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).
Page two of a test report detailing experiments on an Autovac float chamber under various conditions.
| Identifier | ExFiles\Box 40\4\ Scan338 | |
| Date | 20th April 1934 guessed | |
| -2- sucked out of the float through the hole at the top of the self-draining tube. These conditions were tried two or three times, with the same result. The petrol always being sucked out. (2) With the soldered joint at the top and one 1/16" hole drilled at the joint. On starting up the engine the float immediately failed with petrol and dropped to its fullest extent; allowing the suction valve to remain open, thus filling the entire float chamber with petrol, and before the engine could be stopped, the petrol had started to be drawn into the induction pipe. (3) Standard float which had failed on 12-G4 owing to faulty solder on the bottom joint. The same procedure was adopted as in (1). The Autovac was run for two hours and then left for three hours. After that period, the float was seen to have sunk slightly, but on starting the engine up the petrol was immediately sucked out as in (1) and had gone back to its normal position. This was tried two or three times with the same result, the petrol always being sucked out. The engine was again started up, but this time the petrol in the can was gradually heated until it reached 86F. The engine was then stopped with the normal amount of petrol in the float chamber. The Autovac was then left to cool down, when it was quite cold it was seen that the float had sunk to the bottom of the float chamber. The Autovac was then fitted on 1-WJ. The suction side being attached to the pump. The engine was started up and it was seen that the float did not operate, the float chamber immediately filling with petrol. | ||