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).
Fuel gauge system discussing hand pumping, gauge lag, and different pump types.
| Identifier | ExFiles\Box 44\3\ Scan173 | |
| Date | 23th January 1929 | |
| Messrs.Rolls-Royce,Ltd., Date 23.1.29. Page 2 reading feature of our gauge. (2). This precludes the introduction of hand pumped air at the top of the tank unit, or at any point above datum level, owing to dependence on a moving part, and two extra joints for air tightness. (3). The hand pumping the gauge will usually be done when the car is stationary, and not whilst running. (4). Owing to gauge lag, even if the tank unit is suddenly completely filled with air, it will take 30 to 60 seconds before the gauge ceases rising. Pumping of either the spring loaded or positive type is likely to be continued during this period. (5). Consequently spring loaded pumping might only present the advantage of single action under these circumstances. (6). Should it be found practical to arrange a spring loaded pump of appreciable capacity, delivering air for 40 to 60 seconds, by restricting the flow, or other means, it would certainly appear worth while. (7). This arrangement would call for an entirely open ended bottom bell, to let air into, and petrol out of, the bell system at the necessary speed. (8). The open-ended bell appears to work quite satisfactorily on the writer's car under present conditions, so that | ||