GAP TREATMENT MATERIALS FOR LOW OBSERVABLE AIRCRAFT

A very rapid curing conductive putty and gap filler resin is needed by the Air Force to fill in gaps between frequently removed panels and plates on stealth type aircraft. The fuselage and wing surfaces must be as smooth as possible prior t each mission. The current gap fillers are two part resin systems, which require at least several hours to completely cure and may have long term room temperature storage problems. Sunrez is proposing the development of a one part light cured conductive resin system which cures within tem minutes, has satisfactory elongation at low temperatures, and can be cured with a smooth surface requiring minimum surface finishing. Sunrez has found that thin layers of carbon fiber filled one part resins, based on polysulfide and polyurethane, can be satisfactorily light cured. Carbon fiber in at least the top resin layer of the filled gap, or even throughout the resin in the filled gap, will be demonstrated in Phase I with respect to conductivity, low temperature elongation, adhesion, and rapid cure. Resin optimization, field service kits and filling techniques will be developed in Phase II.