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).
Analyzing engine cooling performance and water temperature rise under various loads and gear selections.
| Identifier | WestWitteringFiles\L\July1924-September1924\ Scan25 | |
| Date | 11th September 1924 | |
| R.R. 493A (40 H) (SL 42 12-7-23). J.H., D.{John DeLooze - Company Secretary} -4- EXPERIMENTAL REPORT. Expl. No. REF: Hs{Lord Ernest Hives - Chair}/ACL/LG11.9.24. the water temperature would rise until it reached boiling point. We have however the alternative of changing to 3rd. gear and if we reduce our throttle opening so that the road speed falls to say 25 m.p.h. requiring 31 1/4 H.P. to drive the car, we shall be running on a load of approx. 63% of that which the engine is capable of giving at that speed. The engine revs. will be approx. 1330 r.p.m. and our radiator should be able to deal with 1900 B.Th.U's/min. At half load the radiator is just on the border line of being able to deal with the heat liberated to the jacket water but for the above example the load is only .63 of maximum therefore given a sufficiently long hill the water would still increase in temperature to boiling point but we should be better off than running on top gear because our heat flow is not so much in excess of that with which the radiator can deal, consequently the time before boiling takes place will be longer. Again, we can change to 2nd. gear and reduce our speed to 20 m.p.h. - we shall therefore be running at 45% the load which the engine is capable of taking at this speed. The radiator will deal with the heat liberated at this load consequently the hill could be climbed without over-heating. Sheet 4 gives the heat flow for various loads plotted against the horse power. We can determine from this the heat flow to the water for any H.P. and consequently what it is for any condition of gradient and speed. It is seen that under throttled conditions the heat flow to the water for the same power is slightly contd :- | ||