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 and summary of cooling fan tests, comparing different fan and cowl configurations.
| Identifier | ExFiles\Box 155\1\ scan0256 | |
| Date | 2nd September 1936 | |
| (2) Conclusions. For test results see attached sheet. Referring to the sheet, it will be seen that (a) Comparing (1) and (2) indicates that the rear cowl is a disadvantage. (b) Comparing (2) (3) (5), and (9), indicates that the front cowl makes no appreciable difference. (c) Comparing (3) (4) and (6) indicates that the Cadillac five blade fan is the best of the three fans for cooling. (d) Comparing (1) (4) and (5) indicates a big gain from the high speed fan ratio, if the belt can be made to stand it. (e) Comparing (6) and (7) indicates a slight loss of cooling with the wire mesh grille fitted. (f) Comparing (6) and (8) indicates the maximum amount gain to be obtained by improving the under bonnet ventilation. Summary. It appears that we cannot hope to improve the Ph.III cooling by means of radiator cowls, and that our best line is to use a fan similar to the five bladed Cadillac fan tested and raise its speeds ratio to 1.125/1, using a suitable drive for the purpose. The Cadillac five blade fan was by far the quietest of the fans tested, and with the high speed ratio was not too noisy to be practicable. HS {Lord Ernest Hives - Chair} /Std. We think that a suitable high speed drive should be developed for the fan as soon as possible. We propose to try a scheme as shown on Rm. {William Robotham - Chief Engineer} 224 attached | ||