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).
Wind tunnel tests conducted on a 1/8th scale model of a 'Bensport' car.
| Identifier | ExFiles\Box 160\2\ scan0140 | |
| Date | 1st June 1933 | |
| Vickers (Aviation) Limited WEYBRIDGE WORKS JUNE, 1933 REF: RKP/23871. REPORT OF WIND TUNNEL TESTS ON 1/8TH SCALE MODEL OF ROLLS-ROYCE "BENSPORT" CAR. It was originally proposed to test two models with various modifications, using each model alternatively as the "image" in the reflection method of testing for the effect of the ground. Only one model (No. I) was received in time for the tests, so the experiments were confined to modifications of this car using a flat plate to simulate the effect of the ground. This flat plate was arranged just to clear the front wheels of the model and inclined downwards towards the back wheels 1° so that the surface of the boundary layer formed the "ground" and not the plate itself. The model was suspended by wires, allowing the model to swing freely longitudinally, the drag being applied to the balance by means of a pivoted strut at the tail of the model. Drags were measured at one speed only, viz. 70 f.p.s., except Test No. 4, which was done at every five feet per second from 40 to 70, in order to ascertain whether there was any scale effect or not. No scale effect was observed so it was considered correct to assume that the drag varied as the square of the speed and scale up to the full size conditions. The results of the tests are tabulated below, the drags being fully corrected and give the wind resistance only of the full size car at 90 m.p.h. The test numbers and descriptions of parts modified are those suggested by Mr. Evernden who was present throughout the tests. The modification for Tests Nos. 20, 21, with radiator and front wings faired with plasticine is illustrated in the accompanying photograph. | ||