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Gazelle
	Napier Gazelle at the Royal Air Force Museum London
Type	Turboshaft aero engine
Manufacturer	D. Napier & Son
First run	December 1955
Major applications	Westland Wessex; Bristol/Westland Belvedere

The Napier Gazelle is a turboshaft helicopter engine that was manufactured by D. Napier & Son in the mid-1950s. In 1961 production was nominally transferred to a joint venture with Rolls-Royce called Napier Aero Engines Limited.^[1] But the venture closed two years later.^[2]

Variants

NGa.1: Emergency rating 1,260 shp (940 kW) at 20,400 rpm, 1 hour rating 1,100 shp (820 kW) at 19,800 rpm, Max continuous rating 920 shp (690 kW) at 19,000 rpm^[3]
NGa.2: Emergency rating 1,650 shp (1,230 kW) at 20,400 rpm^[3]
NGa.2(R): ^[4]
NGa.2 series 2
NGa.3: Emergency rating 1,800 shp (1,300 kW) at 20,400 rpm^[3]
NGa.4: Emergency rating 2,000 shp (1,500 kW) at 20,400 rpm^[3]
NGa.13(R): ^[4]
NGa.13 series 2
NGa.18
NGa.22
Mk.101: ^[4]
Mk.161: ^[4]
Mk.162: (NGa.13 series 2)^[4]
Mk.165: ^[4]
Gazelle 501: ^[4]
Gazelle 503: ^[4]
Gazelle 512: ^[4]
Gazelle 514: ^[4]
Gazelle E.219: ^[4]

Applications

These helicopter engines were used on the Westland Wessex HAS 1 and HAS 3 (other versions of the Wessex had two Rolls-Royce Gnome engines) and the Bristol Belvedere (later Westland Belvedere) transport helicopter.

Engines on display

A preserved Napier Gazelle is on display at the Royal Air Force Museum London. A preserved Napier Gazelle from a Westland Wessex helicopter is on display at the Queensland Air Museum, Caloundra, Australia. A Napier Gazelle is on display at the South Yorkshire Aircraft Museum, Doncaster A further Napier Gazelle is displayed at the Solent Sky Museum, Southampton

Specifications (Gazelle 501 / Mk.101 / NGa.2(R))

Data from Jane's All the World's Aircraft 1962-63 and Flightglobal archive.^[4]^[5]

General characteristics

Type: Turboshaft
Length: 70 in (1,778 mm)
Diameter: 33.5 in (851 mm)
Dry weight: 830 lb (376.5 kg)

Components

Compressor: 11-stage axial flow
Combustors: 6 flame tubes
Turbine: 2-stage gas generator power turbine + 1-stage free power turbine
Fuel type: Aviation kerosene
Oil system: Pressure spray / splash with gear pump and dry sump

Performance

Maximum power output: 1,650 hp (1,230 kW) + 260 lbf (1.2 kN) thrust at 3,000 output shaft rpm, maximum rating for 2.5 minutes
Overall pressure ratio: 6.25:1
Air mass flow: 16.8 lb/s (7.6 kg/s)
Specific fuel consumption: 0.688 lb/(hp h) (0.4185 kg/(kW h))
Power-to-weight ratio: 1.458 hp/lb (2.397 kW/kg)

References

Notes

^ "ENGLISH ELECTRIC-ROLLS ROYCE Napier Aero Engines Ltd." Times [London, England] 1 June 1961: 24. The Times Digital Archive. Web. 30 Aug. 2016.
^ Napier Aero Engines Ltd (closure) Hansard, 8 March 1963 vol 673 cc921-32
^ ^a ^b ^c ^d Wilkinson, Paul H. (1957). Aircraft engines of the World 1957 (15th ed.). London: Sir Isaac Pitman & Sons Ltd. pp. 154–155.
^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l Taylor, John W.R. FRHistS. ARAeS (1962). Jane's All the World's Aircraft 1962-63. London: Sampson, Low, Marston & Co Ltd.
^ Flightglobal online archive

Bibliography

Gunston, Bill. World Encyclopedia of Aero Engines. Cambridge, England. Patrick Stephens Limited, 1989. ISBN 1-85260-163-9
Taylor, John W.R. FRHistS. ARAeS (1962). Jane's All the World's Aircraft 1962-63. London: Sampson, Low, Marston & Co Ltd.

External links

Flight, July 1967, Napier Gazelle

[nae-1] "ENGLISH ELECTRIC-ROLLS ROYCE Napier Aero Engines Ltd." Times [London, England] 1 June 1961: 24. The Times Digital Archive. Web. 30 Aug. 2016.

[2] Napier Aero Engines Ltd (closure) Hansard, 8 March 1963 vol 673 cc921-32

[AEotW57-3] Wilkinson, Paul H. (1957). Aircraft engines of the World 1957 (15th ed.). London: Sir Isaac Pitman & Sons Ltd. pp. 154–155.

[JAWA62-63-4] ^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l Taylor, John W.R. FRHistS. ARAeS (1962). Jane's All the World's Aircraft 1962-63. London: Sampson, Low, Marston & Co Ltd.

[5] Flightglobal online archive

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Napier Gazelle