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).
Tests and conclusions on improving engine cooling systems and under-bonnet temperatures.
| Identifier | ExFiles\Box 155\1\ scan0297 | |
| Date | 24th June 1937 | |
| -3- Tests with the calorstat spring removed from the radiator calorstat gave an average running temperature of approximately 73°C. i.e. 7° lower than standard. This lowering of the average temperature means that when idled stationary the car will take 3 - 4 minutes longer to reach 100°C. than it would from the standard temperature of 80°C. PART II. In order to improve the cooling generally, i.e. at low and high speeds full throttle, the schemes enumerated in Part I. were tested at 40 M.P.H. full throttle and maximum speed full throttle (approx. 85 M.P.H.) on 37-X. car. In addition, in an effort to lower under bonnet temperatures, we tested a Mk.V.l. matrix unit with 1" of matrix removed from each side edge in order to permit cool air to flow around the matrix. Top and bottom water temperatures, temperatures at front and rear of cylinder heads, air temperatures behind fan and at petrol pumps, petrol feed temperatures and atmospheric air temperatures were all noted during tests. CONCLUSION FROM TESTS. Attached sheets (Nos.) 3 & 4) show the results of the tests at 40 M.P.H. and maximum speed respectively, while sheet 5 shows the effect of the bonnet shutters, bonnet louvres, air slots at side of matrix etc. on underbonnet temperatures. The results indicate:- (1) That the standard Mk.Vl.{V. Lewis / Mr Valentine} core tested is the best matrix we know at the moment - none of the other matrices tested equal it. Further, the results it gives are so good compared with the original test figures on this type of matrix (when first made by Marstons) that we have carried out a check test on the road at Derby with another std. Mk.Vl.{V. Lewis / Mr Valentine} matrix - this gave results equally as good as the one tested at Brooklands, so that there is no question of an individually good matrix being used for comparisons. (2) Gains in cooling are obtained using the 5 blade fan running at higher speeds - the higher the speed the larger the gain - but the ratios above 1/1 were too noisy to be acceptable. continued | ||