Son of many fathers |
Douglas PD1 1933 The chief long range patrol flying boats of the United States Navy at the end of the First World War were the Curtiss H16 and the similar Felixstowe F5L, a Liberty engined license built Bristish Felixstowe, which was itself a derivative of Curtiss's earlier H 12. The Naval Aircraft Factory, which had built F.5Ls during World War I, continued development of the design, which was re-designated PN-5 in 1922 (although in practice continued to be known as F.5Ls), with the final two being built to an improved design, the F-6L (later designated PN-6). In 1925, it produced a version with new wings with a high lift aerofoil section and powered by experimental 525 hp Wright T-2 engines, designated PN-7. Although the new wings proved successful, the engines were unreliable, and the wooden hull inherited from the F.5 required much maintenance, so two aircraft with metal hull construction and powered by 475 hp Packard engines were built as the PN-8. Further, similar aircraft were built as the PN-9 and PN-10, but the water-cooled V-12 Packard engines were disappointing and radial engines were substituted to produce the PN-12. This combination of the revised wings introduced by the PN-7, with a metal hull and radial engines met the requirements of the Navy and therefore the PN-12 formed the basis of more extensive production to re-equip its patrol squadrons. As the production capacity of the Naval Aircraft Factory was limited, production was contracted out to several aircraft companies, with versions being built by Douglas (PD-1), Keystone Aircraft (PK-1) and Martin (PM-1 and PM-2). The PN-12 was a twin engined biplane with fabric-covered metal-framed wings, and its engines mounted in nacelles between the wings. While the hull was constructed of metal, it was otherwise similar to that of the F.5L, with the large sponsons that were a feature of both that aircraft and the Felixstowe and Curtiss flying boats to which it could trace its heritage. It had a standard crew of five, but was capable of carrying a relief crew for long patrols. A revised hull, eliminating these sponsons and introduced a twin tail was a key feature of the PH-11, four of which were built. These formed the basis of the Hall PH flying boats, some of which remained in service until World War II. Crew: Five Length: 49 ft 2 in (14.99 m) Wingspan: 72 ft 10 in (22.21 m) Height: 16 ft 9 in (5.11 m) Wing area: 1,217 ft² (113.1 m²) Airfoil: USA 27 Empty weight: 7,699 lb (3,500 kg) Loaded weight: 14,122 lb (6,419 kg) Powerplant: 2× Wright R-1750 D Cyclone 9-cylinder single row radial engine, 525 hp (392 kW) each Maximum speed: 99 knots (114 mph, 184 km/h) at sea level Range: 1,139 nm (1,310 mi, 2,109 km) Service ceiling: 10,900 ft (3,300 m) Wing loading: 11.6 lb/ft² (56.8 kg/m²) Power/mass: 0.074 hp/lb (0.12 kW/kg) Climb to 5,000 ft (1,520 m): 16 min Armament Single .30 in (7.62 mm) calibre machine gun in bow and amidships cockpits Four 230 lb (105 kg) bombs underwing USN 93 René Hieronymus Scale 1:72 Building time: approx. 43 hrs. |