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).
Inconsistent servo action and a new woven cotton disc servo lining.
| Identifier | ExFiles\Box 16\3\ Scan052 | |
| Date | 29th May 1929 | |
| To R.{Sir Henry Royce} from Hs{Lord Ernest Hives - Chair}/an. c.c. to SG.{Arthur F. Sidgreaves - MD} Wor.{Arthur Wormald - General Works Manager} c.c. to E.{Mr Elliott - Chief Engineer} DA.{Bernard Day - Chassis Design} c.c. to BY.{R.W. Bailey - Chief Engineer} 47370 Hs{Lord Ernest Hives - Chair}/an3/LG29.5.29. S.S. BRAKES AND SERVO. 47420 With reference to OY/4.6.23. In our experience inconsistent servo action has been mainly due to the servo lining. Occasional cases of rusty cams or driving pins have arisen but on the whole we have few complaints of inconsistent brake action. We believe we have found a better servo lining than anything we have previously used, it is a woven cotton disc with no bonding material. Naturally it can only be used where the duty it has to perform is very light; the RR. servo lining never gets really hot or wears appreciably. A still further improvement in consistency is obtained if this cotton fabric is soaked in oil. This produces a surprisingly small drop in co-efficient of friction which can of course easily be compensated for by cam angle. Additionally, however, it enables the cams and driving pins to be lubricated from the central oiling system. The cotton discs require only a few drops of oil occasionally to keep it in the required state of oiliness. We have standardised the dry woven cotton disc on the S.S. but we think the fully lubricated servo is worthy of attention now that we can get oil to any part of the car by means of the Bijur. contd :- | ||