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

Present state of development: Total running time to date 754 hours. Engine V.1 completed a 150-hour endurance test at type test conditions, except for avoidance of the critical speed range of 6,500 to 8,500 rpm. V.4 has carried out two 10-hour test at increased thrust rating 13,400 rpm. V.3 Govenor checks of differing specific gravities have been completed. V.6 Strain gauge checks on the 1st 2nd and 3rd row compressor rotor rows were carried out. In the case of the 1st row stresses were too high and the 2nd and 3rd were very low and considered acceptable. Outstanding troubles Compressor thrust bearing (Expendable engine) Hoffmann bearing 4989 is now standardised. Centre bearing (expendable) had problems because of air locks in the Pilgrim Way metering pump. This has now been corrected and is satisfactory