The Rolls-Royce Gnome is a British

turboshaft A turboshaft engine is a form of gas turbine that is optimized to produce shaftpower rather than jet thrust. In concept, turboshaft engines are very similar to turbojets, with additional turbine expansion to extract heat energy from the exhaust ...

engine originally developed by the

de Havilland Engine Company The de Havilland Engine Company was an offshoot of the de Havilland aircraft building company, which started life as the 'Engine Division of the de Havilland Aircraft Company' in 1926 producing the famous de Havilland Gipsy aero-engine. The c ...

as a licence-built

General Electric T58 The General Electric T58 is an American turboshaft engine developed for helicopter use. First run in 1955, it remained in production until 1984, by which time some 6,300 units had been built. On July 1, 1959, it became the first turbine engine t ...

, an American mid-1950s design. The Gnome came to Rolls-Royce after their takeover of

Bristol Siddeley Bristol Siddeley Engines Ltd (BSEL) was a British aero engine manufacturer. The company was formed in 1959 by a merger of Bristol Aero-Engines Limited and Armstrong Siddeley Motors Limited. In 1961 the company was expanded by the purchase of t ...

in 1968, Bristol having absorbed de Havilland Engines Limited in 1961. A licence to manufacture the T58 was purchased in 1958. The T58 had begun bench testing in 1955 and by 1958 had already been used in helicopters and de Havilland were able to test their first engines in a

Westland Whirlwind Westland or Westlands may refer to: Places *Westlands, an affluent neighbourhood in the city of Nairobi, Kenya * Westlands, Staffordshire, a suburban area and ward in Newcastle-under-Lyme *Westland, a peninsula of the Shetland Mainland near Vaila, ...

and

Wasp A wasp is any insect of the narrow-waisted suborder Apocrita of the order Hymenoptera which is neither a bee nor an ant; this excludes the broad-waisted sawflies (Symphyta), which look somewhat like wasps, but are in a separate suborder. Th ...

helicopters in August 1959 and March 1960 respectively. A

free-turbine turboshaft A free-turbine turboshaft is a form of turboshaft or turboprop gas turbine engine where the power is extracted from the exhaust stream of a gas turbine by an independent turbine, downstream of the gas turbine. The power turbine is not mechanically ...

, it was used in helicopters such as the

Westland Sea King The Westland WS-61 Sea King is a British licence-built version of the American Sikorsky S-61 helicopter of the same name, built by Westland Helicopters. The aircraft differs considerably from the American version, with Rolls-Royce Gnome engin ...

and

. The design was sub-licensed to

Alfa-Romeo Alfa Romeo Automobiles S.p.A. () is an Italian luxury car manufacturer and a subsidiary of Stellantis. The company was founded on 24 June 1910, in Milan, Italy. "Alfa" is an acronym of its founding name, "Anonima Lombarda Fabbrica Automobili." ...

. There were two series produced: the "H" turboshaft for helicopter use, and the "P"

turboprop A turboprop is a turbine engine that drives an aircraft propeller. A turboprop consists of an intake, reduction gearbox, compressor, combustor, turbine, and a propelling nozzle. Air enters the intake and is compressed by the compressor. Fuel ...

for fixed-wing aircraft.

Design and development

A two-stage turbine drives the 10 stage all-axial

compressor A compressor is a mechanical device that increases the pressure of a gas by reducing its volume. An air compressor is a specific type of gas compressor. Compressors are similar to pumps: both increase the pressure on a fluid and both can transp ...

, whilst a single-stage free power

turbine A turbine ( or ) (from the Greek , ''tyrbē'', or Latin ''turbo'', meaning vortex) is a rotary mechanical device that extracts energy from a fluid flow and converts it into useful work. The work produced by a turbine can be used for generating e ...

drives the load. Taylor 1982, p. 764. The combustor is

annular Annulus (or anulus) or annular indicates a ring- or donut-shaped area or structure. It may refer to: Human anatomy * ''Anulus fibrosus disci intervertebralis'', spinal structure * Annulus of Zinn, a.k.a. annular tendon or ''anulus tendineus com ...

. The Gnome differed from the T-58 in having a British developed fuel control system (

Lucas Lucas or LUCAS may refer to: People * Lucas (surname) * Lucas (given name) Arts and entertainment * Luca Family Singers, also known as "lucas ligner en torsk" * ''Lucas'' (album) (2007), an album by Skeletons and the Kings of All Cities * ''L ...

). 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 Centrifugal compressors, sometimes called impeller compressors or radial compressors, are a sub-class of dynamic axisymmetric work-absorbing turbomachinery. They achieve pressure rise by adding energy to the continuous flow of fluid through th ...

. The engine was the first developed with a full authority analogue computer,

de Havilland Propellers de Havilland Propellers was established in 1935, as a division of the de Havilland Aircraft company when that company acquired a licence from the Hamilton Standard company of America for the manufacture of variable-pitch propellers at a cost ...

' own, as part of the fuel control system, specifically to anticipate helicopter power demand from pilot control inputs and to limit fuel flow during acceleration to prevent engine surge from occurring. The system developed relieved the helicopter pilot of the need to control rotor speed directly; it delivered constant rotor speed under varying rotor load. and in this way was the analogue forerunner of all subsequent

full authority digital engine control A full authority digital engine (or electronics) control (FADEC) is a system consisting of a digital computer, called an "electronic engine controller" (EEC) or "engine control unit" (ECU), and its related accessories that control all aspects of ai ...

(FADEC) systems worldwide.

Variants

;H.1000: (Mk.101) , first production version for use on later marks of Westland Whirlwind ;H.1200: , the

Westland Wessex The Westland Wessex is a British-built turbine-powered development of the Sikorsky H-34 (in US service known as Choctaw). It was developed and produced under licence by Westland Aircraft (later Westland Helicopters). One of the main changes ...

uses two H.1200, as the Coupled Gnome, with a coupled gearbox with a power limited to at the rotor. ;H.1400: for the Westland Sea King HAS.1 ;H.1400-1: , uprated from the 1400 by increasing the gas-generator speed and using improved blades that can operate at higher temperatures for the Westland Sea King HAS.2. ;H.1400-1T:For the Westland Commando HC.4 troop carrier variant of the Westland Sea King ;H.1400-2: for the Westland Sea King HAS.5. ;H.1400-3: with new two-stage power turbine. ;H.1600: 11-stage compressor with 2-stage free power turbine ;P.1000:Turboprop version of the H.1000 ;P.1200:Turboprop version of the H.1200 ;P.1400-3: Turboprop version of the H.1400-3 rated at . ;Gnome Mk.101: ;Gnome Mk.110: Handed H.1200 engines for Coupled Gnome units used in Westland Wessex helicopters. ;Gnome Mk.111: Handed H.1200 engines for Coupled Gnome units used in Westland Wessex helicopters. ;Gnome Mk.112: Handed H.1200 engines for Coupled Gnome units used in Westland Wessex HU.5 helicopters. ;Gnome Mk.113: Handed H.1200 engines for Coupled Gnome units used in Westland Wessex HU.5 helicopters. ;Gnome Mk.501:Civilianised H.1000. ;Gnome Mk.510:Civilianised H.1000. ;Gnome Mk.610:Civilianised H.1200. ;Gnome Mk.640:Civilianised H.1200. ;Gnome Mk.640A:Civilianised H.1200. ;Gnome Mk 660: Used in the civilian Westland Wessex 60 helicopter variant of Wessex HC.2 ;Coupled Gnome:Twin engines driving through a common gearbox to a single output.

Applications

* Agusta A.101 * AgustaBell AB204B * Agusta-Bell 205BG * Kawasaki KV-107 (Swedish Navy only) * Saunders-Roe SR.N5 hovercraft * Saunders-Roe SR.N6 hovercraft * Vertol 107 *

and Commando *

Engines on display

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

de Havilland Aircraft Heritage Centre The de Havilland Aircraft Museum, formerly the de Havilland Aircraft Heritage Centre, is a volunteer-run aviation museum in London Colney, Hertfordshire, England. The collection is built around the definitive prototype and restoration shops fo ...

Imperial War Museum Duxford Imperial War Museum Duxford is a branch of the Imperial War Museum near Duxford in Cambridgeshire, England. Britain's largest aviation museum, Duxford houses the museum's large exhibits, including nearly 200 aircraft, military vehicles, artill ...

London Science Museum The Science Museum is a major museum on Exhibition Road in South Kensington, London. It was founded in 1857 and is one of the city's major tourist attractions, attracting 3.3 million visitors annually in 2019. Like other publicly funded ...

. *

The Helicopter Museum (Weston) The Helicopter Museum in Weston-super-Mare, North Somerset, England, is a museum featuring a collection of more than 80 helicopters and autogyros from around the world, both civilian and military. It is based at the southeastern corner of the fo ...

Caernarfon Airworld Aviation Museum Caernarfon Airworld Aviation Museum is an air museum located on the former Royal Air Force station at Llandwrog, near Caernarfon in North Wales. History The airfield was known as RAF Llandwrog, opening in January 1941 as a RAF Bomber Command a ...

Specifications (Gnome H1400-1)

References

Notes

Bibliography

* Gunston, Bill. ''World Encyclopedia of Aero Engines''. Cambridge, England. Patrick Stephens Limited, 1989. * Taylor, John W.R. ''Jane's All the World's Aircraft 1982-83.'', London, Jane's Publishing Company Ltd, 1982. .

External links

de Havilland engines
{{Rolls-Royce aeroengines 1950s turboshaft engines

Gnome A gnome is a mythological creature and diminutive spirit in Renaissance magic and alchemy, first introduced by Paracelsus in the 16th century and later adopted by more recent authors including those of modern fantasy literature. Its characte ...

Axial-compressor gas turbine engines