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 on different thrust springs for the Borg & Beck clutch on the 25/30 HP model.
| Identifier | ExFiles\Box 129\3\ scan0093 | |
| Date | 11th February 1936 | |
| To H.{Arthur M. Hanbury - Head Complaints} c. to By.{R.W. Bailey - Chief Engineer} c. to Da.{Bernard Day - Chassis Design} c. to Hdy.{William Hardy} X110 Ha/Smth.3/KW.11.2.36. Borg & Beck Clutch for 25/30 HP. The thrust springs at present specified for the 11" clutch for 25/30 HP. are of 130 lbs. load and are painted cream. These springs were the recommendation of Borg & Beck and give a /u of .160. With these springs the pedal load in the "up" position is 38 lbs., i.e., 5 lbs. morethan the present standard. All our running up to date with the 11" clutch has been done with these springs, but we are now trying 110 lb. springs (painted green) which give a /u of .190 and a pedal load of 32 lbs., i.e., slightly less than the present standard. So far these springs have been satisfactory during tests on Green Bank, but we are continuing the tests in London traffic. Pending the completion of these experiments we recommend that the spring load is left in abeyance in the specification for the clutches. The clutches should, of course, have the strengthened eyebolts in S.82 material and with turned threads which are being fitted to the Bentley clutches. Ha/Smth. | ||