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).
Secret internal memorandum discussing car radiator and fan design for the 20 HP and 40/50 HP models.
| Identifier | ExFiles\Box 38\2\ Scan218 | |
| Date | 29th August 1924 | |
| V324-50 S E C R E T. To RG.{Mr Rowledge} HS.{Lord Ernest Hives - Chair} } FROM R.{Sir Henry Royce} c. to CJ. BJ. DA.{Bernard Day - Chassis Design} E.{Mr Elliott - Chief Engineer} BY.{R.W. Bailey - Chief Engineer} EP.{G. Eric Platford - Chief Quality Engineer} RL/M29.8.24. RE. VISIT OF RG{Mr Rowledge} & HS.{Lord Ernest Hives - Chair} TO WW. ON 27th. & 28th. INST. X.766 X.3456 X.3438 RE. CAR RADIATORS. X.9250 X.4214 X.4240 From figures the 20 HP. has ample size and efficient fan, and should be O.K. Compared with the Hispano the big 40/50 engine heats a lot of water. Our radiator face area is proportionately smaller and as regards natural air currents, indendent of fan, it is worse than Hispano, but with a following wind our more efficient fan makes us superior, What can be done - Both our 20 HP. and 40/50 HP. cars can have louvred bonnets, (which we think a decided advantage and very generally fitted to all other large cars) to partly meet the complaint, but as these have the disadvantage of noise, and appearance, we do not propose to fit them as standard. The 20 HP. should have no other changes made unless we can find a better scheme. Two years ago the 40/50 had a 19" matrix (height). At present it is 20". We are arranging for this to be 23" and the fan also will be increased in diameter, and greater freedom for the escape of the heated air has been arranged. Greater size than this 23" matrix would drive us into difficulty and to go down would force us to adopt complex and costly construction, while to go up we should get German appear-ance, and would make it difficult to see if the front wing would clear near objects. The width is at present great, and up to the full limit. FAN. (SIZE & SPEED). With the larger matrix the fan will be increased in diameter, but owing to noise and slipping belt we do not propose to alter the standard speed which is already fast, being 1 1/4 times engine speed. DESIGN OF FAN. I propose that the Aircraft people be asked if they could suggest a better design of a 2, 3, 4, or 6 bladed fan, either one that will increase the air circulation, or for equal circulation, one that would be easier to drive. In my remarks on radiators it should be understood contd :- | ||