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).
Design considerations for a new cam for rollerless rockers, focusing on spring pressure and operating characteristics.
| Identifier | ExFiles\Box 43\3\ Scan126 | |
| Date | 2nd February 1927 | |
| X.4003 To E.{Mr Elliott - Chief Engineer} RG.{Mr Rowledge} BY.{R.W. Bailey - Chief Engineer} HS.{Lord Ernest Hives - Chair} from R.{Sir Henry Royce} c. to BJ. Wor.{Arthur Wormald - General Works Manager} RR. F.10. CAM FOR ROLLERLESS ROCKERS. I do not know if these are being made. I have not seen any diagrams of the proposed accelerations and decelerations. One supposes we shall make some slight difference in the lift and lower sides of the cam so that we shall get quicker opening than closing, to allow for air effects on induction and friction. My impression is that the high rating springs are good to prevent the rocker leaving the cam at the highest point. These springs should be less liable to surge, and we hope very much less inclined to break. Their merits should be investigated at once. Do not be satisfied with the best of the old springs unless tests shew they are better than these with the new characteristics, with which E.{Mr Elliott - Chief Engineer} and myself have such great hopes. In setting out the new cams I should keep a good margin of spring pressure at the highest point so that there would be much less change in the character of the lift than the spring rating would suggest. I should also recommend that less than the full theoretic amount should be allowed in the difference in speed of opening and closing than the air effect and friction might suggest. This means a safe and moderate policy of not being too clever, or we come to grief. R.{Sir Henry Royce} | ||