Engineering Wonders of the World
Volume III

330 ENGINEERING WONDERS OF THE WORLD. HÉMERY ON A DARRACQ OF 1905. On this car he won the Circuit des Ardennes and the American Vanderbilt Cup. Wagner, on a sister machine, was at one time leading in the French Gordon-Bennett trials, but was hindered by tyre troubles. A comparison of this picture with the Darracq of 1904 shows the very great alteration in dasign made by M. Darracq. during the first day, and covered the 770 miles at an average speed of 63 miles an hour. A notable innovation used during this race —which, in fact, influenced the wholo result of the Grand Prix—was the detachable rim. This enabled the driver (who, under Detachable new regUiatiOns, was com- Rims. „ . , n pelled to carry out all repairs and replacements aided only by his mechanic) to remove the rim and the damaged tyre simul- taneously, and replace it by another rim carrying a fresh tyre already inflated. This reduced the time for a tyre replacement to about two minutes, whereas previously ten minutes had been con- sidered very short time for the skilled racing mechanics to effect a change. After the big race another alteration of the rules was made, in which the important step of abolishing the weight limit was taken. Instead, a regulation was imposed re- stricting the fuel allowance Prix cars to approximately gallon, and by Limitation in Fuel. of the Grand 9 J miles to the this rule it was hoped to limit the huge engines which had come into vogue during the last few years. But it certainly failed in its object, for so large an allowance permitted an engine of the same size as before, and only resulted in fine adjustment of the carburettor —in fact, the big race of 1907 was won by Nazzaro with an engine of th© same size as THE THOMAS SIX-CYLINDER RACING CAR OF 1905. In this car the length of the bonnet was greatly increased by the position of the tanks, which were in front of, instead of behind, the driver. The latter, with the mechanic, sat behind the back axle.