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).
Four performance graphs for a J III Rear 40/40 LB Low Pressure double diaphragm system at various RPMs.
| Identifier | ExFiles\Box 179b\3\ img004 | |
| Date | 23th December 1932 | |
| Top Left Panel: J III REAR 40/40 LB LOW PRESSURE R.R.S.269 VALVE SPRING RATING 80LB/IN APPROX 1" STROKE 90 R.P.M. DOUBLE DIAPHRAGM - A.C. & P.B. CONTROL | LOAD MAX | 80 75% | 53 50% | 29 25% | 12 ZERO | 5 Graph Axes: 308 LB/D" - 133 LB, 120 ' I.S. Top Right Panel: J III REAR 40/40 LB LOW PRESSURE R.R.S.269 VALVE SPRING RATING 80LB/IN APPROX 1" STROKE 180 R.P.M. DOUBLE DIAPHRAGM - A.C. & P.B. CONTROL | LOAD MAX | 93 75% | 66.5 50% | 42.5 25% | 27 ZERO | 18.5 Graph Axes: 308 LB/D" - 133 LB, 120 ' I.S. Bottom Left Panel: J III REAR 40/40 LB LOW PRESSURE R.R.S.269 VALVE SPRING RATING 80LB/IN APPROX 1" STROKE 360 R.P.M. DOUBLE DIAPHRAGM A.C. & P.B. CONTROL | LOAD MAX | 120 75% | 82.5 50% | 53 25% | 36 ZERO | 22.5 Graph Axes: 308 LB/D" - 133 LB, 120 ' I.S. Bottom Right Panel: J III REAR 40/40 LB LOW PRESSURE R.R.S.269 VALVE SPRING RATING 80LB/IN APPROX 1" STROKE 540 R.P.M. DOUBLE DIAPHRAGM A.C. & P.B. CONTROL | LOAD MAX | 166 75% | 122 50% | 89 25% | 66.5 ZERO | 90.5 Graph Axes: 308 LB/D" - 133 LB, 120 ' I.S. | ||