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).
The American Bosch battery ignition coil, its properties, cost, and materials.
| Identifier | ExFiles\Box 39\3\ Scan032 | |
| Date | 15th May 1921 | |
| X3613 Extract from Cyl/G7.3.21. X.4275 - AMERICAN BOSCH BATTERY IGNITION. In continuation of my letter of March 4th 1921 on this subject, replying to Mr. Royce's letter of Feb.16, I wish to add the following notes :- (3). X1918. X.2494. X.3513. X.800. Coil. The American Bosch coil is claimed by the makers to be water proof in the sense that it will operate perfectly under a shower of water representing a heavy rain. With regard to its cost, this is $ 5.00, but of course this low price is entirely due to the enormous numbers which are produced. The makers claim a high efficiency for the coil, due to the close packing of the wires, which are not silk covered but have a very thin insulation of enamel. The brown mouldings to which Mr. Royce refers are "High-Tensite", corresponding closely, we are told, to the German Bosch distributor material. This is only used by the American Bosch Company for rubbing tracks of distributors, etc. where Bakelite gives trouble with spark tracking. (The Delco Company use hard rubber tracks for this condition). The American Bosch Company use this material, however, for mouldings on new designs and experimental work, but will change these mouldings to which Mr. Royce refers to Bakelite, now that the coil is fully standardised. [Footer, upside down] R.R. (D) NO. 81. H.S. L. D.{John DeLooze - Company Secretary} 5000. C-15-5-21. | ||