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).
Brake testing a 40/50 HP car with cast iron servo liners, noting noise issues and comparison to the Hispano system.
| Identifier | ExFiles\Box 22\1\ Scan080 | |
| Date | 30th January 1924 | |
| R.R. 403A (40 H) (SL 42 12-7-23). J.H.,D.{John DeLooze - Company Secretary} Expl. No. 9910 REF: Hs{Lord Ernest Hives - Chair}6/LG30.1.24. EXPERIMENTAL REPORT. To R.{Sir Henry Royce} from Hs.{Lord Ernest Hives - Chair} c. to CJ. RG.{Mr Rowledge} c. to DA.{Bernard Day - Chassis Design} E.{Mr Elliott - Chief Engineer} c. to BY.{R.W. Bailey - Chief Engineer} WOR.{Arthur Wormald - General Works Manager} SECRET. BRAKES. We have run a 40/50 HP. car 800 miles under brake testing conditions with cast iron liners fitted to the servo. The total adjustment necessary on the servo during this run was 4 notches. This, in our opinion, means that with cast iron liners on the servo the wear will not be serious. The chief disadvantage with the cast iron, is noise. We have how got so used to quiet acting brakes that the swish from the servo fitted with cast iron liners sounds very noisy. The car is still running with this scheme fitted. At the present time it is on its way to North Devon where tests will be made descending the steep hills and measurements taken of the temperature of the servo. We shall be testing tomorrow on another car the increased leverage between the servo and rear brakes. We also have ready for test the servo with the increase wind-off - N.sch.1723. With reference to your telegram instructing us to - "test same movement of rear brake shoes for full stroke of servo as the Hispano - fear we have considerably more, therefore unfair". The work done by the Hispano servo is greater than ours due to (1) Having less leverage on the brakes (2) Having to operate 4 brakes instead of 2. When adjusted according to instructions, the Hispano brakes have more clearance in the off position - .035" compared with .023" RR. contd:- | ||