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 effects of fan drive and radiator shutters on radiator temperature at high speeds.
| Identifier | ExFiles\Box 29\3\ Scan128 | |
| Date | 8th July 1925 | |
| H.R. 493A (50m) (D.B. 175 25-9-24) J.H.D. EXPERIMENTAL REPORT. Expl. No. REFHS/Rm{William Robotham - Chief Engineer}/LG8.7.25. Condition of Fan Drive. Top radiator temp. Standard. 89°C Fan removed. 94°C Drive pulled choc-a-bloc. 85°C Average speed 72 M.P.H. Air temp. 25.5° sun. 24.8° shade. (d) RESTRICTION CAUSED BY RADIATOR SHUTTERS AT HIGH SPEEDS. For this test the bonnet ventilating panels were opened to allow the air a reasonable chance of escaping. It was found that the radiator shutter control could be closed four notches without any appreciable rise in temperature. The fifth notch caused a definite rise in temperature of 4°C. We should be inclined to say that this demonstrates that even with the present standard ventilation in the bonnet the restriction opposing the egress of the air is such that the air is piled up on the front of the radiator. Hence a considerable obstruction can be caused on the external face of the radiator before it reduces the quantity of air passing into the bonnet below that which is able to pass out. Air temp. 26.5° sun. 25° shade. Condition of rad. shutters. Top radiator water temp. All open. 88°C Control closed 4 notches. 88 - 89°C. " " 5 " 92°C Throughout this test the four bonnet ventilating panels were open. contd :- | ||