Armstrong Siddeley Viper position meetings: Notes on a meeting held to review the...

Present state of development: Total running time to date 1234 hours. Plus 53 hours have been carried out in the high-altitude plant at Burnley. Engine V.1: Carried out a repeat 150-hour test with long-life type flame tubes. Test interrupted after 80 hours by centre bearing failure; and after 83 hours and 114 hours by front bearing trouble. For the last 40 hours of this test a Lucas control unit (SCH.3032) with improved altitude characteristics and hardened half ball seat with wire-wound strainer was fitted and functioned satisfactorily throughout. Engine V.2: repeat strain gauge tests carried out on 1st three compressor rotor blades with standard build and with 4 1/2deg twisted 1st row blades. Engine V.3: 25-hour test to Special Category Conditions (avoiding critical speeds between 6,500 to 8,500 rpm) carried out at 1850 lbs thrust rating; engine built to production standards (including fuel system) except for fitment of Nimonic 90 turbine rotor blades. Engine V.4 despatched to Burnley. Engine V.6 Strain gauge carried out with 1st row compressor rotor blades shewed 4 1/2deg. Outstanding troubles: 1. Compressor 1st row rotor blades: 1st row rotor blades have failed. Centre bearings: We have had a number of caes of the centre bearing failing, Turbine blade failure Rex.467 material. Flight report: Engine V.5: 19 hours flying time. Severe turbine rub developed and a new stator ring, machined to give greater tip clearance was fitted Fuel system: 1 Short-life engine. Tests at Burnley limited to 50,000ft on full throttle. Reheat: Production position. Long-life engine