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, cooling, and required alterations for Spectre brake drums.
| Identifier | ExFiles\Box 92\4\ scan0093 | |
| Date | 21th September 1935 | |
| To E.{Mr Elliott - Chief Engineer} c. to Da.{Bernard Day - Chassis Design} x306 Hs{Lord Ernest Hives - Chair}/AFM.{Anthony F. Martindale}9/KW.21.9.35. SpectreCodename for Phantom III Brake Drums. We are investigating the rate of cooling of different designs of brake drums with a view to reducing the fade we get at present, and to increase the life of the linings. We are not in a position to send a report through on this subject at the moment, but we would like to inform you of one important point. We have noticed on several brake drums, such as standard Bentley Rear drums, that where the drum is not fully ribbed opposite the foot brake shoe, it is possible for the drum to reach a red heat locally while the fully ribbed parts are below 300°C. We would therefore like alterations made without delay to the SpectreCodename for Phantom III drums. The rear drum is a particularly bad example of this fault, and we attach a sketch of a 14" Bentley rear drum which shows a more desirable form of ribbing. The front drum is much more satisfactory, but we would like to have one extra small rib, making two small ribs in all. We would like to point out that in the case of the rear drum we have used two strengthening ribs, one opposite the inside of the foot brake shoe, and one above the water excluder flange to prevent the latter distorting and rubbing during brake applications. Hs{Lord Ernest Hives - Chair}/A.F.Martindale. | ||