Table of ratios for fan speeds corresponding to various thrusts of different fan types.
| Identifier | ExFiles\Box 75\3\ scan0031 | |
| Date | 19th December 1924 guessed | |
| Ratios. FAN SPEEDS CORRESPONDING TO VARIOUS THRUSTS OF VARIOUS FANS. 1st Sac N | THRUST (lbs.) | 1. Std. 40/50 6-bladed fan. | 2. Std. 40/50 6-bladed fan with 3 blades removed. | 3. Eagle(Aero Engine) 4-bladed fan. | 4. Hispano fan. | 5. High speed 6-bladed fan. | 6. High speed fan with 3 blades removed. | 7. Goshawk(Aero Engine)(Codename for 20HP Car / Aero Engine after Kestrel(Aero Engine)) fan. | 8. 40/50 Std. fan with backing back blades. | 10. (Crossed Out) 40/50 Std. fan with Eng-ine jack blades - 3 places removed. | 9. Prof. Watts fan. | |---|---|---|---|---|---|---|---|---|---|---| | 1 | 1.00 | 1.19 | 1.03 | 1.33 | 1.00 | — | 1.37 | 1.07 | .935 | 1.02 | | 2 | 1.00 | 1.29 | 1.13 | 1.43 | 1.03 | — | 1.49 | 1.13 | .936 | 1.09 | | 3 | 1.00 | 1.33 | 1.16 | 1.42 | 1.04 | — | 1.52 | 1.14 | .950 | 1.11 | | 4 | 1.00 | 1.33 | 1.16 | 1.41 | 1.03 | — | 1.51 | 1.13 | .961 | 1.11 | | 5 | 1.00 | 1.33 | 1.16 | 1.38 | 1.03 | — | 1.50 | 1.12 | .965 | 1.11 | | 6 | 1.00 | 1.31 | 1.12 | 1.36 | 1.00 | — | 1.48 | 1.09 | .940 | 1.09 | | 7 | 1.00 | 1.31 | 1.10 | 1.36 | .99 | — | 1.46 | 1.07 | .930 | 1.09 | | 8 | 1.00 | 1.30 | 1.09 | 1.36 | .99 | — | 1.45 | 1.07 | .929 | 1.09 | | 9 | 1.00 | 1.27 | 1.08 | 1.37 | .98 | — | 1.44 | 1.06 | .923 | 1.08 | | 10 | 1.00 | 1.26 | 1.08 | — | .99 | — | 1.44 | 1.06 | .925 | 1.08 | | 11 | 1.00 | 1.23 | 1.07 | — | .98 | — | — | 1.05 | .921 | 1.07 | | 12 | 1.00 | — | 1.06 | — | .98 | — | — | 1.06 | .919 | 1.08 | | 13 | 1.00 | — | 1.04 | — | .98 | — | — | 1.07 | .922 | 1.08 | | 14 | 1.00 | — | — | — | .98 | — | — | 1.06 | .921 | 1.08 | Handwritten summary row: 1.00 1.30 1.10 1.00 1.48 1.08 .93 1.10 | ||
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).