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 Mr. Robotham detailing fuel economy improvements after modifications to a vehicle's choke and throttle.
| Identifier | ExFiles\Box 143\3\ scan0005 | |
| Date | 3rd December 1939 | |
| 120H DIAL 71822. 12, BROAD ELMS LANE, SHEFFIELD, 11. Sunday Dec 3/39, Rolls Royce Ltd, Derby. Attention Mr Robotham. Dear Rm{William Robotham - Chief Engineer}, I am unhappy to have to say that I am in bed with a tonsillitis throat and a temperature. This being so you may be interested to know in what condition 12 B 5 now stands. By weakening off as far as we dare part throttle without weakening the top end appreciably, and using 1 3/32" choke, we seem to have obtained remarkable economy at a very low cost - Eg. 28.6 MPG at 30, 20 MPG at about 55, and even an improvement of about 3/4 MPG at 70. This means that on the run to Buxton and back averaging 45 MPH there seems to be absolutely no reason why a consumption of | ||