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).
Modifications to an aluminium split piston for a 40/50 chassis.
| Identifier | ExFiles\Box 77\3\ scan0236 | |
| Date | 10th February 1920 | |
| X.3924. COPY FOR CK.{Mr Clark} To R from DA.{Bernard Day - Chassis Design} Copy to BN.{W.O. Bentley / Mr Barrington} X3924. RE SPLIT PISTON IN ALUMINIUM. 40/50 CHASSIS. DA{Bernard Day - Chassis Design}6/CB10-2-20. With reference to E4/G28-1-20 we have modified drawing No. 2820 and send a print of N.3510 herewith:- (1). The piston top is made conical, of uniform thickness, and slightly thinner than shewn on N.2820. (2). With reference to the gudgeon pin locking screw. At present one pin does the locking, the other is merely to balance and is put in a clearance hole. It is thought that failures hitherto have been due to relative expansion between the piston and the gudgeon pin when both pins are fitted. To be on the safe side we have, however, provided for a ¼" pin in this new position. (3). It is arranged by the pattern making to take away the sharp corner at the top portion of the horn. (4). Piston rings are raised to .550 from the top and .250 added to the portion of the piston below the gudgeon pin to conform with LeC1B. (5). The width of the slot both circumferentially and longitudinally has been increased, and the slope of the latter made a little more in order to conform with LeC.1186. (6). However, the Production Department do not appear to like the wide slot and would have liked to have retained the .050 slots that have hitherto been used as they say that it is easier to keep the saws in condition and the work dne on the piston is less. It is not so easy to make a job of the top edges of the horn if the narrow split is used. DA.{Bernard Day - Chassis Design} | ||