Fortunately, the test was unmanned, the pilot's place being taken by of ballast, since the aircraft suffered a structural failure and crashed. It was not rebuilt. Voisin then designed and built a glider equipped with floats for Archdeacon. This aircraft marks the first use of Hargrave cells, used both for the empennage and the wings. Voisin successfully flew it on 8 June 1905, having been towed into the air behind a motor boat on the river Seine between the Billancourt and Sèvres bridges, managing a flight of about . While working on this aircraft Voisin had been approached by Louis Blériot, who asked him to build him a similar machine, later known as the Bleriot II. This differed principally in having a smaller span lower wing, resulting in the outer 'side-curtains' between upper and lower wings being angled outwards. After this first flight Bleriot suggested to Voisin that they form a partnership to build aircraft, and so Voisin ended his association with Archdeacon's syndicate. Voisin attempted flights in both aircraft on 18 July 1905. Although the weather was unsuitable, with a strong crosswind, Voisin decided to attempt to fly the aircraft since it was difficult to obtain the necessary permission to use the river. He made a short flight in his own glider and then attempted a flight in Bleriot's. This took off quickly, but Voisin could not control it and it crashed into the river. Voisin was trapped inside and was lucky to escape drowning. Louis Bleriot's cine footage of this experiment survives in the Smithsonian's National Air and Space Museum. The next aircraft built by Voisin for Bleriot during 1906, the Bleriot III, was a tandem biplane powered by an Antoinette engine driving two tractor propellers with the wings formed into a closed ellipse as seen from the front: according to Voisin's account, Bleriot had originally wanted the lifting surfaces to be circular in front elevation, having experimented with models of this form, and the adoption of their eventual form was the result of a compromise between the two men. This aircraft was unsuccessful, as was its subsequent modification (the Blériot IV) in which the forward wing was replaced by a conventional biplane arrangement and a second engine added. Experiments were made first with floats and then with a wheeled undercarriage, and the aircraft was wrecked in a taxiing accident at Bagatelle on the morning of 12 November