From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
500-hour endurance test for a Wraith chassis oil pump with a Bakelite casing.
| Identifier | ExFiles\Box 149\2\ scan0187 | |
| Date | 31th March 1939 | |
| To RMC. from HPS{Horace Percy Smith - Experimental Factory Mgr}/Bl. c. to Rm.{William Robotham - Chief Engineer} c. to Da.{Bernard Day - Chassis Design} c. to RMC/DWB.{D. W. Brown} CHASSIS OIL PUMP. Wraith Pump with Bakelite Casing, after 500 hours Endurance Test. EW.964/5 Gears. Following previous tests of 2, 50 and 100 hours duration, interim reports being issued at each stage, the pump was subjected to a further 500 hours run under the same conditions - i.e. 2,000 P.R.P.M., 25 lb./sq. in. delivery pressure, using Motorine "C" at 75°C temperature - making the total running time 652 hours. These running times were composed mainly of 12 hour periods with occasional continuous day and night runs. Comparing the deliveries and inlet depressions, measured initially, and after the completion of the 652 hours running, (see BL.2316) there was very little variation - approximately 120 pts./hr. delivery, whilst a depression increase of 0.2 lb./sq. in. was recorded. Incidentally, that this pump was not as efficient as the standard A/C casing pumps, was attributed mainly to the fit of the thrust plate, a further contributory factor being the higher coefficient of expansion of the Bakelite casing. Throughout the previous tests, the general condition of the pump on examination was observed to be good, but when stripped after the final test, the casing was found to be cracked as indicated in BL.2318, although throughout the tests, there was no evidence of oil percolating through the casing, the only leakage being through the joint face, and of course, past the driving spindle. The difficulty experienced in obtaining accurate dimensions due to the roughness of the machined surfaces, has previously been recorded. This was further increased in the final examination by the distortion due to the cracking of the casing. However, reviewing generally the records of the dimensional changes throughout the tests, as given in BL.2317.A/B/C, the wear on the Bakelite casing itself was negligible, the tendency generally being for the material to contract. The maximum variation is shown continued. | ||