Photograph:
Bell 47G with an Allison 250 turbine engine on display at Schofields, NSW in March 1981 (David C Eyre)
Country of origin:
United States of America
Description:
General purpose utility helicopter
Power Plant:
(Series 600 transmission)
One 195 kw (261 shp) Allison 250 C20B turboshaft
Specifications:
- Max speed: 169 km/h (105 mph)
- Max cruising speed: 161 km/h (100 mph)
- Endurance with standard fuel: 2.56 hours
- Range: 344 km (214 miles)
- Vertical rate of climb: 296 m/min (970 ft/min)
- Max rate of climb: 381 m/min (1,250 ft/min)
- Hovering ceiling at 1,202 kg (2,650 lb) in and out of ground effect: 4,877 m (16,000 ft)
- Fuel capacity: 216 litres (47 Imp gals)
- Empty weight: 748 kg (1,650 lb)
- Useful load: 590 kg (1,300 lb)
- Loaded weight: 1,338 kg (2,950 lb)
History:
For many years Soloy Conversions in the United States has been involved in the convertsion of aircraft and helicopters to turbine power, using the Allison 250 range of turbines. The Company, founded by Joseph Soloy, commenced conversions of helicopters in the 1970s, commencing with the Hiller UH-12E. Work proceeded for eight years before certification of the UH-12 with an Allison 250-C20 was received in April 1975. Work immediately commenced on conversion of the Bell 47 series and following proof-testing of the airframe, the Bell 47 received its Supplemental Type Certification in September 1978.
For conversion, buyers sent their Bell 47 to the factory, or could purchase a zero-timed machine, or bought a kit and converted their own machine. The same choices were available in Australia through Hawker Pacific, the conversion taking 350 to 400 hours to install, depending on the modification status of the airframe. New factory warranty applied to the powerplant.
A number of models of the Bell 47G were acceptable for conversion, from the 47G-2 to the 47G-5 but most conversions were to the 47G-3B-1 model. The conversion involved, other than the new engine, new engine mounts and transmission mounted lower, a new wiring system, a reduction gearbox, turbine instrumentation and controls, and a new low-profile instrument console. The engine was mounted at roughly a 45 degrees angle connecting with the lower transmission half by a Soloy-designed driveshaft.
Two transmissions have normally been used, the 600 Series Transmission, the specifications of which are set out above, and the 900 Series Transmission, the latter having the 320 kw (429 shp) engine de-rated to 201 kw (270 shp). The 900 Series model had increased performance with an increased all-up weight to 1,452 kg (3,200 lb).
A number of Soloy conversions have been registered in Australia, one of the first being VH-PSH (c/n 6738) registered on 22 April 1981. At least two were registered and operated in New Guinea, these being P2-AHG (c/n 3375 – ex ZK-HBB, N8534P) and P2-AHI (c/n 6502 – ex VH-AHI). Another example became VH-DTA³ (c/n 7753) which was registered on 26 March 2004 but was withdrawn from service on 9 September 2015. Another, VH-PRK³ (c/n 7743), was a conversion of a Model 47G-4A and was exported to the United States in October 2017.