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).
Technical memorandum suggesting alterations to the 20 HP Bijur starter to improve performance.
| Identifier | ExFiles\Box 40\5\ Scan187 | |
| Date | 9th July 1927 | |
| X.3587. To Hs.{Lord Ernest Hives - Chair} from R.{Sir Henry Royce} c. to BJ. Wor.{Arthur Wormald - General Works Manager} BY.{R.W. Bailey - Chief Engineer} R7/M9.7.27. 20 HP. STARTER. Apparently if the RR. Bijur is correctly made, and of the best proportions, it will give satisfaction. To improve the proportions Hs{Lord Ernest Hives - Chair}/GWH.{George W. Hancock - Head Chateauroux} has suggested alterations to the springs which have been agreed upon. I am suggesting however that these alterations be carried still further until they shew signs of the hold-off spring being too weak, and the springs producing the initial friction on the cork being too strong. Should the shock at engagement become too much, a quicker pitch worm might be tried - i.e. less self jamming. A suggested alteration to the pinion in addition to increasing the strength of thr spring D.51133 from 7 lbs. to 12 lbs. is to try a second cork surface behind the friction collar. With these two alterations it is thought that the initial clutch friction may increase 3 times. If this causes a thud owing to it being too self-gripping, it suggests that the thread - at present .9" pitch - be increased 10%, and experimentally varied to give the best results. This change should increase the reliability of the pinion, removing it further from the risk of slipping, and also from the heavy thud when the friction of the cork appears to be too self gripping. The result should be that both oiled and dry the slipping should occur with a motor torque of approximately 60" lbs. What current this corresponds to on the motor can be obtained from EFC. We expect this to bear being lubricated freely with engine oil provided the oil is allowed to drain away. Test dry, oiled slightly, and liberally - thick and thin, until we know what it will do. R.{Sir Henry Royce} | ||