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).
Analysing the effects of an exhaust baffle and butterfly system on engine temperature and performance.
| Identifier | ExFiles\Box 24\5\ Scan035 | |
| Date | 30th April 1925 | |
| 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}/LG30.4.25. Test (A) shewed no difference. Test (B) shewing a difference which could only just be measured, and which amounted to 1.25°C in favour of the exhaust baffle being fixed in the full open position. Test (C) shewing a rise in mean running temperature of 1.75°C due to the exhaust baffles slight restriction on partial throttle. - We should therefore say that, unless there has been something radically wrong with the initial setting, we should not expect dismantling the exhaust butterfly to produce any appreciable result on the over-heating troubles in Australia. Tests on the dynamometer shewed that we could detect a loss of H.P. on partial throttle with the butterfly connected to the accelerator. We suggest that if the exhaust butterfly was arranged to open fully for half the accelerator movement, and that the control was then designed so that the pedal movement could continue and open the carburetter throttle fully, all the present benefits of heat to the carburetter when starting up would be maintained, while no loss in power or increase in radiator temperature would be detectable on the road or dynamometer. Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} | ||