Gobron-Brillié opnieuw: Rigolly's 100 mph-racer

This Gobron-Brillié seems to be a continuing story and indeed about the car itself little information can be found. Photos can be found everywhere on the internet and these have been regularly captioned with incorrect text. In general one can say, that basically the car remained unchanged from 1903 to 1907 at least regarding the engine and frame. It is not clear if the difference in power output, which is sometimes said to have been 100hp, sometimes 110hp, was caused by different engines or by incorrect information. Visible differences can be mainly found in the changes in the shape and location of the tubular cooling block, and in the body. There must have been at least three cars, as there were three participants with this car type in the 1903 Paris-Madrid race (Rigolly, Koechlin and Duray) and also in the 1904 french trials for the Gordon Bennett cup (Rigolly, Duray and Burton). In all of the many other events in which the car participated there were only one or two of them. It seems hardly possible to figure out if there were built more cars than three or that they were modified during these years to improve their performance. A complicating factor is that the cars regularly posed with bonnets before the race, but these were normally removed during the race to improve engine cooling.
It is remarkable that Gobron-Brillié continued to use this tubular frame till and with the 1907 Grand Prix de l’ACF, when in fact all other makes had already changed to pressed steel frames for years. As I stated before, the car was fast and performed well on relatively short races, but during long distance races, especially during the circuit races with their many turns and braking moments, they either didn’t perform well or were even forced to withdraw by mechanical failure like worn-out tyres or broken radiators. It could well be that a lot of trouble was caused by frame torsion due to the large and powerful engine.
In the uploaded image I’ve collected the different appearances of the car in the 1903-1907 period, showing the first time a change was observed: 1. Semaine de Nice 1903 (Rigolly); 2. Paris-Madrid 1903 (Duray); 3. Kilomètre de Dourdan 1903 (Duray); 4. Semaine de Nice 1904 (Rigolly); 5 and 6. Gordon Bennett trials 1904 (Rigolly resp. Burton); 7. Gordon Bennett trials 1905 (Rigolly); 8. Grand Prix de l’ACF 1906 (Rigolly); 9. Grand Prix de l’ACF 1907 (Rigolly). The 1906 and 1907 Grand Prix cars seem to be more or less identical.
To be continued …?

Here is another photo of a 110 HP race car from 1903 which may interest readers and which is extracted from the ever wonderful W. Worby-Beaumont publication---Archibald Constable & Company Ltd, 16 James Street, London--1906. Volume 2. (42 Shillings net).

...."Of the car illustrated, it may be mentioned that the engine is of nominally 110 HP and it has cylinders of 140mm, or 5.51 inches bore. The combined strokes of the two pistons in each cylinder is 200mm, or 7.87 inches, the stroke of the upper pistons, with the long connecting rods, being shorter than that of the lower pistons, and as arranged in the smaller engines. The stroke of the lower pistons is about 1.27 times greater than that of the upper pistons. During 1904 Rigolly drove the racing car of that year's construction at a recorded speed of nearly 95 miles per hour."....