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).
Brake lever modifications and testing for Bentley and Wraith models to adjust braking proportions and prevent servo judder.
| Identifier | ExFiles\Box 83\2\ scan0271 | |
| Date | 28th February 1938 | |
| To Rm{William Robotham - Chief Engineer}/IMW.{Ivan M. Waller - Head of Chateauroux} from Rm{William Robotham - Chief Engineer}/AFM.{Anthony F. Martindale} Rm{William Robotham - Chief Engineer}/AFM.{Anthony F. Martindale}10/WH.28.2.38. Handwritten notes: 200 also 600 O.B.IV & 20.G.VI BRAKES. We send you herewith three levers, Rm.{William Robotham - Chief Engineer}495/6/7, and some star springs. Bentley. Proportions of braking front to rear are as follows :- 1 As now 1.23 2 With Rm.{William Robotham - Chief Engineer}497 in place of 1.25" cos. 1.12 lever on cross shaft. 3 With Rm.{William Robotham - Chief Engineer}496 (T lever) and the two 1.02 long levers on the cross shaft interchanged. 4. Standard 0.92 The position is this, that you are getting fairly satisfactory results on 6.B.IY with a high proportion of front braking but we are frightened that customers would get into trouble with front brakes squeaking, diving, or otherwise misbehaving, if we standardise the brakes as they are; we dare not take the risk. We send you two levers which enable you to reduce this to two different amounts, and we want you to try both arrangements, and report your impressions. You will note that we are in both cases slightly higher than standard. In each case you will lighten the brake pedal pressure, in case (3) you will increase the power of the hand brake and prevent flexing of the cross member without a stay. Wraith. We find that we can absolutely prevent servo judders in one or two different ways, the simplest being increasing the number of star springs used. We have not finished our investigation in this matter yet and the writer cannot come to France until the matter is settled. | ||