Abstract: A mixer which provides axial flow in a non-uniform flow field, such as may be established by gas which is sparged into a medium being mixed in a tank, and provides large axial flow volume without flooding and withstands variable loads on the blades thereof, thereby providing for reliable operation. The mixer impeller is made up of paddle shaped blades, which near their tips (e.g., at 90% of the radius of the impeller from its axis of rotation) are of a width at least 40% of the impeller'a diameter. The blades also having camber, twist and flat sections. The flat sections being at least in the center area of the base of the blades. The hub for attaching the blades to the shaft of the mixer has radially extending arms with flat surfaces. The base of the blades are spaced from the shaft to define areas therebetween.

Abstract: The disclosure is directed to a mixed flow impeller with a low noise, to be used for a blower of an air conditioner or the like. The mixed flow impeller of the present invention is characterized in three points, i.e., thin thickness blade member increased in its thickness only at its leading edge, a plate-like triangular protrusion provided at an outer peripheral portion of the leading edge, and blade curvature line having its maximum curvature position deviated toward the trailing edge side through employment of a cubic curve. Since each of the above features may be caused to function independently, noise reduction is possible even if it is executed singly, but the maximum effect is available when the are effected in combination.

Abstract: Each blade (2) of a propeller fan projecting radially outwardly from the outer peripheral surface of an annular boss (1) has on at least part of its suction side (3), a coarsened surface (4).

Abstract: Each blade of a low speed propeller fan extended radially outwardly from a member connected a rotating body has a coarsened surface at least part of its suction side. The coarsened surface has a coarsened density or depth which gradually increases from the front edge of the blade to its rear edge.

Abstract: Each blade of a high speed propeller fan extended radially outwardly from a member connected to a rotating body has a coarsened surface at least part of its suction side. The coarsened surface has a coarsened density or depth which gradually increases from the rear edge of the blade to its front edge.

Abstract: A propeller having blades designed to achieve maximum thrust at lower static velocities in both forward and reverse pitch modes is disclosed. Each blade has a generous leading edge radius leading to an upper surface having positive camber and a lower surface having positive camber adjacent the leading edge and negative camber adjacent the trailing edge. Each blade also has a high thickness-to-chord ratio and lower span-to-chord ratio or aspect ratio. This thicker blade profile and aft loading leads to a more uniform pressure distribution and laminar airflow across the blade surface resulting in a higher coefficient of lift, increased blade life and reliability, and lower noise levels.

Abstract: A fan apparatus for preventing the occurrence of a burble on a surface of a blade while the resistance to air flow into the fan is increased and the generated noise is kept small. Each fan of the blade has a first area which extends from the bottom portion of the blade to the intermediate portion and a second area from the intermediate portion of the blade to the top portion of the blade. The setting angle of the blade is a first, predetermined angle at the first area of the blade but is increased at the second area of the blade. Further, the chord length of the blade gradually increases from the bottom to the top of the blade. Additionally, a first wing axis of the blade in the first area is not parallel to a second wing axis of the blade at the second area but, rather, the second wing axis is inclined towards the rotational direction of the fan apparatus.

Abstract: A through-hull speed sensor of the magnetized paddlewheel sensor type wherein a paddlewheel is rotatably supported in a cavity adjacent a magnetic sensing device which generates electrical pulses corresponding to paddlewheel speed as the wheel rotates when the vessel moves through water. The sensor has improved low speed characteristics provided by a housing which extends the paddlewheel into the water below the hull. The bow of the housing provides a new leading edge, generating a smaller thickness boundary layer at the paddlewheel, so that the paddles project beyond the layer at low speeds. High speed performance is improved by having a high ratio of paddle fore-to-aft drag coefficient shape; keeping the periphery of the paddlewheel hub within, or flush with, the bottom of the cavity; a low paddle projection versus paddlewheel radius ratio; and by keeping the ratio of paddle cross-section versus available cavity cross-sectional space within an optimum range.

Abstract: A blade is comprised of a plurality of a family of airfoil sections, each section being characterized by a large leading edge radii, a camber having an apogee at approximately 45% of the airfoil section chord length and relatively blunt trailing edge. The airfoil sections taper in thickness ratio (h/b) from about 20% near the blade root to about 2% near the blade tip. The maximum thickness for each airfoil section increases along the chord length from about 39% of the airfoil section for a 20% airfoil section to about 42% of the airfoil section chord length of a 2% airfoil section. As such, the novel blade of the invention provides superior aerodynamic performance to the NACA Series 16 airfoil in the Mach 0.50 to 0.70 range with less susceptibility to foreign object damage and handling problems.

Abstract: A system for fabricating fan blades wherein the assembly includes a flat hub plate having generally radially oriented notches defined therein intersecting the plate periphery. Individual blades each include a hub connection portion adjacent an inner end region which includes parallel flat portions angularly related to the general blade configuration interconnected by a transition portion. The flat blade portions are located upon opposite sides of the hub plate and the transition portion extends through the hub plate notch. The flat portions are attached to the hub plate, and by predetermining the position of the hub connection configuration on the blade, the fan characteristics can be predetermined and accurately duplicated. The system permits a standard set of tools to form a variety of sizes of fan blade components having various characteristics.

Abstract: Method of manufacturing a workpiece of any given cross-sectional dimensions from an oxide-dispersion-hardened nickel-based superalloy available in the form of coarse-grained longitudinally directed columnar crystals by connecting previously very finely machined workpiece parts derived from a semi-finished product by diffusion-bonding using hot isostatic pressing, the workpiece parts being first heat-treated under a protective gas in the temperature range of 50.degree. to 100.degree. C. below the recrystallization temperature, under a pressure p.sub.k of not more than 5 MPa with the machined surfaces to be connected joined together, the workpiece then being heated at least to a critical temperature T.sub.K, above which no further cold working takes place, and the pressure then being gradually increased to the diffusion bonding pressure p.sub.max of 100 to 300 MPa with simultaneous increase in temperature are a heating rate of not more of 2.degree. C./min to the diffusion bonding temperature T.sub.D of 0 to 50.

Abstract: A hovering or VTOL aircraft with a propulsion unit using a fan in a shroud whose upper end is toroidally shaped and rotationally symmetrical with a convex curvature with a radius of curvature between 0.2 r.sub.f and 1 r.sub.f from a location 1.4 r.sub.f upstream of the blade plane to a location 0.2 r.sub.f downstream thereof. The blade, whose tip radius is r.sub.f has a twist at least from a range of .+-.0.25 r.sub.f around a mean radius between hub and tip to the tip such that the airflow velocity through the meridian increases outwardly from the hub of the fan toward the periphery of the fan.

Abstract: Turbo-machine blade, including: a continuously curved profile contour having convex curved leading edge, suction side and trailing edge regions, and a concave curved pressure side region; the leading edge section being formed of a first ellipse section and a second ellipse section adjacent the first ellipse section;the suction side region being formed of a first circle section adjacent the second ellipse section and a first parabola section of a first second-order parabola being adjacent the first circle section; the trailing edge region being formed of a second circle section adjacent the first parabola section; and the pressure side region being formed of a third circle section adjacent the first ellipse section and a second parabola section of a second second-order parabola being disposed between the second circle section and the third circle section.

Abstract: The mean line (F) of each blade (1) is formed by a flat continuous curve contained in a plane OZ-OY.sub.o forming with the plane of rotation of the propeller an angle .phi..sub.o between 35.degree. and 55.degree. and preferably between 40.degree. and 50.degree., said curve having a first part of negative Y.sub.o and positive Z coordinates, and a second part of positive Y.sub.o and positive Z coordinates, the coordinate point Y.sub.o =0 being situated between the values of Z included between 0.75 and 0.85 R (R designating the radius of the propeller), the tangent to this curve has its end corresponding to the end of the blade forming with the axis Oz an angle between 30.degree. and 50.degree. and preferably between 35.degree. and 45.degree..

Abstract: A multi-bladed marine propeller designed for efficient operation in intermediate, partially cavitating flow regions between fully cavitating flow and noncavitating flow. Each of the blades has a radially inner subcavitating section and an outer section which is configured to have a higher angle of attack and tapered trailing and leading edges so that it supercavitates at high speeds either with or without ventilation and subcavitates at low speeds. Various other features of each blade include different length chords on the pressure and suction sides of the outer section and an inclined trailing surface area extending between the chord ends for improved off design, design point, and astern operation. A minimized transition area is included between the inner and outer sections, and narrow chord lengths are provided in the tip area to minimize and balance overall tip section drag.

Abstract: A fluid foil for use in a marine propeller having an upper surface with a uniform, continuous convex shape commencing at the leading edge and terminating at the trailing edge of the foil section and a lower foil face having a convex shape extending from the said leading edge to the foil mid/chord position and having a concave shape extending from the said mid-chord position to the said trailing edge. An effective pitch line extending from the foil leading edge to the foil trailing edge is intersected tangentially by the concave shape of the lower foil face.

Abstract: This invention relates to airfoils which have particular application to rotors of helicopters and rotorcraft and to aircraft propellers. Two airfoil profiles, the RC(4)XX and RC(5)XX are shaped to permit (1) the development of high air loads without causing an extensive separation of the boundary layer air, (2) a distribution of airloads which results in a near zero pitching moment coefficient about the quarter chord for a range of lift coefficients from -0.2 to 1.0 for Mach numbers up to 0.63, and (3) the development of a local supersonic flow field which is so shaped that the wave losses are minimal until higher free stream Mach numbers over a range of lift coefficients from 0.0 to 0.30. Thus, both airfoils have high maximum lift coefficients, low pitching moment coefficients, and high drag divergence Mach numbers to result in improved rotor or propeller performance. The two invention airfoils are related in shape and purpose.

Abstract: The vane of the impeller in a high-speed or mixed-flow centrifugal pump for the conveying of liquids which contain high or low concentrations of strands or strips of vegetable, plastic or other material has a convex inlet edge whose curvature increases gradually in a direction radially outwardly from the axis of rotation at such a rate that the resultant of the centrifugal force and the resistance encountered by a strip or strand at a particular point of the inlet edge is invariably tangential to the respective point of the inlet edge. This ensures that the strips or strands do not overlie and circulate with the inlet edge but are entrained by the resultant force to become separated from the vane. The stagnation paint of the vane in a region which is remote from the axis of rotation is disposed at the suction side of the vane; this also contributes to prevention of accumulation of strips or strands along the inlet edge.

Abstract: An aerator (10) is disclosed which includes a hollow outer tube (12) and a hollow inner tube (14) rotatably supported therein. The inner tube is drivingly connected to a drive shaft (28) of the motor (18). A mounting flange (34) extends from a first end (36) of the outer tube and a mounting bracket (30) is interposed between the mounting flange and the motor. The mounting bracket and mounting flange are removably attached to the motor. A bearing mechanism which includes a bearing (44) and a ceramic wear sleeve (46) rotatably support a second end (40) of the inner tube adjacent the second end (42) of the outer tube. A propeller (20) is attached to the second end of the inner tube and has a pitch which is sufficiently high to move liquid past it at a velocity wherein cavitation of the liquid above the propeller is prevented at a preselected operating rotational speed.

Abstract: The invention relates to improvements to air propellers in so far as the profile of their blades is concerned. The law of evolution of the curvatures of the extrados 2 is the following: the curvature, maximum at the leading edge A, increases first of all rapidly to reach a value of about 4 at the point B at about 4% of the length of the chord, and then decreases regularly to reach a substantially zero value at the trailing edge F. The law of evolution of the curvatures of intrados 3 is the following: the curvature, maximum at the leading edge A, decreases first of all rapidly to reach a value of about 8 at a point D at about 3.5% of the length of the chord, then decreases less rapidly to reach a zero value at a point E situated between 10% and 60% of the length of the chord, decreases further to a slightly negative value and then remains practically constant as far as the trailing edge F.

Abstract: The invention pertains to a fan blade and a method for making a fan blade wherein the stresses within the blade material are substantially constant throughout the length of the blade and the unique construction of the blade reduces the concentration of loading on the blade material. Preferably, the blade is molded of a synthetic plastic material and includes a ribbed structure locating material offset from the concave convex configuration of the blade air flow portion such that the section modulus of blade sections from the air flow portion toward the root portion increases by increasing the distance of the blade material from the neutral bending axis in such a manner that no abrupt changes occur and the stresses imposed upon the blade material throughout its length are substantially constant.

Abstract: A family of airfoil cross sections, termed SC21xx, for use in a helicopter blade is disclosed. The airfoil (36) achieves maximum lift performance equivalent to prior art airfoil configurations without incurring increased aerodynamic drag at high velocities. The airfoil (36) was developed by thickening and drooping the leading edge region (38) of the prior art airfoil (30) improving lift in the leading edge region (38) and delaying the formation of sonic shock waves at high velocities.

Abstract: The invention minimizes selected tones present in buzz-saw noise, otherwise known as multiple pure tone noise. This noise arises from the production of unequal shockwaves during the rotation at sonic or supersonic velocities of a bladed rotor, the dimensional characteristics of whose blades are subject to manufacturing tolerances. Minimization of selected buzz-saw noise tones is achieved by arranging the blades around the rotor in a sequence which minimizes selected Fourier coefficients of the shockwave strengths; alternatively, the blades are arranged to minimize selected Fourier coefficients of the dimensional characteristics of the blades, such as thickness, t, stagger angle .theta., and camber. The invention is particularly applicable to the fan propulsors of turbofan aeroengines.

Abstract: Improved prop-fan stability is achieved by providing each blade of the prop-fan with a leading edge which, outwardly, from a location thereon at the mid-span of the blade, occupy generally a single plane.

Abstract: Airfoil for vehicle fan which operates in low Reynolds number and varying turbulent conditions having a discontinuity formed on the suction surface thereof adjacent to its leading edge to trigger early formation of a laminar flow bubble so that sufficient suction surface remains downstream of the air bubble whereby air circumventing the bubble can reattach to the suction surface for sufficient pressure recovery for high lift and low drag performance.

Abstract: A rotor or stator blade for an axial flow compressor has one or both of its end portions designed to minimize the interference between the annulus boundary layer and the blade. The basis of the invention is that the aerofoil is designed so that each section of the aerofoil through the boundary layer performs a constant amount of work per unit height.

Abstract: Construction of impellers of various dimensions are manufactured from tubular hub stock and sheet-like blade stock by cutting a hub of particular length from said hub stock and blades of corresponding length from said blade stock and attaching said blades to said hub. The bore of the hub may be enlarged according to a specified support shaft diameter, and the overall diameter of the impeller may be altered, preferably by trimming ends of the blades prior to mounting on the hub.

Abstract: An outboard region of a helicopter rotor blade of aerofoil cross section has a thickness to chord ratio not greater than twelve percent and an inboard region has a thickness to chord ratio greater than twelve percent. Preferably, the thickness to chord ratio of the inboard region is greater than eighteen percent and may increase towards the root end to about twenty four percent. The inboard region may extend outwardly to a position not exceeding sixty percent of an operating radius of the rotor blade.

Abstract: A motor-driven fan including a hub adapted to be driven by a motor, a plurality of fan blades provided on the hub to extend in radial directions, a shroud including a ring-shaped portion encircling the fan blades and stay members for supporting the ring-shaped portion, each of the fan blades being formed at a tip end thereof with a deflector which is bent in a direction of rotation of the fan by a width which increases from a leading edge to a trailing edge of the blade.

Abstract: The external part at least of a propeller blade, having a maximum relative thickness between about 2 and 6%, has a profile whose thickness variation law along the chord comprises a first zone (I) going from the leading edge to about 8% of the length of the chord in which the curvature decreases rapidly, from a maximum value at the leading edge, followed by a second zone (II) extending between about 8% of the chord and midships in which the curvature decreases linearly. In a third zone, extending from midships to 75 to 85% of the chord, the curvature is substantially constant. A fourth zone (IV), extending from the end of the third zone (typically at 80% of the chord) to the trailing edge, comprises a curvature inversion.

Abstract: A propeller (10) including a hub (12) and a plurality of blades (16) having a leading edge (22), outside edge (24), tail edge (26) and inside edge (28). Each of the blades (16) extend substantially radially from the hub (12) and include a body portion having a regressive pitch from the leading edge (22) to the tail edge (26) and cupped portions (30) and (32) extending along the inside edge (28) and outside edge (24), respectively. A method of making the propeller (10) includes the steps of forming the hub (12) and forming the plurality of blades (16) having a regressive pitch and extending substantially radially from the hub and forming the first cupped portion (30) extending along the inside edge (28) and the second cupped portion (32) extending along the outside edge (24).

Abstract: An aircraft is disclosed as having the components of a high wing airframe, a single engine of the 360 type, and a propeller formed with airfoil cross sections along the blades thereof having profiles which, when particularly matched with the designated engine and type of aircraft, result in superior performance than is available when any of the components is matched with other components. Specific disclosures of the front and rear cambers of the blades provide aerodynamic characteristics which optimize the performance capabilities of the high wing airframe in conjunction with the designated engine.

Abstract: A guide vane ring for a return flow passage in axial fans comprises a ring (3) intended for placing in the return flow passage (4) coaxial with the impeller (6). A plurality of guide vanes (7) are formed integral with the ring and distributed round its exterior circumference. In a method of producing such a ring integral with its vanes, separate longitudinal slits are formed in a line one after the other in a metal strip. A cut is made transverse the strip between one end of each slit and one long edge of the strip. Portions of the band thus cut free are bent out from its plane and formed to a desired configuration, whereafter the formed band portions are bent such that the transverse cut lines will extend substantially at right-angles to the unformed flat band portion. This flat band portion is cut to desired length, formed and joined together into a circular ring with the portions formed to desired configuration forming exterior, substantially axially disposed guide vanes.

Abstract: An aircraft propeller blade comprising an inner section which extends from the propeller hub toward the blade tip, a middle section adjacent to said inner section, and an outer section which extends from adjacent to said middle section to the blade tip; where the largest camber in the inner section decreases linearly over the blade length from adjacent to the propeller hub toward the blade tip, and the greatest camber height location shifts linearly over the blade length toward the blade tip; the largest camber in the middle section increases linearly over the blade length toward the blade tip, and the greatest camber height location shifts approximately linearly from adjacent to the inner section toward the blade tip; and the camber in the outer section decreases elliptically over the blade length toward the blade tip, and the greatest camber height location remains constant from adjacent to the middle section to the blade tip.

Abstract: To make vane airfoils for an axial flow compressor metal strip is first contour rolled to a cross section comprised of two opposing airfoils separated by a center rib, where one of the faces of the strip is kept planar. The rib is used to guide the strip into dies where it is notched and slotted to define individual airfoils. Next, die stamping makes concave the planar surface of each airfoil.

Abstract: An improved airfoil blade for aircraft propellers and the like which exhibits high aerodynamic performance and low far and near field noise levels at a minimum weight is provided with a novel high lift and high lift to drag cross-sectional airfoil shape characterized by a blunt, generally parabolic leading edge portion (10) which fairs into a pressure surface (15) characterized by a leading convex portion (20). For thickness ratios less than approximately 0.15, the pressure surface includes a concave trailing portion (25) at one end thereof, fairing into the leading convex portion (20) and at the other end thereof, terminating at a blunt trailing edge (35). The leading edge portion also fairs into a suction surface (30) which is convex along substantially the entire length thereof to the blade trailing edge.

Abstract: A speed indicator for water vehicles which has a vane wheel transmitter mounted for rotation about an axis is exposed to the extent of one half thereof to the flow of water. In order to obtain a high measurement precision, the vanes of the vane wheel on their outgoing side with respect to the flow are formed with the profile of a convex streamlined airplane wing.

Abstract: Profile design for aircraft lift-wings in general aviation up to flight speeds of about 700 km/h, the profile design being determined by the path of the center line with a forward (first) and rear (second) camber maximum and with a profile droplet superposed on the center line and of a specific thickness distribution, and by the design of the profile nose to have a relatively small nose radius and relatively strong camber.

Abstract: The present invention relates to turbine blades and in particular to turbine blades for use in gas turbine engines. Tensile stresses are introduced into turbine blades when they rotate at high speeds on a turbine rotor. In order to minimize the stresses in an outer skin of an aerofoil of the turbine blade, the outer skin is secured to a platform and an inner core, and in operation a temperature difference is set up between the outer skin and the inner core. The temperature difference produces a thermal compressive stress in the outer skin which opposes the tensile stress produced due to the rotation of the turbine blade. The extremities of the outer skin may be secured to the platform with either a tensile or compressive prestress depending upon the temperature difference between the outer skin and inner core at normal operating conditions.

Abstract: An improved hydro-turbine having a casing with an inlet port and an outlet port. A driveshaft is journaled in the casing and a rotor is secured to the driveshaft. The rotor has a cylindrical member whose radius is at least greater than 50 percent of the radius of the peripheral wall casing. A plurality of vane members extend outwardly from the outer radial surface of the cylindrical member. The vanes are spaced around the perimeter of the cylindrical member and each vane has a front surface and a rear surface. The front surface is substantially flat and the rear surface is convex in cross-section. The bottom edge of the rear of each vane is located substantially adjacent the bottom edge of the front surface of the adjacent vane member. The vane members extend substantially across the entire width of the cylindrical member.

Abstract: This invention is an airfoil which has particular application to the blade or blades of rotor aircraft and aircraft propellers. The airfoil thickness distribution, camber and leading edge radius is shaped to locate the airfoil crest at a more aft position along the chord, and to increase the freestream Mach number at which sonic flow is attained at the airfoil crest. The upper surface of the airfoil has a general reduction in the surface slope back to the maximum ordinate which is about 40 percent of the airfoil chord. The reduced slope causes a reduction in velocity at the airfoil crest at lift coefficients from zero to the maximum lift coefficient. The leading edge radius is adjusted or shaped so that the maximum local Mach number at 1.25 percent chord and at the designed maximum lift coefficient is limited to about 0.48 when the Mach number normal to the leading edge is approximately 0.20.

Abstract: A low drag surface comprises at its upstream edge an intermittent linear vortex producing means extending transverse to the flow of fluid across the surface. The vortex producing means produces a succession of rolling vortices which roll across the surface reducing the drag between the main flow and the surface.

Abstract: A flow directing assembly 14 having an airfoil section or shape 28 of the type adapted for use in an axial flow gas turbine engine is disclosed. The cambered meanline MCL of the airfoil shape is formed of a front circular arc FA and a rear circular arc RA. A thickness distribution TD is applied to the meanline to form the convex suction surface 20 and the concave pressure surface 22. The airfoil section exhibits good aerodynamic performance as compared with an equivalent circular arc airfoil in a transonic flow field. A method for making the airfoil shape is disclosed. The method includes the steps of: forming a cambered meanline of two circular arcs; forming a thickness distribution about the conical chord line B.sub.t ; and applying thickness distribution to the cambered meanline such that a portion of the suction surface is stretched and a portion of the pressure surface is compressed.

Abstract: Disclosed is a two step process of peening for workpieces having small radii fillets or fragile edges, such as gas turbine airfoils have. In the first step, relatively small size shot of less than 1 mm dia is used to impart a first peening intensity to a workpiece. This results in a first relatively rough surface finish. In the second step, shot of substantially uniform diameter in the range 1-2.5 mm is impacted with uniform velocity to provide a surface finish smoother than 30AA (10.sup.-6 inch). When fillets are peened, improved fatigue life results from the duplex process. When used on edges, where direct edge impact is avoided in the second step, deformed edges are avoided by the process. Yet the workpiece is substantially smooth and the edges have the requisite residual stress distribution.

Abstract: A helicopter rotor blade is disclosed having a root end for attachment to a rotor head, a tip end defining the end of the blade fartherest from the root end with a central portion of aerofoil section extending between and attached to the root end and the tip end to define a rotor radius wherein an outboard region of the central portion has a negative basic pitching moment coefficient of absolute value not less than 0.02 and an inboard region having a basic pitching moment coefficient more positive than that of the outboard region.

Abstract: The present invention relates to a blade section for rotating wings of an aircraft comprising, between the leading edge and the trailing edge, a convex lower surface and an upper surface which is convex over the greater part of its length, but concave near the trailing edge. According to the invention, the upper surface of the section comprises a region of small extent, close to the leading edge but not contiguous thereto, in which the curvature is substantially constant. The invention is applicable to the improvement of the performances in maneuvering flight, while hovering and in advance flight of the aircraft.

Abstract: This invention is an airfoil which has particular application to the blade or blades of rotor aircraft such as helicopters and aircraft propellers. The airfoil thickness distribution and camber are shaped to maintain a near zero pitching moment coefficient over a wide range of lift coefficients and provide a zero pitching moment coefficient at section Mach numbers near 0.80 and to increase the drag divergence Mach number resulting in superior aircraft performance.

Abstract: A fluid propeller fan useful as but not limited to an air-circulating cooling fan for an automotive engine, wherein each of the vanes of the fan has a pitch angle which is gradually reduced from the tip or an intermediate portion toward the radially innermost end of the vane so as to provide an increased draught volume and improved draught flow characteristics.

Abstract: In a lateral channel pump, the rotor blade compartments of a ring of blades in the rotor alternate in length, toward the center of the rotor, between long and short rotor blade compartments. The associated lateral channel has an outer contour concentric with the center of the rotor and an inner contour which tapers helically towards the outlet port. At the inlet point of the lateral channel, a partial circulating current is separated from the main circulating current as a result of the longer blade compartments. The partial current, due to its higher speed, causes the main current to circulate more rapidly between the rotor blade compartment and the lateral channel. As a result, the main current is accelerated and a higher level of efficiency is obtained.

Abstract: The present invention relates to a high performance blade for helicopter rotor presenting an aerodynamic surface produced by profiles of which the aerodynamic twist increases from the end profile towards the root profile and is then reversed and becomes zero at the fastenings of the blade. According to the invention, the angle of twist formed by the zero lift chord C.sub.o of a profile of the aerodynamic surface and a reference plane P passing through the center of the fastenings of the blade to the hub of the rotor, is, for the end profile, at the most equal to a value .theta..sub.1 of 0.3 degrees. The invention is more particularly applied to the obtaining of rotary wings, for example for helicopters, capable of very high performances, particularly in rapid forward flight under high load.