Abstract: An end closure for honeycomb structures is disclosed. The end closure effectively provides for the sealing of the end of a honeycomb structure in order to prevent moisture from entering and propagating into the structure. The invention includes a structure and method for closing the end of a honeycomb structure with a molded closure. A foam adhesive, in combination with a tape adhesive, forces the tape adhesive to conform to the shape of the irregular honeycomb core, thereby providing an effective bond and seal of the honeycomb face.

Abstract: Helicopter rotor blades require tip weights for spanwise and chordwise bace to assure that all of the blades rotate in the same track. The improved rotor blade tip weight assembly of the present invention comprises an elongated spar, preferably formed of a reinforced plastic, adapted to be connected at one end thereof to a rotor hub. An aft fairing structure is carried by the spar and a balancing weight assembly is bonded and/or cured in place within the spar, proximate the free end thereof. The balancing weight assembly includes, in the preferred form thereof, a fiberglass weight tube housing having a pair of internally threaded weight tubes positioned therewithin. The weight tubes form bores having longitudinal axes in a common, substantially horizontal plane, and the axes each extend in a direction parallel to the axis of the spar. One or a plurality of externally threaded cylindrical weights are locked in each weight tube during balancing of the rotor blade.

Abstract: A simplified layup mandrel with no contour or twist is utilized by the method of this invention for forming the spar member of an aerodynamic rotor blade. A fiber glass tape is wrapped (laid-up) to a desired thickness onto the simplified mandrel to form a strap as the initial step. Because of the simple design of the mandrel, the laid-up strap when removed from the mandrel has a basic U-shaped configuration with straight extending legs having substantially parallel vertically oriented faces. This strap is then placed on a forming mandrel and contoured to the desired shape either by hand or by coining in a forming die. The contoured strap is then utilized in any of the various subassemblies or final assembly of the composite aerodynamic rotor blade.