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).
Car aerodynamics, wind tunnel testing, and comparing the frontal designs of various cars including Bentley and American models.
| Identifier | ExFiles\Box 161\1\ scan0175 | |
| Date | 15th June 1938 | |
| -2- We do not think that it is logical to spend as much time and energy as we do in extracting H.P. from our engines, and then waste the power driving an uneconomic shape through the air. This applies of course more to the Bentley than to the Rolls-Royce. The Americans work with wind tunnels and models. Until the results of our predictions from wind tunnel tests had been very good. We have so little experience, however, that we can hardly expect to know very much about the subject. Working with apparatus belonging to an aircraft firm to-day is hardly a practical proposition. We presume that Rolls-Royce will eventually have a wind tunnel of their own and would like to emphasise that when it is available we believe that it will be of considerable value to the car division. We are going to continue with our full scale experiments and hope to get hold of the latest Chrysler, Buick, Lincoln, Zephyr and possibly a Cord. In the meantime it is evident that if we are not to be at a disadvantage, we shall ultimately have to make a radical alteration to the frontal appearance of B.III. The two arrangements that seem to us to be least distasteful are the Paulin Bentley and the Lincoln Zephyr front ends. The low horizontal radiator on the Lincoln allows the greatest latitude with regard to the treatment of what is now the top radiator tank. The attached photograph shows the general appearance of the front of the cars tested. Owing to the inevitable photographic distortion, these photographs give an entirely erroneous comparison of frontal areas. A print is attached to Hy{Tom Haldenby - Plant Engineer}'s copy showing how the true frontal areas have been arrived at. The increased frontal area of B.III over B.II is confirmed by the fact that B.III actually requires more H.P. to lap at a given speed than B.II as represented by G.B.IV. Rm.{William Robotham - Chief Engineer} | ||