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).
Cooling system fan belt performance, mixture strength, and fuel supply issues at high speeds.
| Identifier | ExFiles\Box 29\3\ Scan226 | |
| Date | 9th July 1930 | |
| -3- by such leaks in service has been brought to our notice. COOLING SYSTEM - FAN - We confirmed our previous result that the standard spring loaded whittle belt is incapable of driving the fan satisfactorily at high speeds. We have an alternative endless canvas rubber belt which has a much better life and will drive the fan when spring loaded but causes it to dance about rather too much. We think that this might be used with the tensioning spring tightened choc-o-bloc. It was run on the last 10,000 miles test and stretched very little. GRAPH (I) shews that the radiator top water temperature is no less than 9.5°C. higher without a fan than with a fan used to the best advantage. We did not think that the fan was so vitally important at road speeds as high as 60 M.P.H. The disadvantage of moving the fan nearer the matrix is that it tends to roar at high speeds with the radiator shutters in certain positions. MIXTURE STRENGTH. At 60 M.P.H. going from full strong to full weak makes a difference of 4°C. to the top water temperature (Graph II) when everything under the bonnet is thoroughly hot (say mean temperature 45°C & 50°C) and gets the impression that the carburation becomes erratic. At full speed the autovac definitely acts as the high speed jet after running all out for about three minutes. As the fuel supply is inadequate there is a loss of power through weakness which certainly is bad for valves, | ||