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).
Technical memorandum describing the operation and potential issues of a new type of petrol gauge.
| Identifier | ExFiles\Box 147\3\ scan0176 | |
| Date | 2nd November 1938 | |
| 1247 1263 COPY FOR FILES. Rm{William Robotham - Chief Engineer}/JBD.{John B. Dixon - Fuel Systems}......2.11.38. New Type petrol gauge. Capt. Hartoup brought a car up to the Works today fitted with a petrol gauge he is anxious to get on the market. The gauge is not electrically or hydrostatically operated. It consists of a small dial mounted on the instrument board with a milled edge and connected to the tank by a flexible armoured cable (Aerens or Bowden type). The tank unit consists of a vertical rod with ratchet teeth on the side. Round this rod there is an annular float free to slide up and down the rod according to the fluid level in the tank. Attached to the cable there is a small bush also sliding on the rod, which carries a pawl free but hanging just above the ratchet. To take a reading the milled edge on the instrument is turned from the full position towards zero. This causes the bush to slide down the rod until it comes in contact with the float which locks the pawl in the ratchet and prevents further movement downwards and also locks the dial in a position equivalent to the level of fluid in the tank. The instrument fitted to the car was hand made with a dial about 2" in diameter. It was astonishingly free to turn in spite of the 9' to 10' of cable and consecutive readings taken were very consistant and once calibrated should remain dead accurate being vertually a remote reading dip stick. The parts are all simple and very little to go wrong. The objections to the use of this gauge in the petrol tank are (1) The cable must project from the top of the tank and could not have less than 2" radius which would seriously affect the luggage space. (2) As there is no really effective seal where the cable leaves the tank, petrol would leak out when the tank was filled right up or possibly cause small due to leakage owing to surge. | ||