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).
Specification document detailing the features and dimensions of pistons for the Phantom and 20 HP chassis.
| Identifier | ExFiles\Box 15\3\ Scan027 | |
| Date | 2nd November 1928 guessed | |
| contd :- -2- of the pistons we wish to get adopted :- We want 3 narrow rings and a perfect circle ting all pinned as shewn on Lec.2430 for both chassis. B. for the 20 HP. We understand you are following Lec.2577 type The following are the features of the pistons we wish to get adopted :- | | CROWN. | TOP BAND. | RING. | BETWEEN RINGS. | PERFECT CIRCLE RING. | TYPE. | |---|---|---|---|---|---|---| | Phantom. | Flat top. | .250 | .100 | .125 | .175 | } single bolt pedestal, all rings pinned. | | 20 HP. | Ditto. | .200 | .087 | .100 | .150 | } | There should be a stiffening ring or rib of some kind at the bottom of skirt. the only modification from this would be the 20 HP. with diagonal webs - Lec.2577. To avoid waste of time we think it is better to work on no other type or proportion until these have proved wrong, as we believe they are right providing the best clear-ances and dimensions are found for them, such as the grinding of the piston clearances, and stiffness of the rings. R.{Sir Henry Royce} | ||