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).
Cost and design comparison between the company's shock dampers and Armstrong dampers.
| Identifier | ExFiles\Box 152\2\ scan0072 | |
| Date | 30th October 1937 | |
| 1293 NOT SENT Rm {William Robotham - Chief Engineer} /Les.4/MH. {M. Huckerby} 30.10.37. SHOCK DAMPERS. Factory cost for R.R. damper - £3. 10. 0d. each RHC {R. H. Coverley - Production Engineer} estimates our factory cost for the Armstrong damper - £1. 15. 0d. Cost of Armstrong damper bought-out - £1. 2. 6d. From the attached sheet it can be seen that the Armstrong twin cylinder damper construction would save 6,942 shillings per damper in our factory. In these figures we have neglected the items which are common to both dampers, such as our present bellows valve assembly which is considerably more expensive than necessary. For the single cylinder damper it is necessary to have a detachable cover one end in order to remove the piston, and at the other end we have a plug which was found necessary so that a location could be made for both ends of the cylinder core during casting the casing. The Americans permanently seal both ends of the damper, so that the piston cannot be removed for attention to replenishing valves or piston pads. The single cylinder damper also requires a long transfer passage. The twin cylinder damper has the following further advantages over the cylinder damper. (1) No knocking from the main spindle due to inaccurate bearings. (2) No line contact between the lever and the piston. (3) No high pressure cylinder joints. (4) Compactness. Items (1) and (2) are the cause of customer's complaints with our present production dampers. | ||