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).
Experiments to stop brake squeaks, detailing issues with different brake types, linings, and friction coefficients.
| Identifier | ExFiles\Box 120\2\ scan0197 | |
| Date | 31th August 1937 guessed | |
| -2- but a mechanical servo increases this to give a pull equivalent to a hookup ratio to 44 to front, 53.6 to rear. I think this is all the information you asked for. We have temporarily stopped experimenting with different types of brake gear to stop squeaks, following an experiment on a certain brake which showed that the squeak frequency coincided with none of the natural frequencies of drums and shoes. It is generally admitted that Bendix brakes squeak very little although we have heard Packard brakes squeak badly on occasion. We are trying to get away from thermosetting oil soluble resins as bonding agents in linings because they seem to glaze very easily and then squeak. A high lead content lining has given very good results as have certain semi rubber linings. We find that linings that squeak badly generally have a rising value of the coefficient of friction as the rubbing speed falls, and the coefficient is high. High temperature operation leads to squeaks when the brakes have cooled. I would like to know if you agree with these remarks, and await your comments on our brake gear with interest. Yours very truly, | ||