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).
Technical discussion on the design and effectiveness of square tube radiators and bonnet ventilation.
| Identifier | ExFiles\Box 15\1\ Scan341 | |
| Date | 31th August 1930 | |
| -2- SQUARE TUBE RADIATOR. Concerning this, I naturally had a funk that this would not be as effective as the round tube type. It has proved to be practically equal. We have not however, carried it out quite as intended. With the square tubes they need not be expanded at the ends, but the waterway formed by the vertical strip between the tubes. This matrix should be freer for the passage of air through the tubes and also for the circulation of water by the pump. It should carry less water and perhaps make a stronger structure. It should not cost any more money, but possibly may not weight less owing to the increased cooling surface presented, the area inside the parallel tubes being greater than the area in the present round tubes. Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} was particularly anxious that we should save water in the radiator matrix which he finds holds more than we had imagined, and perhaps more than is necessary. I think however, it would be a fatal mistake to make any modifications to the radiator which would slow down the air passing through the radiator. To keep a cool engine house in summer is very desirable and it will be observed that this particular radiator should give several advantages over the present. We should not expect to be able to clear a blocked radiator without taking off the top or bottom tank, but we do think this would be preferable to having to scrap the whole matrix. This leads us to the next point. BONNET VENTILATION. There is no doubt that the pressure shewn under the bonnet suggests the absolute necessity of using increased means of getting the air away. Possibly something can be done with the under-shielding but I fear the only satisfactory way of meeting the trouble permanently is to have louvres in the bonnet, and the best form of these will be horizontal because one would expect that the noise coming out through the radiator would be less, and certainly the appearance would be better because one could not see the oily engine parts through the louvres. It will be noticed that we have with the new bonnet catches a small horizontal louvre already at the bottom of the bonnet. This might be increased. No disadvantage has ever been found from this which was an excellent move, | ||