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).
Ignition advance requirements and control modifications for an aluminium engine with a turbulent head.
| Identifier | ExFiles\Box 37\1\ scan 308 | |
| Date | 6th May 1927 | |
| X 3949 To R.{Sir Henry Royce} from Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} c. to BJ. Wor.{Arthur Wormald - General Works Manager} c. to RG.{Mr Rowledge} R.{Sir Henry Royce} c. to DA.{Bernard Day - Chassis Design} BY.{R.W. Bailey - Chief Engineer} Hs{Lord Ernest Hives - Chair}/Rm{William Robotham - Chief Engineer}2/LG6.5.27. EAC.7. - IGNITION ADVANCE CURVES. X7685 As we have now got the ignition advance requirements of the aluminium engine fitted with the turbulent head, we have been going into the question of the controls and relay designed for this engine. The only ignition advance curve available when these controls were designed was that of the cast iron engine. At low speeds the aluminium head with synchronised plugs requires some 15º less advance than the old head - at 2000 r.p.m. only 4º less. Therefore the total automatic range now required is 28º + 2º small initial advance, the total hand range on the battery to get a flick start about 22º. We can make the relay and controls do all that is required if we slightly increase the length of the arm on the relay cylinder to increase the automatic range. The only difficulty we then encounter is that owing to the large hand range provided we are working to the absolute limit of the magneto advance range. We attach a print of the ignition as we have at present arranged it, the only alteration being a slight increase in the automatic range. We should additionally like to reduce the hand range to .7 of what it is at present on both the magneto and battery, leaving all the synchronisation as originally instructed but if this is not considered advisable the controls as set out in 'A' are still a workable proposition. Hs{Lord Ernest Hives - Chair}/W.A.Robotham. | ||