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).
Comparison of thrust and power requirements for various 20 HP fans.
| Identifier | ExFiles\Box 75\3\ scan0213 | |
| Date | 9th February 1925 | |
| EFC1/T9.2.25. -6- Contd. (1) Present standard 20 HP. fan. (2) Hispano. " (3) Most efficient expl. 20 HP fan. From these curves it will be seen that whereas the thrust for a given speed for the new fan is somewhat greater than for the standard, the power required to drive is still considerably less. Hence there is considerable justification for retaining the standard belt drive ratios. [Watermark: DICKINSON BOND EFC. 1804 MADE AT CROXLEY] | ||