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).
Responding to queries on brake adjustments, servo engagement, and braking distribution for 'Phantom' and 'India' models.
| Identifier | ExFiles\Box 105\4\ scan0028 | |
| Date | 16th September 1925 | |
| R.R. 493A (50 H) (D.D. 31. 12-6-25) J.H.D. EXPERIMENTAL REPORT. Expl. No. +5370 REF Hs{Lord Ernest Hives - Chair}/Rm{William Robotham - Chief Engineer}3/LG16.9.25. BY/NW.{N. Walker - Patents} from Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} In reply to BY/NW{N. Walker - Patents}2/VM15.9.25. The answers to your queries are as follows :- 1. The pedal travel to engage the servo measured from the top of the pedal to the dash should be not less than .230. The clearance between the straight faces of the servo cams when the servo is just engaged should be .025". 2. Further pedal travel of 1.23" should apply the rear brakes. This differs from the standard rear wheel brake 20 HP. movement. We have recommended .020" clearance at the shoe centre for the rear wheel brakes. This gives a movement of .600 at the end of lever G.56949 when the brakes are correctly adjusted. 3. The clearance at the centre of the shoes on the 20 HP. front wheel brake should be initially .025" This setting can be checked by observing the movement of the lever G.52475 on the front axle. The centre of the pin in this lever should move in .625" approx. before the brake clearance is taken up. 4. The distribution of braking on the 'Phantom' is 40% to the front and 60% to the rear. On the 'India' - 33% to the front and 66% to the rear. 5. The hand brake adjustment remains unaltered. We attach notes on further adjustments for customers. The pedal movement will want converting if measured from the top of the pedal to the dash. The movement we give at the centre of the pedal should be multiplied by 1.23 if the top of the pedal is to be used. Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} attc. copy of Hs{Lord Ernest Hives - Chair}/Rm{William Robotham - Chief Engineer}/LG24.7.25. | ||