Rolls-Royce Gnome

Gnome
Rolls-Royce Gnome at the Imperial War Museum Duxford
Type	Turboshaft
Manufacturer	Rolls-Royce
First run	5 June 1959
Major applications	Westland Whirlwind Westland Wessex Westland Sea King
Developed from	General Electric T58

The Rolls-Royce Gnome is a single spool turboshaft engine originally developed by the de Havilland Engine Company as a licence-built General Electric T58—a mid 1950s design.^[1] The Gnome came to Rolls-Royce after their takeover of Bristol Siddeley in 1966, Bristol having absorbed de Havilland Engines Limited in 1961.

A free-turbine turboshaft, it was used in helicopters such as the Westland Sea King and Westland Whirlwind. The design was sub-licenced to Alfa-Romeo.^[2]

There were two series produced: the "H" turboshaft for helicopter use, and the "P" turboprop for fixed-wing aircraft.^[3]

Design and development

A single-stage turbine drives the 10 stage all-axial compressor, whilst a two-stage free power turbine drives the load. The combustor is annular. The Gnome differed from the T-58 in having a British developed fuel control system (Lucas).

Because an all-axial design is employed, the final stage compressor rotor blades are amongst the smallest ever manufactured. Normally, a small engine such as this would feature an axial/centrifugal or even a double centrifugal compressor.

The engine was one of the first developed with an analogue computer, de Havilland's own, as part of the fuel control system, specifically to control fuel flow during acceleration to prevent engine surge from occurring.^[4]

Variants

H.1000

1,050 shp, first production version for use on later marks of Westland Whirlwind

H.1200

1,250 shp, the Westland Wessex uses two H.1200 with a coupled gearbox with a limited power of 1,550 shp at the rotor.

H.1400

1,400 shp

H.1400-1

1,535 shp, uprated from the 1400 by increasing the gas-generator speed and using improved blades that can operate at higher temperatures.

H.1400-2

1,660 shp

H.1400-3

1,720 shp with new two-stage power turbine.

P.1400-3

Turboprop version of the H.1400-3 rated at 1,700 shp.

Applications

• Agusta A.101
• AgustaBell AB204B
• Agusta-Bell 205BG
• Kawasaki KV-107 (Swedish Navy only)
• Saunders-Roe SR.N6 hovercraft
• Westland Sea King and Commando
• Westland Wessex
• Westland Whirlwind

Engines on display

Rolls-Royce Gnome engines are on display at the following museums:

• de Havilland Aircraft Heritage Centre
• Imperial War Museum Duxford
• London Science Museum.
• The Helicopter Museum (Weston)

Specifications (Gnome H1400-1)

Data from Flight^[5]

General characteristics

• Type: Turboshaft
• Length: 54.8 in (1392 mm)
• Diameter: 22.7 in (577 mm)
• Dry weight: 334 lb (151.5 kg)

Components

• Compressor: Ten-stage axial flow
• Combustors: Annular
• Turbine: Single-stage compressor turbine, two-stage power turbine

Performance

• Maximum power output: 1,500 shp (1,119 kW)
• Overall pressure ratio: 8.4:1
• Power-to-weight ratio: 4.5 shp/lb

See also

Related development

• General Electric T58
  

Comparable engines

• Lycoming T53
  

Related lists

• List of aircraft engines
  

References

Notes

1. ^ Gunston 1989, p.155.
2. ^ Flight 1973
3. ^ Flight 18 March 1960
4. ^ http://www.flightglobal.com/pdfarchive/view/1960/1960%20-%200587.html Flight 29th April 1960 Gnome]
5. ^ Flightglobal archive - 1973 Retrieved: 9 November 2008

Bibliography

• Gunston, Bill. World Encyclopedia of Aero Engines. Cambridge, England. Patrick Stephens Limited, 1989. ISBN 1-85260-163-9

External links

• de Havilland engines^{[dead link]}