The Story of Streamlining.
How Science and Design have Overcome Wind-Resistance in the Quest /Or Speed. the course of extensive experiments carried out in the Polytechnic School in Berlin before the war, Dr. Riedler arrived at some extremely interesting conclusions with. regard to the relative importance of the various forms of resistance to its progress which are encountered by a car when running at fairly high speed. As a result of his investigations he laid down that an ordinary touring car fitted with a 4-seater body, absorbed 118 h.p. when travelling at 70 m.p.h., and that the power was absorbed by the various resistances as follows :—
The average touring car of pre-war days had, of course, a body which it is easy enough to see now offered quite an extraordinary amount of wind-resistance, but even allowing for this fact it is nevertheless remarkable that the German Professor’s experiments led to the conclusion that this one form of resistance was nearly twice as important as any other at 70 m.p.h. It is obvious therefore, that builders of cars of which the main object Is speed must of necessity pay consid,erable attention to reducing as far as possible the resistance they offer to progress through the air, and it is interesting to see the influence which efforts towards streamlining have had on the outward appearance of racing cars from the earliest times to the present day.
The Very Early Days. In the earliest days of the petrol vehicle the speeds attained were naturally not high enough to make the form of the cars of any great importance from the streamlining point of view. Pitted with little motors developing about 4 h.p. the original racing cars were only capable of about 20 m.p.h. They were regarded
at this time as ” horseless carriages,” and as such their outward appearance strongly resembled that of the earlier vehicles. Not only high themselves, the seat was usually the highest point of the machine and the whole body of the driver was thus exposed to the air. However at 20 m.p.h. no great inconvenience was apparent from this cause, and. no one bothered much about it. The long distance races which were monopolising attention at this time had entirely excluded from prominence the electric car, which, it had been found, was unsuitable for anything but short journeys owing to the frequent necessity of recharging the batteries. In 1898, however, M. Paul Meyan of “La France
Automobile” instituted the idea of holding a meeting on a deserted stretch of road at Acheres, when cars could be let out and their actual maximum speed recorded. This idea was the origin of the kilometre record which was to become so important in later days. At any rate among the cars which collected at Acheres in 1898 was a Jeantaud electric car driven by the Count de Chasselonp-Laubat which covered the flying kilometre at an average speed of 39.24 m.p.h., and succeeded in. easily outpacing the petrol cars, the fastest among which were certainly two Bailees, though whether owing to their streamline form or not it would be hard to say.
At all events in the Count de Chasseloup-Laubat’s machine an interesting attempt at streamlining had been made. The front of the car consisted of a vertical knife-edge like the prow of a boat, the sides were vertical and there was a flat deck, while the flat tail sloped downwards to end in a horizontal knife edge. The driver, however, sat on the top of the deck, with his legs in a well, and was thus almost entirely exposed. The success of the Count resulted in a challenge on the part of the great Camille Jenatzy, who in January, 1899, also appeared at Acheres with an electric car. This famous machine, named” La Jamais Contente ” had a cigar shaped body, with
a sharp point in front and a fairly blunt tail.
At his first attempt Jenatzy clocked 41.42 m.p.h.; the Count answered with 43.69 m.p.h. ; Jenatzy reached 49.92 m.p.h., and then the Count 58.25 m.p.h., and finally in April, 1899, Jenatzy recorded the really astounding speed of 65.79 m.p.h., at which one feels that he must have considered that it would be advantageous to provide rather more protection for the driver !
The next machine which is worthy of mention is probably the Vallee ” Slipper,” as it is possible that in this car one finds the first attempt to achieve this object of including the driver in the streamline form. Equally interesting were the De Dietrich cars which were built for the ParisMadrid race, and which bore a most striking outward resemblance to a modern racing car. In this machine, the bonnet started in a vertical knife edge behind, the gilled tube radiator, and gradually swelled outwards to its broadest part about level with the driving seat, behind which was a streamline tail of most modern appearance ending in another vertical knife edge. The cars were thus eliptical in plan. The topline of the bonnet rose steadily from behind the radiator to the centre of the scuttle, and behind the seat fell again to join the vertical knife-edge at the back. The undershield of the car was quite carefully streamlined, and the top of the scuttle was about on a level with the driver’s throat. Thus these cars were among the most interesting from the streamlining point of view that had as yet been built ; but unfortunately when it came to the weighing-in for the race it was found that they were considerably
above the 1,000 kgm. limit, with the result that their tails had to be cut away and their undershields removed in an attempt to get the weight down. The condition in which they ran in the actual contest therefore, did not allow of any interesting comparisons being made with the more orthodox designs of the day.
‘While energetic attempts were thus being made to save the wind resistance caused by the driver, little attempt had so far been made to facilitate the passage of the car through the air by building it lower. The credit for this development must probably go to the Wolseley Company. A car built by this firm had actually run in the Paris-Vienna race of the year before, 1902, and its designer, by using an underslung frame had succeeded in getting it so low that the top of the bonnet was not higher than the top of the front wheels. Little attempt was mad,e to streamline the car, and the driver and mechanic were almost entirely exposed, but it obviously contained the germ of the right idea. It was succeeded in 1904 by the Wolseley ” Beetle,” the outward appearance of which is probably familiar to all. In this case, although the und.erslung frame was dispensed with, the car was built very low, by virtue of the use of a horizontal engine, and the bonnet represented quite a good example of the ” beetle-back ” form of streamlining. The driver, however, sat very high up, quite unprotected, and, no attempt was made to treat the tail to conform to the bonnet.
Thus streamlining was relegated temporarily to the background and little of interest happened for several years. Mention may just be made in passing of the Hotchkiss which took part in the French Eliminating Trials for the Gordon Bennet Cup Race in 1904, and which had a bonnet reminiscent of Gabriel’s Mors ; and of the racing Napier of 1905, which had a bonnet of the wind-cutting type, with the radiator tubes running along its sides and brought to a vertical knifeedge in front. But neither of these designs can be considered as advanced, as those of the Paris-Madrid Mors and De Dietric.hs, and it was not until the cylinder capacity limit led designers to seek to gain speed by methods other than that of increasing the engine size that streamlining was again accorded serious study.
The Intermediate Period,.
In the early Grand Prix races from 1906-8, Continental designers thus showed considerable indifference to streamlining as an aid to speed,. Even, in the early Voiturette races, where the bore of the engines was limited, designers seem to have been too intent on increasing piston speed by using longer strokes and higher revs, to pay much attention to the outward form of the little racers. In the meantime, however, Brooklands track had been built and opened, and there can be no doubt that the speedway which permitted continuous very high speeds focussed, attention on air resistance problems to a degree never attained in the continental road races. By about 1910 in fact the Brooklan.ds racer in its most specialised form consisted of a very narrow single-seater, built fairly high and with a long tail ending in. a vertical knife-edge, thus approximating in general design to a modern American track-racer. It was not until 1911, however, that the principle really gained general recog
nition. In that year the limitedlbore regulations were done away with for the Coupe des Voiturettes, and the cars thus lost the enormously high appearance necessitated by their exaggeratedly long piston strokes. In its place the 3-litre capacity limit was instituted, and immediately the outward appearance of the cars underwent a remarkable change. The Sunbeams which ran in the race had rather low radiators, but showed distinctly that the lessons of Brooklands had been learnt. The bonnet sloped up steeply to the scuttle, there was very little cut-away for the cock-pit, and the tail fell away also rather sharply to end in a vertical knife-edge. The Vauxhalls in the same race were fitted with windcutting V radiators, but had, fairly workmanlike tails which were, however, more boat-shaped at the back. Some of the Continental designs were no less interesting. The Peugeots, whose designers were still faithful to the long-stroke engine, had, of necessity rather high bonnets, and, behind the cock-pit they were fitted with full streamline tails ending in a vertical knife-edge of most modern appearance. The top of the tail, however, was not nearly high enough to carry on the top line of the bonnet and, from backview a rather large proportion of the
driver’s back was thus exposed. The Excelsiors also were fitted with long streamline tails ending in a blunt point, while among the non-starters an interesting design was that of the Sizaire, which had a long narrow tail ending in a very short vertical knife-edge behind a rather bulbous bonnet. In 1914, however, there came a marked revival. In the first place Peugeot, then the unquestioned leader in the racing world, decided to fit his Grand Prix cars with streamlined bodies. The racers thus had good full tails, sharply up-swept underneath and ending in a short rounded
vertical line, while a large faring in the top enclosed the spare wheel. That year also Fiat returned to racing, and the Italian racers also had full streamline tails, commencing as high as the top of the scuttle and ending in a bulbous point at the back. Thus on the eve of the War streamlining was beginning to find its way back into favour for road racing, though it was still far from universal.
The Post-war Racer. The War itself, as a time of intensive study of aeroplane design, naturally focussed attention on streamlining to a degree never previously witnessed, and when after it was over, designers again turned their attention to racing cars they naturally attempted to apply the lessons
which they had learnt in the air during the previous four years. The early postWar Brooklands cars, such as the A..C., and the machines built for the international races such as the Ballot, thus tended to assume an extremely smooth exterior appearance terminated by a long blunt-pointed tail at the back. The Ballots which ran in the first post-war Grand Prix at le Mans in 1921 were excellent examples of this type of racing car, while they borrowed from the pre-war Peugeots the idea of mounting the spare wheel vertically in the tail.
The most interesting cars from the streamlining point of view which appeared in 1921, however, were undoubtedly the 3-litre Fiats which ran. in the Italian Grand Prix. These cars were designed after very lengthy and exhaustive experiments in wind tunnels, and represented a definite breakaway from the rounded, cross-section. fashion of the day. Their sides in fact were nearly vertical, and converged in the tail to a vertical knifeedge, while the underside was also flat. They were in fact streamlined on specialised automobile as opposed to aeronautical lines, and their interest lies chiefly in the fact that the design has survived to this day as the ordinary form of what may be termed the typical racing car such as the Maserati or Bugatti. The opposing school, however, were to reach the limit of their advance in the next year. The 1922 Grand Prix Fiats
were, it is true, externally developed editions of the 1921 racers ; but the Ballots and Bugattis which ran in the race had a most extraordinary outward appearance. In. the case of both these makers the idea prevailed to make a vertical cross-section of the cars almost perfectly circular, which earned the latter machines the appelation of the ” Barrel Bugs.” The nose consisted of a truncated cone shaped cowl, and, the bodies tapered away at the back. By the next year, however, Bugatti had had yet another idea, and again curiously enough, the same result was
arrived at by another maker in the form of ‘Voisin. The fundamental idea of these two entrants for the 1923 Grand Prix was that the best form for a racing car was not something resembling an aeroplane’s fuselage but a thickened edition. of its wing. The new Bugattis were termed the ” beetle-backed Bugs.”, and. there is perhaps no better way of describing them. In elevation their outline was semi-elliptical ; the undersides were quite flat, the sides vertical, and the top plane only broken in front by an oval orifice through which air reached the radiator. All four wheels were sunk in recesses in the vertical sides, the wheelbase and track being reduced to about 6ft. and Mt. respectively for the purpose. The design of these cars was undoubtedly of very great interest, and the principle was afterwards adopted for the highly successful 1,100 c.c. Chenard et
Wale keys As far as the Grand Prix is concerned, however, the ” beetle-backs ” represent the last machines of outstanding interest from the streamlining point of view, and in 1924 even the original Bugatti had come round to what may be termed the Fiat streamline form. It is true that the 1927 Talbots represented something of a combination of this now almost universal form with that of the “beetle back” exponents, possessing as they did sloping radiators and decidedly flat tops. But the Grand Prix was by then definitely on the wane, and it is not surprising that manufacturers lacked the interest to try their hands at novel streamline forms.
The Modern Record-Breaker.
With the decline of the Grand Prix, coincided a revival of interest in world’s short-distance records, and it is to this field of activity that one must now turn to trace the further development of stream lining as applied to automobiles. It is in fact curious how for a good many years after the War interest in the short distance records was practically non-existent, with the result that the field was for long held by such cars as the original 12-cylinder Sunbeam and Elcl,rid.ge’s veteran Fiat ” Mephistopholes.” The change, however, came in 1926/7, for that winter saw the completion of three special cars all built or reconstructed specially with a view to capturing the kilometre record.
The first of these cars, the NapierCampbell was very carefully streamlined, and attention was chiefly directed on keeping the car narrow. As a result the machine was not particularly low, but in order to save width a special faring was made on either side of the bonnet to accommodate the heads of the lateral blocks of the Napier “broad arrow” engine. The driver’s head projected well above the top of the bonnet and had behind it a faring above the level of the narrow tail which ended in a vertical knife-edge.
The second of this season’s record breakers, J. G. Parry-Thomas’ Ifigham Special known as ” Babs,” was also by reason of its origin, fairly high, but was streamlined on quite a different principle. In this case a sloping ” cow-catcher ” cowl was used to deflect air over the fiattopped bonnet which merged into a fairly narrow body ending in a long tail of which the top line dropped sharply to the final point. The underside of the car was kept as flat as possible, and, the bottom line of the tail did not rise at all to the point in which it ended. This car, in fact, represents the halfway house to the famous 1,000 h.p. Sunbeam which was to prove the most successful of the trio. In the case of the Sunbeam the beetle-back principle was adopted whole-heartedly, and no attempt was made to keep the car narrow, the body being built right out to enclose the wheels. It differed, however, very materially from the 1923 Grand Prix Bugatti, which was in some respects its prototype. In the first place no effort was made to
reduce the length of the Sunbeam which amounted to 23ft. 6ins. overall, and in consequence the top consisted of a nearly flat deck, while the angle between this deck and the sides was bevelled ‘,over and not acute as in the case of the Bugatti.
Segrave’s success on the Sunbeam in raising the record to over 200 m.p.h. spurred Campbell on to further effort, and in the following winter the Napier Campbell was entirely reconstructed. By far the most interesting feature of the redesigned car was undoubtedly the attempt which was made to deal with the rad.ator problem. The most careful streamline form, designed to allow air to flow freely past the sides of the car at speed must of necessity be vitiated if air has to be allowed to enter the shell in order to pass through a radiator. For this reason in the revised edition of the Napier-Campbell the radiator was removed altogether from its traditional place in the front of the car and in its place four sets of cooling tubes were mounted, two on either side of the tail, above and behind the back wheels. Much less attempt was made to keep the car narrow, and the bonnet was swept down in front to a horizontal line level with the front spring shackles so that the front of the car resembled the toe of a boot. Finally as a most interesting innovation a large stabilising tail fin was used.
Lockhart’s Stutz. Campbell’s success with this car was followed by an attack on the record by the ill-fated Stutz racer driven by Frank Lockhart, and this little car is of interest in that its designer employed a streamline form radically different from that which had been used on the English cars. The general outline of the machine in fact resembled a long and narrow cigar, with a blunt nose in front and the radiator arranged saddle-wise across the top of the bonnet, while each wheel was protected by a special streamlined faring. In view of the fact that this little 3-litre racer attained a speed of over 200 m.p.h., the streamline form adopted was obviously more successful than its defiance of accepted principles in automobile streamlining would have led one to expect. In fact, it must have owed its speed largely
to its outline and it is curious that immediately afterwards the protagonists of careful streamlining should have received a moral blow when the record was lowered by White’s Triplex which consisted of three engines set upon a chassis with no more bodywork than a bonnet to cover the front one.
” Schneider” Influence.
The next year, 1929, however, saw the appearance of an entirely new record breaker embodying the result of further streamlining research, in the form of the “Golden Arrow.” This car was designed largely on the lines which had proved so successful in the Schneider Cup aeroplanes, and owed its shape in part to the special features of the Napier broad-arrow engine which was used. The car may in fact be said to have been built in. two sections, Me of which was represented by a low beetle-backed shell enclosing the inclined cylinder blocks and on the centre of which was mounted the second stream-lined structure covering the central vertical block and providing faring in front and behind for the driver’s head. The radiators for this car were used as part of the separate streamlining for the wheels, between which they were arranged, and the striking success of the car provided perhaps, one of the best examples of how the automobile and aeroplane can contribute to their mutual development.
At the same time the redesigning of Captain Campbell’s ” Bluebird” for its record attempts at Verneuk Pan provided further interesting solutions of streamlining problems. In this case, owing to the particular nature of the place chosen for the record runs, it was found desirable to restore the radiator to its normal place at the front of the car. The machine was therefore, divided from thes treamlining point of view into two halves, consisting of a low flat-bottomed barrel-shaped bonnet with an annular cowl in front, through which air was allowed to pass ; and behind it a much higher beetle-backed shell which enclosed the driver. This car must be considered something of a makeshift, but in view of the adverse circumstances with which it had to contend, it was remarkably successful. The Spring of 1930 saw the appearance of another car designed specially for
records in the form of the” Silver Bullet.” This machine incorporated many of the features of the earlier 1,000 h.p. Sunbeam, and was built on the beetle-back principle. Probably, however, it had been found that the very large surface area of the earlier car had negatived some of its advantages in creating little disturbed air currents by causing considerable skin-friction, and the new car was therefore built much narrower and no attempt was made to include the wheels in the streamlining. In the “Silver Bullet” also, air was not allowed to enter the shell in order to reach radiators, as in the case of the 1,000 h.p. Sunbeam, but the problem of engine cooling was solved by the use of ice-chests and water pumps—this machine being perhaps the only motor car ever made in which engine was neither directly nor indirectly air-cooled.
Le Dernier Cri.
The story of streamlining may fittingly be closed with a few remarks on Captain Campbell’s latest record breaking car. This m_ici.ine is another most interesting study in streamlining and differs in material respects from those already described. In this case quite the same use is not made of the special features of the Napier engine as in the” Golden Arrow.” The body, however, consists of a beetlebacked section covering the engine and continued right through to the tail, while the driver sits behind the highest point of the curved top line and has his head streamlined by a separate faring projec: ing very slightly from the main body in. front and terminating in a huge directional fin at the back. In this case the cooling problem has been solved by placing the radiator of streamline shape at the front of the car but not allowing the air which passes through it to enter the streamline shell, with which it is connected simply by the pipes leading to the water tank.
It is a far cry from the boat-shaped Boll& racer of 1898 to Malcolm Campbell’s latest ” Bluebird,” but the change which has taken place has been brought about by gradual evolution and is one of the many arguments against those people who cannot understand the value of attempts to drive motor cars ever faster and faster.