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).
Specifications for the 40/50 radiator and fan, including water capacity, pulley diameters, and a table of fan speeds.
| Identifier | ExFiles\Box 75\3\ scan0113 | |
| Date | 29th September 1923 | |
| X3438 29.9.23. 40/50 - RADIATOR - AND FAN. X3456 X3438 Capacity of 40/50 HP. water system -- 7 galls. 3 1/4 pts. Dia. of bottom of crankshaft pulley - 4.837". Dia. of bottom of Fan pulley------- 3.878" Fan Speeds. Theory | Practice 1 1/4 STANDARD. 1.18 | 1.2 HIGH SPEED 1.46 SUPER HIGH SPEED 1.58 | ||