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).
Analysis of the factors affecting engine water temperature at various speeds, including comparisons with other vehicles.
| Identifier | WestWitteringFiles\U\May1930-July1930\ Scan129 | |
| Date | 9th July 1930 | |
| -5- Hs{Lord Ernest Hives - Chair}/An.1/B.L.9.7.30.Contd. INCREASE OF MAXIMUM WATER TEMPERATURE WITH SPEED. Graph 1b. shews the increase of water temperature with speed. The car runs approximately 6°C. hotter at 75 M.P.H. than at 60 M.P.H. Naturally the car is more likely to suffer from weak mixtures when being driven all out, which may make the apparent difference greater than this figure. It is hardly fair to congratulate the American Phantom I car on not over-heating at 71 M.P.H. when we know that our own cars would be better cooled at similar speeds under similar conditions, and only get into trouble because they can develop considerably more power and do 14 M.P.H. more speed. SUMMARY. It will be seen from Graph III that given an efficient fan, a rich mixture and a ventilated bonnet the car should not over-heat at air temperatures below 35°C. when driven all out continuously in still air, and if driven at 75 M.P.H. infinitely should not over-heat below atmospheric temperatures of 40°C. Under these circumstances we should say that the limiting factor in driving the car fast would be the tyres and not the cooling system. The effect of a following wind is very marked if the fan is not working. Even when the fan is working a following wind can easily raise the top water temperature 5°C. We think this may account for some of the figures in the Daily Reports such as that of 6.7.30. Max. Water Temp. 100°C. | ||