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).
Revised specification for the performance of a 6-cylinder magneto, including experimental work on annular spark gaps.
| Identifier | ExFiles\Box 4\5\ 05-page307 | |
| Date | 20th October 1924 | |
| To R.{Sir Henry Royce} & E.{Mr Elliott - Chief Engineer} from EPC. c. CJ. & PN.{Mr Northey} c. Wor.{Arthur Wormald - General Works Manager} Hy.{Tom Haldenby - Plant Engineer} EP.{G. Eric Platford - Chief Quality Engineer} c. De. HB.{C. E. Harcombe} X8790 EFCS/T20.10.24. RE MAGNETOS. X8790 X4645 Following the formulation of our Specification of Performance of 6-cylinder Magneto (with automatic advance) for RR. 40/50 Car (EAC.II), preliminary incomplete copies of which have previously been issued, but up-to-date and complete copies of which are now attached (which kindly allow to replace those others dated 27.5.24), the schedule of experimental bench tests of magnetos has been revised. Version 2 In view of the somewhat unsatisfactory nature of 3rd point spark gaps as applied to the exact comparison of magnetos, some experimental work on annular gaps has been performed. The advantage of the annular gap is that a given length of gap corresponds much more exactly to a definite spark-over voltage. It should be stated that in this connection we have received gratis from the M.L. Magneto Syndicate (Mr. E.A.Watson) one of their annular spark gaps (dia. of H.T. spindle .051", inside dia. of earthed concentric conductor .253", ratio 5.01, and gap 2.56 mm.), and also from the Lucas Elec. Co. (Dr. E.O. Turner) one of their combined annular spark gaps and variable leaks (dia. of H.T. spindle .073", inside dia. of earthed concentric conductor .348, ratio 4.78, and gap 3.5 mm. Variable leak from 2 to 33 microhhos. At the same time experiments have been made on the suitability of the various types of chemical leak with which to shunt the spark gaps. Most of these leaks suffer from a big | ||