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 with very marked dihedral, and four Pratt & Whitney R-1830radial 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, with the floats' buoyant hulls acting as the wingtips when retracted. The price of the PB2Y-2 was US$300,000, or approximately three times that of the PBY Catalina. Development continued throughout the war. The PB2Y-3, featuring self-sealing fuel tanks and additional armor, entered service just after the attack on Pearl Harbor and formed most of the early-war Coronado fleet. The prototype XPB2Y-4 was powered by four Wright R-2600 radials and offered improved performance, but the increases were not enough to justify a full fleet update. However, most PB2Y-3 models were converted to the PB2Y-5 standard, with the R-1830 engines replaced with single-stage R-1830-92 models. As most existing PB2Y-3s were used as transports, flying low to avoid combat, removing the excess weight of unneeded superchargers allowed an increased payload without harming low-altitude performance.
Operational history
Coronados served in combat in the Pacific with the United States Navy, in both bombing and antisubmarine roles. PB2Y-5 Coronados carried out four bombing raids on Wake Island between 30 January and 9 February 1944. However, most served as transport and hospital aircraft. The British Royal Air ForceCoastal Command had hoped to use the Coronado as a maritime patrol bomber, as it already used the PBY Catalina. However, the range of the Coronado compared poorly with the Catalina, and the Short Sunderland. Consequently, the Coronados supplied to the RAF under Lend-Lease were outfitted purely as transports, serving with RAF Transport Command. The 10 aircraft were used for transatlantic flights, staging through the RAF base at Darrell's Island, Bermuda, and Puerto Rico, though the aircraft were used to deliver vital cargo and equipment in a transportation network that stretched down both sides of the Atlantic, from Newfoundland, to Brazil, and to Nigeria, and other parts of Africa. After the war ended five of the RAF aircraft were scrapped, one was already lost in collision with a Martin PBM Mariner and the last four were scuttled off the coast of Bermuda in 1946. Coronados served as a major component in the Naval Air Transport Service during World War II in the Pacific theater. Most had originally been acquired as combat patrol aircraft, but the limitations noted above quickly relegated them to transport service in the American naval air fleet also. By the end of World War II, the Coronado was outmoded as both a bomber and a transport, and virtually all of them were quickly scrapped by the summer of 1946, being melted down to aluminum ingots and sold as metal scrap, or used as targets for fighter gunnery practice.
