The PB2Y Coronado was a large flying boat patrol bomber designed by Consolidated Aircraft. After deliveries of the PBY Catalina, also a Consolidated aircraft, began in 1935, the United States Navy began planning for the next generation of patrol bombers. Orders for two prototypes, the XPB2Y-1 and the Sikorsky XPBS-1, were placed in 1936; the prototype Coronado first flew in December 1937.After trials with the XPB2Y-1 prototype revealed some stability issues, the design was finalized as the PB2Y-2, with a large cantilever wing, twin tail, and four Pratt & Whitney R-1830 radial engines. The two inner engines were fitted with four-bladed reversible pitch propellers; the outer engines had standard three-bladed feathering props. Like the PBY Catalina before it, the PB2Y's wingtip floats retracted to reduce drag and increase range.