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 distributor condenser capacity, materials, and performance after a 10,000-mile test.
| Identifier | WestWitteringFiles\U\August1930-November1930\ Scan125 | |
| Date | 4th October 1930 | |
| SPC3/AMB4.10.30 contd. -2- of the benefit derived from the scrubbing action of the points, but that together with that scrubbing action this reduced capacity contributes considerably to good performance. In the first instance, it was observed that the contact points removed from the battery ignition distributor on experimental chassis 24-GX after a 10,000 mile test did not show any of the blue oxidation of the screw point surface as is usually found in the case of standard distributors. Upon investigating the reason for this we found that the only difference from standard was in the capacity of the condenser which was found to be .23 m.f. i.e. considerably less than that to which standard condensers are produced. This fact also led to the suggestion which we have since confirmed by test on one or two condensers which have been in service, that owing to the use of varnished paper as a dielectric there is a tendency for the condenser capacity to become reduced due, we presume, to the evaporation of the more volatile constituents of the oil. Condensers made with paraffin wax paper do not appear to suffer this secular change and also do not increase their capacity so much when the temperature is raised. A number of condensers made up with paraffin wax paper are being tried. Since the above we have had a number of lower capacity condensers made up and we fitted a low capacity | ||