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).
Tests on brake pressure distribution, servo operation, and the effects of unequal braking.
| Identifier | ExFiles\Box 30\6\ Scan155 | |
| Date | 17th January 1924 | |
| R.R. 492A (40 M) (SL 42 12-7-23). J.H., D.{John DeLooze - Company Secretary} -4- Expl. No. 9940 REF: H24/L.G.17.1.24 EXPERIMENTAL REPORT. The pressure on each front shoe with standard arrgt. is approx. 11 X pedal pressure. We should therefore expect to get 1573 lbs. at front shoes when the rear shoes just came into contact with drum. This again would result in having to alter the pressure distribution in the system and it would be necessary to use higher pedal pressures to obtain same braking effort. (2) The angularity of the pull rod operating the servo would have to be increased which would result in increased pedal movement to operate servo as it rotated. These figures were got out with the original pressure on the servo with the reduced leverage. We tried the following scheme. The pedal lever on the differential distributing shaft is connected with a lever on the servo intermediate shaft through a set up spring of stiffness just sufficient to take up rear brake clearance against tension of brake springs. This also has the disadvantage of increasing the load on the brake pedal before the brakes come into operation although it is not as great as the other scheme. It would also tend to upset the distribution of pressure. We have tried reducing the pull off springs on the rear brakes. We suggest we try a dash pot to prevent the servo operating so quickly. Effect of unequal front braking on steering. We have tested the Hispano and find that with unequal braking before rear brakes came into operatio contd:- | ||