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 performance of a 4-wheel braking system on a 40/50 HP model.
| Identifier | WestWitteringFiles\K\December1923\ Scan51 | |
| Date | 7th December 1923 | |
| R.R. 493A (40 H) (SL 42 12-7-23). J.H., D.{John DeLooze - Company Secretary} EXPERIMENTAL REPORT. Expl. No. 9940 A559 REF: Hs{Lord Ernest Hives - Chair}4/107.12.23. To R.{Sir Henry Royce} from Hs.{Lord Ernest Hives - Chair} c. to CJ. c. to Rg.{Mr Rowledge} c. to Ds. BRAKES. We have been running a car fitted with the original type brakes (not floating fulcrum) in which the Ferodo on the forward shoe had been reduced to 120º (FROM PIVOT). The back shoe had the full amount of material. With this front brake we had 50% efficiency forward and good braking backwards. The car also had the latest epicyclic equaliser. On the road the car was the best example of 4-wheel braking which we have yet had on the 40/50 HP. We still get the effect that if the brake pedal is pressed suddenly, the back wheels immediately lock. If the pedal is pressed gradually we get fair 4-wheel braking but on a greasy road, the back wheels skid before much front braking comes on. We also get that unpleasant thump which occurs due to the speed at which the 'servo' takes up the slack. On the present standard car, with rear brakes only, on top gear we can pull the engine down so that the car just runs at 20 m.p.h. full throttle and run like this for an hour - on this car we ran about 4 miles under a similar condition. The brakes behaved satisfactorily and although the 'servo' was blue from heat, it did not appear to suffer. After running for some time and using the brakes, the front brakes became more effective. As the brakes became more effective, jaggers were apparent. So on this car we have a case of front contd:- | ||