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).
Confirming B.P. Ethyl fuel meets the required knock-rating standard for experimental work.
| Identifier | ExFiles\Box 150\1\ scan0255 | |
| Date | 11th December 1936 | |
| 1282 Roy. {Sir Henry Royce} from Rm. {William Robotham - Chief Engineer} Rm {William Robotham - Chief Engineer} 15/R.11.12.36. B.P. ETHYL. We have now had the necessary confirmatory information that B.P. Ethyl is up to the required knock-rating standard which is necessary for Experimental work, and that the Manufacturers will not change this octane number without reference to us. We, therefore, agree to supplies being obtained for the Experimental Dept. Rm. {William Robotham - Chief Engineer} | ||