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).
On ignition system improvements, including condenser design and a future shift to battery ignition.
| Identifier | ExFiles\Box 181\M11\ img063 | |
| Date | 1st July 1917 | |
| To Mr. Ellis & EH. from R.{Sir Henry Royce} 2. R2/B10:7:17. ignition has the same lead and angular advance as the magneto ignition. This will result in the two ignitions being always synchronized, which may benefit the running of the engine considerably. Regarding the position of the condensor, I think this should be between the beginning end of the primary winding and the earth contact on the contact maker. This will avoid the rush back of current having to pass through the non-inductive high resistance. [handwritten annotation: heavy arcing across the contact Breaker as at present] To avoid damaging the platinum on the make and break, (and also to reduce the risk of damage to the platinum points on the ordinary trembler coil,) I suggest that the condensor be made larger than is necessary for the greatest length of spark. That is to say, one feels that by gradually increasing the capacity of the condensor, the length of secondary spark would grow to a maximum, then gradually reduce. Now one feels as though [handwritten insertion: this] that size of condensor is not necessarily. the best one for preserving the life of the contact points, which I presume would show less and less sparking as the condensor was increased in capacity. It will be necessary to make the observations of the condition of the platinum points and the size of condensor at various speeds, up to an engine speed of 3,000 revolutions, when our 6 point contact maker would be running at 1500 revolutions. We have decided that all chassis after the War will have electric self starters, and it would seem that this form of battery ignition would be preferable to the one we are at | ||