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).
The development and testing of floating fulcrum brakes for the EAC.2 model.
| Identifier | WestWitteringFiles\L\Jan1924-March1924\ Scan17 | |
| Date | 11th August 1920 | |
| R.R. 325A (100 T) (S.H. 159 11-8-20) G.{Mr Griffiths - Chief Accountant / Mr Gnapp} 2880 (2) This confirms that for the brakes as well as engine efficiency nothing should stand in the way of EAC.2. getting into production as quickly as ever possible. FLOATING FULCRUM BRAKES. There appears to be an important mystery about these because they avoid jaggers. If we can make them efficient and they still avoid jaggers then I believe they will be found consistent but We await further tests. No-one would desire to change from the standard more or less rigid shoes and fixed fulcrum brakes unless some definite advantage can be gained, as these are the most practical, but the long lapping shoe type with fixed fulcrum does not (I understand) give consistent braking effect when worn, and this is the cause of variations in brakes both of 4 wheel and 2 wheel types, but I should like it definitely proved if condition of surface also has any effect. At present we do not definitely know. Owing to the efficiency of the servo being great-er than anticipated the braking on the front wheels has been proportionately less than anticipated. This DA.{Bernard Day - Chassis Design} & adjusted before I left WW. but if the proportions are still different to those desired another adjustment can be made, but care should be taken not to increase the re-quired torque needa from the servo because of the heat and also we must not greatly increase the leverage (from the foot) to the front brakes because we do not want fre-quent adjustment or insufficient clearance. There is insufficient stroke in some of the parts of the temporary arrangement which HS.{Lord Ernest Hives - Chair} has fitted, and an examination of the fitted car would give a better idea of some better arrangement. Forces low and stroke long I should prefer. I also understood that it was experimentally de-sirable to force the servo shoes apart with a stronger spring, and possibly alter the lower lever (i.e.1.4-5") to some other proportion (say 2.4 - 4) so as to keep the pull on the rod T. about the same as originally, and it was also desired to alter the direction of this pull so that follow up was necessary by the pedal. DA.{Bernard Day - Chassis Design} can shew how this can be conveniently and easily arranged. Perhaps some of these ideas will be on trial at the moment, but I mention them for fear they have been forgotten. They had for their object the less sudden way the rear brakes take up their clearance. The report does not suggest which form of shoe is to be preferred. I had the impression that possibly for consistent and smooth action a short lapping shoes would be preferred on the front, and backwards long or jointed shoes, and if with fixed fulcrum the single pull off stop should not be impractical. | ||