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 pumping system test, detailing petrol levels, cup positions, and gauge readings.
| Identifier | ExFiles\Box 44\3\ Scan099 | |
| Date | 5th December 1928 | |
| Messrs.Rolls-Royce,Ltd., Date 5.12.28. Page 3 Our experience has been that before any considerable pumping can take place, the cup must be something between 1¼" and 1½" above the normal petrol level. This is more or less borne out by our commencing to pump between 12¾ and 12½ gallon level in the tank. The type of road and the speed at which the car is driven, undoubtedly have an effect on the rate of pumping. The point with regard to the position of the top cup will be able to be checked by you on N.sch.2576/2578 (K.S.175), and further on the new unit which we shall be sending you for this actual installation. With regard to the second test, starting from the 10½ gallon level, we should expect approximately a gallon to be used before the second cup was capable of doing a great deal of pumping. Possibly during this test both the top and second cups were working, which increases the rate of pumping. During this test, starting from the 10½ gallon level, the contents at the end of 25 miles would be between 9½ and 9¾ gallons. The gauge was then reading 7½ gallons. The next half gallon reading on the gauge would have corrected the unit down to the bell, and thereafter pumping would be so slow as to be difficult to observe, owing to the difference | ||