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).
Technical discussion on braking issues, including front brake ineffectiveness and brake fading, for existing and future cars.
| Identifier | ExFiles\Box 84\2\ scan0227 | |
| Date | 17th December 1934 | |
| -5- Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer}E/KW.17.12.34. Future Cars. We think the new water seal mentioned in (2) will largely eliminate the trouble even with M.R. linings. (7) Front Brakes ineffective when rear wheels are locked. This has always been considered a virtue of Rolls-Royce cars because it is likely to prevent front wheel skids. It is more or less inherent in the direct braking to rear wheels only system at present used on all our products. Personally, after living with the system for about 10 years, we do not consider that this is a very serious disadvantage. The only solution is to go to direct braking to all four wheels, a scheme of which we have running on the Bentley, but as previously pointed out, a major alteration would be required before this can be considered satisfactory. (8) Brakes "Fading". Existing Cars. We have satisfied ourselves that a large proportion of brake fading is due to the servo. When the servo loses its efficiency through getting too hot, the amount of back braking also increases. By means of a better servo lining and an improved method of attaching the lining to the servo which permits of better cooling, we have been able to reduce fading to a marked extent. We still maintain, however, that to demonstrate fading on the ordinary standard Bentley brakes, once the car has been run sufficiently for the linings to have settled down, necessitates driving in a manner which cannot be considered reasonable in view of the fact that we are producing a touring and not a racing car. Future Cars. Direct braking to all four wheels will eliminate variation between front and rear brake distribution due to servo inefficiency. As previously pointed out, however, this is not likely to be available for some time. In addition we are running drums with increased cooling ribs. The 14" drums at present instructed are another way of obtaining the same result. There is no doubt that more can be done by attention to the servo than to the brakes themselves. | ||