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).
Page discussing experiments with fan designs and the fitting of radiator cowls to improve engine cooling.
| Identifier | ExFiles\Box 24\5\ Scan084 | |
| Date | 15th July 1925 guessed | |
| -3- fan was polished there was a marked improvement in the suction of air, and that erratic currents were not caused inside the bonnet. Eventually nothing but polished aluminium fans were used, chiefly of the 3 and 4 blade type, though some two-bladed fans seemed to be efficient, but in this case, of course, the blades were rather larger. (3) Eventually in the autumn of 1916 we fitted cowls on the engine side of the radiator, the diameter of which corresponded as nearly as possible with the diameter of the fan blades. The cowl was deep enough to enclose the fan blades in one type, and in the other type the fan blades were outside the cowl. In the former a marked improvement was noticeable in the cooling effect of the radiator, and experiments showed that instead of the air being drawn only through the centre of the radiator as formerly, the air was now drawn through the whole of the radiator. With the ordinary fan we noticed that at each corner of the radiator when the vehicle was standing still there was a tendency for the air to go outwards and not inwards. The conclusion I came to was that a fan surrounded by a cowl was about a third more efficient in cooling the water in the radiator than if the cowl was not fitted. And eventually I recommended, and I believe this was carried out after I left | ||