Development and testing of different engine fan models and their respective drive ratios.
| Identifier | ExFiles\Box 75\3\ scan0074 | |
| Date | 20th March 1925 | |
| To EY. from EFC. {E. Fowler Clarke - Electrical Engineer} c. Hs. {Lord Ernest Hives - Chair} G. {Mr Griffiths - Chief Accountant / Mr Gnapp} Ey/Shn. Y1017 EFC {E. Fowler Clarke - Electrical Engineer} 4/T20.3.25. X.1017. RE FANS. Please see our report EFC {E. Fowler Clarke - Electrical Engineer} 3/T20.3.25. Recently we handed to your Mr. Shelton a fan (No.15) to enable the production instructions of this item to be proceeded with. This fan is suited to an engine fan speed ratio of 1.2 (as standard on old 40/50) and with that drive ratio will take considerably less power than the old standard 40/50 fan at all speeds, and at the same time will give somewhat more thrust or cooling effect. We are now handing to your Mr. Shelton another fan (No.18) which shows some further general improvement over fan No.15, but for which the most satisfactory drive ratio may be 1.1 to 1 rather than the old 40/50 standard of 1.2 to 1. We have suggested in the report (q.v.) that fans which are copies of this sample should be made up for experimental EAC. chassis with pulleys giving three different ratios which we think might be suitably be 1.05 to 1, 1.02 to 1 and 1.20 to 1. In working out the size of these pulleys a radius of action of the V belt should not be taken at the centre of the belt, but at a point only 1/4 of the way down from the outer periphery to the inner periphery of the belt, and the speed ratio calculated accordingly. EFC. {E. Fowler Clarke - Electrical Engineer} | ||
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).