Crankshaft vibration tests, the effectiveness of a spring drive as a shock damper, and further testing with a flywheel.
| Identifier | ExFiles\Box 43\3\ Scan142 | |
| Date | 16th March 1927 guessed | |
| contd :- -4- the end of the crankshaft and appeared more severe when the engine was operating under the inertia of the propeller, we attempted to find if the timing drives, magneto and valves were relieved of stress due to these vibrations by means of the spring drive. Some apparatus was employed which was already at hand and indicated an oscillation at the end of the spring drive relative to the end of the crankshaft. This movement appeared to follow the crankshaft oscillation but the oscillation peaks shewn on the diagram at the resonant speed lagged behind those of the crankshaft somewhat, indicating that the spring drive was fulfilling to some degree its function as a shock damper. The diagrams at other speeds are rather erratic and having more than one line traced become difficult to interpret. We are continuing work on this and hope to supply more positive information at an early date. Prints attached shewing the vibration of the end of the crankshaft and spring drive. Since the above was written we have made a test on the bed in which a flywheel of approx. the same inertia as the prop: was fixed to the front end of the crankshaft and the drive coupled to the water brake in the usual way. Diagrams of crankshaft oscillation taken under these conditions revealed vibrations of greater amplitude at the timing gear end of the crankshaft than when operating without the flywheel. This is a similar result to that obtained on the Goshawk(Aero Engine)(Codename for 20HP Car / Aero Engine after Kestrel(Aero Engine)) when it will be remembered we could not reach a condition of resonance when the flywheel was coupled by light friction to the crankshaft. Further tests are in progress. Hs {Lord Ernest Hives - Chair} /A. C. Lovesey. | ||
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).