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).
Blueprint graph of pressure-velocity curves for a 20° valve with a soft spring using 'Shokoil' at various temperatures.
| Identifier | ExFiles\Box 151\2\ scan0384 | |
| Date | 6th February 1939 guessed | |
| PRESSURE-VELOCITY CURVES FOR 20° VALVE WITH SOFT SPRING USING 'SHOKOIL' PRESSURE LBS/D" SPEED M.P.H. 20°C 30°C 40°C 50°C 60°C 100°C SHEET 3 | ||