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).
Thermostat modifications and their effect on engine performance and petrol consumption.
| Identifier | WestWitteringFiles\V\October1930-February1931\ Scan036 | |
| Date | 27th October 1930 | |
| HS.{Lord Ernest Hives - Chair} FROM R.{Sir Henry Royce} ORIGINAL R1/M27.10.30. Copy to SG.{Arthur F. Sidgreaves - MD} [Strikethrough] " WOR.{Arthur Wormald - General Works Manager} " BY.{R.W. Bailey - Chief Engineer} " EP.{G. Eric Platford - Chief Quality Engineer} THERMOSTATS. x3499, Referring to HS{Lord Ernest Hives - Chair}/RM{William Robotham - Chief Engineer}1/AD221030., personally I think it would be doing quite wrong to adopt thermostat B., but to compromise I am willing to go to modification A, which is nearer like our standard. The reason why I am saying this is that with the exhaust heating and better cold distribution on P. 2. we ought to be able to run with a lower water temperature, also the risk of boiling is greater than that of a cold engine. The impression I got from my own experience is that a hot engine appears to run with less petrol consumption, but I am not sure that there is much in this because it means that when the engine is hot the volumetric efficiency of the air intake is less, and less petrol is needed. On my 25HP. here I have had very good petrol consumption without bothering much to keep the temperature high, even with water heated throttle. The L.H. experimental car lately brought to WW. appeared to be rather weak in the high speed setting which spoilt the crispness of the acceleration and induced one to desire a hotter engine. I think the hotter engine would not be the right way to cure the trouble and the petrol consumption would probably have been actually lower with a proportionately stronger high speed jet. I always prefer relatively stronger high speed jets than Derby Expl. Dept. [Stamp: RECEIVED 30 OCT 1930] R.{Sir Henry Royce} | ||