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).
Design and cold-weather testing of an improved ignition coil.
| Identifier | ExFiles\Box 164\5\ img333 | |
| Date | 3rd March 1938 | |
| To Rm.{William Robotham - Chief Engineer} Rm{William Robotham - Chief Engineer}/RC.{R. Childs}12/JH.3.3.38. re Improved R.R. Ignition Coil. HPS{Horace Percy Smith - Experimental Factory Mgr}/TT. has made an ignition coil which has been designed to work without a ballast, also to give better performance when working under low primary voltage conditions. This coil has been constructed along the lines of the Delco-Remy coil which was recommended recently. The main difference being a bakelite case instead of metal, and a primary winding of thicker gauge wire for cooler running. The Bench test performance of this coil is very good giving a better output for both normal and low primary input. Further tests in the cold chamber at a temperature of 8°F.{Mr Friese} were also very satisfactory, a good start being made on 28.G.VI. after remaining therein over night. In a second test, under the same conditions, but using the inferior 13 plate Wraith type battery, instead of the 25/30 type, a start was made in 19 seconds: the primary voltage being only 5.5 and the engine speed 29 r.p.m. We recommend that three more of these coils be made as soon as possible for further testing. Rm{William Robotham - Chief Engineer}/RC.{R. Childs} | ||