Clément Ader invented the plane – the avion – s the name and the machine. Indeed the life of “the father of aviation” stays imbued with a mythological dimension, which invariably aims to reveal the eternal, and in his time unrecognised, glory of the inventor of genius. In reality, Ader is far from having been a martyr, and even amassed a considerable fortune during his brilliant career as entrepreneur and inventor. Finding its sources in the Ader archive at the CNAM (Centre national des arts et métiers), this paper retraces he way the inventor’s black legend gradually imposed itself over and against historical reality.