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 conditions of a 40/50 model vehicle.
| Identifier | ExFiles\Box 24\5\ Scan024 | |
| 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}/Rml/L39.4.25. (a) If a 40/50 fitted with a 2 1/2" matrix and no ventilation is driven at full throttle, it will boil in time - (1) At 30 m.p.h. if the atmosphere temperature exceeds 22oC. (2) At 40 m.p.h. if the atmospheric temperature exceeds 26oC. (b) If a 40/50 fitted with 2 1/2" matrix and four ventilating standard bonnet panels open, is driven for sufficiently long on full throttle, it will boil in time - (1) At 30 m.p.h. if the ats. temp. exceeds 26.3oC. (2) At 40 m.p.h. if the ats. temp. exceeds 30.3oC. According to the cable from Dalgetty's, the atmospheric temperature at which the second test on 67-AU was carried out appeared to be 29oC 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 emphasize 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 10oC. If the overheating complained of is at high speeds, far the best palliative will be found to be increased ventilation, and the customer must be persuaded to run with his bonnet panels open. Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} | ||