sentences:  Delivered to the U.S. Navy in 1947 for trials, they were rejected due to problems with exhaust fumes leaking into the cockpit.The first prototype was subsequently to receive a number of engine changes, first powered with a 320 hp Lycoming R-680-13, then finally with a horizontally opposed 350 hp Lycoming GSO-580.The aircraft was destroyed in a crash in 1950.