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).
The results of endurance tests for a standard steel shaft, a second steel shaft, and a cast iron crankshaft.
| Identifier | ExFiles\Box 132\1\ scan0020 | |
| Date | 18th April 1927 guessed | |
| -7- were made. The results of the tests are as follow:- (1). Standard Steel Shaft. This shaft was run for - 2 hours with the centre bearing deflected 0.010". 39 " " " " " 0.020". 46 " " " " " 0.050". the speed of rotation being approximately 1875 r.p.m. Failure of the crankshaft occurred across the web, adjacent to the centre bearing, after a total running period of 87 hours. It was observed on dismantling the engine that the white metal bearings were somewhat scored, and the metal showed signs of crushing: slight score marks were observable on the crank journals. Second Steel Shaft. This test was carried out as a repeat of Test No. 1, to establish, if possible, whether a true condition of failure had been obtained. After 40 hours running under conditions exactly as in Test No. 1, it was found that the crank journals were scored, and that partial failure had occurred of the white metal bearings. The Crank journals, therefore, were reground by removing 0.005" of material, and new bearings fitted. The test was continued up to a total of 124 hours, when an inspection revealed a fatigue crack had developed in the centre main bearing. The exact time at which this crack had started could not be determined, but it may have been in existence for some time because the crankshaft was observed to be running freer in its bearings on reaching the 100 hour stage. CAST IRON CRANKSHAFT. This shaft was run for 100 hours with the centre main bearing deflected the same amount as in the tests with the Steel Crankshafts. At the end of this time the crankshaft was found to be perfectly sound, and the main bearing journals were in excellent condition. There were no score marks, and the amount of wear was almost | ||