l'Aérophile carried an article by Chanute that included drawings of his gliders as well as the Wright glider and a description of their approach to the problem, saying "the time is evidently approaching when, the problem of equilibrium and control having been solved, it will be safe to apply a motor and a propeller". Chanute's lecture moved Ernest Archdeacon one of the founder members of the Aéro-Club, to conclude his account of the lectures: In October 1904 the Aéro-Club de France announced a series of prizes for achievements in powered flight, but little practical work was done: Ferdinand Ferber, an army officer who in 1898 had experimented with a hang-glider based on that of Otto Lilienthal continued his work without any notable success, Archdeacon commissioned the construction of a glider based on the Wright design but smaller and lacking the provision for roll control which made a number of brief flights at Berck-sur-Mer in April 1904, piloted by Ferber and Gabriel Voisin (the longest of around , compared to the achieved by the Wrights in 1902) : another glider based on the Wright design was constructed by Robert Esnault-Pelterie, who rejected wing-warping as unsafe and instead fitted a pair of mid-gap control surfaces in front of the wings, intended to be used in a differential manner in place of wing-warping and in conjunction to act as elevators (as what are known today as elevons): this is the first recorded use of ailerons, the concept for which had been patented over a generation earlier by M. P. W. Boulton of the United Kingdom in 1868. This was not successful and Esnault-Pelterie was later to use its failure to support the position that the Wright Brothers claims were unfounded. However his design was not an exact copy of the Wrights' glider, particularly in having a greatly increased wing camber. Ferber's copy was likewise unsuccessful: it was crudely constructed, without ribs to maintain the wing camber, but is notable for his later addition of a fixed rear-mounted stabilising tail surface, the first instance of this feature in a full-size aircraft. Archdeacon abandoned the 1904 glider after the first attempts and commissioned a second glider, which was constructed by Gabriel Voisin in 1905; this broke up in mid air when towed into the air behind a car, fortunately carrying sandbags in place of a pilot. Voisin then constructed another glider, mounted on floats and