Demoiselle

The Demoiselle, conceived and built by Brazilian aviation pioneer Alberto Santos‑Dumont in 1907, is widely regarded as the world’s first truly practical ultralight aircraft. Inspired by his earlier success with the 14‑billion‑franc airship, Santos‑Dumont designed the Demoiselle as a simple, low‑cost monoplane that could be constructed by amateur builders. The aircraft featured a 100‑cm (3‑ft) wingspan, a lightweight wooden frame covered with silk, and a 12‑horsepower Anzani engine that drove a single propeller mounted above the wing. Its twin horizontal tail surfaces and a single vertical fin gave it stability, while the open‑cage fuselage reduced weight to roughly 50 kilograms (110 lb). First flight took place on 17 October 1907 at the Château de Bagatelle, Paris, where the plane completed a 100‑meter hop; within weeks Santos‑Dumont refined the design and achieved flights of over 300 meters at speeds of 30 km/h. Over 300 kits were sold worldwide, making the Demoiselle the first mass‑produced aircraft and a catalyst for the early hobbyist movement. Its economical construction, ease of operation, and pioneering status cemented its role as a cornerstone in the transition from experimental flyers to commercial aviation.