Consolidated PBY Catalina

Design and development

Background

Development of the PBY Catalina can be traced back to the early 1930s, a time in which American dominance in the Pacific Ocean began to face competition from Imperial Japan. As part of its response to a potential conflict in this theatre, the United States Navy (USN) opted to invest considerable resources towards the development of long-range flying boats, which had the advantage of being able to land in any suitable waters. Naval doctrine of the 1930s and 1940s used flying boats in a wide variety of roles that today are handled by multiple special-purpose aircraft. In 1931, the service had procured both the Consolidated P2Y and Martin P3M to perform this role, however, both aircraft were relatively underpowered and hampered by inadequate range and limited payloads.

Accordingly, in October 1933, the USN contracted Consolidated, Martin, and Douglas to build competing prototypes to meet its needs for a new patrol bomber flying boat. These prototypes were designed to provide a relatively long operational range, which was intended to be used to locate and attack enemy transport ships across the sea to disrupt enemy supply lines. Both Consolidated and Douglas delivered single prototypes of their new designs, the XP3Y-1 and XP3D-1, respectively. The XP3Y-1 was an evolution of the company's earlier XPY-1 design, which had originally competed unsuccessfully for the P3M contract two years earlier and of the XP2Y design that the USN had authorized for a limited production run. Although the Douglas-built competitor proved to be a satisfactory design, the USN opted for Consolidated's proposal, largely due to its projected cost being only $90,000 per aircraft.

In terms of its general configuration, the XP3Y-1 (which received the internal designation of Model 28 from the company) featured a parasol wing with external bracing struts and mounted on a pylon over the fuselage. It was equipped with retractable stabilizing floats at its wingtip; when retracted in flight, these floats formed streamlined wingtips; Consolidated had licensed this feature from the British Saunders-Roe company. While its two-step hull design was broadly similar to that of the P2Y, the XP3Y-1 was provisioned with a cantilever cruciform tail unit in place of the earlier strut-braced twin tail arrangement. Furthermore, cleaner aerodynamics resulted in the XP3Y-1 possessing better performance to the firm's earlier designs. It featured all-metal construction and was covered by stressed-skin aluminum sheet, except for the ailerons and trailing edge of the wing, which were fabric covered instead.

The XP3Y-1 was initially powered by a pair of 825 hp (615 kW) Pratt & Whitney R-1830-54 Twin Wasp radial engines mounted on the wing's leading edge. Armament comprised four .30 in (7.6 mm) Browning AN/M2 machine guns and up to 2,000 lb (910 kg) of bombs, the latter of which were carried underneath the wings. It was also provisioned with crew amenities, including a galley. Via the use of beaching gear, the type could be operated from both land and sea as required.

Into flight

On 21 March 1935, the XP3Y-1 conducted its maiden flight. Shortly thereafter, it was transferred to the USN for service trials. The XP3Y-1 demonstrated a significant performance improvement over previous patrol flying boats, leading to the service requesting further development to permit the prospective production aircraft to better perform the patrol bomber mission. Accordingly, in October 1935, the prototype was returned to Consolidated for modification, after which it was redesignated XPBY-1. Changes included the installation of 900 hp (670 kW) R-1830-64 engines and the implementation of redesigned vertical tail surfaces, which resolved a problem with the tail becoming submerged on takeoff, which had made lift-off impossible under some conditions. The XPBY-1 made its maiden flight on 19 May 1936, during which a record non-stop distance flight of 3,443 mi (2,992 nmi; 5,541 km) was achieved.

The XPBY-1 was delivered to VP-11F in October 1936. The second squadron to be equipped was VP-12, which received the first of its aircraft in early 1937. The second production order was placed on 25 July 1936. Over the next three years, the design was gradually developed further and successive models were introduced. In 1939, in spite of some assessors considering the type to be obsolete, Consolidated restarted the production line.

PBN Nomad

The Naval Aircraft Factory (NAF) performed significant modifications to the PBY design, many of which would have significantly interrupted deliveries had they been incorporated on the Consolidated production lines. The resulting aircraft, officially referred to as the PBN-1 Nomad, featured several key differences from the basic PBY. The most obvious upgrades were to the bow, which was sharpened and extended by two feet, and to the tail, which was enlarged and featured a new shape. Other improvements included larger fuel tanks to increase range by 50 percent and reinforced wings that permitting a 2,000 lb (908 kg) increase in gross takeoff weight.