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).
Graphs comparing valve performance at various RPMs and overlap settings.
| Identifier | ExFiles\Box 105\3\ scan0335 | |
| Date | 5th May 1933 guessed | |
| Top Chart: J III REAR. 90 LB L.P. LOAD. LOW PRESSURE 28.4.33 N.S. 3670. HDY{William Hardy} VALVE. OVERLAP NIL. WITH VALVE DAMPING CYLINDER. 1" STROKE. RPM 540 360 180 90 308 LB / □" = 133 LB. 120" IS Middle Chart: J III REAR. 90 LB L.P. LOAD. LOW PRESSURE 27.4.33 N.S. 3670. HDY{William Hardy} VALVE. OVERLAP + .015. WITH VALVE DAMPING CYLINDER. 1" STROKE. RPM 540 360 180 90 308 LB / □" = 133 LB. 120" IS Bottom Chart: J III REAR. 90 LB L.P. LOAD. LOW PRESSURE 28.4.33 N.S. 3670. HDY{William Hardy} VALVE. OVERLAP - .015" WITH VALVE DAMPING CYLINDER 1" STROKE RPM 540 360 180 90 308 LB / □" = 135 LB 120" IS | ||