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).
Article from 'The Motor' magazine discussing car design, performance, aerodynamics, and market segmentation.
| Identifier | ExFiles\Box 160\4\ scan0078 | |
| Date | 4th April 1939 | |
| Arbuthnot/Rm {William Robotham - Chief Engineer} 1379 April 4, 1939. 337 The Motor Topical Technics Theme and Variations in Design and Development VINTAGE.—A comparison between the performances of old and new type cars is given on this page; here is one of the old brigade, Elgood's Bentley at Brooklands, travelling at well over 100 m.p.h. 100 m.p.h. I WAS interested to read the views put forward in our correspondence columns recently by “Vintagent” comparing the performances of some older-type cars, rather, I think, to the belittlement of the modern 100 m.p.h. types as exemplified by the later Bentley, Lagonda, Alvis and some others. The cars he mentions as having achieved the equivalent, or even greater, speeds are all of the open type and, although not streamlined, probably have a frontal area at least a third less than any saloon that could be produced. The power required to drive at a given speed is, therefore, reduced by 20 to 25 per cent., and this is a very important point when relatively large outputs, which are in any case necessary, are being considered. Furthermore, the more modern types of car combine this speed with real versatility on top gear. This is a quality which “Vintagent” may despise, but it is one that is in popular demand, and it is only by satisfying such demand that manufacturers remain in business. I think it should be quite clear that to do 100 m.p.h. is in itself a matter of no vast difficulty although to maintain it for an hour certainly constitutes the problem. To be able to keep up a sustained speed of this nature, however, without sacrificing qualities desirable on the modern motorcar, represents a very considerable technical achievement. AN interesting feature of a lot of the faster Continental cars is that they have in every case restricted headroom and, in the majority of cases, a sub-standard track. This, of course, reduces their frontal area to no small extent. To cite examples: the 4.3-litre Alvis which we timed to do just over 100 m.p.h. is 5 ft. 1 in. high and has an overall width of 5 ft. 9¼ ins. A Continental car of 3½ litres which does approximately the same speed, although having much the same width, is only 4 ft. 5 ins. high and this reduction is something of really considerable importance, being equal to about 25 per cent. on frontal area. Although from the mechanical point of view the lower the car the better, it must be recognized that there are certain disadvantages, apart from the obvious ones of relative difficulty of getting in and out, and the inability to wear a hat inside the body. The invisible objections, as it were, are that engine and rear-axle noises come through into the passenger compartment far more readily if the floor is broken by a large tunnel for the gearbox and transmission than if it is placed some way above these components. Most of the high-speed British cars have tried to combine quietness of running with their performance. Once one starts to reconcile these two factors, which even now find themselves in opposition, difficulties of design are increased enormously. Wind ALTHOUGH I fear it must be nauseating reiteration to talk further in these notes about wind noises, experience on the road is continuously confirming my impression that for the high-speed driver suppression of these is even more important than quietening the mechanical noises. I was recently testing a small car which was by no means quiet when driven around town and had a definite rumble from the power unit whenever one opened the throttle. Away from town, however, on the open road at cruising speeds of between 50 and 70 m.p.h., one's general impression was not that it was a noisy car, but a fairly quiet one, this being due entirely to the fact that it had a streamlined body and wind noises were virtually absent. The eliminating of these pests seems to follow either with a body of good streamlined form or one which is so unstreamlined and box-like that the air is shoved aside in great waves and does not form violent eddies all over the body surfaces. Data I FEEL that the car-owning community is becoming steadily divided, like ancient Gaul, into three main classes of owner. There are the under 12 h.p. buyers, who constitute not only a majority but an overwhelming preponderance of purchasers; that is to say, between 75 and 80 per cent. There are another 15 per cent. who are attracted by quality, comfort, or ease of travel offered by higher-powered and more expensive cars, and of the balance of 5 per cent. there are some who purchase high-speed motoring. This high-performance market can, I think, only survive if the cars in it are not only better than the more touring types which are their rivals but are overwhelmingly better. Designers and producers in this field must, I think, always bear in mind that success can only come from constant improvement, difficult though it may be for this to be commercially justified. L.P. A23 | ||