Hartzell Propeller Inc.

Trw Limited

W Benjamin Harlamert

David F Thompson

Richard V Grimes

Donald C Stackhouse

A propeller hub supports a plurality of adjustable pitch propeller blades which are rotated on corresponding radial axes by a hydraulic actuating system supported by the hub. The hub and pitch changing system are enclosed by a spinner assembly including a substantially flat circular bulkhead member having a core molded between skins of resin impregnated high modulus fiber material. The bulkhead member supports a spinner dome of molded resin impregnated high modulus fiber material, and concentric slip rings are supported by a member connected to the rearward face of the bulkhead member. Terminal posts extend from the slip rings through the bulkhead member to receive conductor wires for supplying electrical current to de-icing heating elements mounted on the blades. A fairing is bonded to the spinner dome for each blade to provide for optimum aerodynamic flow around the base portion of each blade, and each fairing is formed by a molded resin skin material covering a rigid foam core.

Aircraft propeller with improved spinner assembly

An adjustable pitch aircraft propeller has peripherally spaced composite blades each including an elongated core of expanded rigid foam material extending from a metal base member having a reduced neck portion and an outwardly projecting flange portion. A casing or skin of plastic resin impregnated fabric material surrounds the core of each blade and extends inwardly along the neck portion and also has a flange portion overlying the flange portion of the base member. The skin material overlying the neck portion of the base member is retained by a filament winding impregnated with plastic resin, and the blade is coupled to the propeller hub by an annular lip portion which projects inwardly and overlies the flange portion of the skin material. The foam core of each propeller blade has longitudinally extending slots, and strips of resin impregnated fabric material extend through the slots to form corresponding webs which connect the skin material forming oposite side of the propeller blade.

Method of fabricating an aircraft propeller assembly with composite

An adjustable pitch aircraft propeller has peripherally spaced composite blades each including an elongated core of expanded rigid foam material extending from a metal base member having a reduced neck portion and an outwardly projecting flange portion. A casing or skin of plastic resin impregnated fabric material surrounds the core of each blade and extends inwardly along the neck portion and also has a flange portion overlying the flange portion of the base member. The skin material overlying the neck portion of the base member is retained by a filament winding impregnated with plastic resin, and the blade is coupled to the propeller hub by an annular lip portion which projects inwardly and overlies the flange portion of the skin material. The foam core of each propeller blade has longitudinally extending slots, and strips of resin impregnated fabric material extend through the slots to form corresponding webs which connect the skin material forming opposite side of the propeller blade.

Aircraft propeller assembly with composite blades

Air craft propeller assembly with composite blades

A propeller hub supports a plurality of angularly disposed propeller blades which are movable by a hydraulic cylinder between a high pitch position and a reverse position through a low pitch position. Hydraulic fluid is supplied to the cylinder from a governor unit driven by the aircraft engine, and a fluid pressure responsive relief valve controls the pressure of the hydraulic fluid. The pressure responsive relief valve is manually adjustable by the aircraft pilot to change the fluid pressure at which the valve responds in order to change the pitch of the propeller blades. The fluid pressure must be increased above a predetermined normal operating limit for actuating the cylinder against the bias of a spring within the propeller to move the blades to their reverse pitch position. In addition, a centrifugally actuated lock unit prevents actuation of the cylinder and movement of the blades to their reverse pitch position until the speed of the propeller is reduced to a slow idle. The pressure responsive relief valve also incorporated hydraulic means to assure that the valve responds immediately to the pilot's command.

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Piqua, OH, United States of America

W Benjamin Harlamert