Problem of boiling water in the 40/50 model's cooling system at various engine speeds and conditions.
| Identifier | WestWitteringFiles\L\2July1924-September1924\ Scan91 | |
| Date | 8th August 1924 | |
| TO BY. {R.W. Bailey - Chief Engineer} HS. {Lord Ernest Hives - Chair} RG. {Mr Rowledge} SJ. DJ. PN. {Mr Northey} E. {Mr Elliott - Chief Engineer} BA. EP. {G. Eric Platford - Chief Quality Engineer} FROM R. {Sir Henry Royce} re. BOILING WATER in 40/50. X766 3456 4214 (1) We ought to make the car right without boiling when running on top gear on the level, through still air, at reasonable temperatures of say 80.F - 27.C. We know of only one way of doing this, namely, to let the heated air escape by louvres, and every means possible. (2) A dynamotor does not give a conclusive estimate. It must be on the road at car speeds. (3) The Hispano can be compared on the dynamometer at Derby. (4) I feel sure there is a distinct advantage in changing to a lower gear which in our case is not done, because the engine pulls well at slow speeds. (BY. {R.W. Bailey - Chief Engineer} says 'yes', then 'no'.) (5) We must accept that the water will boil under certain circumstances as we cannot possibly have a radiator and fan speed large enough to prevent boiling at 700/1000 revs., because the fan is not going fast enough. (6) After pointing out that engine speed must be maintained while the throttle is wide open for long periods, if boiling gives any trouble we must arrange to allow of boiling at slow engine speeds without distress to the driver; therefore prevent overfilling, leaky radiator caps, and avoid whistles, because we can continue to boil for a longer time than would happen in use and still only using 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 speed [handwritten: velocity] is enormous. (1) | ||
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).