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 of a fuel gauge, considering factors like fuel type, surge during acceleration, and dial dimensions.
| Identifier | ExFiles\Box 61\3\ scan0166 | |
| Date | 13th March 1931 | |
| Messrs.Rolls-Royce,Ltd., Date 13.3.31. Page 2 called for on the print of the dial enclosed in your letter would be a safe proposition for use with this gauge. We have to make allowance for the necessary factors of safety required, which include 5% high reading for use with a benzole mixture, and a further 7 - 10% increase in reading due to surge on violent acceleration. It must be remembered that this figure can only be ascertained on test when the unit is situated at the back of the tank, as the liquid in the unit on the dash board and the liquid in the tank are both surging in the same direction on acceleration. If the unit were situated at the front of the tank, these forces would practically cancel out. In addition to this there might be a slightly high zero setting in individual cases. We estimate that a 2 1/8" scale is the maximum which will be safe with this gauge - 2" would be preferable. On drawing NSOH 3144 it was indicated that it would be preferable to make the height of our unit as shown, for appearance purposes. We accordingly extended the splash chambers slightly beyond those of the original unit made up for the writer's car. We can, however, return to these original areas, as it is obvious that the fitting of an apron over this portion of the tank will | ||