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).
Development of the Peregrine car unit, focusing on valve and crankshaft damper design.
| Identifier | ExFiles\Box 1\8\ B001_X100 Engine Chassis-page235 | |
| Date | 18th November 1932 | |
| r u o m W. To R.{Sir Henry Royce} from E.{Mr Elliott - Chief Engineer} E.8/HP.18.11.32. c. Sq. Ldr. Hs.{Lord Ernest Hives - Chair} By.{R.W. Bailey - Chief Engineer} re Peregrine Car Unit Development. Referring to Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer}6/MA.14.11.32, we would like to comment on the following points: Valves. Owing to the reduction in diameter of the inlet valve for improving low speed turbulence and power, the exhaust and inlet valve heads are now of the same diameter, but different design, being mushroom and tulip respectively, the mushroom being of heavier section. Since the stems are at present of the same diameter, there is now a possibility of the valves getting misplaced, and we have, therefore, instructed the exhaust valve stems to be made .343" instead of .312" as on the cylinder head designed for the Bensport. This move should also strengthen the valve, and improve the cooling, and the fracture which has occurred should, therefore, be less likely to occur again. We are also looking into the design of the valve guide, and boss to see if a little more shrouding cannot be introduced without choking the exhaust gas flow. Crankshaft Dampers. In connection with the clattering of the crankshaft damper which is the phenomenon that has given us trouble on other engines, we made a simple cast iron housing for carrying a ball bearing on the front end of the existing crankshaft and damper flywheel, as shown on LeC.3191, blueprint attached. This gave the effect of a double bearing on the front end of the crankshaft, and so far as we can see prevented any wagging of the front end of the crank. This extra support did not alter the clattering of the damper flywheel in any way and it therefore seems evident that the crankshaft lengthens and shortens when in a state, or approaching a state of torsional oscillation. It will be remembered that on Peregrine and J.2. the shaft is located by the middle bearing, but since the node point at which there is no end movement of the crankshaft will be determined more by the position of the centre of gravity of the crankshaft assembly, together with the flywheel and | ||