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).
Drawing Lec.1069 for a 20 HP chassis piston and connecting rod, detailing design choices and modifications.
| Identifier | ExFiles\Box 77\3\ scan0250 | |
| Date | 24th March 1919 | |
| To Da.{Bernard Day - Chassis Design} from E.{Mr Elliott - Chief Engineer} c. to EH. c. to EFC. X. 3487 - RE 20 H.P. CHASSIS PISTON AND CONNECTING ROD I send you herewith drawing No. Lec.1069 shewing details of the above. This drawing also illustrates a scheme of fixing the piston pin to the connecting rod by central biting-in bolt, which was rejected on account of weight and complication. The piston shewn is approximately to a compression ratio of 5 to 1. Would you please have it checked and adjusted exactly to 5 to 1 ratio. Fig. 2 shews a section on CC with the shape of the connecting rod stem superimposed on it. The stem and the ends of the big end should be machined to this section, and the bolt bosses should then be finished by a milling operation, with a cutter to the form XXXX in plan view. We have retained pressure lubrication for the small end of the connecting rod, because although additional complication is entailed by the pressure feed pipe, this is the most reliable system we know, as it makes the lubrication at this point independent of the cylinder lubrication. We had considered relying on the oil scraped by the groove which accommodates the spring ring securing the piston pin. Would you kindly put in hand the necessary quantity of material to this drawing. E.{Mr Elliott - Chief Engineer} | ||