<p>Consolidated's XP3Y-1 was to be developed to become the most extensively-built flying-boat in aviation history. The company identified its design as the Model 28 and this had a parasol-mounted wing. The introduction of internal bracing resulted in a wing which was virtually a cantilever, except for two small streamlined struts between hull and wing center-section on each side. Thus, the Model 28 was free of the multiplicity of drag-producing struts and bracing wires which had limited the performance of earlier designs. Another innovation adding to aerodynamic efficiency was the provision of stabilizing floats which, when retracted in flight, formed streamlined wingtips.
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<p>First flown on 28 March 1935, the XP3Y-1 was soon transferred to the US Navy for service trials, which confirmed a significant improvement in performance over the patrol flying-boats in service. Its extended range and improved load-carrying capability caused the US Navy to request further development to bring this new aircraft into the category of a patrol-bomber. In October 1935 the prototype was returned to Consolidated for the necessary work to be carried out, including installation of the 900-hp (671-kW) R-1830-64 engines which had been specified for the 60 PBY-1s (a patrol-bomber designation) which had been ordered on 29 June 1935. Production PBY-2s, -3s and -4s followed. In April 1939 the first example of the PBY-4 production aircraft was returned to the company for the installation of wheeled landing gear so that these aircraft could operate as amphibians, thus making them far more versatile. Of tricycle-type configuration, the landing gear featured a nosewheel retracting into the hull beneath the flight deck, and the main units (mounted externally on each side of the hull beneath the wing) folding to fit into small recesses. This aircraft, when completed in November 1939, emerged with the designation XPBY-5A. Testing confirmed, if confirmation was needed, the very considerable advantages of the amphibian configuration.
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<p>USAAF operation of the Catalina began with the transfer of 56 PBY-5As (41-18772, 41-18773, 42-107401 to 107405, 42-109020 to 42-109025, 43-3259 to 43-3270, 43-43839 to 43-43863, 43-47956 to 43-47961) which were designated OA-10 under USAAF nomenclature. These were followed by 230 PBV-1 aircraft, this variant being similar to the PBY-5A but built by Canadian Vickers. These received the designation OA-10A. The Catalinas were used throughout World War II for search and rescue missions, some carrying air-dropped lifeboats beneath each wing. A small number were used in North Africa as makeshift bombers, carrying a 2,000-lb bomb load on wing racks. The final production aircraft to be received were 75 PBY-6As built by Consolidated, and which were designated OA-10B. In 1948, survivors were redesignated A-10, A-10A and A-10B. The USAAF also used 16 PB2B-2 flying-boats (a Boeing Canada-built PBY-5), which retained their Navy designation and BuAer numbers.
<item><hi format=bold>Powerplant (OA-10):</hi> two 1,200-hp (895-kW) Pratt & Whitney R-1830-92 Twin Wasp radial piston
<item><hi format=bold>Performance:</hi> maximum speed 179 mph (288 km/h at 7,000 ft (2,135 m); long-range cruising speed 117 mph (188 km/h); service ceiling 14,700 ft (4,480 m); maximum range 2,545 miles (4,096 km)
