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).
Results of a pump endurance test after 100 and 500 hours.
| Identifier | ExFiles\Box 149\2\ scan0200 | |
| Date | 24th March 1939 guessed | |
| -3- The rate of delivery was un-changed, and there were no signs of oil leaks, or any sign of oil percolating through the material. (3) After 100 hours Test :- At the end of the 100 hours test run the pump was still in good condition. The radial gear clearance remained unaltered from the previous reading. The end clearance still showed a tendency to decrease - in this case a maximum decrease of .0005" was recorded - presumably due to distortion or shrinkage of the Bakelite. The wear on the driving gear bushes had again increased, the main casing bush having increased to a fairly general .001" whilst the casing bush had worn unevenly - the maximum wear being .002". There was no appreciable change in the delivery, and no indication of oil percolating through the casing. (4) After 500 hours Test :- At the end of the 500 hours endurance run, the total hours running completed by the pump were 652. This time was made up chiefly of 12 hour periods with occasional day and night runs. Comparing the deliveries and inlet depressions measured initially and after the 652 hours running there was very little variation (see Fig.I.) - approximately 120 pints per hour delivery, and an increase of 0.2 lbs. per 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 co-efficient of expansion of Bakelite. Throughout the previous tests, the general condition of the pump was good, but when stripped after the final test, the casing was found to be cracked as indicated in Fig.II - although there was no indication of oil percolating through the casing during the test. The only oil leakages were from the joint face and, of course, past the driving spindle. The difficulty of obtaining accurate dimensions due to roughness of the machined surfaces has already been mentioned, and in the final check, this difficulty was further increased owing to the distortion caused by the crack. Continued............ | ||