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).
Modified flexible coupling for the Wraith III and Bentley III dynamo drive, aimed at increasing torsional flexibility to reduce noise and wear.
| Identifier | ExFiles\Box 108\2\ scan0120 | |
| Date | 12th July 1938 | |
| BY/NS.{Norman Scott} c. Rm.{William Robotham - Chief Engineer} c. Rm{William Robotham - Chief Engineer}/Swdl.{Len H. Swindell} 600. Cancelled replaced by ExScheme DA.{Bernard Day - Chassis Design}3/G.12.7.38. WRAITH 111 and BENTLEY 111 DYNAMO DRIVE WITH INCREASED TORSIONAL FLEXIBILITY. Please receive herewith E.CD.793 Modified Flexible Coupling for Dynamo Drive. Wraith 111. In view of recent experiments, which have proved that timing gear noise and wear is considerably lessoned by allowing greater torsional flexibility to the dynamo drive, we have produced the design E.CD.793 showing the driving rubbers altered from circular to square, and the durometer hardness reduced from 60 to 40-45, and with the casing for rubbers in the dynamo fan casting relieved locally to allow greater freedom for the rubbers to deflect under torsional load. It is intended that the final die casting for the dynamo fan should have the recesses for the rubber blocks die cast to finish size. As an alternative to the general design, we have shown a scheme Fig.(1) which should be tried as a preliminary experiment, as it calls for new rubber blocks only, all the remaining parts being standard. Will you please detail and instruct both schemes experimentally as soon as possible. It may be found that some variation in the rubber hardness from that specified will be required to give the best result. In the Fig. (1) scheme we have shown the flats of the rubber blocks parallel to the radial axis of the driving pins to give the maximum flexibility; this may cause a tendency for the rubber to slide a little in its housing which will not be good for the rubber. It is therefore suggested that the rubbers should also be tried moulded to the pins at right angles to the position shown on design, this will reduce their flexibility, but will also remove the possibility of them scrubbing. DA.{Bernard Day - Chassis Design} | ||