Anthony Blight certainly made his point in his letter (Motor Sport, May 1989), by showing that due to being supercharged the 2900B Alfa Romeos were barred from most of the major sports-car races except Le Mans in 1939. However, I feel that his statement that the big French sports-cars of 1936 and 1937 “showed the supercharger to be redundant” needs closer examination.
Good cars though they were, the 3.6-litre six-cylinder Delahayes in the 1937 Mille Miglia hardly “seriously alarmed” the blown 2900A Alfa Romeos when Pintacuda’s 2900A finished just over 18 minutes ahead of his team-mate Farina in second place, and Farina was nearly 20 minutes in front of the first Delahaye to finish, that of Schell/Carriere in third place (I might add that in the 1938 Mille Miglia Biondetti’s winning 2900B Alfa Romeo finished over 40 minutes in front of Dreyfus’ fourth-placed unblown 4.6-litre V12 Delahaye, with two 2900Bs coming in between).
I would concede that the unblown 3.3-litre “tank” Bugattis at Le Mans in 1937 were certainly competitive with the Sommer/Biondetti 2.9B Alfa Romeo which retired very early in the race, but the following year Sommer in another 2.9B put up fastest lap and was 100 miles ahead of the leading Delahaye when he retired early on the Sunday afternoon with either valve or transmission trouble after the right front tyre burst at 130 mph and probably the engine was used as a brake in order to slow down. The car stopped on the circuit shortly after the wheel was changed and retired.
It seems that in the 1938 Belgian 24-hour race at Spa, Louis Gerard’s 3-litre Delage held the lead for a short time when the blown Alfas made pitstops, but, bearing in mind his push-rod-engined car was of almost the same capacity as the Alfas, yet unblown, the fact that he came second and averaged only 0.61 mph less than the winning 2.9 Alfa is truly noteworthy.
The final proof that the supercharger was still not redundant (except by the rules for most sports-car races) came in the last pre-war Le Mans, in 1939, when despite the admitted speed of the unblown “tank” cars, Jean Bugatti chose to make the single Bugatti works entry a supercharged Type 57C. This car, driven by Wimille and Veyron, won the race at a record average speed thanks to its reliability, although the fastest lap was put up by the supercharged 3.6-litre Delahaye of Mazaud and Mongin before it retired, as a last and fitting shot in the arm for the Blight theory.
Peter Hull, Newbury, Berkshire