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).
The development of ignition advance curves for the J.I. Head engine, detailing adjustments to prevent detonation.
| Identifier | ExFiles\Box 163\7\ img201 | |
| Date | 29th September 1932 | |
| X6013 29.932. Files. IGNITION ADVANCE J.I. HEAD. Various ignition advance curves were taken on this engine and it was found that whilst the best power setting was 24 B.T.D.C. at 500 r.p.m., the setting necessary to prevent detonation was 13º B.T.C. The <strike>maximum</strike> advance curve was therefore arranged which gave only 23º auto advance, and which is shewn on the attached curve 7. of Hs.{Lord Ernest Hives - Chair}714. On the road with this curve there was slightly too much detonation between 20 and 45 m.p.h. and so the springs were slightly strengthened up to flatten the curve slightly. This gave the required result. Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} | ||