The Grumman G-21 Goose is an amphibious flying boat designed by Grumman as an eight-seat commuter aircraft 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 United States 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.
Design and development
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."Goose." Antilles Seaplanes history page. Retrieved: August 30, 2008. In response, the Grumman Model G-21 was designed as a light amphibious transport. Grumman produced a high-wing monoplane of almost all-metal construction—the trailing half of the main wing and all of the flight control surfaces except for the flaps were fabric-covered. It was powered by two Pratt & Whitney R-985 Wasp Junior nine-cylinder, air-cooled, radial engines mounted on the leading edges of the 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 May 29, 1937."Grumman Goose." Aerofiles.com Grumman page. Retrieved: August 30, 2008.
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.Truelson 1976
Modifications
A number of modifications were made for the Goose, but the most numerous are those by McKinnon Enterprises of Sandy, Oregon, which holds 21 supplemental type certificates (STCs) for modifying G-21-series aircraft and which also manufactured four different conversions that were recertified under a separate FAA type certificate as brand-new "McKinnon" airplanes."FAA Type Certificate no. 4A24". FAA. Retrieved: August 26, 2011. The first was the McKinnon model G-21C which involved replacing the original R-985 radial engines with four Lycoming GSO-480-B2D6 piston engines. It was approved under TC 4A24 on November 7, 1958, and two examples were converted in 1958–1959.
New production In November 2007, Antilles Seaplanes of Gibsonville, North Carolina, announced it was restarting production of the turbine-powered McKinnon G-21G Turbo Goose variant, now identified as the Antilles G-21G Super Goose. Pratt & Whitney Canada PT6A-34 turboprops flat-rated to would have replaced the original PT6A-27 engines, and the airframe systems and especially the avionics (aviation electronics – i.e. radios and navigation systems) would have been updated with state-of-the-art "glass panel" instrumentation and cockpit displays. However, as of 2009, Antilles Seaplanes' manufacturing center has been foreclosed and sold at auction. The fate of new Goose production is currently unknown.
Operational history
Envisioned as corporate or private flying yachts for Manhattan millionaires, initial production models normally carried two to three passengers and had a bar and small toilet installed. In addition to being marketed to small air carriers, the G-21 was also promoted as a military transport. In 1938, the U.S. Army Air Corps purchased the type as the OA-9 (later, in the war years, examples impressed from civilian ownership were designated the OA-13A). The most numerous of the military versions were the United States Navy variants, designated the JRF.
The amphibious aircraft was also adopted by the Coast Guard and, during World War II, served with the Royal Canadian Air Force in the transport, reconnaissance, rescue, and training roles. The G-21 was used for air-sea rescue duties by the Fleet Air Arm, who assigned the name Goose. A single aircraft was used briefly by No. 1 Air Ambulance Unit, Royal Australian Air Force in the Mediterranean.
After the war, the Goose found continued commercial use in locations from Alaska to Catalina and the Caribbean.
A total of 345 were built, with about 30 known to still be airworthy today (although around 60 are still on various civil registries, many of them are known to have crashed or been otherwise destroyed), most being in private ownership, some of them operating in modified forms. "Seven confirmed dead in B.C. plane crash." canada.com. Retrieved: December 19, 2009.
Variants G-21 The original production version, these were powered by two Pratt & Whitney Wasp Junior SB engines, at gross weight, with six passengers, and 12 were built, all converted to G-21A standards.Francillon and Killion 1993, p.55.
Increased gross weight (), 30 built. 2-bladed Hartzell constant speed propellers. G-21B Export coastal patrol flying boat armed with machine gun in bow and dorsal hatches and two bombs underwing, 12 built for Portuguese Naval Aviation. G-21C Conversion by McKinnon Enterprises, these were re-engined with four Lycoming GSO-480-B2D6 air-cooled, geared, and supercharged flat-six engines and fitted with retractable wingtip floats, a fiberglass radar nose, a one-piece wraparound windshield, and enlarged cabin windows; gross weight increased to as result of internal structural reinforcements. Two were converted as piston-powered models G-21C in 1958–1959, and two other airframes subsequently were converted in 1968, but with two Pratt & Whitney Canada PT6A-20 turboprops per STC SA1320WE as G-21C Hybrids. Two G-21C Hybrids were identical to the later model G-21E, but they were never certified as such."Aircraft N642" FAA Registry. Retrieved: August 26, 2011. G-21D One G-21C was further converted by McKinnon with an extended nose marked by two extra windows on each side and accommodating another four passengers. Recertified as G-21D in 1960. In 1966, it was re-engined with two PT6A-20 turboprops and fitted with revised Alvarez-Calderon electric flaps in accordance with STC SA1320WE, retaining the G-21D designation, but subsequently identified as the McKinnon "Turboprop Goose".Francillon and Killion 1993, pp. 54–56. G-21E A fully certified new model, it was based on a simplified turbine conversion of the McKinnon G-21C, with PT6A-20 engines ( Pratt & Whitney Canada PT6A-27 engines optional) and more fuel, but without all of the structural reinforcements of the G-21C. gross weight. One converted. G-21G The final McKinnon conversion also was fully certified as a new model with PT6A-27 engines, of fuel, and gross weight. Two converted. and "Aircraft – N70AL." FAA Registry. Retrieved: August 26, 2011.
Kaman K-16B Experimental tilt wing aircraft, with JRF-5 fuselage powered by two General Electric YT58-GE-2A engines; one built but not flown. XJ3F-1 Prototype eight-seat utility amphibian, built for the US Navy; one built in 1938.Green 1968, pp. 169–170. JRF-1 Production XJ3F-1, five built for US Navy. JRF-1A Similar to JRF-1, but with target towing gear and camera hatch added, five built for US Navy. JRF-2 U.S. Coast Guard version with provisions for carrying stretchers; seven built. JRF-3 Similar to the JRF-2, fitted with autopilot and deicing boots on the wing leading edges for Arctic operations. Three built for US Coast Guard.Donald 1995, p. 145. JRF-4 Similar to JRF-1A, these could carry two underwing depth bombs. Ten built for US Navy.
JRF-5 Major production version with bomb racks, target towing and camera gear, and deicing gear; 184 built. In 1953, a modified JRF-5 tested hydroskis for the US Navy."Hydro-Skis On Seaplanes Speed Take-Off." Popular Mechanics, January 1953, p. 119. JRF-5G 24 JRF-5s transferred to the US Coast Guard. JRF-6B Navigation trainer purchased for supply under Lend-Lease; 50 built. OA-9 Transport and air-sea rescue for United States Army Air Forces, 26 ordered in 1938, supplemented by five JRF-6Bs under the same designation. OA-13A Three G-21As impressed by the USAAF.Green 1968, p.169. OA-13B Two JRF-5s transferred to the USAAF. Goose Mk.I British designation for three JRF-5s supplied to the Fleet Air Arm.March 1998, p.127. Goose Mk.IA British designation for 44 JRF-6Bs, supplied under Lend Lease for observer training by the 749 Naval Air Squadron in Trinidad. Goose Mk.II British designation for two JRF-5s staff transports for British Air Commission in the United States and Canada.
Operators Military operators
Argentine Naval Aviation Six aircraft were used 1947–1966.Núñez Padin, Jorge Felix (2009).
Royal Australian Air Force A single aircraft was used briefly by No. 1 Air Ambulance Unit RAAF in the Mediterranean.http://www.adf-serials.com.au/goose.htm Brendan Cowan
Bolivian Air Force At least two aircraft (one JRF-2 and one JRF-6B) received in 1942.Francillon 2008, p. 37
10 used for anti-submarine patrols during Second World War.
Royal Canadian Air Force 36 received.
Honduran Air ForceHagedorn 1993, p. 68.
Indonesian Air Force"Indonesian aviation 1945-1950." adf-serials.com. Retrieved: 9 February 2021.
Japan Maritime Self-Defense Force
Paraguayan Naval Aviation
Peruvian Air Force
Portuguese Naval AviationNiccoli 1998, p. 39. Portuguese Air ForceNiccoli 1998, pp. 38–39.
Swedish Air Force
Royal Air Force (several impressed examples by 24 Squadron and ATA)Thetford, 1978, p.592 Royal Navy (44 Lend Lease examples)
United States Army Air Corps United States Army Air Forces United States Navy United States Coast Guard
Civil Government operators
The United States Fish and Wildlife Service and the Bureau of Land Management each operated several G-21 aircraft.
Royal Canadian Mounted Police "Grumman Goose has served coast for many years as 'flying-boat workhorse'." canada.com. Retrieved: December 19, 2009.
Civil operators
Asiatic Petroleum
British Guiana Airways
Pacific Coastal Airlines Wilderness Seaplanes
European Coastal Airlines
Koninklijke Nederlandsch-Indische Luchtvaart Maatschappij
Yaukuve Resort
Loftleiðir
Airfast Indonesia Merpati Nusantara Airlines – Leased a Goose from Indonesian Air Force. SAATAS-East Indonesia
Mount Cook Airline Sea Bee Air
Alaska Airlines – Alaska Airlines called their turboprop-powered aircraft the "Turbo Goose" propjet. They also operated piston-powered versions.http://www.timetableimages.com , June 1, 1969 Alaska Airlines system timetable Alaska Coastal Airlines Alaska Coastal-Ellis Airlines Alaska Island Air Alaska Fish and Game Amphib. Inc. Antilles Air Boats Avalon Air Transport Catalina Air Catalina Channel Airlines Chevron of California Devcon Construction Flight Data Inc. Ford Motor Co. Gulf Oil Kodiak Airways Kodiak Western North Coast Aero Ozark Management Pan Air PenAir Reeve Aleutian Airways SouthEast Skyways Superior Oil Sun Oil Co. (Sunoco) Teufel Nurseries The Texas Company (Texaco) Tuthill Corporation Virgin Islands Seaplane Shuttle Webber Airlines
Accidents and incidents 19 November 1943 Grumman JRF-2 of Port Heiden, Alaska (USCG), crashed with three crewmen and one passenger missing. It was found in 1987. 13 March 1947 A Grumman JRF-6B of Loftleiðir with a pilot and seven passengers crashed immediately after takeoff on Hvammsfjörður by the town of Búðardalur in Iceland. The pilot and four passengers evacuated the plane and were rescued by a boat, but one of those passengers later died. Three of the original seven passengers died in the crash. 21 August 1958 N720 crashed in the Brooks Range, near the upper Ivishak River, in Alaska, killing U.S. Fish and Wildlife Agents Clarence J. Rhode and Stanley Fredericksen, and Clarence's son Jack. The crash site was not found until August 23, 1979.