Abstract: An aircraft propeller has adjustable pitch blades which are reset from a low pitch in-flight idle position to a lower pitch ground idle position by a beta feedback and reset mechanism. The reset mechanism includes a set of cam elements supported for movement in response to rotation of the blades and positioned to engage a follower plate adjustably mounted on the beta feedback control rods.

Abstract: A multiple blade aircraft propeller hub has a bulkhead supporting concentric slip rings connected by slide blocks to the aircraft electrical system. Electrical conducting flexible leads connect the slip rings to electrical heating elements or de-icing boots carried by the propeller blades. Each of the leads includes an elongated flexible braided copper tube for conducting electricity and which loosely surrounds a flexible multiple strand stainless steel cable, and an extruded flexible vinyl insulating tube loosely surrounds the braided tube. The leads provide for minimizing stresses and metal fatigue in the electrical conducting braided tube with changes in blade pitch and thereby provide for a substantially extended service life.

Abstract: An aircraft propeller has adjustable pitch blades which are reset from a low pitch in-flight idle position to a lower pitch ground idle position by a beta feedback and reset mechanism. The reset mechanism includes a set of cam elements supported for movement in response to rotation of the blades and positioned to engage a follower plate adjustably mounted on the beta feedback control rods.

Abstract: A generally flat core of foam material extends outwardly from a wedge-shaped metal base plug, and the core is covered with overlapping plies of resin-bonded plastics materials having unidirectional fibers. The plies are covered by outer layers or skins of resin-bonded woven fabric plastics materials. The fibers of the inner plies are orientated at positive and negative acute angles relative to the longitudinal axis of the blade to provide the blade with predetermined torsional stiffness, and the fibers of the outer plies extend generally parallel to the axis and wrap around the base plug in an interleaving manner to provide high stiffness and strength to bending forces. Some of the plies extending around the base plug receive metal shell elements, and the shell elements engage propeller hub lip portions which cooperate to define an under-cut recess and clamp the plies to the base plug.

Abstract: 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.

Abstract: 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.

Abstract: 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.