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).
The overheating and boiling tendencies of the 40/50 HP model under various conditions.
| Identifier | ExFiles\Box 38\4\ Scan082 | |
| Date | 25th September 1924 | |
| R.R. 493a (50m) (D.B. 175 25-9-24) J.H.D. EXPERIMENTAL REPORT. -3- Expl. No. REF: Hs{Lord Ernest Hives - Chair}/Rm{William Robotham - Chief Engineer}/LCS.4.25. (a) If a 40/50 fitted with a 2 1/4" matrix and no ventilation, is driven at full throttle, it will boil in time - (1) At 30 m.p.h. if the atmospheric temp. exceeds 22°C. (2) At 40 m.p.h. if the atmospheric temp. exceeds 26°C. (b) If a 40/50 fitted with 2 1/4" matrix and four ventilating standard bonnet panels open, is driven for a sufficiently long on full throttle it will boil in time. - (1) At 30 m.p.h. if the ats. temp. exceeds 26.3°C. (2) At 40 m.p.h. if the ats. temp. exceeds 30.3°C. According to the cable from Dalgetty's, the atmos-pheric temperature at which the second test on 67AU was carried out appeared to be 29°C. While we are therefore surprised that it should boil on a level road at 50 m.p.h., when full throttle would not be necessary, we do not consider it would require a very large defect to produce this result in view of the tendencies of the 40/50 to overheat, as exemplified in the figures previously quoted. We feel it necessary to emphasise once more the vital importance of having a satisfactory fan and fan drive on the 40/50 HP. If the fan belt is slack the condition of the car at once becomes hopeless in any normal climate, as it can be made to boil with an atmospheric temperature of only 10°C. If the overheating complained of is at high speeds, far the best palliative will be found to be increased ventil-ation, and the customer must be persuaded to run with his bonnet panels open. Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} | ||