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).
Conclusions from cooling system tests on the Wraith car.
| Identifier | ExFiles\Box 131\5\ scan0029 | |
| Date | 24th November 1937 | |
| -2- 30.MPH. full throttle and maximum speed full throttle in order to check up with - (a) The Harrison Radiator Corporation of U.S.A. alleged standard of cooling. (b) The Vauxhall alleged standard of cooling. CONCLUSIONS FROM TESTS. (1) Sheet (1) indicates that the five blade Cadillac type fan is the best possible compromise (from the point of view of noise and adequate cooling while idling) of the fans which we have tested on the wraith car. Further it indicates that we gain in idling cooling by reducing the distance between the blade leading edges and the matrix, and that we can go as near as approximately .700 mean distance of loading edge from matrix without running into complaints of noise. Further the speed ratio of .85/1 is satisfactory for the fan drive. (2) Sheet (2) indicates that:- (a) The undershields tested (Ex. scheme) do not appreciably affect the cooling under any conditions. (b) Bonnet flaps are definitely worth retaining as an aid to cooling. (c) Idling cooling conditions can be improved by means of a large diameter pump rotor, but high speed conditions will not benefit unless pipe bend sizes are increased. (3) Sheet (3) indicates that with the specification having minimum deviation from wraith as designed (Sheet 3 section 1) the wraith car is adequately cooled underall conditions except those of idling dead slow after prolonged flat out running, and normal dead slow idling on days with air temperatures above 33°C (or 91.4°F). In this respect it is about equal to the present standard 25/30.HP. car. This sheet also indicates that with the optimum specification, the cooling is still further improved and should be entirely satisfactory except under the peculiar condition of dead slow idling after prolonged full speed running on a day with an atmospheric temperature above 29°C. (or 84°F.{Mr Friese}) continued | ||