Gliders fly engine-free for hundreds of kilometres on rising air
Around 1005 an English monk named Eilmer strapped on wings, leapt from Malmesbury Abbey and reportedly covered about 200 metres before crashing. He blamed the missing tail. Today's engineless sailplanes, riding invisible currents of warm air, routinely cover hundreds of kilometres in a single day, and sometimes more than a thousand.
Early stories are hard to check, often written down centuries later. A 17th-century source says the poet Abbas Ibn Firnas tried a winged flight near Córdoba in the 9th century and was badly hurt, and Hezârfen Ahmed Çelebi supposedly glided across the Bosphorus from the Galata Tower around 1630. The first man-carrying gliders built on published scientific principles were George Cayley's, which made brief hops from about 1849. Otto Lilienthal later made more than 2,000 flights and was the first to use rising air to stay up longer.
Recreational gliding took off in interwar Germany, and in Elmira, New York, the Schweizer brothers built sport sailplanes for the new market. Near the end of World War II prisoners at the German camp Oflag IV-C secretly built a glider, the Colditz Cock, as a possible escape. Modern sailplanes use glass, carbon and aramid composites and long slender wings to cut drag, and since shortly after the war pilots have trained in two-seaters with dual controls.
Hang gliding traces back to a 1951 patent by Francis and Gertrude Rogallo for a fully flexible wing. NASA tested the Rogallo wing from 1957 as a way to bring Gemini capsules home, and by the early 1960s enthusiasts were flying it from their feet. In the classic design the pilot hangs beneath the wing and steers by shifting body weight.
Paragliders have no frame at all. Domina Jalbert patented the ram-air parafoil in January 1963: air rushing into open cells along the front edge inflates the fabric into a wing. NASA coined the term paraglider in the early 1960s. The whole aircraft packs into a large backpack, and competition wings reach glide ratios near 1 to 10 at about 45 kilometres per hour.
Source: Glider (aircraft)
