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).
Comparison of engine overheating characteristics between the 40/50 and Goshawk models, including thermometer reliability.
| Identifier | ExFiles\Box 38\2\ Scan173 | |
| Date | 30th May 1922 | |
| Contd. -3- Hsl/T30.5.22. In one way we may be fortunate in the 40/50, inasmuch that even if the car is run without water we do not crack cylinders. There have been any number of cases where the cars have been run accidentally without any water and have got so hot that all the paint has been frizzled off the outside water jacket, but we have not known of a case where this has occurred when the cylinders have been cracked. With the 40/50, if the engine is run at all short of water, detonation becomes very bad indeed, in fact this is the first warning one gets of overheating. With the Goshawk, the detonation being so very much less, one does not receive this warning. X3565 During our tests we have found that the thermometers we fit to the cars are not to be relied on for recording when the engine is boiling. We have found several which have recorded 6 or 7° low. The fact of our being able to run a Goshawk full power at boiling for 10 minutes with no fan working at all, which means of course that the water throughout the whole system is boiling, we think is reasonably good. Hs.{Lord Ernest Hives - Chair} | ||