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).
Letter to Lucas Elec Co. detailing alterations to the specification for a six-cylinder magneto.
| Identifier | ExFiles\Box 4\5\ 05-page315 | |
| Date | 27th October 1924 | |
| X8790 Also sent to:- Lucas Elec. Co. (EFC4/T. M.L. Magneto Syndicate (EFC5/T. EFC4/T. 27th October, 1924. Messrs. The Lucas Elec Co., Well Street, Birmingham. Dear Sirs, With further reference to our 'Specification of Performance of six-cylinder Magneto (with automatic advance) for E.R. 40/50 Car', copy of which, dated 27.5.24, was passed to you in connection with the suggestion of your making up a magneto as nearly as possible to this specification, would you kindly note that we have further decided on alterations as follows :- (1) As a result of our experiments on annular gaps with shunted chemical leaks, we have standardised for the purpose of magneto tests, a 3.0 mm. annular spark gap (dia. of central electrode .087", inside dia. of earthed electrode .325") in air, shunted by a constant non-inductive chemical leak of value 3 micromhos (not 4 micromhos as previously stated). (2) We have put in the speed range in par.5, e.g. 700 to 2100 r.p.m. (3) We have added the speed in the B item, par. (7), namely 210 r.p.m. These alterations, together with the alteration from 450 to 600 r.p.m. in par. (3), of which we previously informed you in our letter ref. EFC8/T of Aug 27th last, are the only respects in which the up-to-date specification differs from that previously sent to you. Therefore, to put the matter right a complete new specification, dated 20.10.24, which will supersede the one previously sent, is attached. Contd. | ||