Abstract: An all-composite article comprising two composite parts pivotally joined by a composite hinge which is fabricated integrally therewith. The method of making such an all-composite article.

Abstract: A flexbeam helicopter rotor having an improved connection between the flexbeam and the hub of the connecting pin variety but in which the high tensile fibers of the flexbeam do not wrap around the connecting pin, wherein the blade centrifugal loads and the blade lead-lag loads are reacted by the connecting pin at a station where it passes through drilled holes in the flexbeam inner end, and wherein the blade flapping motion imposed loads are reacted through two load paths in the flexbeam-to-hub connection, the first load path being created by a prying reaction between the flexbeam and the hub connecting flanges, and the second load path being created by the differential bending reaction between the flexbeam at the station of the drilled holes and the connecting bolts.

Abstract: A structural member made up of a plurality of bonded plies of high tensile strength woven fabric and molded to include at least one stiffener bead having elliptically shaped ends, and a structural part so fabricated.

Abstract: The method of fabricating selectively shaped dog-leg plies of composite material comprising unidirectionally extending high tensile strength fibers or filaments extending for the full length of the ply and embedded in a resin matrix comprising winding high tensile strength filament onto a mandrel of generally cylindrical shape but having circumferentially extending frustoconical projections extending radially therefrom so that the filament wound onto the cylindrical portion of the mandrel forms the straight legs of the dog-leg ply and so that the filament wound on the frustoconical projection of the mandrel form the arcuate central portion of the dog-leg ply.

Abstract: A helicopter collective control stick having a pilot grip positioned by a linkage assembly whose kinematics permits the control stick to occupy a small envelope and to have the pilot grip motion to be about a large radius. Our collective stick includes a biasing member to balance the control stick and linkage in the mid collective position and which provides a force gradient when the control stick is moved from the mid collective or trimmed position. Further, our collective stick is operable in concert with the full authority side arm controller to operate in either a tracking or a command mode.

Abstract: An unmanned flight vehicle wherein two counter-rotating rotors are positioned within a toroidal fuselage and in which rotor pitch solely is utilized to generate all required lift, pitch, roll, yaw and vibration and stress control for the vehicle.

Abstract: A retractable helicopter rotor in which the rotor and its blades, the swashplate and the pitch change rods are retracted and extended as a unit during the helicopter rotor retraction/extension mode of operation, wherein the connection between the rotor support system and the fuselage constitutes a single interface between overlapping circumferentially extending flanges of each, and with the bolts joining those flanges being loaded in compression.

Abstract: A tool mountable on a helicopter blade for selectively bending the trailing edge trim tab of the blade about a selected axis along the span of the trim tab, and including a device to counterbalance the weight of the trim tab bending mechanism so that the true degree of bending of the trim tab can be determined at any time during the bending operation. The tool also includes apparatus for simultaneously calibrating the counterbalance device and the mechanism used to measure the degree to which the tab has been bent, prior to commencing the bending operation.

Abstract: The method of manufacturing a multi-legged (preferably five) flexbeam for a hingeless flexbeam helicopter rotor, which flexbeam is of one-piece construction and made solely of composite materials, and includes full length plies of unidirectional high strength fibers extending from a first leg and splitting in passing through the hub portion of the flexbeam, and then extending into two substantially diametrically opposite legs, and having cross and unidirectional plies interspersed between the full length plies to effect the desired taper and shape of the flexbeam hub and legs, and wherein the final ply lay-up is made on a rotatable lay-up tool of dodecahedron shape.

Abstract: A fixed frequency vibration absorber adapted to be fixedly mounted in a fixed vibration prone system. The vibration absorber is of the pendular-type with two dynamic masses suspended in pendular fashion from a base member, and with at least one coil spring acting upon the masses to establish and linearize the vibration absorber natural frequency.

Abstract: A variable frequency vibration controller includes a cantilever beam supported from the vibration prone structure whose vibrations are to be controlled. The cantilever beam has selectively shaped hollow interior portions into which fluid can be selectively injected or withdrawn to vary the total mass of the cantilever beam. The cantilever beam natural frequency is thus tuned to match or selectively mismatch the frequency at which the vibration prone structure is vibrating. Thereby, the beam is used to optimally absorb or excite the vibrations of the structure.

Abstract: A helicopter rotor having blade trailing edge tabs which are actuated in response to control rod loading to reduce or cancel the blade pitching moments imposed upon the blade and hence the control rods by blade aerodynamic and inertial loads, or other loads, encountered during rotor operation.

Abstract: An improved jam-proof control including a cylinder-piston assembly in which the piston is controllably positioned within the cylinder to perform the control function and in which the cylinder snugly envelopes a deformable sleeve so that when the cylinder is deformed by sharp impact, the piston is permitted to continue to reciprocate within the cylinder due to the deformation, either due to frangibility or softness, of the sleeve.

Abstract: A rigid soundproofing panel is supported from a vibration-prone wall through a support system which includes an elastomeric plate isolator of selected spring rate to tune the suspension system so that minimal wall vibrations are imparted to the soundproofing panel, and a second elastomeric member in parallel with the first in the form of an acoustic edge seal extending between the wall and the soundproofing panel throughout the full periphery of the soundproofing panel so as to prevent acoustic flanking therebetween and being of substantially reduced spring rate as compared to that of the elastomeric plate isolator so as not to interfere with system tuning.

Abstract: A helicopter rotor blade to hub arm attachment configured to react centrifugal loads from the blade through a blade cuff, spindle, and elastomeric bearings utilizes a bolt in the bore of the spindle for secondary load path operation and a spindle integrity monitoring indicator to provide a visual showing of a deviation from the normal load path.

Abstract: To provide the pilot with the "feel" that he is inadvertently moving his cyclic control stick from its midposition when the helicopter is on the ground, and thereby possibly changing the rotor plane from a safe to an unsafe position for ground personnel, a restraint member is provided which includes an over-center spring, and which may be pivoted from its stowed position into an operable position where it bears against the cyclic stick so midpositioned. The over-center spring thereof offers resistance to cyclic stick motion if the pilot inadvertently begins to move the stick forward or laterally of its midposition, but the spring biasing force can readily be overcome by the pilot by manually pushing the cyclic stick forward and thereby cause the restraint member to move to its stowed position.

Abstract: A vibration isolation system in which a supported body is supported from a vibration excitation body which is prone to vibrate at a predominant frequency and to impart such vibratory forces and motions to the supported body. The isolation system is of the antiresonant type and operable to provide vibration force and motion isolation of the supported body from the vibration excitation body both axially along and rotationally about three mutually perpendicular axes, thereby giving the supported body six degrees of vibration isolation from the vibration excitation body.

Abstract: A helicopter rotor blade to hub arm attachment configured to react centrifugal loads from the blade through a blade cuff, spindle, and elastomeric bearings utilizes a pre-loaded bolt through the spindle for load sharing therewith and a spindle integrity monitoring indicator to provide a visual showing of a deviation from the normal load sharing proportion.

Abstract: A variable frequency vibration absorber adapted to be fixedly mounted in a fixed vibration prone system to coact with the system principal vibration excitation source to control system vibration. The vibration absorber is bifilar in construction and the natural frequency thereof is varied in proportion to the frequency of the vibration being generated by the principal system excitation source.