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).
Table of ratios for 20 HP fans, showing fan speeds corresponding to various thrusts.
| Identifier | ExFiles\Box 75\3\ scan0072 | |
| Date | 10th February 1925 | |
| Ratios FAN SPEEDS CORRESPONDING TO VARIOUS THRUSTS OF VARIOUS FANS. 20 HP. THRUST (lbs). | Stand/rd | 3 | 9 | 10 | 14 | 18 ---|---|---|---|---|---|--- 1 | 1.00 | 1.03 | 1.02 | .935 | .820 | .926 2 | " | 1.13 | 1.09 | .936 | .888 | .948 3 | " | 1.16 | 1.11 | .950 | .918 | .935 4 | " | 1.16 | 1.11 | .961 | .934 | .903 5 | " | 1.16 | 1.11 | .965 | .942 | .892 6 | " | 1.12 | 1.090 | .940 | .932 | .871 7 | " | 1.10 | 1.09 | .930 | .926 | .865 8 | " | 1.09 | 1.09 | .929 | .917 | .854 9 | " | 1.08 | 1.08 | .923 | .899 | .845 10 | " | 1.08 | 1.08 | .925 | .899 | .842 11 | " | 1.07 | 1.07 | .920 | .897 | .840 12 | " | 1.06 | 1.08 | .919 | .893 | .842 13 | " | 1.04 | 1.08 | .922 | .897 | .841 14 | " | — | 1.08 | .921 | .894 | .840 10.2.25. Av | | 1.10 | 1.09 | .935 | .910 | .850 | | 1.10 | 1.09 | .93 | .91 | .85 | ||