Inside Out Library · ExploreThe Sikorsky Twin Engined Amphibian, Type S-38, Model 1928 (1928)NASA Technical Reports Server (NTRS) · leaf 17NASA Technical Reports Server (NTRS)Internet Archive · NASA Technical Reports · Public domain (US government work). Free to use for anything.More pictures from The Sikorsky Twin Engined Amphibian, Type S-38, Model 1928More like this
