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).
Graph comparing Autovac and Grav-Vac petrol feed systems at various engine speeds and throttle settings for a 20 H.P engine.
| Identifier | ExFiles\Box 40\3\ Scan065 | |
| Date | 29th March 1927 | |
| AUTOVAC AND GRAV-VAC PETROL FEED. TESTS CARRIED OUT ON A 20H.P ENGINE WITH STANDARD CARBURETTER AND INDUCTION PIPE. FUEL RAISED 32" THRO A PLAIN PIPE .250 DIAM 6FT LONG. TESTS AT FULL AND HALF THROTTLE. GRAV-VAC: ----- AUTOVAC: _____ INDUCTION PIPE DEPRESSION Ins Hg PETROL DELIVERY PTS/HR ENGINE R.P.M. FULL THROTTLE. 1/2 THROTTLE 1/4 THROTTLE 5.3" 4.75" 3.9" 2.25" 1.6" 1.55" 1.25" 1.05" .30" | ||