Armstrong Siddeley Viper

Design and development

The design originally featured a seven-stage compressor based on their Adder engine — the Viper is in effect a large-scale Adder.

Like the similar J85 built in United States, the Viper was developed as an expendable engine for powering production versions of the Jindivik target drone, but, again like the J85, the limited-life components and total-loss oil systems were replaced with standard systems for use in manned aircraft.

Because it was initially developed as an expendable engine, the Viper was subject to many recurring maintenance issues. This led to the development of the first Power by the Hour program in which operators would pay a fixed hourly rate to Bristol Siddeley for the continual maintenance of the engines.

Variants

Data from Jane's All the World's Aircraft 1962-63.

ASV.3

Short life for missile/target applications, 1,640 lbf (7.30 kN).

ASV.4

Short life for missile/target applications, 1,750 lbf (7.78 kN).

ASV.5

Extended life version for manned aircraft.

ASV.6

Short life for missile/target applications, 1,900 lbf (8.45 kN).

ASV.7

ASV.7/R

2,470 lbf (10.99 kN) with re-heat.

ASV.10

Viper 8

(Mk.102 / Mk.104): Engines for the Hunting-Percival Jet Provost TMk.3 (Mk.102) and GAF Jindivik Mk.102B target drone (Mk.104).

Viper 9

(Mk.103): Powered the Bell X-14 and Handley Page HP 115 among others.

Viper 11

(Mk.200): Powered the Hunting-Percival Jet Provost TMk.4(Mk202) and GAF Jindivik Mk.3 among others.

Viper 20

(Mk.500 series): Powered the Hawker Siddeley HS.125 and Piaggio-Douglas PD.808 among others.

Viper 22

Built under licence by Piaggio for the Aermacchi MB.326

Mk.102

Mk.103

Mk.104

Mk.200

Mk.201

Mk.202

Mk.204

Evidence found on a surviving Mk204 engine suggests this is a Mk202 variant with increased temperature and oil pressure transmission capabilities. These are thought to be safety measures installed for use in Jet Provost aircraft used by HRH Prince Charles during his Royal Air Force flight training programme.

Mk.301

Mk.500 series

Mk.520

Mk.601

M.D.30 Viper

Engines licence-built and developedby Dassault Aviation

Specifications (Viper ASV.12)

Data from

General characteristics

Type: Turbojet

Length: 64.0 in (1,625 mm)

Diameter: 24.55 in (624 mm)

Dry weight: 549 lb (249 kg)

Components

Compressor: Seven stage axial

Combustors: Annular, 24 burners

Turbine: Single stage

Fuel type: AVTUR, AVTAG

Oil system: scavenge, metered

Performance

Maximum thrust: 2,700 lb (12 kN) at 13,800 rpm

Overall pressure ratio: 4.3:1

Air mass flow: 44 lb/sec (20 kg/s)

Specific fuel consumption: 1.09 lb/hr/lb

oil consumption=1.25 pints/hr (0.7l/h)

Thrust-to-weight ratio: 4.9:1