In 1928 The Consolidated Aircraft Company received a contract from the United States Government  to   produce a single XPY-1 patrol flying boat for the United States Navy. The XPY-1 would become the Navy’s first large monoplane flying boat. Although the Martin Company won the contract for the production version for the Navy, Consolidated was undeterred and they submitted a modified design, the XP2Y-1 to the Navy. The success of this design resulted in a contract for 23 production aircraft. The design was further improved and as the P2Y-2 a further 23 production aircraft were ordered.

In 1932, Consolidated submitted its new Model 28 design in response to a design competition announced by the US Navy for a new flying boat. Consolidated, along with Douglas was awarded a contract for production of a single aircraft on 28th October 1933.  Consolidated's new aircraft, now designated XP3Y-1, was a streamlined airplane with very clean lines and retractable wing tip floats and propelled by the new Pratt and Whitney Twin Wasp R-1830-58 engines developing 825 HP each.

The XP3Y-1 flew for the first time 21st of March 1935.  Following rigorous testing, the Consolidated design team was awarded a production contract of the Model 28, now re designated XPBY-1 (PBY means Patrol Bomber, Y is the manufacturer’s code for Consolidated Aircraft Company).

Production of the PBY continued for a further ten years; with aircraft designated PBY-1 to PBY-6A.

PBY-1: This was the first production version of the PBY, 60 were ordered for the U.S. Navy in 1936. These aircraft were near identical to the XPBY-1 in its final configuration. Engines were R-1830-64 rated at 850hp each & gross weight was 20,671 lbs.

PBY-2: The next production variant, the PBY-2 was identical in almost every respect to the preceding PBY-1. The only real changes were subtle modifications to the aircraft’s tail surfaces. 50 were ordered for the U.S. Navy in 1936. Gross weight increased to 21,780 lbs with under-wing bomb racks being adapted to carry heavier ordinance.

PBY-3: The PBY-3 was externally similar to the PBY-2. New engines were introduced, the R-1830-66 which produced 900hp each. 66 were ordered for the U.S. Navy in late 1936. Gross weight increased again to 22,078 lbs.

PBY-4:  The PBY-4 introduced a further engine change. The R-1830-72 engine produced 1,050hp each, gross weight increased to 22,295lbs. The propeller bosses were fitted with large spinners and these became an identifying feature of the PBY-4s. The final 4 production PBY-4s introduced the large rear blister gun positions, a feature that would be retained on all subsequent PBY production variants. The very last production PBY-4 was fitted with landing gear to become the prototype for the PBY amphibian (the XPBY-5A). A total of 33 PBY-4s were ordered for the US Navy in late 1937.

PBY-5: The PBY-5, introduced in 1939, was the first PBY variant to be ordered in quantity. With the onset of World War 2, 1196 aircraft were ultimately ordered from Consolidated and licensed manufacturers Boeing Canada and Canadian Vickers (as P2B-1, P2B-2 and PBV-1). These were supplied to the U.S Navy and lend-leased to many other countries air arms. Power plant changes saw the introduction of the R-1830-82 of 1050hp. Later models would have R-1830-92 engines of 1,200 hp. Visible changes were the introduction of new horizontal and vertical tail surfaces. The PBY-5 also introduced the rear bulbous blister gun positions as standard fittings. Gross weight gradually grew from 26,200lbs to 35,000lbs as ‘war’ equipment was added. This is the variant used by the RNZAF which flew both PBY-5s and Boeing P2B-1s

PBY-5A:  The PBY-5A was the first amphibious version and most numerous production version of the PBY Catalina. With the addition of retractable wheels, the value of the amphibians was significantly improved beyond that of the flying boats. Over 1480 airframes were built by Consolidated and licensed manufacturers Boeing Canada and Canadian Vickers. The PBY-5A was essentially just a PBY-5 airframe with wheels. Engine power was provided by R-1830-92s producing 1,200hp each, while gross weight increased to 33,975 lbs. The New Zealand ‘Catalina’ ZK-PBY is actually a Canadian Vickers license built PBY-5A or Canso.

PBY-6A: The final production variant of the PBY Catalina, the amphibious -6A variant introduced a lightened structure and adopted the taller tail and revised elevator modification developed by the Naval Aircraft Factory for the PBN-1 Nomad (itself a revised version of the PBY flying boat). 900 of this variant were originally ordered from Consolidated by the U.S Navy in 1945, with the cessation of hostilities only 175 were completed. When the final PBY-6A rolled off the production line it marked the end of the largest production run of any single flying boat design

Most Catalina's that fly today are PBY-5As along with several PBY-6As, all surviving operational aircraft are amphibians.   Most PBYs retained their faithful Pratt and Whitney engines, but others became "Super Cats," their R-1830s replaced by North American B-25 medium bomber engines and cowlings. These Wright R-2600 Cyclone engines boosted horsepower from 1,200 to 1,700 per engine, increased the cruising speed from 110 miles per hour to 145, and increased the gross weight from 34,000 pounds to 40,000. Many PBY-5As had their rudders replaced by ones with balance horns to ease the load on the rudder pedals. PBY-6As, particularly Super Cat conversions, received squared off fins and rudders, the additional area aiding in stability and control.

 SOURCES

'PBY the Catalina Flying Boat' By Roscoe Creed

‘PBY Catalina’ By Bert Kinzey.