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).
Graph of horsepower versus fan speed for a standard 6-blade fan and a modified 3-blade fan.
| Identifier | ExFiles\Box 181\M8\ img009 | |
| Date | 20th November 1924 guessed | |
| 51 HP - FAN SPEED CURVES of VARIOUS FANS. 1. STD 40/50 6 BLADE FAN. 2. STD 40/50 FAN WITH 3 BLADES REMOVED. H.P R.P.M | ||