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).
Test procedure for comparing fuel gauges with different tapered glass.
| Identifier | ExFiles\Box 61\3\ scan0099 | |
| Date | 11th September 1930 | |
| with the bad tapered glass to see the liquid as clearly for zero setting purposes as with the good glass, but before the 1-gallon mark is reached the liquid is as easily visible in one glass as in the other. For the purposes of this test we are sending you two gauges arranged and suitable marked with a bad, or high taper, and one with a good, or low taper. We are sending you also a dual air line for attaching to these gauges with a single connection at the other end. This should be connected to a suitable 202 - 20 H.P. tank unit and immersed either in a petrol tank or in a vase with the calibration strip of the 202 tank, which we are also sending you, suitably placed in relation to the tank unit. Petrol could then be added to the tank or the vase to the level shown on the strip, and a comparative reading of the two gauges taken on the first and any other gallons on the scale. The gauge heads should both be set at their normal angle of approximately 10°. From the series of tests made here, no variation in reading between these two glasses can be determined greater than the thickness of the broad line on the dial marking. It is curious to us that so little variation exists, as the first gallon should show more variation than it does, but on the test, under identical conditions, given a good zero setting | ||