United Technologies Corporation

Sikorsky Aircraft Corporation

Kenneth M Nowak

William V Forster

Darryl Mark Toni

Larry J Osiecki

Peter L Grant

Stephen R Norko

Steven R Hayse

Craig F Johnson

Method for making honeycomb core composite articles

A duct cover for use with a duct within a vehicle, the duct cover operative for directing a fluid flow. The duct cover being further operative for minimizing the entrance of foreign object debris into the duct. The duct cover has a flow directing honeycomb portion for conducting the passing fluid flow in a preferred direction. The flow directing honeycomb comprises an array of continuous, polygon shaped open cells which are biased with respect to the initial fluid flow direction. The periphery of the flow directing honeycomb is rigidized to stiffen the same for minimizing the displacements thereof. The rigidity is provided by a framing member comprising upper and lower skin structures affixed to a core material. The framing member is preferably adhesively bonded to the flow directing honeycomb by means of a foaming adhesive and a barrier member. The barrier member is operative for minimizing the expansion of the foaming adhesive into the open cells of the honeycomb. In order to improve the low observability characteristics of the structure, the cells of the flow directing honeycomb are preferably coated with a radar absorbent material, such as carbon, which acts to minimize the amount of electromagnetic energy that is reflected therefrom.

Duct cover for directing a fluid therethrough

A composite sandwich structure which includes upper and lower skin structures, first and second honeycomb core structures, and an intermediate portion disposed between the first and second honeycomb core structures. The intermediate portion comprises a composite laminate, a barrier member and a foaming adhesive layer disposed between the composite laminate and the barrier member. The foaming adhesive layer is of a type designed to expand when exposed to an elevated temperature. The composite laminate and the barrier member operate to limit the expansion of the foaming adhesive layer into the open cells of the first and second honeycomb core structures. The foaming adhesive layer, upon expansion, applies pressure against the composite laminate. This pressure, acting concomitantly with the applied curing pressure and the elevated temperature, cures the laminate. Furthermore, the expansion of the foaming adhesive urges the composite laminate and the barrier member apart so as to fill any core discrepancies, i.e., mistrimmed or damaged core, that may exist in the honeycomb core structures.

Complex composite sandwich structure having a laminate and a foaming

A selectively-flexible, selectively-rigid, reusable, one-piece mold is used to fabricate a composite part having a complex shape on an outer surface of the mold. Disposed within the interior of the shell is a grid-type support truss structure having a plurality of individual support members attached at one end to headers that are attached by clips to the inside surface of the shell at predetermined locations. The support members are locked in place relative to each other by the use of pins placed in holes formed at various locations in the support members. When locked in place in this manner, the shell is stiffened, thereby facilitating the fabrication of the composite part on the mold. When the pins are removed, the shell is allowed to flex, thereby facilitating the removal of the cured composite part from the outer surface of the mold.

Selectively-flexible mold having a shell supported by a collapsible

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Easton, CT, United States of America

Kenneth M Nowak