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).
Development of an automatic starting system for the Wraith model, including choke and carburettor options.
| Identifier | ExFiles\Box 151\3\ scan0370 | |
| Date | 22th February 1938 | |
| Rm {William Robotham - Chief Engineer} /GR. {George Ratcliffe} from Rm. {William Robotham - Chief Engineer} Rm {William Robotham - Chief Engineer} /Swdl. {Len H. Swindell} Rm {William Robotham - Chief Engineer} /CTS. {C. Trot Salt - Carburation} WRAITH STARTING. We have been asked by Sales to provide an automatic start for Wraith. Having regard to the disposition of our exhaust pipe, we believe that the electrically operated thermostat choke spring will be most easily applicable. Also, in view of the fact that with an automatic choke the customer can make his car immobile if he stamps on the accelerator pedal before the engine fires, we should like an over-riding hand control to be considered which can be used when the car fails to start in the ordinary way. Fisher of Strombergs has agreed to rig up a carburetter on these lines for us, and submit it to us. As an alternative to the thermostatic operated choke, we should like consideration to be given to using the S.U. thermostatically operated carburetter in conjunction with the Stromberg. We like this little starting carburetter because it is similar in general principle to the ones we fitted to the P.II, and has the advantage that it only deals with a small quantity of mixture, the result being that the engine cannot be completely swamped in fuel. It will take us sometime to develop an automatic control, and in the meantime, in view of the trouble with sticking chokes, we should like a Wraith to be rigged up with a positive shutting choke. In order to positively close the choke, the hand control should be arranged so that it has to be held closed. When the hand control is released, it should move to half-way position, where a rich mixture will be provided for driving before the engine is warmed up. The last half of the hand control should be notched as at present. We propose to have a discussion as to exactly how these various schemes are likely to work out, when those concerned have had time to consider them, which we expect will be in about a week. Rm. {William Robotham - Chief Engineer} | ||