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 about the principles and benefits of streamlining in motorcars.
| Identifier | ExFiles\Box 161\1\ scan0074 | |
| Date | 25th January 1938 | |
| The Motor 1380. 1142 JANUARY 25, 1938. STREAMLINE ANY statements or articles regarding streamlining and its possibilities must start with some sort of apology and with a definition of what is really meant by a streamlined motorcar. The apology is necessary because there have in the past been many so-called streamlined and airlined cars advertised and marketed in which the wind resistance was lowered not in deed and in truth, but in name only. As a result of this we had but a little time ago a spate of rather queer-looking cars that performed rather worse than the standard product, being somewhat heavier and having just as much resistance to motion through the air. What I am considering in this article is the car that is scientifically and properly streamlined. It is necessary, therefore, to make some statement of my references so that these types may be distinguished from their entirely unworthy predecessors. Speed and Power It is, of course, impossible to streamline any four-wheeled land vehicle to the same extent as can be seen on the modern military monoplane, but we must not overlook that on racing types we are not far from this ideal. Rosemeyer's 253 m.p.h. was achieved with an engine developing probably some 700 b.h.p. and this compares more than favourably with, say, the Gloster Gladiator, which has a top speed of 255 m.p.h., derived from its 840 h.p. Bristol Mercury engine. This machine is, of course, a biplane with military equipment. If, however, one takes an example of the Messerschmitt monoplane, which now holds the world's landplane speed record, it can be calculated that it would need 610 h.p. to achieve 260 m.p.h. The similarity of speed and power of racing cars and aeroplanes is striking evidence that the streamlining of racing cars has made tremendous strides in the past twelve months. It is interesting to note that already there are in existence touring cars to which these lessons have been applied and which I can properly use as examples. A photograph of one of these, built by the Adler company, is shown on the right and I can state from personal trial in the four-seater model that its performance is quite astonishing, as will be seen from details which I will give later in this article. At the moment, however, I feel it necessary to draw attention to the fact that the true merit and gains of streamlining are only realized when travelling at much higher speeds than are normally attained on British roads. This factor is shown vividly by the accompanying illustrations indicating the relative horse-powers required to achieve various speeds with the conventional and with the thoroughly streamlined car. It will be seen that the latter will achieve a speed of 90 m.p.h. with an engine the same size as is required for 70 m.p.h. on the normal type. If 90 m.p.h. is required, the engine size of the normal car is very large indeed; in fact, for a four-seater car at least 120 h.p. is needed. DIMINUENDO. At low speeds such as 50 m.p.h. the gains that accrue from the use of streamlining are not great. Only about 20 h.p. is required to drive a normal car at this speed and of this about seven is needed to overcome friction losses. The relative engine horsepower required may, therefore, be represented by the areas of engine shown in the drawing (right). | ||