LOW COST MANUFACTURE OF LAMINAR WINGS

Abstract

The purpose of this construction method for wings and tails is to greatly reduce the labor costs and also to increase the wing's surface accuracy to the level required by laminar flow without profiling by hand. This method is suitable for any wing loading or planforrn, except that it requires that all curvature be simple and not compound. The accuracy is expected to come from the use of flat sheets and ribbons of precured prepreg of aramid/epoxy or carbon/epoxy, rather than having the prepreg's cure take place in the mold, as it is believed that the volume changes of the epoxy during cure is the major cause of warping and the consequent need for refinishing the wing's surface by hand. The adhesive used to form the wing surfaces and sandwiches from precured prepreg sheets and foam is a liquid, which cures to a rubbery plastic, and whose elasticity prevents warping due to shrinkage during cure. All of the materials and processes used here are presently in commercial use for other purposes. The major piece of assembly equipment is a clamshell mold, of conventional design for the manufacture of sailplane wings, but with a modified method for applying a vacuum to the top and bottom wing surfaces to conform them to the mold.