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).
Progress report on the development and testing of mica and paper condensers for the 'Goshawk' ignition system.
| Identifier | Morton\M1.5\ img001 | |
| Date | 1st December 1921 | |
| ORIGINAL To R & E.{Mr Elliott - Chief Engineer} from EFC. EFC2/T1.12.21. c. CJ. & PN.{Mr Northey} c. By.{R.W. Bailey - Chief Engineer} & EP.{G. Eric Platford - Chief Quality Engineer} c. Rg.{Mr Rowledge} & Da.{Bernard Day - Chassis Design} c. R.R. of America Inc. c. Wd.{Mr Wood/Mr Whitehead} X.4430 - CONDENSERS FOR "GOSHAWK" IGNITION. Further to our EFC2/T24.11.21, we feel we have made considerable progress with the Goshawk condenser problem since sending that report. Mica di-electric Condensers. We have now been able to make a mica condenser of .25 mf. capacity, nearly to the LeC. design, i.e. although the extra depth on the condenser to the extent of 25% has been obtained by replacing one of the bakelite plates by a piece .062" thick of bakelite micarta, it has not been necessary in this instance to delete the clamping bolts in order to obtain this result. The mica thickness is .0015", as nearly uniformly as possible and foil thickness .0005" as before. This represents a relative efficiency of about 95% and is considered to be as far as we can practically go with a mica condenser, at any rate on production lines. For this reason we are making up several condensers like this for experiment on the various bench tests and chassis. Paper Condensers. Attempts to make paper condensers of similar space efficiency with single paper have so far failed, but we have only had available paper similar to that used for insulating coil secondaries. In saying that these are a failure, we do not imply that the capacity cannot be secured in the space, in fact more capacity can be secured with this thickness of single paper, namely, .0012" when compressed, than with the mica condensers, but we do not consider the condenser a success unless it withstands the voltage test which we have specified for the 40/50 condensers, which consists of the application of 400 R.M.S. A.C. volts for a period of 10 minutes. We duly received your three telegrams with reference to paper condensers, and we now have numerous enquiries in hand for suitable materials, having already received certain sample materials. We feel that the matter is progressing satisfactorily. contd. | ||