Racing car evolution part IV: 1928-1933

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by Flt.-Lieut. John Scafe, R.A.F.

We present herewith the last article in this outstanding and valuable series of contributions, commenced by Cecil Clutton and so ably carried on by Anthony Heal and Laurence Pomeroy. Collectively these articles describe the evolution of the racing car from 1895 to 1933, and the data therein contained also constitute a very useful reference to individual racing car design and to racing history. The races of 1934 to 1939 were dealt with in a rather different form in “Motor Sport” in 1940. This final article was written for us under very difficult conditions by Flight-Lieut. John Scafe, R.A.F., who failed to return from an operational flight shortly after the MSS. was completed. Of this young enthusiast Cecil Clutton writes:

When I asked John Scafe to contribute to this series it was only with great difficulty that he could be persuaded to do so—he was sure he did not know enough about it. When it is remembered that Pomeroy, Heal and myself, in writing the previous instalments, had access to all available records, and that John wrote this almost entirely from memory, in his few leisure moments on an operational R.A.F. station, I think that this article shows up as a truly phenomenal performance.

It might appear at first sight that the period of racing between 1928 and 1933 is of little interest compared with those immediately preceding and following it, consisting, as it did, of a great deal of uninteresting Formule Libre racing, with sports car events as the main focus of interest. The French Grand Prix, the race of the year in the 1924-26 period, lost all its old glory, and the Grand Prix d’Endurance at Le Mans assumed a new and greater importance.

After the intensive period of Grand Prix racing from 1922 to 1925, with cars up to 2-litres capacity, in which Fiat, Delage, Sunbeam, Alfa-Romeo and Bugatti participated, it was decided to adopt a formula limiting engine size to 1.5 litres for 1926 and 1927. Bugatti, Delage and Talbot all built cars to comply with straight-eight roller-bearing engines, and with 2-seater bodywork conforming to the dimensions laid down under the A.I.A.C.R. formula. The Delages and Talbots were probably the fastest makes in 1926, but were beset by various irritating ”teething troubles”; those of Delage being given by the layout of the twin Roots-type superchargers fitted, and also by the fact that the right-hand exhaust pipe passed very close to the drivers’ feet, which became well and truly fried in a race of any length. The Talbots had trouble with their front axle and brake lay-out, the whole front end of the car shuddering horribly under application of the brakes at speed. ‘This was overcome by the close of the season, in time to give the marque victory in the.J.C.C. 200-Miles Race at Brooklands.

For 1928 the A.I.A.C.R. had decided on a Formule Libre for any size or type of car. Bugatti, practically alone, continued to build racing cars during the next three years, selling them as part of their range of production models. Maserati occasionally built one or two, and some of the older Grand Prix cars were brought out and raced. Sports car races for standard models, with certain allowable modifications, assumed more prominence in 1928. With a larger number of makes competing, these races were a rather more interesting spectacle than the remaining Formula events.

A very successful sports car of 1928 was the 4.5-litre Bentley, which was just replacing the 3-litre. The 3-litre Bentley, together with the 3.5-litre 6-cylinder Lorraine, had been the outstanding car at Le Mans during the previous two years. Among the smaller machines came Alvis in the 1.5-litre class, Amilcar and Salmson dominated the “1,100s”, while Austin was alone among the “750s”.

From the technical point of view there was, in 1928, a considerable gap between sports and racing cars, the latter, as would be expected, having progressed during their intensive period of development in 1922-26. Such features as hemispherical combustion chambers, supercharging, twin overhead camshafts,. and roller bearings had become accepted practice in racing design. Streamlining had made little headway, but frontal area remained reasonably low. Alcohol fuels, which became fashionable around 1924, were universally used in 1927.

The sports cars of 1928 were, on the other hand, far more normal machines, being more akin to fast touring cars than detuned racing cars, and were, for the most part, heavy with engines of low efficiency, developing modest power outputs and with low power/weight ratios. The chassis was heavy and harshly sprung. The pump fuel of 1928, which had to be used at Le Mans, was of lower octane value than that of later years. Amilcar and Salmson and Sunbeam alone embodied racing features such as twin o.h.c. in their production sports cars.

By 1931 a new type of sports car had been developed, typified by the 2.3-litre Alfa-Romeo. This car, descended from the 1.5-litre and 1,750 c.c. Alfa-Romeos, had a straight-eight supercharged twin overhead camshaft engine; it was comparatively light, and in its original long-chassis form it was capable of about 115 m.p.h., while it was much more controllable than a car such as a Bentley. It is interesting to note that at Le Mans in 1930 the winning Bentley, a 6.5-litre weighing over 2 tons, averaged 75.8 m.p.h., while the next year Howe and Birkin won quite easily on a 2.3-litre Alfa at 78.13 m.p.h.

For the next two years Alfa won at Le Mans, but one cannot compare their speeds with the earlier averages, as the circuit was different, and they could run on better fuel than was allowed by the race regulations in the late ‘twenties. In short-chassis form, and fitted with racing bodywork, this type of Alfa-Romeo ran in events such as the French Grand Prix and Targa Florio, with success, thus showing how in three years the gap between the racing cars and the sports machine had narrowed to almost nothing. The wheel had turned a full circle, and sports car designers, in quest of increased performance, had made use of such aids as supercharging and twin overhead camshafts, until the sports cars of 1931 were virtually camouflaged racing cars. Another example of this trend were the team of 2.5-litre Maseratis run in the “Double Twelve” and at Phoenix Park in 1931. The fitting of a racing body at once made these “sports” machines full-blooded 100 per cent. racing cars.

Thus, Grand Prix racing was revived once more in 1931, and in the next two years technical development proceeded at an increased pace. Bugatti was faced with real rivalry, and there was some excellent and evenly-matched racing between the Molsheim marque, the Alfa-Romeos and the Maseratis, each producing new racing models in an effort to achieve superiority.

In the smaller classes the 750 c.c. M.G. was developed to an extremely high pitch of efficiency, achieving speeds only reached seven years previously by cars of twice their capacity. In the 1,100-c.c. class the M.G. Magnette proved its superiority over the 4-cylinder 1,100-c.c. Maserati reaching speeds that were remarkable for an “1,100.”

Turning now to the more outstanding cars of the period, Bugatti is a name that figures prominently. During 1928, 1929 and 1930 these cars formed the bulk of the entries for Grand Prix events.

In 1928 the three most widely-used types were the 2-litre Type 35C, the 2.3-litre Type 35B and the 1.5-litre Type 39. The Type 35C was based on the Type 35, which was originally designed in 1929 and ran in the French Grand Prix of that year at Lyons. The engine was a straight-eight with a bore and stroke of 60 x 88 mm. (1,955 c.c.). The three valves per cylinder were operated by a single overhead camshaft and the main and big-end bearings were roller-type. In the Type 35C, introduced in 1927, a Roots blower was mounted on the offside. The chassis employed half elliptic springing in front, while the Bugatti system of reversed quarter elliptics was used at the rear. The steering column had a universal joint just above the steering box, another Bugatti feature, while it was on this model that the famous spoked aluminium wheels with integral brakedrums first appeared. These cars typify the Bugatti to most enthusiasts. With their beautifully proportioned lines and exquisite workmanship they have a real personality and fascination, equalled by few other cars.

The 1.5-litre Type 39 was built to the 1926 Grand Prix formula and won the European Championship for that year. It was really a smaller edition of the Type 35, being similar in practically every respect, except that the bore and stroke were 60 x 66 mm. (1,492 c.c.). The 2.3-litre Type 35B was also a straight-eight with a single o.h.c. engine, the bore and stroke being 60 x 100 mm., giving 2,263 c.c. Mechanically it, too, was a variation of the original Type 35 and it was brought out in 1927 for Formula races. A number of the 1.5-litre Type 37 Bugattis were also racing at this period. These had a 4-cylinder engine with a bore and stroke of 69 x 100 mm. (1,496 c.c.), and plain bearings were employed. The 37A was the supercharged version.

In 1928 Bugatti won the French Grand Prix, run as a handicap race (Ichabod!), Williams being the driver. The Targa Florio, perhaps at that time the most arduous race, was won by Divo (Bugatti), while the other important Bugatti win was scored by Chiron at Monza. The 1927 Delages, now sold to private owners, ran in several events, as did the straight-eight Talbots, the latter mostly in Italy.

The sports car racing season began with the Six-Hour Race at Brooklands, organised by the Essex Motor Club. It was won by Ramponi on a 1.5-litre Alfa-Romeo, a car that was to figure very prominently in sports car racing during the next two years. It was a 6-cylinder with a bore and stroke of 62 x 82 mm. (1,485 c.c.). The Roots-type supercharger was driven from the front end of the crankshaft at one-and-a-half times engine speed. The highest average speed in the Six-Hour Race was put up by the late Sir (then Captain) H. R. S. Birkin with a 4.5-litre Bentley, a type introduced in 1927.

The “4.5” had a 4-cylinder engine with a bore and stroke of 100 x 140 mm., giving 4,398 c.c. Four valves and two plugs per cylinder were used, the valves being operated by a single o.h.c. driven by a vertical shaft from the front of the crankshaft. Ignition was by twin magnetos. Transmission was by a 4-speed gearbox with right-band change: 3.53 to 1 was the final ratio normally fitted in the D-type gearbox used for racing. Chassis design was normal with half-elliptic springs all round. The maximum power was 125 b.h.p. at 3,300 r.p.m., giving a speed of some 97 m.p.h., with higher ratios used for racing. The weight was about 35 cwt.

The 4.5-litre Bentley soon made a name for itself as a fast and very reliable car for its day, and was very successful in 1928 sports car races, Barnato and Rubin scoring a notable victory at Le Mans at an average speed of 69.11 m.p.h., after a great fight with a Stutz. In its Le Mans form it made a very pleasant road machine, possessing an appeal that even to-day makes itself felt, although it is in many respects outmoded.

Among the “1,100s” Amilcar and Salmson, as has been mentioned before, were prominent, The Amilcar was a 6-cylinder developed from the 1927 racing “Sixes”; beautiful little cars that had been as supreme in their class as was Delage among the 1.5-litres. The bore and stroke were 56 x 74 mm., giving 1,094 c.c., and a Cozette supercharger was used. Salmson had two models racing in 1928. One was a straight-eight with a bore and stroke of 49.9 x 70 mm., giving 100 b.h.p. at 5,800 r.p.m. The cylinders were cast in two blocks of four, with detachable heads. Twin overhead camshafts and two valves per cylinder were used, with the timing gears in the centre. A Solex carburetter and Roots supercharger were employed. The other Salmson model was the 4-cylinder Grand Prix type, of 1,086 c.c. The bore and stroke were 62 x 90 mm. Like the 8-cylinder car, it had twin overhead camshafts. Suspension was by half-elliptics in front, and quarter-elliptics at the rear. Salmson won the Rudge Whitworth Cup for the best handicap performance in the 1928 Le Mans race.

As far as absolute speed was concerned, Capt. Malcolm Campbell had attained 206.95 m.p.h. at Daytona with the Napier aero-engined “Bluebird”. Shortly afterwards this was narrowly defeated by the American Ray Keech, who managed 207.58 m.p.h. in the Liberty-engined White “Triplex”. This mechanical monstrosity consisted of three 500-h.p. Liberty aero engines mounted in a lorry frame, the whole thing having no proper body and being completely unstreamlined.

By contrast, the other American contender was really beautiful. It was the 3-litre Stutz “Black Hawk”, designed and built by the late Frank Lockhart. It was of much smaller capacity than any previous Land Speed Record challenger and very well streamlined. It did over 200 m.p.h. in practice runs, but crashed before it broke any records. This speed was not approached by any car with engine of comparable size, until the advent of the Mercedes-Benz and Auto-Union cars of 1934. Even then the latter two were of 3.9 litres and 4.9 litres, respectively, and achieved speeds of just under 200 m.p.h. The 3-litre Mercedes and the 1,100 c.c. M.G. both bettered 200 m.p.h. in 1939.

In 1929, as in the previous year, Grand Prix racing was practically entirely a series of Bugatti benefits, their principal victories being in the German Grand Prix, held at the newly opened Nurburg Ring. with Chiron up, the French Grand Prix (this year a scratch race at Comminges), and in the Monaco Grand Prix, run through the streets of Monte Carlo. Williams drove the winning car and had a great duel with Caracciola on a stripped S.S.K. Mercedes-Benz.

In Italy the 1924 P2 Alfa-Romeos were resuscitated and competed in a number of races. Nuvolari and Varzi had a tremendous duel in these cars in the Bordino Grand Prix, both being finally forced to retire, following some most “expensive noises”. The Targa Florio was won by Divo’s Bugatti at 45.65 m.p.h.

Sports car racing provided some excellent and interesting events. The “Speed Six” Bentley made its debut in the J.C.C. “Double Twelve” run at Brooklands for two consecutive days. It had a 6-cylinder engine with a bore and stroke of 100 x 140 mm. (6,397 c.c.). Like the “4.5” it had four valves and two plugs per cylinder, but the single overhead camshaft was driven from the rear by a 3-throw eccentric in a style reminiscent of the Leyland Eight or Maudslay. The engine developed 175 b.h.p. at 3,200 r.p.m., and the car weighed some 34 cwt. in chassis form. The “Big Six” had a good year, with wins at Le Mans at an average of 73.63 m.p.h., and in the Six Hour Race, and second place in the Eirean Cup at Phoenix Park and in the 500 Mile Race at Brooklands.

Another big car which was outstanding in 1929 was the “38/250” Mercedes-Benz. One of these, driven by Caracciola, won the Tourist Trophy at Ards, averaging 72.82 m.p.h. in pouring rain. The engine was a 6-cylinder with a bore and stroke of 100 x 150 mm., giving 7,068 c.c. capacity. It was supercharged by a clutch-controlled blower, which come in when the throttle was fully depressed at any r.p.m. in the range, and blew air through the carburetter. The engine developed rather under 250 b.h.p. in T.T. form, at 3,000 r.p.m. The chassis weight was 25 cwt. and the top speed 109 m.p.h., with a 2.5 to 1 final ratio.

Up to 1932 the different variations of the “SSK” Mercedes were probably the fastest cars racing, and often competed against racing Bugattis and Alfa-Romeos in Grand Prix events, their great speed making up for their having poorer handling qualities. Even so, the road-holding and weight distribution of the “S.S.K.L.” model must have been exceptionally good after certain shock absorber modifications had been made, as Caracciola, when racing against the Bentleys, suffered far less from tyre trouble than they, in spite of his having the heavier car. As regards maximum speed, Caracciola attained 147 m.p.h. on the short-chassis model with the large blower during the Avus races of 1931.

The cars were, however, very prone to supercharger trouble, if the blower was engaged continually, and most Mercedes retirements were due to this cause. The S.S.K.L. had a drilled frame and developed about 300 b.h.p.

A good deal of record work was put in during 1929, Segrave reaching 231.36 m.p.h. at Daytona on the Napier-engined-Irving Special “Golden Arrow”. The car was designed by Capt. J. S. Irving and built at the K.L.G. works in Putney Vale. It was very carefully streamlined, being modelled on the Supermarine S.5 seaplane, which won the 1927 Schneider Trophy.

Campbell took his rebuilt “Bluebird” with a similar engine to Segrave’s car, to Verneuk Pan, South Africa, but was not able to equal the latter’s figures. He obtained the 5-mile record at 211.3 m.p.h. and the 5-kilos at 215.3 m.p.h., however. Another notable run was the 10 kilo record obtained by Borzachini on the 16-cylinder Maserati on the road at Cremona. His speed was 154 m.p.h. All these were, of course, World’s Records.

Sports car racing was again the centre of interest in 1930. Bentley won at Le Mans for the fourth year in succession, the winning “Big Six” averaging 75.8 m.p.h., driven by Barnato and Kidston, after an historic duel with Caracciola and Werner’s Mercedes. Bentley also won the “Double Twelve”. In addition to the factory team of Speed Sixes, a separate team of supercharged 4.5-litres was run by Birkin and the Hon. Dorothy Paget. These cars were similar to the 4.5-litre Bentley already described, but with the addition of an Amherst-Villiers supercharger mounted between the dumb-irons. A certain amount of internal redesigning was, of course, necessary. The engines developed some 260 b.h.p. at 4,000 r.p.m. and were capable of nearly 130 m.p.h. with full equipment. They first appeared in 1929, and, both then and in 1930, were handicapped by various teething troubles, but proved very fast. Towards the end of 1930 they went rather better, and Birkin, in a stripped 4-seater on the 9 ft. 9.5 in. wheelbase chassis, put up a drive that is outstanding in motor racing history. This was in the French Grand Prix at Pau, where he ran against racing Bugatti and Delage cars, finally finishing a very close second indeed behind Etancelin’s Bugatti. The blower Bentley was definitely tricky to handle on a wet road, however, as was found at Phoenix Park and Ulster.

Another sports car which first appeared in 1929 was the 1,750 c.c. 6-cylinder Alfa-Romeo, which proved extremely successful at Phoenix Park and Ulster. In 1930 the works team, consisting of Nuvolari, Campari and Varzi, finished first, second and third, respectively, in the Tourist Trophy at an average of over 70 m.p.h. The cars proved extremely controllable in the wet conditions that prevailed throughout the race. The 1,750 c.c. Alfa was of advanced design, with its 6-cylinder twin o.h.c. engine. The bore and stroke were 65 x 88 mm. Several features of racing design had been incorporated in the search for more power. Alfa-Romeo at this period were in the front line of development towards the production of a fast, moderate-sized controllable road car.

A team of the 2,276 c.c. “90” Talbots was run during 1930 by Fox and Nichol. They were interesting in that they had very normal push-rod o.h.v. engines, but made a reputation for speed, reliability and consistency, attracting much favourable comment.

Continental Grand Prix racing in 1930 was devoid of much interest, being mostly a repetition of 1939. The French Grand Prix at Pau has already been mentioned. The Targa Florio was won by Varzi’s P2 Alfa-Romeo at 48.18 m.p.h. The P2 had been greatly improved since its first successes in 1924 and 1925, due probably to better fuels and raised compression ratio. As an example, the following timed speeds at Cremona are of interest. In 1924 Ascari was timed at 121.4 m.p.h. In 1928 Campari did 135 m.p.h., while the following year Brilli-Peri reached 138 m.p.h. This shows the advances made in fuels and tuning during the late ‘twenties.

The year 1931 was a most important one for it witnessed the revival of Grand Prix racing. Bugatti had some real opposition once more, and sports car racing began to take a secondary place. This opposition was provided by Alfa-Romeo and Maserati. The Milanese firm produced an 8-cylinder car of 2,300 c.c. capacity. The cylinder dimensions were the same as on the 1,750 c.c. car, i.e., 65 x 88 mm. The cylinders were cast in two blocks of four, with the drives for the twin o.h.c. between them. The crankshaft was carried in ten plain white-metal bearings, and built up in two halves. The connecting rods were of I-section. A Roots blower driven at engine speed sucked from a Memini carburetter. The chassis was of normal Alfa design, with half-elliptic springs all round. The car was produced in both racing and sports form. The 1981 racing edition was said to develop 190 b.h.p. and weighed 18 cwt. It was known as the “Monza” type. In sports form, with body conforming to A.I.A.C.R. regulations, the weight was in the neighbourhood of 22 cwt. The 1931 long-chassis edition raced by Birkin was capable of about 115 m.p.h., while with a light body it lapped the Brooklands Outer Circuit at 125 m.p.h. in 1931.

Later in the season, to meet increased opposition, Alfas decided that a faster car than the “2.3” was needed, so a 3.5-litre was built, which consisted of two of the 1,750 c.c. power units mounted side by side in one chassis with the crankshafts rotating in opposite directions to obviate torque. Each engine was entirely separate from the other, with its own radiator, clutch, gearbox and transmission. Using an 8 lb./sq. in. boost, 300 b.h.p. was claimed, and the complete car weighed 20 cwt. Although very fast, the 12-cylinder Alfa was difficult to handle. It was intended for the Italian Grand Prix, but crashed in practice, killing Archangeli, who was driving it. Although repaired, it subsequently raced but little, Alfas relying on the 2.3-litre car, which had a very successful first season. Nuvolari drove one to its first victory in the Targa Florio, while he and Campari won the Italian Grand Prix, which had been increased in duration to 10 hours. Campari won the Coppa Acerbo, and with Borzachini was second in the French Grand Prix at Montlhery. The “2.3” Alfa-Romeos and the twin o.h.c. “2.3” Bugattis were closely matched, and there was little to choose between them.

The 2.5-litre Maserati was Italy’s other effort, and before describing it a few words on the marque Maserati may not be out of place. The firm was started in quite a small way at Bologna by the five brothers Maserati, who began by producing a modified version of the Diatto. An early Maserati car driven by Ernesto Maserati was third in the 1927 Targa Florio. The 2,300-c.c. model put the firm on the map, in the racing class, and scored wins in the 1930 Monza Grand Prix and Coppa Acerbo. At the end of 1930 the 2.5-litre model was produced, and also the 5-litre 16-cylinder, which consisted of two 2.5-litre blocks mounted on a common crankcase. The Bologna works concentrated on assembly, most of the machining being done by Isotta Fraschini, and the brothers would build anyone a car for any purpose, provided the client put up the money. With Fagioli as driver, Maserati were always a formidable rival to Bugatti and Alfa-Romeo. The 2.5-litre was a straight-eight with a bore and stroke of 65 x 94 mm., giving 2,514 c.c. The crankshaft was carried in five bearings, the centre one being of roller type. Tubular con. rods were used, and a Weber carburetter supplied the Roots-type blower. The head was detachable. Transmission was through a 13-plate dry clutch and 4-speed gearbox. The engine gave 175 b.h.p. at 6,000 r.p.m. Great attention was paid to brake compensation, the brakes themselves being rod-operated. One of these cars was brought to England by Birkin, who broke the Brooklands “Mountain” lap record with it.

I have deliberately left Bugatti to the last in describing the 1931 racing cars, as they did not represent anything new in technical development. The Type 51 twin o.h.c. 2.3-litre car was basically similar to the Type 35 of 1924, except for the head. This was virtually identical in design with the twin o.h.c. Miller head, although possessing the typical Bugatti “square” external form. The cylinder dimensions and mechanical details were similar to the 35C Bugatti and 165 b.h.p. was claimed. As has been mentioned, the Type 51 was very evenly matched with the racing “2.3” Alfa-Romeo.

The Bugatti driven by Chiron won its first race—the Monaco Grand Prix. The French Grand Prix returned to Montlhery this year, and Chiron and Varzi drove the winning Bugatti. Williams and Conelli won the Belgian Grand Prix. Like the Italian G.P., these two races were of 10 hours duration.

Later in the season, realising that their twin-cam 2.3-litre was not fast enough, Bugatti produced a 4.9-litre racing car, which was designed, built and put on the road in 13 days. This, the Type 54, was a straight-eight with a bore and stroke of 86 x 107 mm. (4,840 c.c.). Plain bearings were used. A Roots blower on the off side drew mixture from two Zenith carburetters.

The magneto was driven from the rear of one of the twin o.h. camshafts and 300 b.h.p. was produced at 4,000 r.p.m. The chassis was of normal Bugatti design, except for a 3-speed gearbox on the back axle. The weight was just under 20 cwt.

The “four nine” proved very heavy and tiring to handle on a twisty course, although it was fast, and, after a few races, Le Patron decided to rely on the trusty twin-camshaft model as his first string. Varzi had joined Bugatti as a driver, and he had some interesting duels with his old rival Nuvolari during the season. Caracciola drove his specially lightened S.S.K.L. Mercedes with the big blower, and reached a speed of 147 m.p.h. at Avus. He won the German Grand Prix at the Nurburg Ring, holding his own against the Bugatti and Alfa teams on his own home course.

Sports car racing in 1931 continued, although it was beginning to take a back seat. The Mille Miglia was won by Caracciola’s Mercedes against numerous Alfa-Romeos, Maseratis and O.M.s. At Le Mans there were (alas!) no Bentleys, as the firm had withdrawn from racing the previous year, and Dorothy Paget had disbanded the team of blower “4.5s” Le Mans provided a victory for Howe and Birkin, however, on a “2.3” Alfa-Romeo. They were able to average 78.13 m.p.h. for the whole distance quite easily, as against the 75.8 m.p.h. of the 1930 winning Bentley, thus showing the capabilities of this newer type of sports car.

Sports car racing on a handicap basis continued in England. With the absence of the Bentleys there was a dearth of large cars, but the season was marked for the amazing progress of the 750-c.c. M.G.; which won the “Double Twelve” and the Irish Grand Prix in unsupercharged form, while with a blower added it won the Tourist Trophy. Norman Black was the driver on the two latter occasions.

The M.G. “C” Type, better known as the “Montlhery”model, had a 4-cylinder engine of 746 c.c., the bore and stroke being 57 x 71 mm. The single o.h. camshaft was driven by a vertical shaft through the dynamo at the front end. A Powerplus supercharger was driven from the front end of the crankshaft and was supplied by an S.U. carburetter. The “Montlhery” was sold ready for sports car racing at £575 in blown form. A special M.G. driven by G. E. T. Eyston attained 103.57 m.p.h. at Montlhery – the first time 100 m.p.h. had been exceeded by a “750.” Later in the season the same car and driver covered over 101 miles in the hour, the car catching fire at the end.

The single-seater “Magic Midget” was then built, with offset transmission, and broke several records, driven by Eyston and Eldridge, 114.74 m.p.h. being the highest speed obtained. A special single-seater s.v. Austin Seven also broke class H records at over 100 m.p.h. During 1931 the “750” reached speeds that only a few years ago blown 1.5-litre cars had but just managed to attain.

Campbell had his “Bluebird” rebuilt by Messrs. Thomson & Taylor, with a 1,450-h.p. Napier “Lion” aero-engine installed, the result being 245.73 m.p.h. at Daytona.

Thus 1931 saw intensely interesting technical development and Grand Prix racing getting back to its rightful place once more, with a promise of great things for 1932. These great expectations were fulfilled in good measure. Alfa-Romeo improved the “2.3” in the light of their previous year’s experience, and won at Monaco with it. They realised, however, that to achieve superiority something better still was called for, so Signor Jano designed and built the very historic “Monoposto” Model, which was the firm’s most successful and outstanding car. Nuvolari drove it to victory in its first race, the Italian Grand Prix, repeating his success in the French Grand Prix at Rheims. This was a magnificent race, the greatest Grand Prix since the event at Lyons in 1924. The Alfas took the first three places against a bevy of “2.3” Bugattis backed by some “4.9s”. Almost everywhere they raced the Alfas won easily, and their supremacy was as marked as had been that of the Delage in 1927. The “Monoposto”, like the “2.3”, was a straight-eight with a bore and stroke of 65 X 100 mm., giving 2,654 c.c. The engine had aluminium blocks of four cylinders with pressed-in steel liners. The twin o.h.c. camshafts were driven from the centre of the engine. Supercharging was by two Roots blowers on the near side of the engine. Transmission was by twin propeller shafts between which the driver sat. The chassis followed normal Alfa lines, with half-elliptic suspension. The cars weighed about 13.5 cwt. and developed 190 b.h.p. at 5,600 r.p.m. They were capable of over 150 m.p.h., and broke new ground in that they had single-seater bodies, as is indicated by their type-name.

In 1932 Bugatti supremacy waned and has never recovered. As has been mentioned, the “4.9” was a difficult car to handle, while the twin cam “2.3” was not fast -enough, although it showed great consistency and put up a fine run at Rheims, where Chiron finished 4th behind the all-conquering Alfa-Romeos, averaging only 1.21 m.p.h. less than the winner. Maserati raced the 2.5-litres, a 2.8-litre (a bored-out 2.5), and a 16-cylinder, the last-named probably as fast as anything, but too clumsy for a twisty circuit.

Sports car racing was also an Alfa benefit, this make winning the Le Mans and Belgian 24-Hour races. Le Mans was run on a modified circuit, and the average speeds could not thus be compared with earlier races.

British sports car races were dull. Rileys had a good season and won the 1,000 Mile Race and Tourist Trophy with their 1,087-c.c. “Nine,” which they had brought to a high pitch of efficiency for a small unblown car. M.G.s were not favoured by the handicappers, after their brilliant previous season, but put up high speeds. Eyston and the “Magic Midget” again broke records at Pendine and Montlhery, finally bettering two miles a minute, 120.56 m.p.h. being the highest speed reached. After this, with the “Magic Midget” and a stripped blown Midget, Eyston and Denly launched a grand attack on Class H records, securing every one in the class—an unparalleled achievement. Campbell paid his annual visit to Daytona and raised his previous speed to 253.5 m.p.h.

By the end of 1932 Grand Prix racing had regained all its old glory and technical development had progressed at a greater rate than it had done for years. Caracciola had joined the Alfa-Romeo team. For the past few years his Mercedes had held its own among Grand Prix cars because of its superior speed, but when the lighter and handier Bugattis and Alfas were developed and increased their speed, the big Mercedes no longer held its advantage, and Caracciola forsook it for the Alfa-Romeo.

Alfa-Romeo decided to withdraw from racing at the end of the 1932 season, just as Delage had done before them. They refused to sell the “Monoposto” cars, and stored them away for some future date. Their colours were upheld for 1933 by the Scuderia Ferrari, and after failing to obtain any of the “Monopostos”, they resorted to “Monza” models bored out from 65 mm. to 69 mm., bringing the capacity up to 2.6 litres. Nuvolari won the car’s first race at Tunis, and once more evenly matched racing between Alfa and Bugatti was possible, the latter still with the twin o.h.c. 2.3-litre Type 51 model. Later in the season the Alfa works allowed Ferrari to race the “Monopostos”, and immediately they beat all corners, winning the Coppa Acerbo and Czecho-Slovakian Grands Prix. During the early part of the season Nuvolari had driven for Ferrari, but he later drove a Maserati as an independent.

Maserati prepared what was then considered a most startling car. The 2.9-litre engine was similar in mechanical details to the older 2.5-litre model, but the bore and stroke were 69 x 100 mm., and 210 b.h.p. was produced. This power unit was put into a single-seater chassis, with hydraulic brakes, weighing about 14 cvvt. It proved rather unmanageable at first, as the frame was not stiff enough. The 2.9-litre engine was also put into the older 2-seater chassis. One of these, driven by Campari, won the French Grand Prix at Montlhery quite easily at 81.5 m.p.h. against rather mediocre opposition. This was Campari’s second win in the Grand Prix, the previous time being on that great occasion at Lyons in 1924. Maserati lost the services of Fagioli, their mainstay for some years past, when he joined Ferrari at about mid-season.

Alfa-Romeo dominated sports car racing. At Le Mans, Nuvolari and Fournier averaged 81.5 m.p.h. for the 24 hours’ run. Other Alfas were second and third. The increase in speeds at Le Mans cannot be attributed solely to improvement in the cars, although this was the chief factor. Since 1928 the use of special fuels was permitted, and the course had been course had been made shorter and improved. M.G. produced an 1,100-c.c. car, the” Magnette” which had a very successful season. Magnettes won the 1,100-c.c. class and team prize in their first race, the arduous Mille Miglia. They suffered from back axle failure in the races held in the Isle of Man, but remedied this in time to win the Tourist Trophy, driven by none other than Nuvolari, who averaged 78.65 m.p.h., with a lap at over 81 m.p.h. These were speeds that were attained only by the 2.3-litre Alfas a couple of years before, and the lap record for the Ards circuit stood at 83.2 m.p.h., taken by Birkin’s “2.3” Alfa. Although the 1931 Alfa-Romeos ran fully equipped and the M.G. was stripped, this does demonstrate the advance made in small high-efficiency engines during the early ‘thirties. Another notable Magnette success was when Whitney Straight, who was making himself felt as a driver, won the 1,100-c.c. race in the Coppa Acerbo against strong Maserati opposition. The Magnette had a 6-cylinder overhead camshaft engine, similar to the “Midget” in basic design and method of valve operation, with the camshaft driven via the dynamo. The bore and stroke were 57 x 71 mm., giving the Magnette a capacity of 1,087 c.c. An S.U.-fed Powerplus supercharger boosted the engine, and transmission was via a 4-speed Wilson pre-selective gearbox. The frame was upswept in front and underslung at the rear. The cars raced with sports type bodies with a slab-tail formed by the outside petrol tank, although one or two drivers fitted pointed-tail racing bodies. The Magnette was sold in sports-car-racing form at £795, and was probably one of the most reliable and successful supercharged cars produced in any quantity.

As regards record breaking, Campbell, keen to exceed 300 m.p.h., rebuilt “Bluebird” once more, this time with a 2,300 h.p. Rolls Royce “R” aircraft engine. Hampered by bad conditions at Daytona, he reached 272.108 m.p.h. The “Hour” record was taken by Count Czaikowski’s “4.9” Bugatti at Avus at 134.3 m.p.h., in spite of having a sharp bend to negotiate each lap. Avus had been used for some extremely high speeds: Caracciola’s 147 m.p.h. has been already referred to. In 1932 von Brauchitsch had won the Avus race on an S.S.K. Mercedes fitted with a streamlined single-seater body, which very much resembled the later Mercedes-Benz racing cars of 1934, though these are outside the scope of this article.

To return to 1933 record breaking. . . .The “Magic Midget” M.G., after a further resuscitation, reached 128.62 m.p.h. at Montlhery and covered 110.28 miles in the hour. Denly was the driver, setting the seal on the development of this amazing 750-c.c. engine. Class H records were also broken at Montlhery by the late T. Murray Jamieson on a special side-valve Austin. His speeds of 119.74 m.p.h, are among the fastest ever attained by a side-valve car of any capacity.

So ended 1933 and with it an era. For the next year the A.I.A.C.R. formula restricted weight of cars without oil, fuel or tyres to under 15 cwt., as it was thought speeds had become dangerously high!. Bugatti and Maserati prepared models in an effort to challenge Alfa-Romeo supremacy, and rumours of Mercedes racing cars and of a mysterious machine called the P-wagon produced by the Auto Union concern, began to circulate.

Technical development during the period 1928-1933 had been negligible until 1931, when under the stimulus of increased competition firms had carried out research with a view to building new models and improving the existing ones. Nevertheless, no outstanding new technical development took place and no new ground in design was broken, as was the case from the advent of the German cars in 1934. The racing car of 1933 was in point of general design a cleaned up version of the type of car raced throughout the 1922-1926 period. More power had been obtained, due largely to better alcohol fuels being available. In England small engines, such as those of M.G. and Austin, made use of high-pressure supercharging to obtain high power outputs per litre.

Chassis design remained unchanged in main essentials, although those of the 1933 cars were much stiffer and rather heavier than their forbears of seven years earlier; the increased power output accounting for greater speeds. Average speeds rose steadily from year to year in races, although in some cases the circuits had been improved and altered, so that comparison is hardly possible. Le Mans is an example of this, the Pontliere section being deleted in 1932. Streamlining on road racing cars made no progress, and outward appearance did not vary generally throughout the period.

From 1931 to 1933 technical research speeded up, and during these years the basis was laid for the production of those cars which were to revolutionise road racing in the years that followed.

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