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).
Two graphs comparing fan drive pulley performance against engine RPM, and fan drive control systems.
| Identifier | ExFiles\Box 75\3\ scan0203 | |
| Date | 25th July 1923 | |
| Left Graph: COMPARISON OF PULLEYS. DRIVE FROM CRANKSHAFT PULLEY. LARGE FAN PULLEY ------x RATIO 1-1 APPROX. SMALL FAN PULLEY ------o RATIO .8:1 APPROX. Y-AXIS: % FAN SLIP. X-AXIS: ENGINE R.P.M. DATA: 31 LBS TENSION, 30 LBS TENSION, 27 LBS TENSION, 40.5 LBS TENSION. Right Graph: COMPARISON OF CONTROL. SMALL FAN PULLEY. DRIVE OFF CRANKSHAFT. ROD CONTROLLED DRIVE ------o.{Mr Oldham} SPRING CONTROLLED DRIVE ------x. Y-AXIS: % FAN SLIP. X-AXIS: ENGINE R.P.M. DATA: ROD CONTROL - HAND ADJUSTED, SPRING CONTROL 50 LBS TENSION. Stamp: ROLLS-ROYCE, LIMITED. ADM. 25. JUL. 23. DRG. Nọ | ||