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).
Design and materials for an inexpensive condenser for an ignition system.
| Identifier | ExFiles\Box 35\6\ scan 074 | |
| Date | 1st November 1921 | |
| To AFC. from R.{Sir Henry Royce} Copy to C.G. " " HOR. " " HS.{Lord Ernest Hives - Chair} " " HY.{Tom Haldenby - Plant Engineer} X2894 NOV FO [STAMP: RECEIVED] X 2572 RE IGNITION SYSTEM. R1/CG/11/21. X2894 X3656 I consider it one of the most urgent pieces that you have in hand is to learn how to make an inexpensive condenser for our ignition system, which has an efficiency sufficiently high for you to get ample capacity in the space available on both the 40/50 H.P. and "Goshawk" R.R. ignitions. Of the materials available for a suitable di-electric I had the impression that nothing was superior to mica which has a factor of somewhere about 6.000, but perhaps some of the materials used to impregnate paper would give an equally high efficiency. I have not the necessary data to hand. Naturally, the capacity is directly proportionate to the area, and one great thing is to arrange it so that there is the maximum area in the space. The next point would be (and a point of vital importance) that the distance between the tinfoil should be the minimum, as I believe the capacity varies with the square of this distance, and in this respect also the mica ought to be capable of being used thinner than any other material. However, this matter is one which is particularly suited to your experimental investigation, and I hope you will take it seriously and vigorously, so that we can have a condenser of sufficient capacity to enable us to use tungsten points. Then if we have proof that we can use tungsten points, we may fit moderate sized platinum irridium points which will render the ignition quite remarkably reliable. R.{Sir Henry Royce} | ||