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 memo detailing the specifications for new experimental pistons and connecting rods for testing on chassis 7-CA.
| Identifier | ExFiles\Box 35\2\ scan 024 | |
| Date | 1st November 1920 | |
| Contd:- Four pressure rings are fitted, the lowest of these being a scraper, which should deliver its oil into a groove of sufficient capacity with large draining holes. The piston pin bosses are supported by diagonal webs in the manner already employed on the cast iron car piston of this type. These webs should be tapered in thickness on their section to a suitable amount to allow of the withdrawal of the internal piece of the die sideways. The piston pin is situated low down in the piston and special connecting rods .600" shorter than standard must be used in conjunction with these pistons. The piston pin is 1" in diameter and is held in position by the device shewn, which consists of a soft steel ring rolled and expanded into the groove shewn inside the piston pin boss. The ring is split to facilitate this expanding operation. All of the piston rings should be pinned by the split taper pin last standardised for aero work.. The natural thickness of the walls of the piston opposite to the rings will provide a sufficient length of hole for the pins. Would you kindly put in hand some experimental pistons on these lines for immediate application and test on chassis 7-CA. It should be pointed out that the connecting rods require a little end of special proportions, in addition to being shorter in the centres. (Upside down text at bottom): H.M. 235A (500) (S.D.) 408 (1-11-20) H.M. F.E./2158/3 | ||