Abstract: An improved droop stop for a fully articulated helicopter rotor is provided herein curved mating surfaces are employed between the spindle pad and the centrifugal droop stop static support arm to provide surface rather than line contact therebetween during centrifugal operation. The centers of the curved surfaces are coincident at the pivot point of the droop stop centrifugal arm to force the downward load of the blade to pass through this pivot point.

Abstract: A method and apparatus for using pressure changes to indicate volume chan in fluid level indicators or other devices with the required degree of sensitivity and accuracy is provided. A change in fluid volume is indicated by detection and display of a concurrent pressure change in a captive volume of air.

Abstract: In a helicopter rotor in which the blades are supported for rotation and articulation from the hub by elastomeric bearings and including a lead-lag damper which acts to cause radially inward blade motion during rotor braking and including the improvement of utilizing members which move pivotally in response to centrifugal force and which serve blade flapping and droop stop functions both statically and dynamically and which further are programmed as a function of rotor speed to prevent or limit radial inward motion of the blade during the rotor braking operation.

Abstract: A helicopter rotor head mounting assembly includes a rotor drive shaft and rotor hub splined to the shaft for rotation therewith. The rotor hub includes a central bore having an internal tapered portion which is forced downwardly upon a mating tapered portion of the rotor drive shaft. An annular split cone is mounted between the rotor shaft and the hub at a bottom portion of the hub bore and the split cone is forced upwardly into firm engagement with the hub and drive shaft by means of a plurality of individual loading means which are carried by an annular plate affixed to the bottom of the hub. The loading means are individually adjustable and apply loading force directly onto the split cone to thereby assure a secure, non-vibrational rotation of the hub with the rotor shaft.

Abstract: An elastomeric bearing for a helicopter rotor in which the laminates of the bearing are shaped and positioned so that the center of hydrostatic pressure generated in each elastomer laminate and the cross-sectional center of gravity of each metal laminate are in alignment so that the integrated load vectors reacted through the metal and elastomer laminates of the bearing in imparting blade centrifugal loads to the hub therethrough are substantially in alignment to thereby prevent the creating of eccentric internal moments and hence avoid life reducing bending and hoop stresses in the metal laminates and unnecessarily high hydrostatic pressures in the elastomer laminates.

Abstract: A fully articulated helicopter rotor having an elastomeric type main bearing which is reactive of all blade motions about the intersecting blade pitch change, lead-lag, and coning axes, including blade droop supporting and limiting members for static and dynamic operating conditions wherein coupling influences between the separate blade motions are precluded. In reacting these blade weight loadings and dynamic thrust forces, the droop members specifically provide full area contact bearing surfaces to distribute the large forces from the blades into the rotor hub proper while avoiding scuffing or rolling contact between the parts, and the high bearing stresses which would result from either point or line contact only.