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).
Summary of test results and conclusions regarding the cooling system performance, including fan, bonnet, and radiator matrix configurations.
| Identifier | ExFiles\Box 155\1\ scan0298 | |
| Date | 24th August 1937 | |
| -4- (3) The fan ring tested showed no gain in cooling at maximum speeds. (4) A gain in high speed cooling is obtained by opening the bonnet shutters, but no further gain is obtained by fitting a louvred bonnet. (5) The reduction in cooling with the lightened construction Mk.VI. core (15% - 17%) is so great that we intend to investigate this matter - we do not expect to lose more than 5% with this altered construction. (6) The matrix with 1" air slots at sides gives only a small reduction in air temperature at the petrol pumps (of the order of 4°C.) and reduces the cooling considerably - we do not therefore consider the idea worth proceeding with. (7) The latest Harrison matrix tested gave results which were just a little inferior to our standard Mk.VI. core - the American core tested was damaged somewhat in transit from the U.S.A. and has been repaired here - the repairs may have impaired its cooling effectiveness somewhat - According to American test figures it should have the same high speed performance as the Mk.VI. core with a slightly superior low speed performance. It should be remembered, however, that the Harrison construction corresponds to the lightened construction matrix which we tested (see 5 above) i.e. has tinned .005 waterway strip and untinned .003 airway strip, so that strictly speaking it should be compared with the lightened construction matrix. (8) The present std. MK.VI. matrix in conjunction with the five blade fan running at engine speed (1/1 ratio) gives a standard of cooling on the Ph.III. which should be satisfactory under all conditions. (9) With the provisions made in (8) above, the louvred bonnet is not necessary for cooling purposes, the standard bonnet with shutters being adequate. (10) On the car tested, no appreciable difference in temperature was recorded between the front and rear of the cylinder head. However, as such a difference is dependent on peculiarities of the cylinder head, we are arranging to carry out some tests on standard production engines recording the difference between alternative thermometer positions at the front end of 'B' side head and the rear end of 'A' sidehead (standard position). If the new position is satisfactory we shall standardise it - a thermometer reading at the front side of 'A' side head will be fitted on 32.X. which is running 15,000 miles in France. continued | ||