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).
Potential causes for Bentley brake failures, specifically 'brakes dying away'.
| Identifier | ExFiles\Box 84\2\ scan0137 | |
| Date | 12th April 1934 | |
| X 20 6 W/B. To Sg.{Arthur F. Sidgreaves - MD} from E.{Mr Elliott - Chief Engineer} c.c. Mr. Hs.{Lord Ernest Hives - Chair} E.1/HP.12.4.34. re Bentley Brakes. Replying to your memo Sg.{Arthur F. Sidgreaves - MD}5/E.11.4.34, we are very interested to have Bn{W.O. Bentley / Mr Barrington}'s comments on his experiences particularly as we have a number of improvements in hand for these brakes, all of which have a bearing on the criticisms raised. We will deal with the types of failure in the order in which they are mentioned:- (1) Brakes dying away. In the absence of further particulars we do not know quite what is meant here. There are three phenomena which occur on brake systems generally which might be responsible for this, namely: (a) expansion of brakes by overheating causes the pedal to come down on to boards (b) fading away due to the effect of heat on coefficient of friction (c) effect of inefficiency of servo. We assume that the failure experienced was not (a) or the pedal position would have been noted. If the trouble was caused due to (b) our experience is that customers do not drive in a manner that brings on fading due to this cause. We are however experimenting with further friction materials with a view to overcoming this defect. It is somewhat unlikely that servo inefficiency is responsible as when this occurs the defect is present usually all the time, but if it be the case that the servo is involved we are shortly hoping to standardize a spring plate coupling for the servo friction member which should be a very great improvement in maintaining servo efficiency and also a needle bearing on the outboard support of the servo shaft to obviate the effect of wear at this point affecting the servo. | ||