Boeing XPB

The Boeing XPB, company Model 50, was an American twin-engined biplane long-range patrol flying boat of the 1920s, of which a single example was built for the United States Navy. In September 1924 the Naval Aircraft Factory was tasked with designing a flying boat able to fly the 2,400 miles between San Francisco and Hawaii; the initial design came from Isaac Laddon of Consolidated Aircraft and was passed to Boeing for detailed design and construction. It was a very streamlined two-bay biplane with metal wings and a part-metal, part-laminated-wood fuselage, with two 800 hp Packard V12 engines mounted in tandem above the fuselage. It first flew in August 1925, was withdrawn from the planned Hawaii flight by engine trouble, and in 1928 received Pratt & Whitney Hornet radial engines as the XPB-2.