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).
Report page analyzing mud ingress into a brake drum system and testing different dust cover designs.
| Identifier | WestWitteringFiles\O\2January1926-March1926\ Scan58 | |
| Date | 1st February 1926 guessed | |
| contd :- -2- MAJORITY OF MUD ENTERS HERE GRADUALLY DECREASING TO NOTHING TOWARDS BOTTOM OF LEADING SHOE LEADING SHOE DIRECTION OF DRUM ROTATION NO APPRECIABLE QUANTITY OF MUD ENTERS ON THIS SIDE (TRAILING SHOE) Fig I The question was raised as to whether the effect of increasing the clearance between the dust cover and the brake drum consequent upon drum distortion, due to brake application, allows mud to enter. An examination of Fig.1. disproves this theory - it is noticeable that the majority of the mud enters at the point where the clearance between the dust cover and the drum is actually decreased by brake application; we find the maximum increase in clearance to be .030" at the points of centre of pressure of the brake shoes, the clearance level with the toggle and shoe fulcrums decreasing a corresponding amount. In accordance with DA{Bernard Day - Chassis Design}'s suggestions we have carried out tests on the three types of dust cover shown in Fig.11. The types of dust cover shewn in A.{Mr Adams} and B. were found to give no better result than standard. Type C. showed approx. 25% improvement, but mud collects between the drum and contd :- | ||