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).
Methods for reducing under-bonnet air temperature and comparing the 40/50 and 20 HP car models.
| Identifier | ExFiles\Box 53\4\ Scan100 | |
| Date | 19th September 1923 guessed | |
| -2- This third item is less effective than the two preceeding ones and probably it will be found to have a very little effect on the temperature of the air within the scuttle. (4) The fourth item is also of very doubtful possibility. It consists of reducing the temperature of the air in summer under the bonnet. (The thermostat with a bye-pass which fitted to the present English cars is a good item). It is however possible that we could do something in the way of reducing the temperature by lagging the exhaust pipes, by increasing the size of the radiator, by making the radiator somewhat shallower, and so increasing the quantity of air through the radiator, by using rather larger tubes to increase the air through the radiator, by increasing the size of the fan, and by giving extra facility for the air to escape. In conclusion, naturally our 40/50 with its large engine is rather worse than the average car, but our 20 HP. car should be quite as good as any other car of its size. Probably it is better as it is fitted with a larger radiator and not much exhaust pipe surface. We must not howeber overlook the fact that this little engine has probably more HP. for its size than other similar engines. Mr. Hives is working on all these points. R.{Sir Henry Royce} | ||