Abstract: The present invention provides a propeller or windmill blank comprising a planar sheet of material having markings defining, or being shaped to have, a central or hub region and two blades extending in opposite directions along imaginary lines; and wherein the blank has a marking or line of preferential folding inclined to the first mentioned lines which, when the blank is bent therealong, will result in pitch being applied to the blades.

Abstract: A prop-fan of the type having a high solidity factor (1 or greater) near the root fairing to a lower solidity factor (less than 1) near the tip and operable over a critical Mach No. range is designed for sound suppression by contouring the tip so that its sweep and sweep distribution of the leading and trailing edge bears a judicious relationship with the Mach surface. This feature is obtainable by designing the planform from a prescribed linearized or non-linearized acoustic theory and tailoring in the sweep so that the leading and trailing edges fall behind the Mach surface.

Abstract: A prop-fan of the type having a high solidity factor (1 or greater) near the root fairing to a lower solidity factor (less than 1) near the tip and operable over a critical Mach No. range is designed for sound suppression by contouring the tip so that its sweep and sweep distribution of the leading and trailing edge bears a judicious relationship with the Mach surface. This feature is obtainable by designing the planform from a prescribed linearized or non-linearized acoustic theory and tailoring in the sweep so that the leading and trailing edges fall behind the Mach surface.

Abstract: A propeller (18) having an exhaust discharge passage (22) through the propeller hub has blades (24) symmetrical in thickness about the nose-tail pitch line and symmetrical in plan form about a rake line (26). The propeller (18) is particularly effective to increase reverse thrust when used with an outboard drive unit (10) having exhaust gas relief passages (27).

Abstract: An article such as a gas turbine rotor blade or bladed rotor is made by consolidation of metal powders contained in a mould using the technique of hot isostatic pressing. Different properties are produced in different portions of the mould corresponding to those parts with either metal powders of different alloys or with metal powders made from one alloy but differently pretreated, e.g. by rolling, to impart mechanical strain into the powders.

Abstract: The present invention relates to a blade profile for rotary wing of an aircraft, comprising, between the leading edge and the trailing edge, a convex upper surface and a non-concave lower surface, wherein, at the point of maximum curvature of the leading edge, the radius of curvature Ro is approximately defined by the expression Ro=1.7 C. e.sub.max.sup.2, in which C represents the chord and e.sub.max the relative thickness of said profile and the portion of lower surface adjacent the leading edge extends to about 20% of the chord from said leading edge and presents a very small general curvature decreasing continuously in the direction of the trailing edge up to the point of minimum curvature of the lower surface. The invention is more particularly applicable to obtaining rotary wings, for example for helicopters, capable of very high performances both when hovering, and in high speed flight, as well as during manoeuvres.

Abstract: A family of airfoils for use in rotary wing aircraft, particularly helicopters, is disclosed. The family is characterized by having a maximum c.sub.1.sbsb.max at M=0.4 and maximum delay in drag divergence while maintaining zero lift pitching moment levels c.sub.m.sbsb.o correctable within the range of -0.01 to +0.01. The present family of airfoils provide high lift at maximum angle of attack when the blade is retreating and maximum delay in drag rise or drag divergence when the blade is advancing. The airfoil section of the family enable a helicopter rotor to counteract, more efficiently, the rolling moment which would otherwise be induced by a rotorcraft's forward flight; this is achieved by the present family of airfoils while maintaining the airfoil sectional pitching moment coefficient at or about zero thereby enabling the blade in which the airfoil sections are incorporated to impose minimum structural loads on the rotorcraft's control system.

Abstract: The invention relates to a high performance aerodynamic airfoil for aircraft wing, wherein the airfoil is biconvex and is such that the corresponding wing comprises an advanced maximum total thickness and at least substantially zero curvature over the major part of the airfoil surfaces of the upper surface and lower surface, downstream of the maximum total thickness, the point of maximum thickness of the lower surface being nearer the leading edge than the point of maximum thickness of the upper surface. The invention finds particular application to the manufacture of fixed or rotary wings of aircraft.

Abstract: A rotary transducer adapted to be driven in the same direction by air flow therethrough in either axial direction comprises a rotor having blades of aerofoil cross-section which are fixed with their planes of zero lift normal to the axis of the rotor. An apparatus for use in extracting energy from the waves of the sea utilizes such a transducer.

Abstract: Propeller and fan blading comprised of an extruded airfoil having a rib retained at the root for mounting and with a portion thereof removed by flattening the back of the blade truncating the back camber thereof in a plane tapered toward the blade tip with respect to the front camber thereof and having a flap of full configuration toward the root of the blade and continuing tangent from the front camber and extending angularly back from the back camber and reduced toward the blade tip by profiling the trailing edge made thin toward said tip by a flattening truncating the back trailing portion of the blade toward said tip, the said blading being controllably pitched and feathered by a hub having cylinder and piston means responsive to engine oil pressure and rotating the blades on their radial axes to a full pitch position by link and lever means biased toward a feathered position by an adjustor means having adjustable stops and means for maintaining moderate pitch until the engine is stopped.

Abstract: A small diameter, highly loaded multiple bladed variable pitch propulsor having swept blades with thin advanced airfoil sections, integrated with a nacelle contoured to retard the airflow through the blades thereby reducing compressibility losses and designed to operate with a turbine engine and using a single stage reduction gear resulting in a high performance, lightweight propulsion system providing a substantial improvement in efficiency over the high bypass ratio turbofan engine.

Abstract: A box fan comprising a box-like structure having front and rear openings interconnected to form a duct passing through said structure, said duct containing an electric motor and a large axial depth wide-bladed fan blade assembly operable by the motor to rotate about an axis of rotation, which fan blade assembly is so located that the center of gravity of said fan blade assembly is located near the rear opening, wherein the fan blade assembly has a plurality of blades each of which has a shape in a plane normal to the axis of rotation, which shape comprises a neck connecting the blade to a hub defining the center of the fan blade assembly, a slightly convex leading edge extending from said neck, a convex outermost edge, a slightly convex trailing edge and a chin portion connecting the trailing edge to the neck, said trailing edge being heavily set near said chin portion and being decreasingly heavily set as the outermost edge is approached along said trailing edge.

Abstract: A helicopter blade of improved airfoil shape which reduces or eliminates retreating blade stall by reducing the magnitude of the upper airfoil blade surface peak pressure and distributes it over a greater chord section of the blade to thereby reduce flow separation and drag.

Abstract: A propeller blade is rotatable about an axis of rotation and has a leading edge and a trailing edge. The blade has a configuration such that for any fixed point on the leading edge of the blade .gamma. has a maximum value of 90.degree., and for any fixed point on the trailing edge .gamma. has a maximum value of Arc cotg[(tg .beta.).sup.3 ] wherein .gamma. is the angle between a radius extending from the axis of rotation to the fixed point and a vector from the fixed point in the direction of rotation of the blade, the vector lying in a plane which is perpendicular to the axis of rotation and which passes through the fixed point. The vector is normal to a section outline formed by the plane passing through the blade. .beta. is the angle between the plane and the chord of a cylindrical profile or corss-section of the blade formed by an imaginary cylinder concentric to the axis of rotation and passing through the fixed point.

Abstract: The propeller includes a central hub with a plurality of blades extending radially from equal circumferentially spaced points on the periphery of the hub. The width of each blade at its root is equal to the spacing between adjacent blades and the width of each blade at its tip is equal to one half the width of its root. The leading edge of each blade is normal to a line tangential to the point of connection of the blade to the hub periphery while the trailing edge slants from the tip to the broader root. The length of each blade is one half the diameter of the hub and each blade has an angle of attack of about 17.degree.. This structural dimensioning results in a propeller providing a substantially constant air discharge from the roots to the tips of the blades with a substantial elimination of radial air flow, all to the end that a greater static thrust can be realized for a given horsepower input.

Abstract: A sheet metal fan blade of improved performance and efficiency has a varying camber angle and chord angle along radial positions of the blade, such that the angle of attack along at least 70% of the length of the blade is not less than 2.degree. or more than 10.degree.. The fan blade construction exhibits utility in an automotive radiator cooling system.

Abstract: A method of producing a material with locally different properties comprises filling a form with at least two different component powders such that the ratio of contents of said powders in the mixture continuously varies over at least some spatial extent, compacting the mixed powders in the form, and subsequently sintering the compacted powders.

Abstract: A marine propeller with unique blade geometry resistant to cavitation and ventilation at high speed operation. The face of the blade has a special convexly curved portion extending from the leading blade edge to a transition zone along the blade chord length toward the blade trailing edge, and a special concavely curved portion from this transition zone to the trailing blade edge, both defined herein.

Abstract: An axial flow impeller for low pressure ratio applications in the range 1.03 and below and comprising a hub carrying a plurality of similar circumaxially arranged air moving blades. Each blade has a root portion attached to the hub and a radially outwardly disposed tip portion. The camber of each blade decreases from root to tip with 0.1203 root camber and .023 tip camber for a ratio of 5.23 to 1. Pitch also decreases from root to tip with a root pitch of 46.degree. and a tip pitch of 27.4.degree. for a ratio of 1.68 to 1. Chord increases from root to tip with a 1.528 inch root chord and a 2.59 inch tip chord for a 1.7 to 1 ratio. The blade camber and chord both change gradually at the blade inner and mid portions with a 35% camber decrease in the outermost 20% of blade span, and with substantially all of the chord increase occurring beyond the blade midpoint.

Abstract: Disclosed is a multi-blade fan assembly and method for manufacture, the fan assembly having a central hub having means for being attached to a driving assembly and having a plurality of fan blades connected therewith and extending radially therefrom; and further characterized by having the fan blades manufactured in accordance with subcritical aerodynamic air foil criteria so as to be efficient for moving ambient air at low relative speeds between the fan blade assembly and the air and for minimum power consumption and noise at high relative such speeds. Each of the fan blades has a length to width ratio L/W within the range of 1-9; has a length L in the range of 6-18 inches; has an artificially reduced chord thickness to length ratio within the range of 0.03-0.12; has a chord that is totally contained within a perpendicular planar cross section of the blade at the chord location and has a twist for obtaining a substantially uniform flow of air throughout the length of the blade.

Abstract: A device for securement to or incorporating into the exhaust assembly of an internal combustion engine to improve efficiency thereof is disclosed. The device comprises a generally tubular housing open at both ends to enable passage of exhaust gases and a flow of air therethrough, and an axle coaxially positioned within the housing on a laterally extending support member, and a hub rotatably mounted on the axle, and two identical and opposed radially extending blades secured to the hub, the blades being obliquely angled with respect to the longitudinal axis of the hub, at least the forward edge of each blade extending inwardly providing inwardly pointing projections. In preferred construction, the inwardly pointing projection is formed between the forward edge of the blade and a forward inner edge of the blade, the said edges defining therebetween an angle of about 66.degree. - 67.degree.. In a further embodiment, at least the leading portion of each blade lies in a plane at an angle of about 72.degree.

Abstract: A folding boat propeller assembly having a hub and two blades. The radially inner portion of each blade is pivoted to the hub. Upon forward movement of the boat, the blades will automatically be pivoted rearwardly into a closed folded-together position by water resistance. Upon rotation of the hub by the boat's engine, the blades pivot outwardly and forwardly to a driving position.

Abstract: A one-piece blank for a propeller fan having a plurality of substantially identical blade portions extending outwardly from a central hub portion, each of the blade portions having leading and trailing edges which are joined at outer leading and trailing corners to an outer peripheral edge. The leading and trailing edges of adjacent leg portions define a narrow radially extending slot and the leading edges are shorter than the trailing edges. Each peripheral edge has a trailing portion extending from the trailing corner which is generally arcuate and a leading portion smoothly joined to the trailing portion and extending to the leading corner which generally follows an involute curve.