Lockheed-Georgia Company, Marietta, GA
The Lockheed-Georgia Company has recently constructed a one-piece molded front spar for the vertical fin of the L-1011 airplane (Fig. 1). The 26-ft-long graphite-epoxy spar contains integrally molded caps, webs, stiffeners, and rib attachments. This spar was fabricated as part of a contract sponsored by NASA-Langley Research Center with Lockheed-California Company to demonstrate production readiness and provide confidence in the use of composite primary structures. The spar is molded of T300/5208 graphite/epoxy. It replaces 39 metal parts, eliminates almost 1000 fasteners, and weighs about half as much as the metallic counterpart. The caps and webs vary in thickness and ply orientation along the length of the spar. These variations are achieved by build-up and deletion of the plies, all the while maintaining a balanced laminate to avoid warpage in the finished spar. Selected areas of this spar were fabricated separately and tested before the full-size 26-ft-long spar was fabricated. These tests demonstrated that the static strength, fatigue endurance, and damage resistance of the spar exceed all requirements.
Paper ID: CTR10672J