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 carried out on a Phantom III car (31-EX) to investigate brake pedal sponge.
| Identifier | ExFiles\Box 92\4\ scan0100 | |
| Date | 19th October 1935 | |
| FOR FILE. X356 19.10.35. PHANTOM III BRAKE PEDAL SPONGE. Report on a test carried out on 31-EX. Places where lost movement occurred: 200 lbs. on pedal, servo inoperative. (1) Cross shaft between pedal and servo. The end of this shaft nearest to inside of car was inadequately supported, a thin vertical rod being the only fixing, and this was incapable of preventing deflection due to a 300 lb. load at right angles to it. The end of the shaft moved .300", this being equivalent to .500" on the pedal. It was learnt subsequently that a rigid support for this shaft was in general use, but that it had been omitted on this car. (2) Servo. The scissors opened .44" to take up servo .162" at 200 lbs. These correspond to .725" and 1.02" on the pedal respectively. Further tests showed that on a Ph.III car this movement might vary by an equivalent pedal movement of from .85" to 1.0", and that the bulk of this movement was due to the compression of the anti-jagger cruciform springs. On a Ph.II car (28-EX) the corresponding pedal movement was found to be .95". (3) Slack in Brake Rope. This was .16", or .26" on the pedal. (4) In Brake Drum. The clearance was normal. The sponge in the drum, although higher than we should like, was not excessive at this load. The clearance was equivalent to .55" on pedal. The sponge " " " .55" " ". A load of 200 lbs. on the pedal, the servo being stationary, does not give a very big load on the shoes. | ||