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).
Report comparing the performance and efficiency of various fans using curves representing power, thrust, and speed.
| Identifier | ExFiles\Box 75\3\ scan0153 | |
| Date | 17th December 1924 | |
| 2 Contd. EFCL/T17.12.24. In the first instance the various fans referred to in our previous report have been taken in succession through this test (See attached list of fans and ref. Nos.). The curves exhibiting the results are now arranged in a rather different manner than previously. There is in the first instance sheet E exhibiting two groups of curves which really contain the whole story of each fan. They are respectively "Power required to drive" and 'Fan speed", both on a base of axial thrust of fan. The former group are directly indicative of the efficiency of the fan, taking this as being inversely as the power required to produce a given axial thrust, irrespective of speed, whilst the second group of curves gives the speeds at which the various fans have to be driven to produce these thrusts. In curves F and G, the various quantities, power, thrust, speed, and percentage slip, are exhibited on a 40/50 engine or chassis speed base on the supposition that the fan is driven by the standard crankshaft fan driving pulley thereon. Thus these curves (unlike those on group E) are not independent of the size of pulley fitted to the fan, and have been taken with the normal size of pulley. They are therefore of lesser importance than those on sheet E, though interesting from some points of view. Upon inspection of the curves it was noticed that the Hispano fan, though requiring to be driven at a relatively high speed, was the most efficient on the definition of efficiency given. It was therefore decided to | ||