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).
List of probable future tests for analysing engine vibration, stroke, and torsional periods.
| Identifier | ExFiles\Box 137\4\ scan0079 | |
| Date | 27th February 1930 guessed | |
| - 4 - It may be found early in the course of this programme that certain tests can be discarded or new ones may be thought of. Probable Future Tests Tests which we should like to cover now we have the rig all built up are:- (1) On the subject of engine vibrations, we should like to try and measure the effective increase in stroke perceptible at T.D.C. at high speeds (if any), i.e., have a small alum rivet mounted to just touch the piston top (Nos 3 or 4 for preference) at low speeds. This should be held fairly tightly in a clamp. Then we would run the engine up and see if this alum rivet was pushed any further up by the piston top at high speeds. If there was anything detectable this way, say about .015" or so, we might try the effect of light and heavy pistons, balance weights, and then possibly cast iron crankcase. Alternatively, it might be interesting to motor a I-G-I engine which has a very stiff type of crankcase. (2) EFC. has in hand a device for measuring the aplitude of vibration at any point in an engine. It ressembles a gramaphone pick up with its attendant electrical system. We ought to try to bring this in. It could be used for comparing the amplitude of vibration in different parts of the crankcase or on different engines or at different speeds. (3) We should like to try some type of damped srping drive between the crankshaft and flywheel for its effect on torsional periods and perhaps torque reaction. The flywheel would have its own bearings on either side and be almost completely isolated from the crankshaft, the front end to spigot in or on the crankshaft or on a spring drive hub from the crankshaft. On the 20 H.P. we are not troubled with crankshaft torsional vibration on the road as the top period would be at 95 m.p.h. in top gear. On the S.S., however, it is possible to get very near the top period which is actually at the same road speed as the 20 H.P. Rg{Mr Rowledge}/Tsn. | ||