Design of Cocured Multiple Cell Composite Structures

Sikorsky has developed four major cocured multiple cell assemblies for both military and commercial applications. The External Stores Support System (ESSS) and External Tank Support (ETS) two cell structures were designed to carry external fuel tanks for the BLACK HAWK and NIGHT HAWK military aircraft. A three-cell wing flap has been developed for the Cessna Citation s/II and a vertical fin four cell structure is presently being designed for the Gates/ Piaggio GP-180 "Avanti". This paper describes some of the unique design features of the composite components, the evolution of complexity, and the basic tooling concepts used to meet the contract objectives.