Charles Renard was a French military engineer from Damblain, known for his work with airships (notably "La France" built with the assistance of Arthur C. Krebs and his brother Paul in 1884) and inventor of the Renard Road Train in 1903. Renard is credited to be the inventor of flapping blades on rotors and propellers, before Louis Breguet patented his design for hinged rotors in 1908. He built a pilotless machine powered by a two-cylinder engine to experiment with the principle in 1904 (some sources incorrectly say 1908, which is impossible for reasons explained below), though it was not very successful.
In April of 1905 he committed suicide, following depression from being rejected for membership of the French Académie des Sciences, as well as the French governments's lack of understanding of his experiments and refusal to fund them.