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).
Problems with Autovac tanks, suggesting modifications, and requesting further designs.
| Identifier | ExFiles\Box 22\1\ Scan274 | |
| Date | 28th September 1925 | |
| To HS{Lord Ernest Hives - Chair}; from DA{Bernard Day - Chassis Design}/EV.{Ivan Evernden - coachwork} c. to CJ. BJ. H.{Arthur M. Hanbury - Head Complaints} X4214 DA{Bernard Day - Chassis Design}/EV{Ivan Evernden - coachwork}1/M28.9.25. RE. AUTOVAC TANKS. X.3579 X.3593 X.4214 We have examined an autovac and notice that each time the autovac ejects its petrol into the dashboard tank, and the suction in it is put at atmosphere the petrol runs back into the main tank. When the suction comes on again the whole of the highly carburetted air has to be evacuated. Mr. Royce suggests that somewhere in the pipes near the petrol tank, we try a back pressure valve to prevent this petrol from running back. We think this valve need only be a ball which, directly the petrol begins to run back, falls into a conical seating. We would be glad if you would fix this up experimentally, and tell us whether it has any effect. There is likewise a great deal of waste volume over the float, namely, on either side of the actuating lever. We suggest that this be filled up with hard wood as an experiment, so as to reduce the volume of the carburetted air to a minimum. It is appreciated that the ultimate minimum would be the volume of the petrol ejected. In order to help us with further designs we would be glad if you would send us on loan an autovac such as we fit, and also a Weyman vacuum feed of the latest design, as whilst this may have some mechanical defects, it is beneficial from the point of view of carburetted air. We understand that the Hispano has a Weyman tank, and we would be glad if you would tell us whether the slow running of the Hispano is interferred with by the functioning of the auto vac. DA{Bernard Day - Chassis Design}/EV.{Ivan Evernden - coachwork} | ||