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).
Engine vibration, proposing a design for a centrifugal friction damper for the crankshaft.
| Identifier | WestWitteringFiles\V\March1931-September1931\ Scan120 | |
| Date | 14th April 1931 guessed | |
| (2) vibration which is perhaps 20 times greater than the vibration due to the out of balance or variation of kinetic energy of the piston. I conclude that to prevent the fall of friction we must have dry surfaces as well as rigid ones. Now it would seem that we are only limited at slow speed as to the amount of friction we can use, and if we increase this friction with speed we can have much more when we want it. If this is so we should do well to adopt the centrifugal loading. I send a sketch of a simple damper which has the merits of needing no bearings to require lubrication. (A centrifugally loaded damper could drive the fan pulley because there would be ample friction.) I am in favour of fibre because it would not yield without slipping. [Diagram annotations start] Fibre riveted or pegged to split ring which may be cast iron. Light as possible but must not burst at full speed - say 4000 revs. Weights. Sheet steel fan belt pulley. Crankshaft. Aluminium cast or forged brake drum same as for ordinary internal brake, cast iron or steel tube liner, split ring like a piston ring, good outward set for minimum friction, loaded for any proportionate increase with speed. [Diagram annotations end] With reference to (3) - whirling flywheel - this on my car is I believe the 65/70 MPH. vibration and is the only bad one. I am very keen in finding how light we can make this before we get into trouble. It may be better to have some of the flywheel in balance weights. My eight weight scheme is so easy to apply correctly and save the crankcase and bearings for the least weight that it should be tried. I am so surprised that we do not steadily eliminate one trouble after another, until we get a good car. If we could get a definitely lighter flywheel we could run this beyond 80 without much trouble - i.e. without altering flange. I will write again about our future. It will so much depend on what we can do to make a 6 cyl. nearly perfect as we are. If not we must try something more desperate. R.{Sir Henry Royce} | ||