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).
The specifications for three experimental silent ram pistons intended for the 40/50 HP chassis.
| Identifier | ExFiles\Box 77\3\ scan0073 | |
| Date | 27th November 1919 | |
| R.R. 235 A (100 T) (S.F. 575. 16-4-19) G.{Mr Griffiths - Chief Accountant / Mr Gnapp} 2354. To DA.{Bernard Day - Chassis Design} from E.{Mr Elliott - Chief Engineer} Copy to CJ. " " BN.{W.O. Bentley / Mr Barrington} " " EH. " " EFC. RE IMPROVED SILENT RAM PISTON. 40/50 H.P. CHASSIS. E1/G27.11.19. X.3739. We have sent under separate cover, drawing No. LeC.1163 shewing three experimental pistons which should be made and tested. Pistons A and C are fitted with broad bottom scraper rings .200" wide by .150" thick running out of the cylinder surface .050". A piston is suitable for use with the standard cylinder and the old, long connecting rod. C piston is for use with a snouted cylinder projecting into the crankcase and the present connecting rod. It is intended that extensions of the cylinder surface should be screwed into an existing casting as shewn on the drawing, to make a temporary arrangement for test. These snouted cylinders are said, when used by the Austin Company, to have caused trouble by dropping oil on the crank, which oil was then bounced back into the cylinder. The Austin Company accordingly cut away the cylinder in such a manner that oil was drained off fore and aft away from the crank. If any trouble of this sort is experienced, baffle plates might be tried. Piston B shews the best job that can be made of a lower scraper ring without using a snouted cylinder, and using the present connecting rods. The ring is .100" wide by .175" thick. Similar rams shouls be used on all three pistons A, B, and C. The letter box slot above the ram is thought to be Contd. | ||