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 remarks for a split aluminium piston on a 40/50 HP chassis.
| Identifier | ExFiles\Box 77\3\ scan0234 | |
| Date | 28th January 1920 | |
| COPY. X3924 To Da.{Bernard Day - Chassis Design} from E.{Mr Elliott - Chief Engineer} Copy to CJ. " " Bn.{W.O. Bentley / Mr Barrington} " " Ck.{Mr Clark} " " Hs.{Lord Ernest Hives - Chair} E4/G28.1.20. X.3751. RE SPLIT PISTON IN ALUMINIUM. X3924 40/50 H.P. CHASSIS. In reply to your memo Da{Bernard Day - Chassis Design}17/CB20.1.20, I am directed by Mr. Royce to send you the following remarks with respect to scheme N. 2820. (1) The piston too should be made of the conical form without the trunkation, as this appear to provide what you desire in respect to low shoulders, and has the additional advantage that the material in the centre of the piston where it is hottest is formed into a stronger shape. (2) Has it not been decided to use one piston pin locking screw of the larger size, instead of two small ones, owing to the failure of one of the smaller type?. (3) It is desired to avoid a sharp edge in the section of the spring horn, as the maximum stress in this edge at the foot of the horn is considered undesirable - (see sketch below). It is thought that suitable pattern work will avoid this undesirable feature. (4) Mr. Royce would like the crown to be made rather thinner, and of a uniform thickness, and also he would like some of the material behind the rings removed. (5) It is now considered that there is no distinct advantage in the ultra-low position of piston rings and Mr. Royce would like this raised to within about .550" of the top, so as to increase the length of the spring portion of the piston. Contd. | ||