Armstrong Siddeley Snarler

ASSn.1 Snarler

Country of origin	United Kingdom
Manufacturer	Armstrong Siddeley
Liquid-fuel engine
Propellant	Liquid oxygen (LOX) / methanol/water
Pumps	Centrifugal, mechanically driven by external shaft drive from other engine.
Performance
Thrust	2,000 lbf (8.9 kN) [1]
Propellant capacity	LOX 75 imperial gallons (340 L), water-methanol 120 imperial gallons (550 L)

Hawker P.1072

The Armstrong Siddeley ASSn. Snarler was a small rocket engine used for mixed-power experiments with an early turbojet engine^[2][3] and was the first British liquid-fuelled rocket engine to fly^[4] 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.^[4] Work began in 1947 and the final configuration was first tested on 29 March 1950.^[5]

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.^[5][6] This gave approximately^[7] 50% greater thrust, although with twenty times the fuel consumption.^[4] It was first used in flight on 20 November 1950, by Hawker's test pilot Trevor "Wimpy" Wade.^[3] 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 turbopump was externally driven, by a drive from the gearbox of the P.1072's turbojet engine.^[8] This feature continued into the first versions of the subsequent Screamer engine, but was later replaced with a turbine-driven turbopump.

Variants

ASSn.1 Snarler

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

References

1. "United Kingdom Aerospace and Weapons Projects: Rocket Engines". Skomer.
2. S. Allen (7 Dec 1951). "Rockets for Aircraft Propulsion". The Aeroplane.
3. "Snarler" (PDF). Flight: 92–93. 25 July 1952.
4. "Armstrong Siddeley Snarler ASSn.1" (PDF). Flight: 447–448. 6 August 1954. |chapter= ignored (help) (includes external line drawing)
5. "Armstrong Siddeley Snarler" (PDF). Flight: 176–180. 6 August 1954.
6. "P.1072 Armstrong Siddeley Snarler ASSn.1" (PDF). 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. |chapter= ignored (help) (P.1072 being fuelled)
7. Although the Nene's thrust, as for any turbojet, fell with increasing altitude the Snarler's remained constant.
8. "Armstrong Siddeley Screamer" (PDF). Flight: 160–164. 27 July 1956. (not publicly known at the time of Flight, 1954)