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).
Internal memorandum detailing recommended modifications for the Girling brakes on the Bentley II M Series.
| Identifier | ExFiles\Box 85\1\ scan0409 | |
| Date | 23th April 1938 | |
| To By.{R.W. Bailey - Chief Engineer} from Rm{William Robotham - Chief Engineer}/AFM.{Anthony F. Martindale} c. By/CRL.{C. R. Lisson} Handwritten: 1099 (crossed out) 206 Rm{William Robotham - Chief Engineer}/AFM.{Anthony F. Martindale}6/MH.{M. Huckerby}23.4.38. GIRLING BRAKES ON BENTLEY II - M SERIES. We have recently had 3.B.IV built up in the manner proposed for production, i.e. with iron drums all round, iron shoes in the rear brakes, and with the latest leverages. The brakes on this car are now satisfactory. When first built up we ran into the trouble of wheel wobbles at 50 m.p.h. which were started by brake applications. Although this is a steering fault, we thought it advisable slightly to derate the brakes, i.e. increase the pedal pressure necessary to effect a given stop, so as to eliminate the wobbles. We recommend that :- (1) The servo lining used should be Ferodo R.A.D.13 instead of Halo 2L. R.A.D.13 is our previous standard, and the change may reduce the scrap. (2) The lever G.52049 should be used on the servo countershaft in place of the lever G.57128. This is a reversion to our previous standard. (3) The plate lever on the front equalizer should be 2.150" instead of 1.950". This piece is new and can therefore be made any length. We warned By/CRL.{C. R. Lisson} that the exact length could not be determined until 3.B.IV was built. If you agree to these modifications will you please instruct them. This brake set up has given us trouble experimentally owing to the widely differing efficiencies of front and rear brakes and it has taken us rather a long time to find a leverage com-bination which gives a consistent proportion of braking, front/rear. The set up as recommended is satisfactory; the brakes are quite consistent in operation. Rm{William Robotham - Chief Engineer}/AFM.{Anthony F. Martindale} | ||