Abstract: A tilting rotor of a convertible aircraft comprises, between the mast and the hub, a constant velocity drive mechanism and pivoting arrangement comprising two gimbals, each of which is driven by the mast and pivots about one respectively of two diametral axes by two diametrically opposite bearings. Each gimbal is also hinged to the hub by ball joint connections diametrically opposite and centred respectively in a radial plane passing through the axis of the mast and through the diametral axis about which the other gimbal pivots. The two resulting trains transmitting torque between the mast and the hub have substantially the same torsional rigidity, and one at least of the components of each torque transmission train exhibits a flexibility in deformation about the axis of rotation of the hub.

Abstract: A power plant for propeller aircraft has two propulsion devices, each having a propeller, an engine for powering the propeller, and a gear transmission interposed between the engine and the propeller. The transmission has a power input shaft connected directly to the engine, and a power output shaft supporting the propeller and rotated with respect to the input shaft about a hinge axis perpendicular to the output shaft. The gear transmission also has a single gear fitted to the output shaft and having two opposed sets of teeth meshing with a pair of pinions. One of the pinions extends coaxially with the hinge axis, and is connected to the input shaft by a single pair of gears.

Abstract: An aircraft rotor having a drive shaft, a number of blades extending substantially radially with respect to the shaft, and a constant-velocity transmission connecting the blades to the shaft; the transmission having a hub supported adjustably about a fixed pole, a drive member integral with the shaft, a driven member integral with the hub, and a number of torque transmitters, each connected to a first attachment, carried by the drive member, and to a second attachment, carried by the driven member, by means of a first hinge and a second hinge respectively; the axes of the first hinges and second hinges defining respective planes on opposite sides of and symmetrical with respect to a bisecting plane coincident, in stationary conditions, with the plane of the hub.

Abstract: The anti-vibration suspension device includes at least three diagonal bars each articulated on the transmission box and on the structure by a rigid lever supporting a damping weight itself articulated to at least pivot on this structure, and, for each diagonal bar, a tension bar also articulated on the transmission box and on the structure, the corresponding lever being articulated to the structure being articulated to at least pivot on the lower end part of the corresponding tension bar, which is flexible in tension.

Abstract: A centrifugally activated variable damper assembly for a stopped-rotor aircraft is disclosed for adjusting dampening level of teetering motions produced by the rotors during the in-flight conversion process from rotary-wing to fixed-wing flight, or vise versa. The assembly includes a damper valve responsive to centrifugal forces produced by rotational speed of the aircraft rotor. The assembly also includes dampers within the rotor system that operate at variable damping levels in response to centrifugal forces acting upon the damper valve.

Abstract: A flexible beam rotor assembly for an aircraft includes a rotor spar having an axis of rotation and a hole through which the axis of rotation passes. A spindle has a teetering connection to the rotor spar, the teetering connection having a teetering axis above the rotor spar at the rotor axis of rotation. A spindle housing is nonrotatably mounted to the aircraft and rotatably receives the spindle. The spindle housing and spindle protrude through the hole in the rotor spar and are tiltable in response to pilot control on a left-right spindle pivot axis and a fore-aft spindle pivot axis. The left-right spindle pivot axis and the fore-aft spindle pivot axis are located below the teetering axis and above the rotor at the rotor axis of rotation. A pylon is pivotally mounted to the fuselage for fore and aft movement relative to the fuselage to absorb vibration due to rotation of the rotor during forward flight of the aircraft. The spindle housing is attached to the pylon by a universal joint.

Abstract: A tethered model gyroglider having a fuselage, a rotor support extending upwardly from the fuselage, and a unitary two-bladed rotor rotatably mounted onto the rotor support. A teetering mechanism permits the rotor to pivot about an axis proximate the center of the rotor. When the gyroglider is subjected to a relative wind generally from a forward direction, the forward moving blade of the rotor is raised and the rearward moving blade is lowered. This equalizes the aerodynamic forces about the longitudinal axis of the fuselage, thereby eliminating the tendency of the gyroglider to roll in the direction of the rearward moving blade.

Abstract: An autogyro aircraft has freewheeling rotor blades that provide lift. A separate pusher propeller provides forward thrust. The rotor system (20) has a collective arm (30) as a control for selectively setting and maintaining a tension force on a collective cable to regulate the rotor blade angle of attack or pitch angle between a no-lift attitude and a positive lift angle. The collective arm (30) sets a tension on collective cable against a coil spring biasing. The collective arm is connected to pivot or tilt a pitch change horn assembly and, in turn, connected rotor blades. The collective arm can be selectively set and maintained and released and reset both on the ground and in flight.

Abstract: A portable wind machine comprising a vehicle movable along the ground and a support carried by the vehicle and extending upwardly substantially above the vehicle. A transverse member is coupled to the support at a location substantially above the vehicle, and it extends transversely of the support on both sides of the support. The transverse member is pivotable between a travel position in which the transverse member extends generally along the vehicle in generally a direction from fore to aft of the vehicle and an operational position in which the transverse member extends laterally of the vehicle. First and second propellers are mounted on the transverse member on opposite sides of the support for rotation about first and second rotational axes, respectively. A tilt angle between each of the rotational axes and a vertical plane is adjustable. At least one power source is provided for rotating the propellers.

Abstract: Mechanism for controlling pitch changes in helicopter blades, related to the helicopter mast and connected to a lever assembly mounted into the structure, having a pair of command arms, the assembly comprising first and second bars, related by rocker arms, for selective transmission of cyclic and collective pitches.

Abstract: A controllable lifting rotary wing for an aircraft wherein each rotor blade is of torsionally flexible construction and control may be accomplished by twisting the rotor blades. The root end of each blade is mounted to a central hub by means which allow both beamwise flapping and blade twist. The blade root mounting angle may be either variable or fixed. The blade twists uniformly from this root angle to a variable tip angle. Twist of the rotor blades is accomplished through the mechanism of shear flows. Blade twist angle may be automatically established by a balance of dynamic forces on the blade which cause twist angle to increase as root mounting angle is increased. Alternatively, blade twist angle may be manually controlled also. A unique feature of the torsionally flexible blade is that it is hollow throughout its entire span so it is well suited for ducting gases through the interior of the blade to tip-mounted jet propulsion units if desired.

Abstract: A high-capacity elastomeric combination journal-thrust bearing comprises at least one encapsulated lobe. The encapsulated lobe comprises an outer tubular member having a first ring joined along substantially all of its outer periphery to the inner periphery of the outer tubular member at a first end and having a second ring joined along substantially all of its outer periphery to the inner periphery of the outer tubular member at a second end. The encapsulated lobe further comprises an inner tubular member having the same longitudinal axis of the outer tubular member, and having a third ring joined along substantially all of its inner periphery to the outer periphery of the inner tubular member, spaced between the first and second rings. An elastomer separates and joins the rings to each other and to the tubular members, and the tubular members to each other. As the radial distance from the longitudinal axis increases, the thickness of the elastomer increases.

Abstract: A helicopter tail rotor (10, 130) includes a drive mast (12) having an axis of rotation (14). A first blade pair (20) is mounted for rotation about the drive mast (12). The first blade pair (20) includes a pitch change axis (54) perpendicularly disposed to the drive mast axis of rotation (14). A second blade pair (34) is mounted for rotation about the drive mast (12) and is spaced apart from and parallel disposed to the first blade pair (20). The second blade pair (34) includes a pitch change axis (60) parallel to the pitch change axis (54) of the first blade pair (20).

Abstract: A rotor system according to this invention includes a structurally flexible rotor shaft for transmitting rotor torque and other rotor loads to a rotor hub. The rotor hub is adapted to have rotor blades mounted thereon and is mounted by an elastomeric spherical bearing whose center is located at the rotor center. A flexible shaft made from fiber reinforced resin matrix material, connected to the rotor shaft at a connection located below the bearing center, extends vertically from that location through the bearing to a position located above the bearing center where it is connected to a connecting member fixed to the upper surface of the rotor hub.The flexible shaft is structurally stiff with respect to the mode in which it transmits rotor torque compared to the rotor torque stiffness of the other components.

Abstract: Apparatus is provided for protecting crops such as fruit tree groves from frost damage in the form of a vertical tower fixed to the earth against gyration, a rotor on top with two airfoil blades extending upward at a conical angle and drive means drivingly connected to the rotor through a vertical shaft, said tower projecting substantially above the level of the trees to be protected and sufficient to pick up air in the inversion layer and deliver it to the ground in a generally cylindrical mass to provide a ground effect causing the air to spread out radially along the surface beneath a grove's foliage and then flow upwardly through the foliage.

Abstract: An autogyro has rotor blades carried by a rotor head mounted on a support member (10) rotatable about a pitch axis (18) and independently rotatable about a roll axis (22) for control of the autogyro in pitch and roll respectively. The pitch and roll axes intersect one another in order to overcome the problem of rotation about one axis affecting the radius of rotation about the other axis. Means are provided to prevent rotation of the rotor head and support member about an axis orthogonal to both the pitch and roll axes.

Abstract: In a variable pitch wind turbine system, pitch angle is determined by a pneumatically pressurized hydraulic actuator connected between crank arms on the blade pitch axles. The hydraulic line extends coaxially through the rotor drive shaft via a rotary union to a gas charged accumulator on the yaw carriage. The pitch axes are positively coupled for 1:1 counter-rotation by a gear train, preferably lying on the opposite side of the rotor axis from the hydraulic actuator.

Abstract: A two-bladed aircraft rotor is disclosed having blades mounted for freedom of blade motions, at least in the flapping sense and in the pitch-change sense, with the blades driven by flexible bellows.

Abstract: The invention provides a balance bar twin blade hub. A beam is formed of a tube made from a composite material of evolutive form whose section is cylindrical at its end on the blade side and progressively elliptical as far as its central connection part. It is connected to a support stirrup 2 conical stratified stops 4 forming balance bar bearings identical to the conical stratified stops forming the centrifugal force take up and angle of attack bearings providing the connection between the blade 16 and the beam.

Abstract: A collective pitch change system for gyroplane rotary wing aircraft is provided. The system is particularly adapted for teter-bar rotors and is simple and direct. The system can change the blade pitch while the rotor is rotating to permit jump take-offs.

Abstract: A one piece fan blade for a wind machine is sandwiched between a hub and a plate, the fan blade and the hub and is secured thereto by a teeter pin extending through the bore from opposed passageways in the hub. The shaft is centered in the bore of the hub to permit tilting of the hub about an axis coincident with the teeter pin to an angle commensurate with the spacing intermediate the shaft and the bore. Apparatus at the extremities of the teeter pin reduce wear on the teeter pin retaining plates and contribute to lubrication of the opposed journals.

Abstract: A high speed helicopter, ideally suited for use with rotors which are tip propelled, has an offset flapping hub mounted on a tiltable mast which is located a substantial distance off to the retreading blade side of the fuselage of the helicopter. This causes the fuselage to be located completely under the advancing blades. Individual pitch control motors individually vary the pitch of the rotor blades to control the feathering angle as a function of the angular position so that lift is obtained from the advancing and laterally moving blades only.

Abstract: A riding-type surface working machine includes a pair of rotors each of which carries a plurality of trowels or surface working members. Each rotor includes a transmission unit and power from the engine is transmitted through each transmission unit to rotate the individual rotors. To provide directional movement for the machine, the upper end of each rotor includes a shaft that is connected to the respective transmission unit. The shaft is mounted for universal tilting movement with respect to the frame of the machine. An eccentric is mounted on each rotor shaft and is rotatable in a fixed sleeve. Each eccentric is connected through a chain drive to a vertical control stick and the control sticks for the respective rotors are mounted concentrically on the machine. Through manual operation of the control sticks the eccentrics can be individually rotated to thereby tilt the rotors to cause directional movement of the machine.

Abstract: A bladed aircraft rotor is disclosed having blades mounted by means of flexible devices providing freedom for blade motions, at least in the flapping sense and in the pitch-change sense, without employment of flapping or pitch bearings or pivots, the rotor also being provided with a central bearingless joint for transmitting thrust forces while providing freedom for angular movement of the rotor as a whole about a center point on the axis of rotation. A constant velocity torque-transmitting system is also provided.

Abstract: A helicopter has a low profile electric motor mounted in each of the rotor blades to drive a cross-flow fan which draws air in through a slot at the leading edge of the blade and forces it out through an opposing slot adjacent the trailing edge of the blade to provide the thrust for rotating the rotor blade. An engine is located in the fuselage of the helicopter for driving an electric generator to produce the electricity supplied to the motors mounted in the blades. In addition, yaw control is achieved without the necessity of tail structure or a tail rotor using a small electric motor driving or absorbing power from the main rotor shaft. Both the yaw control motor and the main rotor shaft tilt together as a rigid unit. Pitch and roll control is achieved without the necessity of aerodynamic surfaces by movement of the main rotor support mast about a gimbal bearing support located above the center of gravity of the helicopter.

Abstract: A universal joint for use in a pitch cone rotor system in a helicopter is comprised of crossed lift beams, one beam of which is coupled to the rotor hub and the other beam of which is coupled to the driven rotor shaft. The two crossed lift beams are coupled to each other through a cruciform case. The cruciform case in turn is coupled to each of the crossed lift beams by means of a plurality of flexures. The flexures and cruciform case are made of composite fiber materials and the flexures are soft enough to permit angular and translational deflections of the crossbeams with respect to each other thereby tending to smooth out and reduce sudden changes in rotor speed between the shaft and rotor system and thereby tending to make rotor speeds more uniform. The crossed lift beams are further coupled together at the center of their crossing by a flexible elastomeric tension link which conducts rotor loads between the two beams when the rotor develops negative lift loads on the ground and in flight.

Abstract: A one piece fan blade for a wind machine is sandwiched between a hub and a plate. A rotatable shaft penetrably engages a bore extending through the plate, the fan blade and the hub and is secured thereto by a teeter pin extending through the bore from opposed passageways in the hub. The shaft is centered radially inwardly in the bore of the hub between opposed journals extending radially inwardly into the bore from the opposed passageways to permit tilting of the hub about an axis coincident with the teeter pin to an angle commensurate with the spacing intermediate the shaft and the bore.

Abstract: Rotor tilt is permitted by two spherical elastomeric bearings, one above a hub member and one below, that have coincident centers at a tilt point (P) on the rotorshaft axis which is below the rotor plane. Positive rotor thrust is reacted by the upper bearing and negative rotor thrust is reacted by the lower bearing. Techniques for assembling the rotor system, precompressing the bearings, and limiting tilt are also disclosed.

Abstract: Hub moment for a tilt rotor is provided by U-shaped springs that extend outwardly from the rotorshaft and in-plane with the tilt point (P) and inwardly to the tiltable hub member in the rotor plane, which is above the tilt point (P). Driving torque is supplied to the rotor via a torque disc that has a resilient diaphragm portion attached to the rotorshaft in-plane with the tilt point (P) and a rigid rim attached to the tiltable hub member in the rotor plane. The torque disc comprises the lower half of an aerodynamic fairing which encases the hub.

Abstract: This invention relates to a system for mounting a helicopter rotor on a flapping axis and, more particularly, to use of an improved unitary trunnion-bearing structure of minimal parts which may be selectively preloaded and which is readily installed.

Abstract: This invention is directed to helicopter rotor hubs which includes an elastomeric material between an inner and outer hub. The inclusion of elastomeric material transmits torque, thrust and in-plane loads and is flexible in the tilt direction.

Abstract: A helicopter rotor hub for use in an air-driven helicopter comprises a section of a spherical stainless steel ball attached to the end of a hollow rotor shaft. An air compressor within the helicopter supplies air to the hollow rotor shaft which discharges through it to hollow rotor blades which have discharge nozzles at the trailing edges on their tips. The sole support bearing for the blades is in the form of a cup-shaped concave graphite bearing which engages the stainless steel ball and to which the rotor blades are attached. The graphite provides a lubrication-free bearing surface and also provides a seal against air leakage.

Abstract: A countertorque rotor for helicopters in which a transmission shaft keyed transversely onto a drive shaft and disposed obliquely within a hub has each of its ends coupled in a slidable manner within an inner bush of an associated elastomeric coupling this latter carrying screw actuator means which can act axially on the said shaft to displace the said hub with respect to the shaft (3) itself in the direction of the axis of this latter.

Abstract: An aerogenerator is provided with a rotor attached to one end of a variably orientable axis. The axis is, in turn, attached to apparatus for either using the energy produced by the rotatable rotor or apparatus for transforming the energy produced by the rotor. The apparatus includes a system for regulating the velocity of rotation of the rotor as either a function of the force of incident wind on the rotor or as a function of the value of energy which is desired to be produced by the aerogenerator. The system includes a device for automatically controlling the angular movement of the axis as well as a device for measuring the velocity of the rotation of the rotor, whereby the axis can be inclined so that a substantially constant rotational velocity is achieved.

Abstract: A system for opposing helicopter blade flapping applies restraining forces at a low spring rate at low flap angles and at a high spring rate at flap angles greater than a predetermined angle. More particularly, bearings rotatably support the blade yoke on rotor hub trunnions which form a flapping axis. A resilient mechanical coupling between the blade yokes and the hub trunnion applies a restraining force having a characteristic linear with flapping angle. A second restraint mounted to rotate about the flapping axis with the rotor, applies a nonlinear restraining force which preferably rapidly increases beginning at a predetermined flap angle, and over the range short of hard flapping contact between the rotor and the rotor mast.

Abstract: A helicopter including a driven rotor assembly provided with a hub having oscillatable rotor blades extending outwardly therefrom and axially spaced portions of the hub having outer peripheral portions of a pair of annular flexible and elastic supporting diaphragms anchored relative thereto. Inner peripheral portions of the diaphragms are deflected and stretched toward each other and anchored to a supporting flange carried by a central rotary drive shaft of the rotor assembly. A sleeve is longitudinally shiftably mounted on the shaft below the rotor assembly and supports, through the utilization of a flexible and resilient diaphragm, a larger sleeve structure therefrom for universal angular displacement of the sleeve structure relative to the sleeve. The sleeve structure includes control arms operatively connected to the rotor blades for oscillation of the latter in response to axial shifting of the sleeve structure relative to the sleeve.

Abstract: A hingeless helicopter rotor including an aerodynamically shaped hub having a flexible diaphragm as its bottom wall, which diaphragm is connected to the rotor drive shaft and is elastically deformable in response to blade loading to tilt in any direction with respect to the axis of rotation, and further having at least three equally spaced helicopter blades projecting from and supported from within the hub for rotation therewith and for flexing with respect thereto in response to blade loading so that the flexible hub and the blades coact to produce a low equivalent offset rotor and minimized Coriolis effect.

Abstract: A yoke for coupling helicopter blades to a mast is provided. The yoke comprises a long oval loop of glass fibers embedded in a cured adhesive to form a solid strap. The side portions of the loop are reinforced with layers of bias ply glass fibers arranged in parallel planes. Structure is provided to couple to the side portions of the loop for attachment to the mast.

Abstract: For a watercraft which may be a powered craft or a sailboat with an auxiliary engine, a propeller which will pivot relative to its propeller shaft about an axis extending transversely of the propeller shaft so that the propeller retracts into general longitudinal alignment with the propeller shaft. The propeller includes two blades fixed to each other as a unit with a pivot pin passage formed at the juncture of the two blades. In one preferred form, one of the propeller blades is made larger than the other with the smaller blade positioned rearwardly in relation to the pivot pin passage and the larger blade forwardly of the passage. Furthermore, in this embodiment, the pivot pin passage extends at a relatively slight teetering angle to a plane extending perpendicular to the propeller shaft axis.

Abstract: An improved rotor hub and seal assembly for a rotor-craft such as a helicopter includes an improved tri-hinge rotor and an improved oil seal assembly for the rotor pitch bearings. The rotor blades are mounted to the underslung hub by coning hinges, offset from the teetering hinge to which the rotor shaft is attached, so that the stabilizing centrifugal force is always greater than the destabilizing moments. The rotor also includes a teeter hinge restraint, while the oil pitch bearings are sealed by a boot-type seal to permit angular movement of the outer blade root housing relative to the bearing spindle resulting in shear rather than tension on the boot.

Abstract: The present invention relates to a rotor arrangement for rotary-wing aircraft, comprising at least one pair of opposite blades mounted on a common one-piece beam, which is twistable, flexible and whose median part rotates with the shaft of the rotor.According to the invention, this arrangement is characterized in that said beam is mounted on the shaft of the rotor by means of an articulation enabling it to pivot, in limited manner, about an axis transverse to said beam and at right angles to said rotor shaft.The invention is applied to rotors for helicopters.

Abstract: A vertical takeoff and landing airplane has a plurality of rotors which are positioned selectively about the center of balance of the airplane so that it can hover upon failure of any one of the rotors. Each rotor is driven by an associated steam propulsion unit and the rotors and propulsion units are constructed so that they may be tilted about their lateral axes from vertical lift positions to horizontal propulsion positions while the airplane is in flight. The working fluid upon which the propulsion units operate is supplied from two or more combustion centers which are separated from the propulsion units, and which produce a high pressure steam-combustion product mixture, automatically at a constant pressure, which is routed to a common pressure system for powering the individual propulsion units. Should one of the fuel combustion centers fail, the steam pressure requirements are provided for automatically by the remaining fuel combustion centers.

Abstract: A damping mechanism is disclosed for damping the oscillations of the rotor hub which are coupled with periodic motions of the fuselage when on the ground, known as ground resonance, and a waddle when in the air. The rotor includes a freely tiltable rotor head mounted on a non-rotatable universal joint having an outer gimbal ring and an inner ring carried by a pylon. The damping mechanism connected between a gimbal ring and the pylon combines the action of a fluid dashpot in tandem with spring means the output of which is connected into the linkage between the pilot stick and the swash plate. The tandem combination of dash pot and spring means delays the signal to the swash plate by about 90.degree. to insert a corrective movement into the swash plate with feathering of the blades to tilt the rotor thrust vector which damps the oscillations of the rotor hub. The invention includes the damping mechanism per se and its combination with the rotor and with the swash plate.

Abstract: A helicopter fuselage is coupled to a pylon to permit fore/aft pivotal movement of the fuselage relative to the pylon with resilient means connected between the pylon and fuselage to oppose and limit such pivotal movement. Structure is then provided to decouple the rotor control linkages to permit limited fore/aft rotation of the fuselage relative to the pylon upon change of location of the center of gravity without introducing control motion in the control linkages. The control linkages include control tubes extending longitudinally of the fuselage from a pilot input location. Bell cranks are connected to the control tubes and are coupled as to control the pitch of rotor blades. Structure connecting the fuselage and each bell crank alters the pivot points of the bell cranks relative to the fuselage. The positions of the bell crank pivot points depend upon rotation of the fuselage relative to the pylon.