Navy Patrol Flying Boats, 1920-1932
PM-1, XP4N-1, XPN-11, XP2M-2
Page 6
The patrol designation was briefly carried by Navy versions of the twin-engine Sikorsky commercial amphibians, which were not really combat types. One XPS-l with 220-hp Wright R-790s and a gunner’s cockpit in the bow of the short fuselage ordered January 28, 1928, and completed at College Point, NY, on March 16, was too under-powered for service. Two XPS-2 (S-38A) amphibians with 450-hp Pratt & Whitney R-1340Bs and the usual ten-place cabins ordered October 13, 1928, were delivered to Utility Squadron VJ-1 at San Diego in January 1929.
Four PS-3s ordered on April 30, 1929, were completed with gun positions in the bow and stern of the hulls. The first was destroyed at Anacostia during its tests in June 1929, while one did serve VP-2 and the others VJ-1. The gun cockpits were soon covered over when the aircraft reverted to normal S-38B configuration. Redesignated RS-3, these amphibians served with utility squadrons along with six more assorted RS types added later.
Sikorsky did build a true patrol biplane, the three-place XP2S-1 with 450-hp Wasps mounted in tandem over the hull, two .30-caliber flexible Brownings, and two 500-pound bombs. Ordered June 3, 1930, the XP2S-1 was tested in June 1932, but won no production contracts.
The Big Boats
Perfection of patrol types capable of safely flying to overseas bases in Alaska, Hawaii, the Philippines, or the Canal Zone was seen as the major problem facing American flying boat designers. Bureau of Aeronautics engineers planned a 100-foot span monoplane that was a big step toward this capability, and on February 28, 1928, ordered Consolidated Aircraft, then in Buffalo, New York, to build a prototype.
First flown January 10, 1929, the XPY-l had two 450-hp Pratt & Whitney R-1340-38 Wasps suspended on struts between a fabric-covered, metal-frame wing and an all-metal single-step hull with five open cockpits. Isaac M. Laddon designed the first Navy monoplane patrol type with outboard pontoons to keep the wing tips out of the water and a twin rudder tail assembly. At the Navy’s request, a third Wasp was installed above the wing in August, an effort to increase speed that Laddon regarded ith distaste.
Glenn L. Martin, however, underbid Consolidated for production of the type, starting a patrol plane rivalry that continued for over two decades. Consolidated did build a successful commercial XPY-l development known as the Commodore.
Nine examples of Martin’s version ordered June 29, 1929, were designated P3M-l. The first, tested January 26, 1931, was similar to the twin-engine XPY-1 with R-1340-38 Wasps and had five crewmen, four .30-caliber guns, and four 500-pound bombs. All nine were delivered by May 1931, the P3M-ls being modified to P3M-2 standard by September with 525-hp R-1690-32 Hornets, ring cowls, and enclosed pilots’ seats. They served VP-10 in 1932 and VP-15 in 1936, but most of the time were at training stations.
Martin also received a contract June 28, 1929, for a developmental prototype with the same Clark Y wing section, but lowered, and with two cowled 575-hp Wright R-1820-64 Cyclones installed on the leading edge. It was first tested June 22, 1931, as the XP2M-l with a third Cyclone mounted above the wing, but this engine was deleted when the aircraft was modified to the XP2M-2 in 1932. This reduction in power lowered performance, except for an increase in range obtained from reduced fuel consumption.
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