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 of split pistons and the pinning of piston rings for trials cars.
| Identifier | ExFiles\Box 77\3\ scan0008 | |
| Date | 11th November 1919 | |
| To BN.{W.O. Bentley / Mr Barrington} from R.{Sir Henry Royce} Copy to CJ. " " WOR.{Arthur Wormald - General Works Manager} " " EH. " " EP.{G. Eric Platford - Chief Quality Engineer} R2/G1.11.19. 3437 RE TRIALS CARS X.3651. It would appear that we could consider the split pistons as being satisfactory, if we arrange the dimensions sufficiently large for them to run just freely under ordinary working conditions. Under extra ordinary condition of sudden heating of the pistons, the split piston being capable of collapsing, will not seize or pull up the engine, the split being merely looked upon as a safety device for extra ordinary conditions. Realising this point of view, one agrees that they should be fixed generally until we find something we think better. As regards the pinning of the rings, Mr. Elliott suggested that the top ring should be pinned on the power side, On thinking the matter over, I think it is imperativ that the bottom or scraper ring should be pinned on the power side. It therefore suggests thatnif we use an even number of rings, that the top ring would have to be pinned on the opposite side to the power wall of the cylinde 4 You will see that this may have a very important bearing on the amount of oil passing up through the piston. In fact, if it is pinned as I suggest, the oil should be capable of more easily passing downwards than upwards, and I think it is most of all important that the scraper ring Contd. | ||