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).
Costs, production, and potential faults of a new experimental spring plate for servo water exclusion.
| Identifier | ExFiles\Box 152\2\ scan0278 | |
| Date | 13th December 1940 | |
| To Ev.{Ivan Evernden - coachwork} from Rm{William Robotham - Chief Engineer}/MHR.{M. H. Rigby} Copy to Rm.{William Robotham - Chief Engineer} Ev{Ivan Evernden - coachwork}/Tin. 1294 Rm{William Robotham - Chief Engineer}/MHR.{M. H. Rigby}6/ET.13.12.40. WATER EXCLUSION FROM SERVO. ------------------------- With regard to the manufacture of the special spring plate with the deep corrugation, we find that the extra cost entailed is not as large as we anticipated. Stainless spinnings produced 12 experimental plates of this type at 4/- each + 25/- for tools, as against a figure of 3/4 each for 12 only of the production type GB.5114. A production cost for 300 of GB.5114 was given at 10½d.{John DeLooze - Company Secretary}, so the new type is unlikely to be more that 1/3d. The new type, of which we have 12, will be fitted to all the suitable gearboxes in the experimental chassis. There are two possible faults, both of which can only show up in time:- 1. It will have to be ensured that the new type of plate will not have a greater tendency to get squashed in. 2. The oil which passes the oil seal on the gearbox is thrown back by the Acme thread in the oil seal housing and leaks out through a drain in this housing. This drain hole comes inside both the experimental protective shields. That fitted to the gearbox can have a drain at the bottom, but the shield formed by the deep corrugation in the spring plate can clearly have no such provision. Where we have sweated a shield to a standard spring plate, we have of course been able to include a drain, but it remains to be seen whether the oil is more likely to find its way into the servo with the special plate with no drain. Cornercrofts consider the spring plate with the extra deep corrugation to be a difficult pressing operation. They also say that it would be more expensive than spinning for any quantity less than 50,000. The suggestion of dip soldering the spring plate made from two pieces need not be considered, unless it is found essential to provide a drain at the bottom of the shield. It should be mentioned that the drain means that the plate can only be fitted in one position. Rm{William Robotham - Chief Engineer}/MHR.{M. H. Rigby} | ||