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).
Unsatisfactory position of the ignition coil on the Phantom chassis due to overheating.
| Identifier | WestWitteringFiles\S\September1928-October1928\ Scan123 | |
| Date | 1st October 1928 | |
| To R.{Sir Henry Royce} from EFC. c. BJ. BY.{R.W. Bailey - Chief Engineer} E.{Mr Elliott - Chief Engineer} EFC1/T3.10.28. PHANTOM IGNITION COIL POSITION. x8710 There is now some amount of evidence that the position of the Ignition Coil on the Phantom, where it is subject to radiation from the hottest portion of the radiator system and possibly also in an eddy of the hottest air under the bonnet, is unsatisfactory in combination with the electrical heating of the coil. As a result of a number of cases of failure, the matter has already had considerable attention and it has been proved that the coils are subject to more deterioration on Phantom chassis then in an equivalent amount of running (wis both in loading and time) in an oven atmosphere at 100°C. on the bench). It will be remembered that when we had coil case failures at high temperature on the Silver Ghost, we obtained considerable improvement by removing the coil from what we then called the "Engine position" to the "Wheelcase position", a position in which the coil is still situated on the 20 H.P. chassis. It would appear possible for the Phantom coil also to be placed in a wheelcase position. It is true there has been nothing but satisfactory operation in the various Phantom 10,000 mile tests, but we think the circumstances of running in those tests would probably favour the cooling of the coil in the present position, in comparison with more ordinary running. There is no reason for supposing that this is the old effect due to the cases, but good reason that the weakness is due to weakness of the winding insulations at high temperatures. Charring has occurred on some primaries. | ||