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).
Road tests comparing the cooling efficiency of two different fan types (R.R. vs EFC).
| Identifier | ExFiles\Box 75\3\ scan0051 | |
| Date | 2nd February 1925 | |
| To EFC. from Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} Hs{Lord Ernest Hives - Chair}/Rml/LG18. 2. 25. X1017 FAN TESTS. X1017 We have carried out road tests with the two types of EAC. Fan which we handed to you yesterday. The method of conducting the tests was exactly the same as that given in our hs{Lord Ernest Hives - Chair}/Rn{Mr Robinson}/LG25.11.24.(CONSULT FOR CRITICAL ATM TEMP) The car speeds of 30 and 40 m.p.h. gave a fan speed of 1175 and 1445 r.p.m. The average results of our tests are as follows :- Two Fans. Critical atmospheric temp. -------------------------------------------- | 30 m.p.h. | 40 m.p.h -------------------------------------------- R.R. Fan. | 27.7°C | 28.6°C -------------------------------------------- EFC. Fan. | 23.6°C | 25.7°C -------------------------------------------- Another way of expressing this is the difference in temperature required between the atmospheric and mean radiator temperature to enable the cooling system to deal with the heat given out by the engine - this is :- For two Fans -------------------------------------------- | 20 m.p.h. | 40 m.p.h. -------------------------------------------- R.R. Fan. | 67.3°C | 66.4°C -------------------------------------------- EFC. Fan. | 71.4°C | 69.3°C -------------------------------------------- It will be seen from these figures that the efficiency of the cooling system drops 5.5% at 20 m.p.h. with the broad bladed fan, 4.3% at 30 m.p.h. with the board bladed fan. contd :- | ||