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).
Failures of the autovac petrol feed system on Phantom cars and experiments to fix the issue using a larger pipe.
| Identifier | ExFiles\Box 40\4\ Scan254 | |
| Date | 14th June 1927 | |
| X3579 To R.{Sir Henry Royce} from Hs{Lord Ernest Hives - Chair}/AJL. c. to BJ. Wor.{Arthur Wormald - General Works Manager} c. to E.{Mr Elliott - Chief Engineer} DA.{Bernard Day - Chassis Design} c. to BY.{R.W. Bailey - Chief Engineer} OY. Hs{Lord Ernest Hives - Chair}/AJL2/LG14.6.27. AUTOVAC PETROL FEED. X8771 The inability of the autovac petrol feed system on Phantom cars to supply the full engine petrol demand is always a source of complaint. The conditions under which failure and consequent 'drying up' occurs are very seldom met with under road conditions, but they are continually in evidence on the Production Dynamometer Test - much time and money are lost in repeating tests in order to get the chassis through their standard routine work. If every autovac system were 100%, no trouble would be experienced but owing to the border-line of failure being so near to test requirements, very slight losses in efficiency in the system produce failures; the amount of petrol delivered by different autovacs under the same conditions varies slightly, consequently failures often occur. Experiments on the production dynamometer have shewn us that these failures can be eliminated by using a larger diameter supply pipe from the rear petrol tank to the autovac. We have in consequence carried out tests under as near as possible the same conditions as on the dynamometer to ascertain what improvement is affected by using a larger pipe. The present pipe is .230" inside dia., the larger pipe (3/8") is .300" inside dia., both petrol pipe nipples, the petrol elbow and the petrol intake hole in the autovac head are opened contd :- | ||