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).
Instruction sheet detailing maximum ignition coil temperatures and charring conditions.
| Identifier | ExFiles\Box 69\1\ scan0168 | |
| Date | 1st December 1924 | |
| RR 238 (150 BKS.) (DB{Donald Bastow - Suspensions} 461-B 12 24) MP 306975 ROLLS-ROYCE LTD. INSTRUCTIONS. (9) To ............................. ..............................19.. Order No. WD{Mr Wood/Mr Whitehead}15 (Contd) Customer's No. ............. that the 20H.P. wheelcase position does not allow the coil to attain such a high temperature as the 40/50 position. The figure of 120°C obtained on 98NK with a standard coil is we consider dangerous, 100°C maximum ought to be the absolute temperature the coil could reach. The figure of 138°C obtained with a finer primary coil on 17EX is approx the charring condition of cotton. We consider that an ignition coil should not rise more than 30°C above the ambient temperature when working normally or abnormally. Signed H.E.W. This Sheet must be filed on completion of the work. | ||