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).
Radiator tests conducted on a 20-HP car.
| Identifier | WestWitteringFiles\K\July1923\ Scan71 | |
| Date | 12th July 1923 | |
| COPY. RADIATOR TESTS - 20-HP CAR. These tests were carried out climbing from Macclesfield up to the "Cat and Fiddle" Inn on the 11th. July. There was no wind and the road surface was dry. The air temperature at the bottom of the hill varied from 22.5° to 24°C during the course of the day. As far as possible, when comparisons were being made, the tests were carried out consecutively to minimise the affect of atmospheric conditions. The car speed was maintained as nearly as possible at 20 m.p.h. the whole of the way. Where the gradient of the hill was not sufficient to keep it down to this speed, the brakes were applied. Occasionally, on the steeper portions, the speed fell down to 17 m.p.h. or so. The temperature at once rose, and this accounts for the irregularities of some of the curves. In no case were we able to boil the car on the move on the hill with the fan on; on pulling up in all the tests comprising graph 'A' i.e. after running for 19 mins at 20 m.p.h., the car boiled losing about 2 pints of water, but it did not boil while the speed of 20 m.p.h. was being maintained. A summary of the results contained in the graps is as follows :- Graph 'A'. The shutters in position appear to slightly enhance the cooling capabilities of the radiator. The difference, however, is exceedingly small. Graphs. 'B' & 'B'1. Louvres open are a decided advantage in cooling. Graph 'C'. The undershield off in addition to the louvres open does not show any appreciable improvement. It appears that as long as the air can get away from underneath the bonnet, it does not require a very large area by which to escape. The bonnet off gives increased cooling but not so much as one might expect. Graphs. 'D' and 'E'. Emphasize the effect of removing the fan and the advantages of a large fan and high rotating speed. The fan was driven off the dynamo shaft and was rotating at 1.3 times engine speed. N.B. The louvres referred to in the graphs are designated as such because to call them shutters would confuse them with radiator shutters. They are in reality bonnet shutters of the standard type and size fitted to the 40/50 HP. (Hs{Lord Ernest Hives - Chair}/Mn.) | ||