The Wright Brothers are the most famous names in aviation, esteemed for inventing, building and flying the first motorised aeroplane in 1903. But perhaps more impressive than their success was their survival. Far from the first to look to the sky and envy the birds, Orville and Wilbur Wright were born at the right time in history. They benefited from the invention of lightweight engines and centuries of brilliant inventors and madmen who had laid the practical and theoretical groundwork for their soaring success at Kitty Hawk. Aviation pioneers often risked their reputations pursuing a seemingly impossible goal, yet for those who wanted to validate their theories, it meant risking their lives. No one knew this better than Otto Lilienthal, the Berliner who went down with his winged glider on August 10, 1896.
He raised storks in his garden and studied their wing curvature and wing beats before they were fully fledged and flew away.
“Lilienthal worked with motorless gliders,” says Astrid Venn, the aerospace curator for Berlin’s Stiftung Deutsches Technikmuseum. At this time, there were no motors suitable for flight, as the lightweight motors used by the Wrights weren’t yet developed. Lilienthal’s initial question was therefore how to bring the weight of human bodies into the air. That’s why, shortly before his death, Lilienthal had begun to experiment with flight powered by motors. “It’s hard to say if he would have invented the airplane had he lived,” Venn adds, “but he would have definitely gotten closer.”
Karl Wilhelm Otto Lilienthal was born in 1848 in the Prussian city of Anklam, now the site of an Otto Lilienthal Museum. Back then, aviation technology centred around the hot air balloon, which uses heat to expand the air inside of its fabric, making the air less dense than the cooler air outside, causing the balloon to take flight. It was an 18th-century invention by the Montgolfier brothers in France. Otto also had a brother, Gustav, with whom he would work on aviation projects. Even as school children, they were fascinated by birds, fashioning wings to try and emulate their flight. This fascination would later turn into Lilienthal’s 1889 book Birdflight as the Basis of Aviation.
“Otto Lilienthal’s greatest source of inspiration was nature, and specifically the flight of birds,” says Markus Raffael, head of the Helicopter Department at the German Aerospace Center. “He spent years closely observing animals in order to unravel the physical secrets of flight. He raised storks in his garden and studied their wing curvature and wing beats before they were fully fledged and flew away.”
It’s hard to say if he would have invented the airplane had he lived, but he would have definitely gotten closer.
Although Leonardo da Vinci created technical plans for winged aviation in the 15th century, Lilienthal had the benefit of industrialisation, which made it easy for a trained design engineer to come by the materials needed to build a manned glider. After graduating from Berlin’s Technische Hochschule, Lilienthal started documenting experiments on the force of air. But this was interrupted by the outbreak of the Franco-Prussian war. “During the war, he saw the hot balloon technology being utilised,” Venn says. “But this only solidified his idea that the lighter-than-air flight method was going in the wrong direction.”
As the German army was investing in Count Ferdinand von Zeppelin’s eponymous airships, Lilienthal doubled down on winged glider experiments in Berlin, staging public flights on the outskirts of the city, where he soared off hilltops in front of incredulous crowds. The surviving photos show many of his different wing shapes, which include single and double-teared models, some with rounded arches resembling cranes, while others feature arched sections like those attached to the arms of bats.
While the Lilienthal brothers were far from the only men in Europe working on contraptions that could carry the weight of man through the air – notably, Lord Cayley in England and Louis Pierre Mouillard in France were working in parallel – they gained a reputation for their consistent success and detailed scientific documentation that proved it was more than luck. Parisian engineer Octave Chanute, who would later become a consultant for the Wright brothers, compiled much of this information for his reference text Progress in Flying Machines. “It was a lot more difficult at the time to exchange information with other inventors, but it did happen,” Venn says. “There were also large differences between how open people were about their inventions and discoveries. The Lilienthals were very open about sharing their work. Exchanges of ideas were important to them. The Wright brothers, in contrast, played things a little closer to the vest and waited to share successes.”
Otto Lilienthal’s fatal crash, 130 years ago this August, served to many as a cautionary tale, echoing the moral of Icarus and Daedalus: don’t fly too close to the sun. At the time, there was no way of confirming whether it was faulty calculations or an inevitable consequence of man pushing past his natural limits. Since then, the German Aerospace Center has been able to reconstruct the glider model from that day and concluded that the glider was safe to fly in, but the conditions weren’t. “On the day of his fatal crash, Lilienthal attempted to fly at a high altitude in unusually strong, gusty winds,” Raffael says. “The permissible flight envelope defines the aircraft’s allowable operating range. Modern aircraft must demonstrate the ability to fly safely across a very wide operating range.”
Like the mythological wax and feather wings of Icarus, which would become too damp and heavy if flown too close to the sea and would melt when flown too close to the sun, Lilienthal’s glider had its limits. The myth doesn’t explicitly warn against flying but of the hubris that can accompany great achievements. Otto Lilienthal is buried in Berlin. His tomb is inscribed with what were reportedly his last words: “Opfer müssen gebracht werden!” (Sacrifices must be made!).
