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).
Potential solutions to engine overheating, including thermostat removal and radiator design changes.
| Identifier | WestWitteringFiles\L\2April1924-June1924\ Scan59 | |
| Date | 5th May 1925 | |
| TO HS.{Lord Ernest Hives - Chair} FROM R.{Sir Henry Royce} c.c. to CJ. DS. HY.{Tom Haldenby - Plant Engineer} TM. RM.{William Robotham - Chief Engineer} RP COOLING Slight ORIGINAL 'R' CLASSIC OVERHEATING. Y766 X8250 With reference to the Springfield use of copper tubes instead of our brass ones, this should make no difference. Regarding a corrugation of the tubes we think this might make a difference when the car is new, but also think it is a disadvantage when it gets more or less filled up with dirt and paint. Regarding the use of the thermostat this may make some difference in the time in which the water gains a steady temperature, because the radiator will do little or no cooling until the water gets to the prescribed temperature. This is what we call anticipation, that is, the thermostat does not anticipate either if it controls the water circulation or the shutters. HS.{Lord Ernest Hives - Chair} will no doubt be able to tell us what difference it would make if we remove the thermostat, at least from those cars which are located in warm climates. To abandon the thermostat would not be much loss with the exhaust heated throttle, but with the water heated throttle a longer time would be required for heating up, and more care needed, so that unless it was a definite gain in utilising the cooling capacity of the radiator, it would be a decided disadvantage, as the cars would have to be carefully muffled, or radiator shutters fixed, if they were to be used in cooler climates. I do not however anticipate any material difference between the two systems if the temperature is taken over a long time, but for a momentary burst of speed it would undoubtedly be more favourable to have no thermostat. HY{Tom Haldenby - Plant Engineer}'s remarks bring one to think that occasionally we may get trouble with the thermostat through it failing to act correctly. This is an aspect of the situation that I had not noticed. In the 20HP. and the 'New PhantomCodename for PHANTOM I' we have avoided this risk as we have no thermostat, but we depend upon the driver (which may prove worse) to open the shutters. We have for 15 years or more provided shutters to the bonnets. As soon as there was a risk of overheating these should have been opened, but this was not done, even by our own people, who sometimes go out in a demonstration car in hot and mountainous countries even without shutters fitted. Nearly everyone else use louvred bonnets, so that we must expect trouble if the shutters are not used. We have made the radiator as high as permits of seeing the front wings, as wide as the frame allows (which in its turn is as wide as the lock allows). It is as thick as is efficient, and the fan is as good in size, efficiency and drive, as we or others know how to make it, so that the only outlet is what we propose for 'X' series - i.e. to widen the track to 58" drop the ground clearance to 10" normal instead of loaded, and so increase the fan and radiator another 10%. Every little help may make possibly a vast difference. Generally the ignorant fill the radiator full and then try and keep it so, thinking the overflow is boiling. I am not surprised at HS{Lord Ernest Hives - Chair}' remarks, when he has done all he can: often we feel tired after struggles through many difficulties. R.{Sir Henry Royce} | ||