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).
Fitting of double pump units to a chassis.
| Identifier | ExFiles\Box 88\5\ scan0229 | |
| Date | 10th December 1936 | |
| 251 To Hd.{Mr Hayward/Mr Huddy} from Rm{William Robotham - Chief Engineer}/JBD.{John B. Dixon - Fuel Systems} Rm{William Robotham - Chief Engineer}/JBD.{John B. Dixon - Fuel Systems}4/AP.10.12.36. RE: CHASSIS No.B.87.-FC. With reference to your query, regarding the owner of the above car fitting two double pump units. We do not feel that he would increase his factor of safety very much by so doing, unless he made a point of running on each pump alternately, because there is a tendency for the G.5. material to become stiff if it is allowed to stand a long time in a high temperature such as exists under the bonnet. Thus, if after a long period of running, he was forced for any reason to use the second pump, in all probability it would fail to work when required. At the same time, if simple pipe connections are used, the failure of any pair of valves in either pump would cause complete failure of the whole system, and the number of valves under pressure would be doubled. What we suggest is that he only fits the one double unit as at present and has a three way switch fitted, so that either side of the pump could be used separately for test purposes and the two units used together for general running. If an test at any time, one side was found to be faulty, he would not be held up as the car gives very nearly the same performance with only one pump working. This scheme is shortly going to be fitted to all Experimental cars, as soon as the switches become available. Two double units were fitted on E.R.Hall's car with a tap to isolate them as well as a switch, but it is unreasonable to suppose a customer would trouble to use each pump alternately with this scheme. It should be borne in mind that the second pump should be mounted with the valves vertical. If there is no windscreen wiper motor and the pipes are altered there is room to do this Rm{William Robotham - Chief Engineer}/JBD.{John B. Dixon - Fuel Systems} | ||