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 an apparatus for observing torsional oscillations and crankshaft vibrations, with analysis of results at various speeds.
| Identifier | WestWitteringFiles\P\2July1926-September1926\ Scan134 | |
| Date | 4th September 1926 guessed | |
| contd :- -7- Actually this apparatus was constructed from the existing slipper drive, the flywheels being bolted together so that they could rotate freely without friction on the spring drive hub and were driven by two sets of tension springs attached to a plate bolted to the hub. A diagram of the apparatus is appended. With this apparatus we cannot use the damping action of the slipper wheels therefore the diagrams obtained represent the vibrations without the damper. This will have no effect on the speed or frequency but only on the amplitude. We are however modifying the apparatus to make it independent of the slipper drive so that we can observe the effect of varying degrees of damping. A number of diagrams have been obtained with this instrument. They are of interest inasmuch as they clearly shew the presence of torsional oscillations at various speeds. It is logical to state that a periodic force, such as given by either the inertia torque or explosion pressures, would produce in the crankshaft forced vibrations of the same frequency. Also that the amplitude and therefore the stress produced by them will depend upon the relation between the frequency of the disturbing force and that of the free vibration of the elastic body - i.e. the crankshaft. Referring to the diagrams obtained we find that there is an oscillation at a speed of 1100 r.p.m. and it passes through nine complete cycles in one revolution. The second diagram at a speed of 1600 r.p.m. has six complete oscillations per rev. contd :- | ||