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 100-hour endurance test on a gear, noting wear, overheating, and performance.
| Identifier | ExFiles\Box 149\2\ scan0195 | |
| Date | 14th April 1939 | |
| -2- HPS{Horace Percy Smith - Experimental Factory Mgr}/B1.1/CB.14.4.39. The dark brown markings on the teeth at approximately the pitch line, appeared to be due to local overheating. The tooth bedding thus indicated extended only half way along the length of the gear, and reveals the necessity for full tooth bedding with this material. The gear was refitted for a further 100 hours test. Test 2 - 100 Hours Endurance Test. The temperature conditions stipulated for this test being 100°C, a preliminary run was made to prove whether or not the end clearance required increasing to allow for the extra expansion, but the wear resulting from the previous running rendered modification unnecessary. After completing 100 hours at 2,000 P.R.P.M., 25 lb./sq. in. pressure at the increased temperature, the pump was again examined, and whilst the general appearance of the gear was unchanged, a dimensional check showed the end wear to have increased by .006" (making a total of .0104") and the outer diameter of the gear to have been decreased by an average of .003" - i.e. .0045" total. "Scruffing" at the periphery of the gear had continued during this run, and whilst the tooth bedding area had increased, no wear was recorded at the pitch line of the teeth. There was no further evidence of the "local overheating" remarked after the 50 hour run. Incidentally, the teeth contact surfaces were scratched and had innumerable particles of metal embedded into them. The steel driving gear (which had done considerably more running than the "Tufnol" driven gear) was in good condition, no wear being recorded either longitudinally or diametrically, although slight "scruffing" on the periphery was evident. Although dimensionally the casing had not suffered during the 100 hours run, the driven ("Tufnol") gear well was badly marked on the walls and on the face, whereas the driving (steel) gear well was comparatively unscathed. The priming capabilities of the pump were not affected by the 100 hours run, but the delivery was reduced by approximately 150 pts./hr. - making a total of 250 pts./hr. for the whole test - throughout the speed range - see BL.2327. HPS{Horace Percy Smith - Experimental Factory Mgr}/W.Bell. | ||