Grumman / McKinnon G21C Goose
The Grumman G-21 Goose amphibious aircraft was designed as an eight-seat "commuter" plane for businessmen in the Long Island area. The Goose was Grumman’s first monoplane to fly, its first twin-engined aircraft and its first aircraft to enter commercial airline service. During World War II, the Goose became an effective transport for the US military (including the Coast Guard), as well as serving with many other air forces. During hostilities, the Goose took on an increasing number of combat and training roles. In postwar use, the adaptable little transport continued in use.
In 1936, a group of wealthy residents of Long Island, including E. Roland Harriman, approached Grumman and commissioned an aircraft that they could use to fly to New York City. In response the Grumman Model G-21 was designed as a light amphibian transport. The typical Grumman rugged construction was matched to an all-metal, high-winged monoplane powered by two 450 horsepower (340 kW) Pratt & Whitney R-985 Wasp Jr. nine-cylinder, air-cooled radial engines mounted on the leading edge of high-set wings. The deep fuselage served also as a hull and was equipped with hand-cranked retractable landing gear. First flight of the prototype took place on 29 May 1937.
The fuselage also proved versatile as it provided generous interior space that allowed fitting for either a transport or luxury airliner role. Having an amphibious configuration also allowed the G-21 to go just about anywhere, and plans were made to market it as an amphibian airliner. Some had a hatch in the nose, which could remain open in flight.
There were a number of modifications of the Goose, but the most numerous were those by McKinnon Enterprises, who owned 21 Supplemental Type Certificates (STC's) to modify G-21 series aircraft; both original Grumman aircraft still certified under TC 654 and his own conversions under TC 4A24 as well. In addition to the STCs, four “new” models were approved under TC 4A24, the models G-21C, G-21D, G-21E, and G-21G. The first two models (C and D) were powered by four 340 hp Lycoming GSO-480-B2D6 piston engines. Several years after its initial certification as the one and only McKinnon model G-21D, N150M (s/n 1251) was modified by the installation of two United Aircraft of Canada Ltd. (later Pratt & Whitney Canada Ltd.) 550 shp PT6A-20 turbine engines (per STC SA1320WE) in place of the four Lycoming piston engines. Only at that point did it become the “Turboprop Goose”. By comparison, all Grumman G-21A turbine conversions (per McKinnon STC SA1589WE) and McKinnon’s own fully-certified turbine E and G models were collectively referred to as “Turbo Gooses”. Larger (i.e. “picture”) windows and/or retractable floats on the wings were features of every one of them – not just the “final variant”. *
N642, featured here, is a 1968 [year of re-certification] Grumman G-21C (arguably still a G-21A due to incomplete turbine conversion), spotted "For-Sale" online in Nov 2009 with an asking price of US$690,000... Say, Mister, can ya spare a dime? *
* Many thanks to Dave Marion of Antilles Seaplanes for alerting us to errors in our initial descriptions.