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 gas velocity past valves against engine RPM for various models.
| Identifier | ExFiles\Box 69\4\ scan0370 | |
| Date | 26th May 1927 guessed | |
| GAS VELOCITY PAST VALVES / ENGINE RPM ① NEW PHANTOMCodename for PHANTOM I ② 20H.P. STD. VALVES ③ LORRAINE DIETRICH & 20HP WITH LARGE VALVES GAS VELOCITY PAST VALVES (FT. PER SEC) R.P.M. OF ENGINE No3. Y-axis scale: 0, 50, 100, 150, 200, 250, 300, 350 X-axis scale: 0, 500, 1000, 1500, 2000, 2500, 3000, 3500 | ||