The Boeing XPB (company Model 50) was an American twin-engined

biplane A biplane is a fixed-wing aircraft with two main wings stacked one above the other. The first powered, controlled aeroplane to fly, the Wright Flyer, used a biplane wing arrangement, as did many aircraft in the early years of aviation. While ...

long-range patrol

flying boat A flying boat is a type of fixed-winged seaplane with a hull, allowing it to land on water. It differs from a floatplane in that a flying boat's fuselage is purpose-designed for floatation and contains a hull, while floatplanes rely on fusela ...

of the 1920s. A single example was built for the

United States Navy The United States Navy (USN) is the maritime service branch of the United States Armed Forces and one of the eight uniformed services of the United States. It is the largest and most powerful navy in the world, with the estimated tonnage ...

Design and development

In September 1924, the

Naval Aircraft Factory The Naval Aircraft Factory (NAF) was established by the United States Navy in 1918 in Philadelphia, Pennsylvania. It was created to help solve aircraft supply issues which faced the Navy Department upon the entry of the U.S. into World War I. ...

was tasked with designing a long-range twin-engined

, capable of flying the 2,400 mi (3,860 km) between

San Francisco San Francisco (; Spanish language, Spanish for "Francis of Assisi, Saint Francis"), officially the City and County of San Francisco, is the commercial, financial, and cultural center of Northern California. The city proper is the List of Ca ...

and

Hawaii Hawaii ( ; haw, Hawaii or ) is a state in the Western United States, located in the Pacific Ocean about from the U.S. mainland. It is the only U.S. state outside North America, the only state that is an archipelago, and the only stat ...

. The initial design was carried out by Isaac Laddon, an employee of

Consolidated Aircraft The Consolidated Aircraft Corporation was founded in 1923 in aviation, 1923 by Reuben H. Fleet in Buffalo, New York, the result of the Gallaudet Aircraft Company's liquidation and Fleet's purchase of designs from the Dayton-Wright Company as the ...

, and then passed to Boeing for detailed design and construction. The new flying boat, the Boeing Model 50, was a two-bay

of very streamlined design for flying boats of the time. The wings were of metal construction, with wooden wingtips and leading edges. The fuselage had a metal lower part, with the upper half made of laminated wooden frames with a wood veneer covering. Two 800 hp (600 kW)

Packard 2A-2500 The Packard 1A-2500 is an American V-12 liquid-cooled aircraft engine designed by Packard in 1924 as a successor to the World War I-era Liberty L-12. Five aero variants were produced, of which the 3A-2500 was the most numerous. Three marine ve ...

V12 engine A V12 engine is a twelve-cylinder piston engine where two banks of six cylinders are arranged in a V configuration around a common crankshaft. V12 engines are more common than V10 engines. However, they are less common than V8 engines. The fi ...

s driving four-bladed propellers were mounted in tandem between the wings above the fuselage.

Operational history

The Boeing Model 50, designated XPB-1 by the US Navy, made its maiden flight in August 1925.Yenne 2005, p. 15. It was intended to use it to lead a pair of Naval Aircraft Factory PN-9s in an attempt to fly to Hawaii on 31 August 1925, but engine trouble led to its participation in the flight being cancelled.Boeing C to Z, and hyphenates
. ''Aerofiles''. Retrieved 18 June 2010.
''

Flight Flight or flying is the process by which an object moves through a space without contacting any planetary surface, either within an atmosphere (i.e. air flight or aviation) or through the vacuum of outer space (i.e. spaceflight). This can be a ...

'', 10 September 1925, p. 579. In 1928, the aircraft was modified by the Naval Aircraft Factory, its Packard engines were replaced by two 500 hp (370 kW) geared

Pratt & Whitney R-1690 The Pratt & Whitney R-1690 Hornet was a widely used American aircraft engine. Developed by Pratt & Whitney, 2,944 were produced from 1926 through 1942. It first flew in 1927. It was a single-row, 9-cylinder air-cooled radial design. Displacem ...

Hornet

radial engine The radial engine is a reciprocating type internal combustion engine configuration in which the cylinders "radiate" outward from a central crankcase like the spokes of a wheel. It resembles a stylized star when viewed from the front, and is ca ...

s, leading to the new designation XPB-2.

Specifications (XPB-1)

References

;Notes ;Bibliography * Bowers, Peter M. ''Boeing Aircraft since 1916''. London:Putnam, 1989. . * Yenne, Bill.
The Story of the Boeing Company
'. St Paul, USA: Zenith Imprint, 2005. . {{USN patrol aircraft Flying boats 1920s United States patrol aircraft P1B Twin-engined push-pull aircraft Biplanes Aircraft first flown in 1925

Design and development

Operational history

Specifications (XPB-1)

See also

References