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 pressure-velocity curves for a 20° valve at different temperatures using Castrol XL oil.
| Identifier | ExFiles\Box 151\2\ scan0385 | |
| Date | 8th February 1939 guessed | |
| PRESSURE-VELOCITY CURVES FOR 20° VALVE AT 20°C AND 100°C USING CASTROL XL PRESSURE LBS/□" SPEED M.P.H. HARD 20°C HARD 100°C SOFT 20°C SOFT 100°C SHEET 1 | ||