Sports-car development



LAURENCE POMEROY, JUNR., has contributed many articles of extreme interest to “The Motor” since becoming Technical Editor, and he has considerably livened-up this paper. In the issue of January 24th, he deals with five years’ development of sports-type cars. He emphasises that in 1934 the Le Mans 24-Hour Race was won by a supercharged 2.3-litre Alfa-Romeo at 74.7 m.p.h., whereas the 1939 Le Mans Race, under the same rules, was won by a supercharged 3.3-litre Bugatti, at 86.8 m.p.h.

Independent front suspension was considered to have had a material effect on speeds at Le Mans, two cars exceeding a 70 m.p.h. average in 1934, nine in 1935, six in 1937, seven in 1938 and eleven in 1939. Mr. Pomeroy explains Bugatti’s abilities with normal front suspension by saying that Bugatti’s methods, like Nuvolari’s, are not to be compared with those of ordinary mortals. He divides improvements under five headings: —maximum engine power, controllability, brakes, mechanical reliability, stream lining. He suggests that the smallest improvement is in respect of engine output, though Lagonda is an exception, the 1935 six-cylinder 4½-litre, which averaged 77.85 m.p.h., giving 130-140 b.h.p. on a stroke of 130 mm., whereas the 1939 V12 4½-litre, which easily averaged 83.5 m.p.h., gives over 200 b.h.p. on a stroke of 85 mm., or a gain of over 40 per cent. Bugatti and Alfa-Romeo are not considered to have increased greatly in power output, but the blown 3.3 Bugatti engine is considered to give slightly more maximum power than the unblown 4½-litre Lagonda. Synchromesh gearboxes assist by reducing driver-fatigue and the Cotal electric box is used by Delage and Delahaye. Better braking, mainly due to stiff drums and the use of floating cams, has also put up average speed in sports-car races. Reliability has improved by the use of jet cooling, lead-bronze bearings and the reduction in piston-speed by reason of shorter strokes. Softer springing, in conjunction with i.f.s., has reduced body breakages, leaky fuel pumps, broken fuel lines and similar troubles. Streamline of sports-car bodywork is warmly praised. The decrease in wind resistance is calculated to average 30 per cent. to 40 per cent. over 1934 types, and speed goes up over orthodox types, even when these are 10 per cent. lighter and over 10 per cent. more powerful. Reliability is also enhanced by the possibility of using higher gear-ratios. Closed cars at Le Mans were represented by Adler, Alfa-Romeo, and B.M.W., and open streamline by Bugatti and Fiat. The Fiat is extremely warmly praised, putting up as an unblown 1,100 c.c. an average speed equal to that of the 1934 winner which had a supercharged engine of over twice the swept volume. We imagine that when the war is over the streamline Balilla Fiat saloon will have a big following in this country; as it is, a friend of ours has suggested that Italy is keeping out of hostilities because she realises what a fine market there is for the “Topolino” Fiat in countries affected by fuel rationing! The introduction of the four-seater 570 c.c. saloon last year was certainly most opportune.