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).
Exhaustive tests of two schemes for a 20 HP starter motor, detailing failures related to cork washers and buffer springs.
| Identifier | ExFiles\Box 5\6\ 06-page023 | |
| Date | 23th November 1927 | |
| To R.{Sir Henry Royce} From He/GWH.{George W. Hancock - Head Chateauroux} c. to S.J. Wor.{Arthur Wormald - General Works Manager} c. to E.{Mr Elliott - Chief Engineer} DA.{Bernard Day - Chassis Design} c. to HY.{Tom Haldenby - Plant Engineer} X5300 Hg/RHCL/L623.11.27. 20 HP. STARTER MOTOR TO LeC. 2441. SCHS. 1 & 2. X5300 X5650 We have given these schemes exhaustive tests fitted to a standard engine and on the test rig. Our results do not justify adopting the schemes. In dealing with sch.1, we did not find, by fitting the cork washer behind the operating bush flange, the friction required to obviate the slipping before the buffer or clutch spring was fully compressed to its working head. In this test it must be made clear that no additional friction was got by the pressure of the end cap D.50872 pressing on the cork. We state this because with the present type of drive, the cork wax washer is compressed by the end cap and an unknown load of friction is obtained which operates the unit satisfactorily until the cork through wear becomes thin. This has been very clearly demonstrated during the tests on schs. 1 & 2 when precautions were taken to get only the friction as got by the cushion spring re-acting on the cork washers. With this arrangement the unit fails to wind up the operating sleeve against the poundage of the buffer spring, slipping occurring when the buffer spring comes into operation. We found the same failure, but intensified, whilst testing the limited torque (sch.2) when using a buffer or clutch spring of 118/184 lbs. In both cases when fitted to an engine of normal garage temperature, the results appeared to be quite satisfactory but when the car was left out in severe cold, excessive could :- | ||