. The elongated portion has a base end and a tip end, and a base portion for attachment to the receiving member. The base portion extends substantially transverse to the elongated portion and includes openings for receiving fasteners for fastening the spar to the receiving member. The blade also preferably includes an inner and outer sleeve for protecting the spar from frictional and compressive force wear in the base portion from fasteners. Preferably, the blade also includes an outer fiberglass shell and an inner weight tube for optionally adding more weight to the blade. The composite spar is preferably formed from a composite wall defining an interior space, which space is preferably filled with foam.

Bolted-on propeller blade

A composite propeller blade and hub attachment assembly is disclosed. The assembly includes a blade root having a first connecting member and a hub arm having a second connecting member. The first connecting member meshingly engages the second connecting member. A device preloads the blade root and the hub arm. The first and second connecting members form a slot for receiving the preloading device. The preloading device includes an outer movable unit, an inner movable unit, and a mechanism for displacing the outer and inner movable units relative each other. As the mechanism for displacing relatively moves the inner and outer units, the preloading device is caused to expand and tension the blade root and hub arm for mechanically preloading the blade, in a manner which increases the low centrifugal load off lightweight composite blades.

Bar wedge preload apparatus for a propeller blade

A propeller blade retention assembly for use with a propeller having a hub rotatable about a propeller axis, is disclosed. The assembly includes a blade receiver for mounting the blade to the hub and an internal surface of a hub arm for interfacing the receiver with the hub. The receiver is positioned in the hub arm and is non-integral with the blade and the hub arm internal surface. A retention mechanism is used for retaining the blade receiver to the hub arm while allowing relative rotatable motion therebetween. A preload device is provided for preloading the retention mechanism prior to centrifugal loading during propeller blade operation. The blade is separable from the blade receiver without disturbing the operability of the retention mechanism.

Preloaded retention assembly for aircraft propeller blade retention

A composite axial flow rotary machine blade (50) and method of blade construction is disclosed. A partial-length, spanwisely-disposed hollow spar (20) partially captures a shaped foam core (30) which extends from within the spar's cavity (26) along a substantial length of the blade (50) in a spanwise fashion. A resin-impregnated high strength, high modulus cloth (34) and graphite (32) composition overlays the spar-core assembly (36) and forms the casing (50) with airfoil regions (52, 54) of the propeller blade (10). This construction results in a rotor blade (50) with enhanced natural frequencies thereby providing for an enhanced operational speed range.

Composite blade with partial length spar

A method of manufacturing a fiber reinforced article using a fiber preform 10 suitable for impregnating with a curable resin to form the fiber reinforced article. The fiber preform 10 is formed by fitting a plurality of preformed seamless fabric envelopes 20 over an inner mold body 30 one over another in a layered fashion. An outer mold body 40 is placed over the completed fiber preform 10 prior to injecting a curable resin into the mold cavity 50 housing the fiber preform 10. The preform 10 comprises an innermost seamless fabric envelope 20A preformed to closely match a desired contour of the inner surface of the manufactured article, an outermost seamless fabric envelope 20B preformed to closely match a desired contour of the outer surface of the manufactured article, and an intermediate layer of at least one intermediate seamless fabric envelope 20C disposed therebetween.

Method of making contoured fiber reinforced body

A method of manufacturing a lightweight composite propulsor blade of spar and shell construction comprises forming a composite spar (30) having an elongated foam body (20) bonded to a short metal retention tulip (10) and overlayed with a dry braided wrap of angular structural fibers and substantially unidirectional spanwisely aligned structural fiber plies disposed between the braided layers; adding a leading edge foam body (42) and a trailing edge foam body (44) to the spar assembly to form a blade subassembly (50); providing a dry braided fabric wrap over the blade assembly; disposing the fabric covered blade subassembly into a shell molding die and simultaneously impregnating the dry spar fabric wrap and the dry shell fabric wrap with a curable resin material; and curing the impregnated blade subassembly.

Composite blade manufacture

A rotor blade (1) is disclosed which recenters itself in relation to the retention member (10) in which it is installed. Imposition of an external force (A) upon the rotor blade (1) creates a moment (M) which acts about the rotor blade's root (3). Recentering is accomplished by centrifugal forces acting through an offset distance (C') resulting from an off-center rotation of the blade and its captivated shaped retaining pin (6) within a plurality of retention member tenons (12), achieving an enhanced opposing restorative moment (M'.sub.R) on the rotor blade (1). The retention member tenons (12) contain arcuate bearing surfaces (8) which bear against a corresponding arcuate surface (9) with a smaller radius of curvature lengthwise disposed on the shaped retaining pin (6).

Rotor blade retention

A lightweight propulsor blade (10) is constructed 10 of a hollow internal spar (30) and an exterior airfoil shell (20) which defines and encompasses a hollow interior cavity (26). The internal spar (30) is disposed within the cavity 26 and extends spanwisely from its tip portion to terminate in a spar root portion (40). The spar has at least forward and aft spanwisely extending, chordwisely spaced, hollow box-like cavities (52A, 52B), a leading edge shear web (53) projecting chordwisely forward from the forward cavity (52A), a trailing edge shear web (55) projecting chordwisely rearward from the aft cavity (52B), and an intermediate chordwise shear web (57) spanning the space between and interconnecting the forward and aft cavities (52A, 52B). An additional intermediate box-like cavity (52C) may be incorporated in the intermediate chordwise shear web (57) in spaced relationship between the forward and aft cavities (52A, 52B).

Lightweight propulsor blade with internal spars and rigid base members

A composite axial flow rotary machine blade (10) and method of blade construction is disclosed. A substantially full length composite spar (30) is spanwisely disposed within an airfoil planform (18) which supports an airfoil surface (11a). A pad of reinforcing fibers (40) is sandwiched between the spar's periphery and the airfoil surfaces' proximate inner surfaces (24a, b) corresponding to the pressure (22) and suction (24) sides of the airfoil planform in a spanwise distribution. A quantity of structural foam filler (50) is disposed through the balance of the blade's cavity (16).

Reinforced full-spar composite rotor blade

Preloading and retention of a variable-pitch, light-weight propeller blade (10) are achieved through a retention assembly wherein the blade shank (20) is retained within a hub arm (24) with an inboard angular contact pitch change bearing (30) and an outboard angular contact anti-rocking bearing (50) which is elastomerically preloaded. The outboard bearing (50) is disposed intermediate a bearing race (34) on the shank (20) and an annular frusto-conical rigid support member (62) which is biased outboardly against the anti-rocking bearing (50) by an annular frusto-conical body (72) of elastomeric material selected to impart a desired stiffness and/or damping effect to the retention assembly.

Blade retention apparatus with elastomeric preload

A propeller or fan blade is rotatably mounted to a blade retention pitch member by a pin radially outside of a spinner. By mounting the propeller blade for rotation about the axis of the pin, the blade response to a vibratory excitation in a first mode of vibration is modified such that the twisting motion of the blade is minimized. High speed stability of the blade is enhanced thereby. Moreover a damaged blade may be easily replaced.

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Granby, CT, United States of America

John A Violette