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).
The development and materials used for aluminium brake drums.
| Identifier | ExFiles\Box 121\1\ scan0346 | |
| Date | 31th October 1940 | |
| 1029 Aluminium Brake Drums. Brakes To Rm.{William Robotham - Chief Engineer} From Rm{William Robotham - Chief Engineer}/AFM.{Anthony F. Martindale} Notes compiled from memory, no figures of any sort available. 31.10.40. 1) We decided originally to go for an aluminium case with a thin insert liner. Reason - this is the lightest possible construction. 2) We decided to shrink in the liner instead of cast it in. Reasons:- a) We thought we should have complete control of interference fit (not so in practice) b) the Hispano drum always 'crazed' which would ruin the linings of a high efficiency brake system in very little time (See notes on I.M.W.'s "rumbled" drums.) c) cost was not of first importance in these high a-far off days. 3) We first used N.M.C. steel for liner. Only one drum was made, at a cost of about £50 I should think. This drum worked fairly well due largely to the incredible time it took to make - natural ageing of aluminium. 4) We made some drums with 'Brinol' Austenitic st iron liners, expansion coeff 18 x 10⁻⁵. Much experience has convinced me that such a liner is bound to come loose. This is lucky because Brinol is expensive. Reason as follows:- P.T.O. | ||