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 discussing crank web balance weights and the design and function of slipper wheels for damping.
| Identifier | ExFiles\Box 125\2\ scan0053 | |
| Date | 14th June 1929 guessed | |
| contd :- -8- shape is such that for a given degree of out-of-balance they contribute the least amount to the polar inertia of the shaft. As shewn in the sketch attached our previous report, at journals where the two crank webs are at 120°, half size balance weights are used so arranged as to bisect the angle between the webs. This is instead of one full sized weight opposite each web. A total of four complete balance weights is saved this way. SLIPPER WHEELS. These are shewn in fig.5; and are arranged so that the loading increases with speed. This is done by means of a wedge-shaped ring of special heavy rubber, containing lead in the mixture. The density of this rubber is 2.99 ozs/cu.in. as against .875 ozs/cu.in. for RR. engine foot rubber. This rubber ring is a simple arrangement that remains in balance when opened out at high speed. We have no reason to believe that this slipper wheel is arranged this way to avoid 'galloping knocks', but would suggest as a more probable reason the fact that whilst giving max. available damping when required most, i.e. at high speeds, the damping is relaxed at low speeds and thus undue wear and loss of setting is avoided. The whole arrangement is unlubricated, and cadmium plated for protection. When not rotating, the rubber does not come into action at all. The friction material resembles cardboard and is fibrous. The duties of this slipper wheel appear light. contd :- | ||