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).
Proposal to use a dynamometer and a large ventilating fan rig to test car radiators.
| Identifier | ExFiles\Box 27a\3\ Scan167 | |
| Date | 21th February 1931 guessed | |
| works. The car would be run on the dynamometer in the ordinary way and a stream of air from a ventilating fan carried by means of a cowl shrouding the radiator through the matrix tubes. This would exactly reproduce the conditions of the road providing we could get an air blast up to an equivalent of 80 m.p.h. road speed. We could measure our inlet and outlet water temperature by means of sensitive instruments such as Nickel wire resistance thermometer grids, and in fact, get vastly more accurate readings under track conditions. Messrs. Boulton & Paul said that this was far and away the the most satisfactory means of getting results, and volunteered to supply us with all the necessary details to get the required draught which is of course a subject in which they have expert knowledge. They stated that the most serviceable unit which they know of is the combined fan and alternating current motor mounted on a small trolley, which could be wheeled about. They considered that a 25 HP. motor would produce the necessary draught, but did not recommend that the radiator should be cowled. They suggest a 5 ft. diameter outlet for the fan placed about 6 ft. from the front of the car. They are using a hydraulic coupling between the motor and the fan which enables them to run the motor at a fixed speed but get any lower speed of the fan which they require to within fine limits. They suggest that if we purchase the plant which they recommend and have any difficulties in calibrating, etc, they would be only too pleased to send one of their experts down to assist us over any difficulties that would arise, the information they gave re. the plant being supplied gratuitously. They estimated that the outfit may cost about £150 to £200. We consider that if we are to continue making our own radiators and to hope to compete successfully with other proprietary makes, such a fan unit is essential. It is a very much more economical way of making tests than on the track. The results are also likely to be more reliable. We have looked round the existing fans but have found nothing which will give us what we want. Rm.{William Robotham - Chief Engineer} | ||