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).
Analysis of temperature distribution and performance curves for an air-cooled cylinder unit.
| Identifier | ExFiles\Box 133\1\ scan0114 | |
| Date | 17th September 1936 | |
| -10- Hs{Lord Ernest Hives - Chair}/Ed.{J. L. Edwards}1/KW.17.9.36. Air Cooled Unit. The cylinder and head of the air cooled unit were studded with thermo-couples as shown in Figs. IX & X, and the standard running conditions were 70°C. B.A.T., 4,000 R.P.M., and 1" Hg. boost, with a standard car silencer fitted. Power curves, consumption loops and detonation curves with temperatures were taken and are shown in Figs. XI to XXV. It should be noted here that the temperature readings in the head were not particularly consistent, and as mentioned before, it was found necessary to adjust some of them to what was considered a more rational value. This was done by selecting a series of similar conditions - given by power, consumption and cylinder temperatures, which were more reliable - selecting the maximum temperature from these readings for each head couple, it being assumed that the couples could not read high, and then making percentage corrections to all the other readings in the curves. By applying this correction, it is thought that all the temperature figures given will be within about 5% of the true value. A consideration of the temperatures brings out the following points :- Cylinder. (1) The face towards the fan - exhaust side - is easily the coolest, and the temperature gradient up the cylinder appears fairly uniform. (2) The face away from the fan is hottest, the reason being that there are only eddy currents here, and no direct flow of cool air. Once again the temperature gradient is fairly uniform. (3) The side faces do not show much difference, the one from the other. The temperature gradient is not so uniform as for the other faces, but begins to rise rather more rapidly as we go up the block. (4) Average temperatures for the cylinder are :- (a) Base, or plane A.{Mr Adams} 140°C. (b) Half way, or plane B. 160°C. (c) Top, or plane C. 185°C. | ||