The Douglas XP3D was a prototype American patrol flying boat developed by the Douglas Aircraft Company in the 1930s.
This twin-engined high-winged monoplane was designed to equip the US Navy’s Patrol squadrons.
In 1933, the United States Navy placed orders with both Douglas and Consolidated Aircraft for single prototypes of patrol flying boats to replace the Consolidated P2Y and Martin P3M that equipped the Navy’s patrol squadrons.
The P3D was produced in parallel with the smaller YB-11 being developed for the United States Army Air Corps.
The P3D was a pure flying boat rather than an amphibian and was therefore fitted with retractable beaching gear to allow it to be moved to and from shore.
The Douglas prototype, designated XP3D-1, first flew on 6 February 1935, and was delivered to NAS San Diego for testing in March 1935.
Both the XP3D-1 and Consolidated’s P3Y successfully passed the Navy’s performance tests, demonstrated very similar performance, an order was placed for 60 P3Ys (re-designated PBY in May 1936) because the Consolidated aircraft was cheaper, costing $90,000 per aircraft compared with $110,000 for the Douglas aircraft.
Douglas re-designed the P3D to improve performance in order to win follow-on contracts, and rebuilt the XP3D-1, raising the wing by 27 inches (0.69 m) and mounting the engines on the leading edge of the wing.
The fixed wing floats were replaced by retractable floats, and a nose turret was fitted.
The rebuilt aircraft, designated XP3D-2 was re-delivered on 15 May 1935, but production orders again went to Consolidated, for the improved PBY-2.
The XP3D-1 was briefly operated by Patrol Squadron 3 (VP-3) until it was returned to Douglas for re-building.
The re-built XP3D-2 was used by VP-11F as a VIP aircraft until destroyed in a crash at Acapulco Bay, Mexico on 8 February 1937.
The crash was survived by the embarked VIP, Rear Admiral Ernest King. Variants XP3D-1 Prototype aircraft. Two 825 hp (615 kW) R-1830-58 engines. XP3D-2 Rebuilt XP3D-1, with raised wing, engines moved to wing leading edge and retractable wing floats. Two 900 hp (671 kW) R-1830-64 engines. Specifications XP3D-2 Crew 5–7 Length 69 ft 7.5 in (21.222 m) Wingspan 95 ft 0 in (28.96 m) Height 22 ft 5.25 in (6.8390 m) Wing area 1,295 sq ft (120.3 m2) Empty weight 15,120 lb (6,858 kg) Gross weight 22,909 lb (10,391 kg) Max take-off weight 27,946 lb (12,676 kg) Powerplant 2 × Pratt & Whitney R-1830-64 Twin Wasp, 14-cylinder air-cooled radial piston engines, 900 hp (670 kW) each Propellers 3-bladed variable-pitch propellers Performance Maximum speed 183 mph (295 km/h, 159 kn) at 8,000 ft (2,400 m) Range 2,050 mi (3,300 km, 1,780 nmi)3380 Service ceiling 18,900 ft (5,800 m) Time to altitude 5,000 ft (1,500 m) in 6 minutes 6 seconds Wing loading 17.7 lb/sq ft (86 kg/m2) Power/mass 0.0565 hp/lb (0.0929 kW/kg) Armament Guns 3× 0.30 in (7.6 mm) Browning machine guns in nose turret and hull hatches Bombs 3,000 lb (1,400 kg) of bombs. Sources McDonnell Douglas Aircraft Company 1st 75 Years Aviation Book-McDonnell Douglas. McDonnell Douglas Aircraft since 1920, Volume 1-René J Francillon. San Diego Air and Space Museum Archive. The National Museum of the U.S. Air Force.