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).
Brake strap material, discussing issues with rear brake shoes on the 20/25 model and potential improvements.
| Identifier | ExFiles\Box 120\1\ scan0095 | |
| Date | 29th July 1932 | |
| R.{Sir Henry Royce} From Ha/Rm.{William Robotham - Chief Engineer} c. to Sg.{Arthur F. Sidgreaves - MD} Wor.{Arthur Wormald - General Works Manager} c. to By.{R.W. Bailey - Chief Engineer} E.{Mr Elliott - Chief Engineer} c. to Da.{Bernard Day - Chassis Design} Hdy.{William Hardy} c. to Mx.{John H Maddocks - Chief Proving Officer} c. to EP{G. Eric Platford - Chief Quality Engineer} γ 4612 Ha/Rm.{William Robotham - Chief Engineer}2/MJ.29.7.32. BRAKE STRAP MATERIAL. We have known for some time that if the 20/25 was driven sufficiently hard, the rear brake shoes could be made to rub, even when set with 1/8" initial pedal movement clearance. With the introduction of the flexible shoe tip we have to allow a further increase in this lost pedal movement. The easy change, silent third, has accentuated the trouble as the car can be driven continuously on this gear down winding lanes with greatly improved acceleration, and consequently increased use of the brakes. The ribbed drum, though it prevents "fading" when braking from high speeds, does not seem to have much affect on the temp. of the shoes. We find, however, as the attached report shows, that reducing the co-efficient of expansion and conductivity of the shoes effects a material improvement. We used cast iron to get a result quickly. We can experimentally make pressed steel shoes which would be more practical. We will send you a sample, as some quite rigid types are now being produced in England. Ha/Rm.{William Robotham - Chief Engineer} Attached: Report Ha/Rm{William Robotham - Chief Engineer}/FD.{Frank Dodd - Bodies}21.7.32. One Blue Print. | ||