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).
Design for Bentley front brakes, focusing on aluminium drums to eliminate judder and squeaks.
| Identifier | ExFiles\Box 85\1\ scan0074 | |
| Date | 20th April 1936 | |
| GRY{Shadwell Grylls} X206 TO SY. [strikethrough] Copy to ba-HNG. Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} hs{Lord Ernest Hives - Chair}/Martindale [Signature P.A.A] Bentley Front Brakes. We send you herewith N.Sch.4798 showing a design for aluminium brake drums in conjunction with brake operation to eliminate jaggers. With respect to the aluminium drums, these have been made to conform as closely as possible to the design of those already tested by the Expl. Dept. It is intended that they should be die cast and that the fins will not require machining. The material for the liner is still subject to Expl. report, and it will be necessary also to obtain from the Expl. Dept. their recommendations for the shrinkage fit. It has been considered that the angle of embrace of the shoe can be increased to 110° now that the cause of the brake judder has been removed, but this angle of embrace can be varied experimentally. In view of the composite nature of the drum it is thought unnecessary to provide for the Hancock shoe to avoid brake squeaks. Whilst designing this new shoe we have taken the opportunity to simplify the fixing for the pull-off spring nearest the shoe pivot, and at the same time to strengthen the shoe at this point of weakness. In a small subsidiary view we show a means whereby the aluminium drum can be fitted to existing wheel hubs, the casting being made thick enough to take either machining. For test purposes it would be possible to lock up the Hancock shoe of existing brakes, and to utilise the pull-off spring bosses for the toggle fixing, so making use of existing shoes. We show the present standard wheel rim, and wheel discs shown on N.Sch.4796. We have ascertained, can be used. If at some future time we use a smaller rim as proposed, it will be necessary to reduce the height of the inner cooling fin. It appears to be impossible to use a leather gaiter on the cross steering tube joint, and we suggest | ||