THE GRAND PRIX FORMULA FOR 1937-1939

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THE GRAND PRIX FORMULA FOR 1937-1939

CAN IT DEVELOP THE SMALLER RACING CAR AND THE UNSUPERCHARGED ENGINE?

Six months have passed since the announcement by the A.I.C.R.C. of next year’s racing formula, and the most important races in the 1936 calendar have already been held. It is, therefore, unlikely that any new cars other than, possibly, those semi-mythical vehicles the 1f-litre Bugattis and the Merc6des-Benz will appear this year. There may, of course, be some totally new cars on the stocks (rumours that Fiats are to build a national Italian racing car have been broadcast and then emphatically denied) but the experience of the last few years has been that it takes six months to overcome the initial faults of any new

design. This being the case we can reasonably assume that we have sufficient data to Consider the prospects for next year’s racing under the new rules. We may well begin by re-stating the

1937-9 formula. In the first place cars must have oneor two-seater bodies with an inside width measurement of 85 cm., which actually is 5 cm. wider than is required for sports cars running at Ulster. Any type of fuel is permissible, as has always been the case in Grand Prix racing, though at one time of course there was a restriction on the consumption. The most striking change has been in the regulations relating to weight. For the last three years a maximum limit of 750 kgs. has been in. force. The new formula, which provides for minimum weights according to the capacity of the car, limits the capacity of a supercharged car to 3,460 c.c. and furthermore differentiates between supercharged and unsupercharged cars by setting lower minimum weight-limits for the latter cars. The ratio of weights is in the proportion of .77 to 1 and as the supercharged engine is considered to give anything up to twice the power of the unblown unit, the unsupercharged car does not seem to stand much chance. On the -other hand, the larger unsupercharged sports cars have been showing an amazing turn of speed in the road-races held during the past few weeks in Prance and Belgium, and the chances of the unsupercharged engine are worth examining.

First of all let us look at the supercharged cars, as the • formula embraced all capacities from 770 c.c. Upwards, for, at first sight at any rate, even the 759 c.c. racers have to be taken into consideration. To facilitate this a table is given below setting Out the minimum weight allowed by the new formula, the actual weight of the cars, the horsepower (as supplied by the makers !) and the power-weight ratio, in this case horse-power divided by weight in pounds, the dividend being multiplied by 100 to make it easier to compare.

Considering the list from top to bottom, first of all we have the amazing little Austin. In spite of its tiny engine its power-weight ratio is not far behind those of the larger cars and in the Isle of Man, Dodson held his own with the 4-litre cars. On the other hand, on the typical Grand Prix course there are always one or more straight stretches, and then it is engine-power rather than power weight ratio that counts. In the case

of the Austin even the increased horsepower, which will accrue when the engine is taken up to the full 12,000 r.p.m., will not make up for its smaller size.

At first sight the regulations of the formula seem to be intended as a handicap favouring the smaller cars, but in this case practical considerations prevent any such event. As will be seen from the table, in the case of the Austin the minimum weight may be brought down as low as 880 lb. There is, however, very little chance Of getting down to this figure.

The weight has been brought as low as possible at every point by the use of light alloys and as a result of using a wheelbase ,of 6 ft. 4 in. • Many of the components—the wheels, tyres, the petrol-tank, and of course the drivers themselves—must remain almost as heavy. as on cars of twice the capacity. Add to this the extra weight of a body 85 cm. wide and the 750 c.c. car has lost any chance it had in a Grand Prix race.

however that is not likely to worry Lord Austin and his designers very much as they never intended the ” seven-fifty” to take on anything bigger than cars of double its capacity ! In the 1,500 c.c. class pride of place must naturally be taken by the E.R.A. When the cars appeared two years ago the racing public had almost forgotten what could be done with 1 4-litres, and that 180 h.p., in conjunction with a total weight of only 1,500 lb., has brought victory to a number of English drivers

at home and abroad. It is interesting to note that even the E.R.A.. with its light chassis and frame weighs over 350 lb. over the minimum, while the fourcylinder Maserati comes within 140 lb.

of it. As it happens, however, the saving in weight is more than balanced by the lower power output, though, as Rayson demonstrated the other day at Donington, a greater bdost can, with advantage, be applied. It is difficult to tell where the Maserati can save the weight, but one presumes it must be on using four cylinders instead of six, a clash-type gear-box instead of the self-changing type, and also by using a slightly shorter chassis. The latest and most interesting addition to the 1 Hitre cars is the new six-cylinder Maserati. As will be noted, the maker’s horse-power figure is only 5 h.p. behind that quoted for the E.R.A.s. The factory do not disclose any figures for the weight, but now that they have gone over to six cylinders there must be an increase, and the independent springing probably I:rings it higher. A figure gives the same power-weight ratio as the E.R.A has, therefore, been assumed, and cannot be far wrong, for drivers who have coinpeted against the ” sixes ” say that they

are no faster than the E.R.A.s, and the ” Maser’s ” advantage on a course like the Eifel is explained principally by the fact that. the Italian cars have independent suspension. Nothing has been said about Seaman’s Delage, but as it is a little heavier than the E.R.A.s, and, at any rate in its present owner’s hands, more than a match for them, the horse-power must be in the neighbourhood of 200. Except for May’s exploits at Shelsley the 2-litre E.R.A. has been but little raced, though, assuming the transmission would stand the strain, its power-weight ratio and total horse-power would be worth exploiting in a Grand Prix race. It is not, however, until we reach the 3-litre class that we find cars that beat

the 1937-9 formula. The 3-litre and 3.2-litre monoposto Alfas come easily within the necessary 810 kgs., and even with a two-seater body the 3.-litre twoseater cars which ran in this year’s Iilk Miglia were within the magic 750 kgs. The 4.2-litre 12-cylinder Alfa has been included in the list for the sake of comparison, though it is not eligible under next year’s rules, the maximum for a supercharged car being 3,460 e.c. The combination one expects for next year’s events, therefore, is an eight-cylinder engine reduced in capacity from amlitres, the size of the present ” eights,” to 3,460 c.c. Quite how Signor Tam will utilise the • hundred kilogrammes difference between the 750 kgs. of the present two-seaters and the 850 kgs. which they will have to weigh next year is not clear, but no doubt sonic of it will be utilised in strengthening chassis and transmission and some perhaps as ballast to provide better adhesion for the rear wheels. After three years of anxiety to keep below the limit, it will be a pleasant

change to have 220 lb. in hand in an upward direction. What of the Auto-Union ? It looks as though, just when their engineers have Started to make the 5.7-litre sixteencylinder function properly, their labours will be thrown away. certainly it will be no easy task to get from a 3.4-litre sixteen-cylinder that power which can be obtained from an eight, and this was shown very clearly by the way in which tin, capacity of the entfine va,: increased

from 3.1-litres first, to 1-litres, and now to 5.3 or even f), as they were at Tripoli. Rosemeyer and the other drivers have now mastered the control of the reareng.ined chassis, so that presumably will be retained, but one would expect to see an eight-cylinder engine in place of the present one. It seems a shame to fit a two-seater body in place of the torpedo-shaped bodywork which at present adorns the P-Wagon, but one

must move with the times, or rather,. expand in accordance with the rules of the formula. Mercedes-Benz have lately been condueting a nymber of experiments both with engines and chassis. In some races the engine-size has been increased from 4.1 to 4.9-litres, though neither of thesetypes will be eligible under the rew

regulations. The original capacity was 3,800 c.c., and it will not be difficult toreduce this to the maximum allowed for next year’s race.

The lower coachwork which was introduced at the beginning of the year has been a great success as regards higher speed and better visibility for the drivers, but shortening the chassis has had an adverse effect on the road-holding. We should therefore expect a return to the longer wheelbase when it comes to installing two-seater bodywork.

As regards the 4.4-litre Maserati, the same considerations hold. The capacity of the engine will have to be reduced to comply with the formula, but this should not be difficult with an eight. The Bugattis built under the 750-kg. regulations have always had the equivalent of a two-seater body, so the designs of Monsieur Le Patron will for once be in a favourable position when the formula is changed, and will in fact call for no alteration except the addition of ballast.

Little has been said so far about the actual effects of the formula but the figures in the table tell their own tale. The small cars have no hope of getting down to. a power-weight ratio which will allow them to compete with the ” bolides,” at any rate with present methods of construction, while the greater horse-power of the big cars also gives them a superiority in speed which will be more marked with two-seater bodies.

The effect of the formula is therefore simply to reduce the speed of the future Continued on page 406. Grand Prix car by increasing the frontal area, limiting the capacity, and to improve road-holding and safety by insisting on a chassis weight two hundrel 1′. eight greater than has been permitted on Grand Prix cars during the past three years. There is no question that these two objects are well worth attaining, and if the new formula does nothing else but produce safer racing cars, it will have justified itself. Whether makers of smaller-engined cars such as E.R.A.s, and Maseratis will think it worth while trying to reduce the weight of their cars to the minima allowed under the formula is another matter. Even if they do not, this will not worry greatly either the Grand Prix organisers or spectators. Thebig cars for them . ,

every time! The future of unsnpercharged ors demands an article to itself, and will be discussed in next month’s