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).
Low pressure diagram for a J III rear 90/90 lb double area valve.
| Identifier | ExFiles\Box 151\2\ scan0042 | |
| Date | 20th March 1933 | |
| J III REAR, 90/90 LB. LOW PRESSURE. NS {Norman Scott} 3497 DOUBLE AREA VALVE. 172 LB/IN. VALVE SPRING. 1" STROKE. R.P.M 540 360 180 90 308 LB/SQ" = 133 LB. 120' I S | ||