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).
Testing 5% carbon steel brake drums, which resulted in violent brake judder, leading to a recommendation to cease further testing.
| Identifier | ExFiles\Box 120\1\ scan0215 | |
| Date | 30th September 1937 | |
| To By.{R.W. Bailey - Chief Engineer} from Rm{William Robotham - Chief Engineer}/AFM.{Anthony F. Martindale} c. DA.{Bernard Day - Chassis Design} c. HPS.{Horace Percy Smith - Experimental Factory Mgr} 1028 Rm{William Robotham - Chief Engineer}/AFM.{Anthony F. Martindale}7/AP.30.9.37 5% Carbon Steel Brake Drums - Ph.III. Two sets of the above have been made, fitted to cars and tested in accordance with E's suggestion. One car, 35-EX, developed a violent rear brake judder and on examination of the drums these were seen to have polished themselves in patches to a mirror finish, in other patches the rubbing surface remained relatively rough. Changing the drums to C.I. drums stopped the judder. It is generally admitted that C.I. is the best brake rubbing surface. The steel drums would be much more expensive to produce as the cost of forgings and machining is very high. We gain nothing useful from the steel drums at the present juncture so we suggest that no further testing is carried out on them. As they have cost a lot of money to make we will keep one set in our Stores at Shardlow. Rm{William Robotham - Chief Engineer}/AFM.{Anthony F. Martindale} | ||