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).
Report discussing the feasibility of using a wind tunnel for testing car radiator efficiency.
| Identifier | ExFiles\Box 27a\3\ Scan166 | |
| Date | 17th February 1931 | |
| To Hs.{Lord Ernest Hives - Chair} From Rn.{Mr Robinson} TESTING EFFICIENCY OF CAR RADIATORS. We visited Messrs. Boulton & Paul to discuss with them the possibility of using their wind tunnel for testing the various types of radiators which we have at present under construction. The idea was, if possible, to supplement the tests that we have recently been carrying out on the track with results which could be obtained during the winter months with the hope that a scheme might eventually be perfected that would largely take the place of track tests for this particular unit. We first discussed testing models of 1 sq.ft. frontal area. They are very familiar with a large number of results which were carried out by R.A.E. at Farnboro'. They said that in order to get a temperature difference which is sufficiently great to permit of reliable measurements. The conditions of flow in a model have to be perhaps 1/10 of that in the actual radiator with the result that the conditions become far removed from the actual practice. Furthermore, the large ratio of radiator shell to actual matrix produced, a feature which is not encountered on the full sized radiator. They therefore considered that we might have to repeat their model tests on the car before we could establish their exact relative value, and taking all things into consideration we do not recommend such a series of tests. We next discussed the testing of a full size radiator. They agreed that there would be no difficulty in getting the necessary wind velocity but they had no means at their disposal of economically generating the necessary heat for the cooling water which at full throttle high speeds amounts to over 100 HP. They pointed out that to lay down such a plant would necessarily entail a considerable outlay and as they had no interest whatever outside our enquiry we should have to expect to bear a considerable portion of the initial outlay. Considering that even when the complete radiator is tested in the wind tunnel we are far from producing the conditions which exist(i.e. the action of the fan, the back pressure under the bonnet, heat from the exhaust, etc.) it would appear that this would be too extravagant a method for getting even relative values for radiators. We then discussed with them an alternative scheme of testing which we had considered we might rig up at the | ||