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).
The performance of a large gap radiator, comparing it to previous models and detailing tests on water pump flow restrictions.
| Identifier | ExFiles\Box 27a\3\ Scan108 | |
| Date | 10th January 1930 | |
| -3- Hs{Lord Ernest Hives - Chair}/Rm{William Robotham - Chief Engineer}3/MJ10.1.30 contd. present standard S.S. large gap radiator. In considering this it must be borne in mind that the drop across the radiator is about 10°C, and that therefore the highest temperature likely to be reached on the suction side of the pump is 85°C. At temperatures higher than this the delivery water to the radiator is boiling and therefore the cooling system is inadequate for other reasons. Curves (1) Hs{Lord Ernest Hives - Chair}/AJL9.1.30 show that up to an engine speed of 3000 r.p.m. we are, on new cars, within the limit of maximum circulation, but that it would not require very much obstruction to put us outside this limit. On a separate sheet we have compared the hydraulic resistance of various radiators measured on the standard works test rig. It will be seen that with the latest large gap Phantom II radiator we are not quite back to the freedom of V series Phantom I radiators, but very nearly so. We should say that with our anti-corrosion treatment of the cylinder water jackets we ought to compensate for this small difference. With a view to seeing how much we could restrict the water pump flow without impairing the car's cooling we carried out road tests progressively reducing the size of the delivery orifices to the radiator, until further reduction caused a rise in radiator temperature. The flow was then measured with these restrictions compared with | ||