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).
Technical discussion on engine cooling issues, comparing fan and radiator performance to a Hispano model.
| Identifier | ExFiles\Box 38\2\ Scan206 | |
| Date | 21th August 1924 guessed | |
| contd :- -2- a small amount of water as steam. Water thrown out by expansion and steam bubbles is I believe making all the fuss and distress. (7) Our fan has always been very large and efficient unless the belt is slack. I do not agree with attempting to increase the speed of the fan. Our top velocity is enormously higher than Hispano (1 1/4 X 22 / 14 = 33/14) - more than double. (8) Can our fan be improved in shape? Greater efficiency would make it easier to drive. How much power does it take at from 1500 to 3500 revs? Does it go this speed? Will it go faster if there are less blades, or if made more efficient? (9) The matrix of 2 years ago was 19", and the present standard is 20 1/4", an increase of 6%. We are now recommending 22", an increase of 16%. (10) We cannot increase the face area of the radiator either in width, or upwards, because of limitations, and it is difficult construction to go down. (11) We have a large engine which heats a lot of water. (12) Increasing the compression ratio should heat the water more, as also would a too advanced ignition, (benefitted by auto control) and weak mixtures. (13) It is of no use sending a man to Switzerland until we know what he should do or say. (14) The Hispano has a small and low speed fan which cannot be efficient, and this car must be susceptible to a following wind which is the same as testing on road wheel RR. contd :- | ||