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).
Recommendations for engine ignition timing, governor curve, and vernier control settings based on dynamometer test results.
| Identifier | ExFiles\Box 168\3\ img187 | |
| Date | 1st June 1939 | |
| -3- RM{William Robotham - Chief Engineer}/IMS.3/MHY1.6.39. (4) Dynamometer curves were taken for power against ignition advance at various speeds and the results are shown in Fig. III. The power losses for the three settings of the governor curve shown in Fig.II are marked on the curves in Fig. III. It will be seen that at 4° late a most satisfactory result as regards power loss is obtained. (5) We, therefore, wish to recommend for production the governor curve, details of which are given in Fig.IV. We also require the vernier control DCD.1373 as soon as possible, and until this is available, recommend an ignition timing 5° after T.D.C. With the vernier the engine should be timed T.D.C. with the vernier set at the 0 mark, and adjusted by the Test Department to eliminate detonation. The anticipated setting for Shell No.1 is between the 2 and the 4 marks, which indicate actual degrees of retard on the distributor, i.e. half flywheel degrees. The instruction book should recommend running as near the 0 mark as the fuel used will permit. No.3 fuels should not be recommended, although there is sufficient range on the vernier to allow for their use in emergencies only. RM{William Robotham - Chief Engineer}/IMS. | ||