Napier Gazelle

1950s British aircraft turboshaft engine

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]

## Contents

* 1 Variants
* 2 Applications
* 3 Engines on display
* 4 Specifications (Gazelle 501 / Mk.101 / NGa.2(R))
* 4.1 General characteristics
* 4.2 Components
* 4.3 Performance
* 5 See also
* 6 References
* 6.1 Notes
* 6.2 Bibliography
* 7 External links

## Variants[edit]

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[edit]

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[edit]

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.

## Specifications (Gazelle 501 / Mk.101 / NGa.2(R))[edit]

Left view, Fleet Air Arm Museum, Australia

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)

## See also[edit]

Comparable engines

* General Electric T58
* Rolls-Royce Gnome

Related lists

* List of aircraft engines

## References[edit]

### Notes[edit]

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
3. ^ 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.
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

### Bibliography[edit]

* 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[edit]

Wikimedia Commons has media related to Napier Gazelle.

* Flight, July 1967, Napier Gazelle

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