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).
Test report detailing cooling performance comparisons between different radiator blocks and fans, including a competitor vehicle, the Buick.
| Identifier | ExFiles\Box 125\3\ scan0126 | |
| Date | 3rd July 1939 | |
| -2- principally that the second block had the base lowered by 1.500" giving overall dimensions of 24.250" x 19.050" x 84 m/m in place of 22.750" x 19.050" x 84 m/m for the original matrix. Tests showed a gain of 25 - 30 % for the larger block, a surprisingly large increase in view of the fact that the increase in area is only 6.7%. Results were checked both with and without a fan, however, and an investigation to be carried out to find out whether there are any peculiarities of pressure distribution over the front and rear of the matrix. We consider however, that this second block, in conjunction with a Wraith fan with shortened blades should be quite satisfactory from a cooling point of view, and it is also reasonably quiet. Some further work on this latter item, however, may be necessary before the job is finalised. (3) Comparison of Buick, 30.G.VII and 3.B.50. Advantage was taken of the presence of 3.B.50. at the track to run off a set of critical air temperatures, and results are as shown on Fig. III. It will be seen that the Buick is about 4% better than the Wraith 80, when this latter car is fitted with a Buick fan. With a shortened Wraith fan with increased blade set, however, the Buick is approximately 7 1/2% worse, than 30.G.VII. A comparison between 3.B.50. and the Buick shows the former car to be about 15% worse, the critical air temperature only being in the region of 36°C. under maximum speed conditions. The result is not very good, but the test was carried out under rather rushed conditions, and before stating anything definite we should like to check the figures thoroughly. This is being done as far as possible under Derby conditions and results to date appear to confirm the track results. Further investigation is proceeding and a separate report will be issued later. (4) Idling. A considerable number of idling tests were carried out, but some difficulty in presenting the figures has arisen as due to high air temperature, the water boiled in nearly every case. As a fairly representative figure, however, we have taken the rate of increase of mean water temperature as a criterion, and results are as shown on Fig.IV. this appears fair though it makes the assumption that the water temperature increases directly as the time, an assumption which is reasonably | ||