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).
To G.W. Hancock regarding testing and adjustments for car 22-G-V on its clutch, slow running, and carburetter settings.
| Identifier | ExFiles\Box 83\4\ scan0170 | |
| Date | 23th April 1936 | |
| X 264a G.W. Hancock, Esq., Hotel de France, Chateauroux, Indre, France. Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer}11/KW.23.4.36. 22-G-V left for France yesterday, the 22nd inst. The main points in connection with this car are as follows :- (1) Clutch. We have put the propellor shaft damper on this car so that you can transfer it to the Bentley and see if it makes any difference to the Bentley clutch jaggers. We are wondering whether the Bentley engine mounting was disturbed by the crash, and if so whether this brought on jaggers. (2) Slow Running. There is no doubt that the 20/25 slow running is materially affected by the type of plug used. The washer and mica plug has a much smaller air capacity between the central electrode and the casing than the wrapped plug which has up to the present been standard on the Bentley. Waller has got some plugs but we have no washer type available with the increased air gap so these will follow out. (3) In connection with the slow running, we should like to know whether in your opinion there is any difference between the two pipes which you have when both are used with the best sparking plugs. (4) Carburetter Setting. There has been some argument regarding the carburetter setting. The point is that on test the 20/25 cars are running about with a thermometer temperature of about 70°C. for pottering about conditions. It is under these conditions that one is always on the partial throttle conditions which show up the weak spot in the carburation. Of course we know that the actual radiator temperature will be lower than 70°C. due to the difference between one end of the head and the other. In order to overcome weakness picking up, the Test Dept. have asked us to change the setting from 62 to 63 jet. Waller has brought out a spare 63 jet with him. We should like you to check the difference in consumption between these two jets. | ||