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).
Letter to G.W. Hancock discussing solutions for radiator overheating and petrol boiling issues.
| Identifier | ExFiles\Box 91\4\ scan0053 | |
| Date | 1st July 1935 | |
| G.W. Hancock, Esq., Hotel de France, Chateauroux, Indre, FRANCE. Thank you for your notes re cooling, etc. With regard to the overheating of the radiator, you are of course carrying out your tests on the flat and therefore overheating is taking place at high speeds. The reason for this is undoubtedly the grille on the front of the radiator which puts the water temperature up about 12°. If you remove the grille you will get approximately the same results as you will with the next car, which will have shutters. We should therefore like you to do this and let us know what the results are. The next question is the heat under the bonnet which is causing your float chamber boiling, etc. There are several ways of tackling this - (1) To get more air through the radiator, which means that it will have a smaller temperature rise and so the under bonnet temperature will be lower. Removing the radiator grille will help you in this. If this is not sufficient, you might try removing the engine side guards or increasing the ventilation in any other way possible. (2) Taking the air intake from the atmosphere instead of from under the bonnet. We suggest that a simple way of doing this would be for you to have a vertical pipe and cut a hole in the bonnet. If air at about 30°C. was going through the carburetters instead of air at 60°C. one would imagine that this would prevent the petrol boiling. Cadillacs do this. (3) Cadillacs have a more efficient fan than we have which runs at rather a higher speed. This of course is the major factor in mountain work. We shall obviously have to try one of these cars round the Stelvio, etc. under Summer conditions and see whether it really overheats badly. If we have a reliable anti-spill radiator cap I do not see why we should lose an appreciable amount of water even with the radiator as it is. Of course if we put a more efficient radiator on we shall increase all our petrol boiling troubles. | ||