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).
Comparative cooling effects and power consumption of different fan designs, along with fan diameter constraints for a new chassis.
| Identifier | ExFiles\Box 75\3\ scan0057 | |
| Date | 27th February 1925 guessed | |
| -4- Contd. more nearly to the case (b) above for the good fan, in which case we might get, even with this experimental fan, a greater cooling effect at moderate speeds, a still greater cooling effect at high speeds, still with less power to drive and wear of belt. Finally, the question is not so much whether two fans driven with the same pulley will give more or less cooling effect one than the other at moderate speeds - we can always improve the cooling effect (or by altering the blades of a given fan) at moderate speeds by driving any fan faster - but whether we can secure the same or more cooling effect at moderate speeds, and therefore more or still more effect respectively at high speeds, with less power and consequent wear of belt at all speeds. It now appears that the fan tip dia. of 23" cannot be retained on the new EAC. chassis, owing to fouling which would occur. RHC.{R. H. Coverley - Production Engineer} is deciding the maximum allowable fan tip diameter (between 22" and 23"½) and further tests will be conducted with experimental fans of this diameter. For the actual bench observed speed-thrust and power-thrust curves of the two fans tested on the road, see photostat sheet attached. to follow. EFC. | ||