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).
Proposed alterations to the 40/50 braking system, with a table comparing braking percentages for different schemes.
| Identifier | ExFiles\Box 66\5\ scan0078 | |
| Date | 9th December 1926 | |
| To R. {Sir Henry Royce} from Hs {Lord Ernest Hives - Chair} /Rm. {William Robotham - Chief Engineer} c. BJ. Wor. {Arthur Wormald - General Works Manager} Dat. c. Rg. {Mr Rowledge} E. {Mr Elliott - Chief Engineer} By. {R.W. Bailey - Chief Engineer} c. Ov. 48420 Hs {Lord Ernest Hives - Chair} /Rml/T9.12.26. 48370 REDUCED FRONT BRAKING. We are sending you a graph of the proposed alterations to the 40/50 braking. In our opinion altering the servo levers will not reduce the proportion of front braking sufficiently. Also we do not think that on the whole the pedal pressure on the 40/50 is too light, and therefore would rather not reduce the rear braking units. With reference to wear on the servo, this has never caused the least trouble. If it is made less efficient, the driver will merely push harder which will inconvenience him and produce the same unit pressure on the servo. We consider that the factor dictating the load on the servo plates is the pull from the servo required to lock the rear wheels. Altering the leverage between the pedal and the servo does not decrease the amount of work that the servo has to do. We are trying out shortened cam levers on the servo, but consider that even if found desirable, they should be fitted with long levers on the front brake countershaft to reduce the percentage to the front. Scheme. % Front braking. Total braking units for unit pedal press. 1. Present standard. 40.5% 2080. 2. Da {Bernard Day - Chassis Design} 2/Ml 226. 38.7% 1720. 3. Expl. Mod. 34% 1860. 4. 2 & 3 combined. 32% 1550. 7-EX. car which has gone to Le CanadelHenry Royce's French residence is arranged with Scheme 3. Hs {Lord Ernest Hives - Chair} /Rm. {William Robotham - Chief Engineer} | ||