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).
Letter to Ferodo Ltd. regarding slipping clutches, servo torque requirements, and ongoing experiments.
| Identifier | ExFiles\Box 141\3\ scan0203 | |
| Date | 22th August 1933 | |
| x719 Hs{Lord Ernest Hives - Chair}/Cry.3/MA. August 22nd., 1933. Messrs. Ferodo Ltd., Chapel-en-le-Frith. Dear Sirs, We thank you for your FJF/WAC. of the 11th., inst. The maximum torque we need from the 20/25 servo is 2000 lbs.ins., measured at the friction surfaces before the compensating device. We expect this amount with a brake pedal effort of 150 lbs. We are sending you some clutch linings that have been removed from cars complaining of slipping clutches. We should be glad to have your views on the friction surfaces. We only allow for a coefficient of friction of .175 in the design of our clutches but get cases of slip. Perhaps you would test these linings and say whether you think any oil has got onto them. We hope you are being successful with the servo experiments. It is possible that the figure of 500 lbs. output for 300 input that we gave you is wrong. The 500 is for a compensating lever of 6.5" CTS.{C. Trot Salt - Carburation} The one on the box you have may be 8.5" in which case the output we should be satisfied with would be 380 lbs. Please let us know whether we can help you in these experiments by coming over to Chapel, as we shall be only to glad to do so. Yours faithfully, FOR ROLLS-ROYCE LIMITED. | ||