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).
Modifications to the 40/50 chassis slipper flywheel, including spring numbers, friction material, and tolerances.
| Identifier | ExFiles\Box 74\2\ scan0293 | |
| Date | 3rd March 1924 | |
| 43439 Mr Shelton. c. Hs.{Lord Ernest Hives - Chair} c. E.P. c. B.P.F. BY10-P13. 3. 24. 40/50 CHASSIS. SLIPPER FLYWHEEL. In view of the fact that the Test Dept. have now satisfied themselves definitely that it is necessary for them to have the friction moment of the Slipper Flywheel increased, it will be necessary for us to revert to the original number of springs and equipment for the springs for bolting the two flywheels together, that is, 20 instead of 10. In addition to the foregoing, we should specify the use of Continental Bakelite as the friction medium instead of red fibre, in order to cut out the possibility of variation from atmospheric humidity. We must also add a note to our drawing that it is absolutely necessary for the machining of the various friction faces on both the hub and the slippers to be without waviness and as nearly as possible devoid of radial seams. We should also add a note to the drawing pointing out that the ideal friction moment is a weight of 20 lbs. on a 17.500" lever, with limits of minus 3 plus 5. It is possible that these limits may have to be exceeded somewhat, as there are so many varying factors which go to make up the spring pressure, namely;- a/- The depth of the pockets for the springs. b/- The length of the distance piece, or spacer. c/- Variations in thickness in the fibres. d/- Variation in thickness of the hub flange, to which the parts are frictionally held. e/- Also last, but not least, the variation in the springs. With all these factors to deal with it is possible we may have to go to minus 5 plus 5 limit, and therefore I think it would be wisest in the first place to not tie the limit down too much. In the meantime we will try and do our best to try and get closer limits with reasonable workshop requirements, but for the present I think the limits quoted should stand, namely, plus or minus 5 instead of 3 plus 5. cintd. | ||