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 showing when extra oil would work if controlled by vacuum, plotted against throttle opening.
| Identifier | ExFiles\Box 16\1\ Scan077 | |
| Date | 29th March 1915 guessed | |
| Inches of Mercury 2000 1800 1600 1400 1200 Extra Oil 1000 800 Only slots open 600 400 Slots 1" 2" 3" 4" 5" 6" 7" Throttle opening Curve showing when extra oil would be working if it was controlled by the vacuum Full open | ||