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).
Report page detailing experiments with an indicator to graphically show torsional oscillations in a crankshaft.
| Identifier | WestWitteringFiles\P\2July1926-September1926\ Scan133 | |
| Date | 4th September 1926 guessed | |
| contd :- -6- large amplitude until ultimately fracture would occur. Speeds of 1/2, 1/3, 1/4, etc. of the critical speed would also be expected to produce vibrations of larger amplitude than mere forced vibrations but naturally not of such proportions as at the critical speed. EXPERIMENTS WITH INDICATOR FOR SHEWING GRAPHICALLY TORSIONAL OSCILLATIONS. In order to prove if these were pure torsional vibrations and obtain information about them, we constructed the following apparatus which would give a graphical representation of them. An instrument of this type has been used in America and was described in The Automotive Industries of June 10th. 1926. Briefly the instrument consists of a flywheel floating on the forward extension of the crankshaft and, driven by low rated springs, rotates at a nearly uniform speed or the average speed of the crankshaft while a plate rigidly attached to the shaft follows any torsional oscillations of the shaft. A toggle mechanism is connected between the two - i.e. the flywheel and the plate - which gives a small scriber attached to it a radial movement for any difference in the relative angular velocity of the two. This scriber is able to mark a curve on a loose whitened plate which can be guided on to an extension of the crankshaft nut. If there is no difference between the angular velocities of the front flywheel and the crankshaft then the scriber will trace a circle, but any torsional oscillation will be represented by a wave formed curve. contd :- | ||