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).
Proposed ignition governor and advance curve for the EAC engine.
| Identifier | ExFiles\Box 37\1\ scan 262 | |
| Date | 9th August 1924 | |
| To Hs.{Lord Ernest Hives - Chair} from E.{Mr Elliott - Chief Engineer} c. to CJ. c. to EFC. c. to EY. X3949 S E C R E T E1/M9.8.24. E.{Mr Elliott - Chief Engineer} A.{Mr Adams} C. X.9140. X.3949. X.9780. IGNITION GOVERNOR. In dealing with the proposed ignition governor for the EAC. engine, which will automatically advance both magneto and battery ignitions, it is proposed to alter the shape of the curve of advance from that we use on the Goshawk governor to obtain a result more in accordance with the requirements of the engine. EFCL/T9524. On the curves accompanying Mr. Clarke's report it will be seen that the Goshawk governor approximates to a straight line not passing through the origin, whereas the curve of advance required by the engine to figures supplied by EP.{G. Eric Platford - Chief Quality Engineer} rapidly falls away as the speed increases, until at high speeds the engine requires very little advance at all. Mr. Royce would like to know at the earliest possible moment if you are in agreement with this latter curve. We naturally desire to use the minimum advance at all speeds required for the engine to develop maximum power, so that the engine will be running under the best conditions for long life and high efficiency. When the characteristic of the Goshawk governor was originally fixed we rather followed the average adbance values obtained from your report HS{Lord Ernest Hives - Chair}5/LG28421, as shewn on LeC.1550., but it may now appear that the most desirable characteristic is one in which the advance falls away due to the peculiar conditions attached to the operation of the cycle in the engine cylinder relative to speed, and to follow this we have to design a governor in which either the weights are allowed to move out to their zenith, or the advance mechanism itself is mechanically arranged to give very little movement at the higher speeds. Would you also kindly let us know the firing points on the advance curve relative to the dead centre of the engine and the amount of retard required on the hand control for a flick start on the battery ignition. Additionally Mr. Royce would like to know if there is any initial set on the Goshawk governor spring as the curve rather indicates this. E.{Mr Elliott - Chief Engineer} | ||