Armstrong Siddeley Snarler (original) (raw)

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1950s British aircraft rocket engine

The Armstrong Siddeley Snarler was a small rocket engine used for mixed-power experiments with an early turbojet engine.[1][2] and was the first British liquid-fuelled rocket engine to fly.[3]

Design and development

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Unlike other British rocket engine projects that used hydrogen peroxide as an oxidiser, Armstrong Siddeley's used liquid oxygen. The rocket engine is described as having a dry weight of 215 lbf (960 N) thrust of 2,000 lbf (8.9 kN) and a specific fuel consumption of 20 (lb/h)/lbf thrust.[3] Work began in 1947 and the final configuration was first tested on 29 March 1950.[3]

The prototype of the Hawker P.1040 Sea Hawk, VP 401, had a Snarler rocket of 2,000 lbf thrust added in its tail. The Rolls-Royce Nene turbojet, of 5,200 lbf thrust, had a split tailpipe which exhausted either side of the fuselage. The combination was termed the Hawker P.1072.[4][5]

This gave approximately[6] 50% greater thrust, although with twenty times the fuel consumption.[3] It was first used in flight on 20 November 1950, by Hawker's test pilot Trevor "Wimpy" Wade.[4] Half a dozen flights were made using the rocket motor before a minor explosion damaged the aircraft. Although methanol was used in the P.1072, jet fuel could be used for the Snarler. It was decided that reheat was a more practical proposition for boosting jet thrust than rockets.

An unusual feature of the engine was that the fuel/oxidiser pump was externally driven, by a drive from the gearbox of the P.1072's turbojet engine. This feature continued into the first versions of the subsequent Screamer engine, but was later replaced with a turbine-driven turbopump.[7]

ASSn.1 Snarler

The prototype and test engines, (Ministry of Supply designation ASSn.).

• Hawker P.1072

Data from Aircraft engines of the World 1953,[8] Flight:6 August 1954:Armstrong Siddeley Snarler[9]

General characteristics

• Type: rocket engine booster
• Length: 94 in (2,400 mm) (overall length); 25.4 in (650 mm) (combustion chamber length)
• Diameter: 12.5 in (320 mm) (nozzle diameter)
• Dry weight: 215 lb (98 kg)
• Propellant capacity: 120 imp gal (140 US gal; 550 L) fuel; 75 imp gal (90 US gal; 340 L) oxidiser
• Fuel: 65% methanol, 35% water
• Oxidiser: liquid oxygen

Components

• Pumps: externally driven accessory gearbox mounted centrifugal pumps with de-aerators

Performance

• Thrust: 1,350–2,350 lbf (6.0–10.5 kN) at 20,000 ft (6,100 m) (dependent on main engine speed)
• Part thrust: 450–750 lbf (2.0–3.3 kN) at 20,000 ft (6,100 m) (dependent on main engine speed)
• Burn time:
• Thrust-to-weight ratio: 6.28–10.93 (part thrust: 2.09–3.49)
• Specific impulse: 195 seconds (1.91 km/s)
• Burn time: 2 minutes 45 seconds (Hawker P.1072 installation)
• Thrust specific fuel consumption: 20 lb/(lbf⋅h) (570 g/(kN⋅s))

Related development

• Armstrong Siddeley Screamer

Related lists

• List of aircraft engines

1. ^ S. Allen (7 December 1951). "Rockets for Aircraft Propulsion". The Aeroplane.
2. ^ "Snarler: Armstrong Siddeleys Oxygen Water-methanol Rocket Motor : Handling Liquid Oxygen". Flight: 92–93. 25 July 1952.
3. ^ a b c d "Aero engines 1954". Flight: 447–448. 6 August 1954.
4. ^ a b "Armstrong Siddeley Snarler". Flight: 92–93. 25 July 1952.
5. ^ "The Quest for Power..." Flight: 444. 6 August 1954. Transferring liquid oxygen from a B.O.C. spherical tanker to the Hawker P.1072 in which the Sn rocket was tested. The gas is exhausting through the lower vents and rapidly evaporating.
6. ^ Although the Nene's thrust, as for any turbojet, fell with increasing altitude the Snarler's remained constant.
7. ^ "Armstrong Siddeley Screamer". Flight: 160–164. 27 July 1956.
8. ^ Wilkinson, Paul H. (1953). Aircraft engines of the World 1953 (11th ed.). London: Sir Isaac Pitman & Sons Ltd.
9. ^ "Armstrong Siddeley Snarler:THE DEVELOPMENT OF A PUMP-FED LIQUID-FUEL AIRCRAFT ROCKET". Flight. 66 (2376): 176–180. 6 August 1954. Retrieved 7 January 2019.