Rolls-Royce Archives
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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).
Car overheating issues, discussing the effects of driving conditions, fans, and tyres on the cooling system.

Identifier  ExFiles\Box 14\7\  Scan034
Date  9th July 1930
  
-6-

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. indefinitely 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.
Average " " 82°C.
Max. air " 28°C.
Average air " 25°C.

We will ask G.W.Hancock to specify exactly what conditions raise the maximum water temperature 18°C. above the average while the air temperature only rises 3°C.

Incidentally, one of the old standard whittle fan belts is being run on 24-EX. We are sending one of the new belts out as soon as we can obtain a fresh supply.

We think it is wrong to condemn the cooling system of the car because the daily report shows 100°C. as having been reached, because it may only havebeen attained momentarily without loss of water.
  
  


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