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).
Sketch of an engine cooling system showing the thermostat and butterfly valves.
| Identifier | Morton\M3.6\ img010 | |
| Date | 17th November 1921 | |
| Sketch No 2 R/17.11.21 Cylinder water pump thermostat Butterfly valves The thermostat as shown in its hot or expanded position Radiator | ||