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).
Road test results of a finer primary coil on a 20 HP chassis.
| Identifier | WestWitteringFiles\P\2July1926-September1926\ Scan212 | |
| Date | 24th September 1926 | |
| To R.{Sir Henry Royce} from EFC. c. EJ. RE FINER PRIMARY COIL. X4653 Reference your R4/M18.9.26, road tests were made on the 20 HP. chassis with finer primary coil and double ballast resistance (two standards in series) and with a supply from five cells in normally good condition but not charging, and no adverse effect was noticed even at high speeds, though we could not say definitely that the speed of 3000 r.p.m. was reached. We intend therefore to confirm this point by trying out on an engine on the test bed. At the same time we will confirm or otherwise that there is no missing at slow speeds with only four cells, though we are of the opinion that this is an unnecessarily wide margin. As suggested in your last paragraph we will make bench tests of the ignition with several different speeds. EFC. | ||