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).
Experimental secret report on the performance and wear of four-wheel brake systems.
| Identifier | Morton\M20.3\ img020 | |
| Date | 6th June 1924 | |
| R.B. 493A (20H) (D.A. 652 20-3-24) J.H.D. EXPERIMENTAL REPORT. Expl. No. 9940 9941 REF: Hsd/1/M36.6.24. To R.{Sir Henry Royce} from Hs.{Lord Ernest Hives - Chair} c. to C.J. HG. c. to E.{Mr Elliott - Chief Engineer} DA.{Bernard Day - Chassis Design} c. to EY. WOR.{Arthur Wormald - General Works Manager} S E C R E T. FOUR WHEEL BRAKES. Apart from the recent cars sent out to France fitted with the adopted scheme of brakes, 98-NK car fitted with the original MES.60 scheme and 9-PK car fitted with the agreed scheme have completed 10,000 miles in France. Experience with these cars has shewn that we get considerably more wear on the rear brakes when we use servo operated brakes than we do with the present foot-operated rear brakes. On most of the cars with servo operated brakes we have had the rear drums score badly. This has been practically an unknown complaint with the foot operated brakes. On 9-PK car, in 10,000 miles they used up all the rear adjustment on the rear brakes by the wearing of the Ferodo and the wear on the drums. The brakes on these cars were used very much more often and severe than we should expect with the standard car but we believe with the servo we shall get very much more higher pressure on the rear brake than we have ever had with the foot pressure. At high speeds one can put more pressure on the brakes than is possible with foot pressure only, with-out it producing an uncomfortable effect on the passengers. It has been arranged that we increase the brinell of the rear brake drums for future 4-wheel brake | ||