Chain Chatter, June 1950

By “CARROZZINO”

THE battle for honours in the Grand Prix events this season looks as though it is going to be the greatest yet. Although only two countries are represented in first-line road-racing, as far as manufacturers are concerned, the interest is very strong. The real battles will be fought out in the 500-c.c. class, and it is interesting to observe that the “works” bicycles are being developed in every possible detail ; naturally, the power unit is of primary importance and more and more horsepower is being sought. Aided by the improved fuel, of 80 octane, in use this year, the power being obtained from the ” works ” machines is rapidly approaching that of pre-war days on 50/50 petrol-benzol. While the maximum possible horsepower obtainable from any given engine is desirable, the rest of the machine must be so designed that the power can be used. Too many times has one seen a machine with more power than its roadholding, steering or braking can deal with. The b.h.p. developed by the engine is, of course, not the only means for making the machine go quicker than one’s rivals, and the Grand Prix machines, which also include T.T. machines, are beginning to appear with devices other than those required for b.h.p. Light weight and wind-cheating are the two main methods being exploited to the full, and, as far as weight is concerned, the Italians are past-masters at the art of “adding lightness.” Reducing frontal area and smoothing out the passage of the air along the machine is rapidly becoming of major importance.

The new twin-cylinder Guzzi, not a pretty machine at the best of times, now has a most functional petrol tank of unusual shape which has depressions along either side to accommodate the rider’s arms when he is in the “lying down” position. The A.J.S. factory have also been studying airflow, with the result that the “works ” machines now have a saddle-cum-pad arrangement which fits round the rider’s rear portions like a small armchair. Without the rider the thing looks perfectly hideous and rather pointless, but a sideview of Les Graham really travelling quickly at the Circuit of Mettet recently, showed to perfection the idea behind the layout, for there was an unbroken line from the top of the rider’s helmet right down to the extreme end of the rear mudguard and a line of reasonable aerodynamic contour at that. The new “works” Norton, with which Geoff. Duke gave such a convincing demonstration at Blandford recently, also shows signs of experiments in the same direction, while, in addition, its fuel tank is so shaped at the rear that it allows the rider to tuck his knees well in, an important point as far as frontal area is concerned. This type of tank is not completely new, for the Montesas, the little 125-c.c. machines built in Spain, have similar tanks. A further attempt to cheat the wind is the use of cowlings covering the steering head and incorporating a small windshield, behind which the rider can lie when really-getting-down-to-it. While many of the little devices in use are not new, having been used regularly by track racers pre-war, they are new to road-racing and show just how seriously this first-line racing is being taken. At Monza last year, where the lap speed was over 100 m.p.h., many machines were fitted with discs on the rear wheels in an attempt to smooth out the passage of the air. At the same time many of the riders fitted a second pair of footrests near the top of the rear mudguard above the rear spindle, and on to these they hooked their feet so that the lower portions of their legs were horizontal, thus presenting no frontal area.

While all this attention to little details for high speed is commendable and to be encouraged, the dangers involved must not be overlooked. The practice of putting the feet on hooks on the rear mudguard is one that has reached the danger point, for the rider has not so much control of the machine when in this position and when one man starts to take high-speed corners in this position, the others naturally have to follow suit and the result is, as was experienced at the end of last year, riders bunched very close together all riding much too near to the limit for the safety of the sport, and some of the “works” riders who have had to indulge in this practice, or drop behind their rivals, have expressed the view that some sort of ruling should be made to prevent this form of riding. If this wind-cheating continues without due care being taken we may find that the machines become very susceptible to sidewinds and we have already lost more than one good rider through the effects of side-winds, so that wind-cheating with caution is called for.

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There is something quite uncanny about the way in which Italian factories can produce new machines. Whether it is due to plentiful supplies of material, lack of red tape and form-filling, or whether it is due to terrific enthusiasm on the part of the Italian workman is not known. Whatever is the cause, the result is remarkable. A good example of Italian enthusiasm for racing is that of the firm of M. V. Augusta, for at the end of last season their “works” 125-c.c, machines, using two-stroke engines, were reaching over 80 m.p.h., and as this was not sufficient to deal with their rivals who were using four-stroke engines, they decided to give up the two-cycle engine avid, with no previous experience of building four-stroke engines, they produced a twin-o.h.c. four cylinder machine in a matter of a few months. At the same time they decided to enter the 500-c.c. class and, four cylinders being the only reasonable layout to use for a Grand Prix machine, they built a twin o.h.c. four-cylinder motor-cycle during the winter months. Further, they have every hope of having four such machines ready for the T.T. in June.

One must not overlook the fact that the new machine is almost an exact copy of the 500-cc. Gilera and also that the new M.V. was designed by the same man who designed the Gilera, for Ing. Remor went to work for M. V. Augustus just before last winter. Ignoring this, the feat of building the new machines in months, where others take years, is one that gives much food for thought. For many years this country has been supreme in the 350-c.c. class for the simple reason that no one else has built this size of machine, but last year Guzzis made a sporting gesture by entering a single 350-c.c. machine which was in effect a small edition of the 500-c.c. twin. Before this machine appeared rumour had it that they were experimenting with a scaled-down “500” and an enlarged “250,” and which would be more successful they knew not. The twin 350-c.c. bicycle, while showing great promise on occasions, was not very successful, and this year they have begun the season with the other 350-cc. machine, which is an enlarged 250-c.c. “Gambalugghino” in effect, except that an entirely new form of valve operation is used and a five-speed gearbox is employed to deal with the engine’s 7,000 r.p.m. This lone attempt at rivalling this country’s supremacy in the 350-c.c. class is most sporting and it would be nice to see one of our manufacturers reciprocate by scaling down a 350-c.c. bicycle to compete in the 250-c.c. class, which at present is dominated by Italy. Whoever tackled such a job would not be attempting a greater task than Gileras are attempting with their 350-c.c. motor-cycle, and all the encouragement and enthusiasm possible would go out to them from the racing world.

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It only be a matter of time before Germany is admitted back into the F.I.M. and although racing in that country at present is done with supercharged machines, the designers are not forgetting the future. Already rumour is rife about a transverse flat-four B.M.W. taking shape in readiness for competing in International events. In addition, some unsupercharged push-rod B.M.W. twins are being raced which are not so very far behind the supercharged o.h.c. models, and they would certainly not be out of place among the normal run of machines in use today for the smaller races. The beating of the “works” B.M.W. by a supercharged 500-c.c. N.S.U. caused quite a stir and if these two firms re-enter the International field next year, as they most certainly should be allowed to, then we can expect Grand Prix racing to go from strength to strength. It will, of course. mean that the private owner will be wasting his time entering Grand Prix events, but providing the factory machines stop the practice of entering for the small Circuit Races, leaving them to the private owners, then there will be good racing for everyone. The recent entry of the “works” 500-c.c. A.J.S. machines at the Belgian Circuits of Mettet and Floreffe, while providing a nice spectacle, did not prove very popular with the general run of followers of the sport, the feeling being that this type of event should be left to the non-“works” machines.