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).
Analysis of pedal travel and brake performance issues for the Phantom II S.S. brakes.
| Identifier | WestWitteringFiles\T\2July1929-December1929\ Scan113 | |
| Date | 6th November 1929 | |
| To R.{Sir Henry Royce} from Hs{Lord Ernest Hives - Chair}/an. c. SS.{S. Smith} c. HJr. E.{Mr Elliott - Chief Engineer} c. Da.{Bernard Day - Chassis Design} Ey. Hs{Lord Ernest Hives - Chair}/Rn{Mr Robinson}2/AD6.11.29. PHANTOM II. BRAKES. X7420 One or two points have been raised from time to time with regard to the S.S. brakes which we think merit attention. (1) New brakes, insufficient pedal travel available to allow reasonable wear margin before brakes require re-adjustment. Analysing this complaint we have. (a) Total theoretical pedal travel (N. Scn. 2646) to boards. 4.300" (b) Travel left after taking up shoe clearance (.020 at shoe centre) servo clearance, star spring clearance. 2.550" (c) Travel left after severe brake application due to elasticity in the system. 1.425" (d) pedal travel left, condition c. brake drums heated up. .500" This last loss of pedal travel is due to the brakes heating up the drums and causing them to expand. This is more serious than we thought. We should say that on a steep hill such as Porlock, a loss of 1.00" pedal movement is a conservative estimate. We can lose 1.5" of movement if we run with the brakes on until they smell but without damage to the liner. We are worse off in this respect than with the old V.{VIENNA} series drums which had greater heat capacity. | ||