Photograph:
McKinnon G-21G Goose ZK-ERX (c/n B-62 / 1205) of Sea Bee Air at Mechanics Bay, NZ (S Lowe Collection – NZCIVAIR)
Country of origin:
United States of America
Description:
Business and executive amphibious flying boat
Power Plant:
Two 507 kw (680 shp) Pratt & Whitney PT6A-27 turboprops
Specifications:
- Wingspan: 15.51 m (50 ft 10 in)
- Length: 12.1 m (39 ft 7 in)
- Height: 4.57 m (15 ft)
- Wing area: 35.07 m² (377.6 sq ft)
- Max speed: 380 km/h (236 mph)
- Cruising speed: 282 km/h (175 mph)
- Rate of climb: 610 m/min (2,000 ft/min)
- Service ceiling: 6,097 m (20,000 ft)
- Range: 2,575 km (1,600 miles)
- Fuel capacity: 2,218 litres (488 Imp gals)
- Empty weight: 3,039 kg (6,700 lb)
- Loaded weight: 5,670 kg (12,500 lb)
History:
The history of the Grumman Goose is dealt with elsewhere and need not be dealt with in any detail here. Suffice to say many ex- military examples became available after World War II and much effort was made by a number of companies to improve performance and load carrying ability. Following the formation of UAC (United Aircraft of Canada – later Pratt & Whitney Canada) and its very successful PT6A turboprop, McKinnon Enterprises Inc of Sandy, Oregon decided in 1956 to modify a number of Grumman Goose to turboprop power. It also converted a number to horizontally-opposed engines, and fitted examples with four engines.
A number were fitted with PT6A engines and c/ns 1211 to 1225 were chosen to modify to G-21E configuration by installing either the PT6A-20 turboprop of 410 kw (550 shp) or PT6A-27 of 507 kw (680 shp). A G-21A (c/n 1211) was the first completed in May 1970, becoming known as a G-21E. Further development lead to the G-21G with the PT6A-27 engine. This incorporated structural strengthening of the airframe, an increased fuel capacity to 2,218 litres (488 Imp gals), and certification to a gross weight of 5,670 kg (12,500 lb).
One example of a turboprop modified Goose was imported to this region. This aircraft (c/n B-62 / 1205) was manufactured in 1944 for the US Navy with the BuAer No 37809. After service with the Navy it went to Iceland as TF-ISR before returning to the United States as N5558. It was converted from piston engines to Pratt & Whitney PT-6 turboprops by McKinnon and was sold to Peyton Hawes of Portland, Oregon, being sold again in December 1980 to Sea Bee Air in New Zealand and becoming ZK-ERX.
It was subsequently operated on behalf of the Tuvalu Government, the aircraft being based at Tokelau, operating to Samoa, Kiribati, Nauru and the Cook Islands. It was eventually flown to Auckland, New Zealand for an overhaul, said to be paid for by the Tuvalu Government and performed by Air New Zealand. It is reported to have operated some services to the Hauraki Gulf but these ceased in 1983. The Tuvalu Government refused to pay the account for the overhaul and eventually, after much litigation, the aircraft was sold to Aero Quest of Cleveland, Ohio and was shipped to Washington, flown to Boeing Field, Seattle and later ferried to Cleveland, Ohio. Eventually it moved on to a private owner and was still airworthy in 2013 as N77AQ. This was the only G-21G conversion completed.