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).
Report comparing the performance of different Autovac fuel system units and configurations.
| Identifier | ExFiles\Box 40\4\ Scan213 | |
| Date | 2nd February 1927 guessed | |
| 3. - increases, This can be explained by the unit the delivery exceeds that of the standard unit considerably. The deficiency of the Measuring Autovac is probably due to the much smaller petrol port used than on the standard unit; this being necessary due to the incorporation of the petrol valve. We have not investigated this point further but from our conclusions from results obtained during autovac tests in conjunction with the new type petrol tank filler and cap, during which tests it was found that restriction in the petrol line very greatly upset the efficiency of the Autovac unit. Fig II gives similar comparative tests but taken at half engine throttle opening. The Moving Float type retains its 40% superiority over standard up to 5.8" Mercury depression. A fourth curve is given in both Figures I and II. i.e. 'Measuring Autovac without petrol valve'. Comparison of this with the Measuring Autovac curve indicates the advantage to be gained by using a non return valve in the petrol line. For use on a car with the present Autovac reserve tank on the dashboard, the autovac with the moving float would lower the maximum petrol level in the autovac by 1.25". Thus reducing the useful capacity of the tank. To retain the | ||