Yesterday, while tidying up, I found an old stamp among some papers destined for the bin. It showed a strangely shaped flying machine. Looking closer, I read: “125th anniversary of the first gliding flight—Otto Lilienthal.” Then it clicked: this odd contraption was the famous Lilienthal glider, and its creator was the subject of this essay, Otto Lilienthal.
By coincidence, I had recently read about Professor Markus Raffel of the German Aerospace Center, DLR. To honour Lilienthal on the centre’s 125th-anniversary occasion, he built a replica glider, taught himself to fly it and successfully tested it in the United States. Why America? Quite simply, he couldn’t get insurance for his recreated antique in Germany. Germany takes insurance very seriously: say you haven’t got any and jaws drop all around. Every German flying site therefore refused his test flights—a rather ironic situation, this frog thinks! As work happened to be taking him to America for a project anyway, he brought his treasure along.
Figure 1: “125 years of the first gliding flight—Otto Lilienthal” commemorative stamp
Lilienthal’s influence on aviation, especially in America, was profound, so Raffel’s replica flights caused quite a stir there. And here I was, a gliding enthusiast, stumbling upon a stamp almost consigned to the rubbish. It felt like a subject I was meant to write about. Hence this essay.
The Otto Lilienthal Museum’s website describes him as follows:
“Otto Lilienthal is regarded as the first successful pilot in human history. His fundamental investigations of birds and wing profiles established wing aerodynamics and laid the foundations for concepts of flight still used today. His life was closely bound up with that of his brother Gustav Lilienthal (1849–1933), who influenced him deeply. Their lifelong collaboration, particularly in technology, society and culture, produced achievements that remain significant today.”
Wikipedia introduces him this way:
“Otto Lilienthal (23 May 1848–10 August 1896) was a German aviation pioneer, known as the ‘Glider King’ and nicknamed ‘the Bat Man’. He was the first person to make successful gliding flights repeatedly, and the first to identify that a cambered wing produces greater lift.”
Figure 2: Otto Lilienthal, 23 May 1848–10 August 1896
Some call Lilienthal the most important of all the people who tried to solve the problem of flight in the nineteenth century. Many had attempted gliding over the preceding centuries, including Cayley, Spencer, Wenham and Mouillard in the nineteenth, yet their efforts had not produced the breakthrough. For many aviation specialists, Lilienthal’s first glide marks the great moment when humanity began learning to fly. After his death, newspapers and magazines in many countries published photographs of his flights, helping change both public and scientific opinion about flying machines.
His childhood was far from easy. His father died when he was twelve; he was the eldest of eight children. Fortunately his mother was a strong woman who fought to give her children a good education despite their financial difficulties. At his secondary school, one of his teachers was the noted German astronomer Gustav Spörer. His fascination with flight, and with the way birds fly, was already taking root then.
In 1864, at sixteen, he entered the provincial trade school in Potsdam. Money was tight: during his studies he even shared a rented bed with two coachmen. Bed renting wasn’t unusual then; historical records put the proportion at over 13.6 percent. The painting below gives some idea of such shared lodgings.
All right, I’ve wandered off. Back to the story.
He later studied at the Higher Technical Academy in Charlottenburg, whose leading technical figure was Franz Reuleaux, the German mechanical engineer regarded as the founder of kinematics. If the name interests you, look up the Reuleaux triangle. After graduating, Lilienthal became his assistant, gaining mechanical knowledge crucial to his later gliding work. Around this time he and Gustav built a device to investigate the lift produced by human-powered flapping wings. Here it is.
Figure 3: The Late Bed-Renter, by German artist Heinrich Zille
Like the stepping machines used for morning exercise in Chinese residential parks, it worked by pressing pedals with both feet. The pedals drove the wings, generating lift and slowly lowering the large counterweight hanging behind. The experiments showed that human effort could lift a load of up to 40 kilograms. It still looked far removed from his later gliding flights, but these experiments strongly influenced his subsequent research.
From 1874 onward, with Gustav’s support, he systematically measured lift on flat and cambered surfaces. The brothers gradually recognised that a curved wing produces more lift in an airflow than a flat one—a discovery of enormous significance for aviation.
Figure 4: Flapping-wing lift experiment, Altwigshagen near Anklam, 1868
Figure 5: Comparing lift on cambered and flat surfaces at angles of attack from 26 to 16 degrees
Unfortunately, as with so many remarkable figures in history, the establishment wasn’t ready to embrace his work. Physics still struggled to explain the relationship between airflow and lift. The renowned Hermann von Helmholtz said that a person could not leave the ground using wing-like structures powered by their own muscles. Many took that to mean science had proved humans could never fly. I suspect he meant that we cannot flap ourselves into the air like birds, any more than we can lift ourselves by our own hair—a reasonable point. But the brothers’ contraption gave the impression that flapping flight was exactly what they wanted. Lilienthal carried on regardless, with the air of a man thinking, “You simply don’t understand my world.”
Even the grandest ambition suffers when your pockets are empty. This restless young inventor launched himself into business after graduation, but every venture before 1881 ended in failure. In 1883 a small wall-mounted motor finally earned him his first real money. He founded a company that at one stage employed sixty people.
Long before that, he had been studying flight theory. In 1889, after years of work, he published Der Vogelflug als Grundlage der Fliegekunst—Birdflight as the Basis of Aviation. It attracted little enthusiasm. Aviation circles were preoccupied with progressing from balloons to airships and paid scant attention to his apparently outlandish “bird business”. Today it stands as one of the nineteenth century’s most important works on flight. Its accumulated theory provided the solid foundation for his gliding experiments.
He kept pursuing his dream. In 1891 he finally took his own glider into the air from a sand dune in Berlin. He travelled twenty-five metres. Only twenty-five metres—but a momentous distance.
Figure 6: Der Vogelflug als Grundlage der Fliegekunst (Birdflight as the Basis of Aviation), Otto Lilienthal, 1889
Now look back at the stamp. Figure 7 shows the actual scene behind its design. Photographer Carl Kassner captured that thrilling moment, creating one of humanity’s earliest photographs of a person in flight.
His approach was to progress from walking to jumping, then from jumping to gliding. After each flight he modified his machines, extending their range from twenty-five to 250 metres. Over the next seven years he made more than two thousand flights in his various designs. Injuries—twisted ankles and strained arms—were routine. He never gave up; setbacks only strengthened his resolve.
Figure 7: Lilienthal’s first test flight
Figure 8: Lilienthal testing a glider in 1893
He built no fewer than twenty-one different glider designs in his lifetime, including a biplane that looked even more fantastical:
In 1894 he began offering his first production model, the Normalsegelapparat, for 500 marks. His workshop could thus be called the world’s first aircraft factory. The machine below has four curved structural ribs visible across its wings.
He continued testing, attracting ever more attention.
Figure 9: Lilienthal testing a biplane glider
Figure 10: Lilienthal’s Normalsegelapparat
Figure 11: A test flight in 1894
Figure 12: A test flight in 1895
Then, on 9 August 1896, disaster struck. A violent gust caught him during a flight. He fell from fifteen metres, broke his neck and died the next day.
Figure 13: A test flight in 1895
Figure 14: A test flight in 1895
On 23 October 1989, pilot Dieter Kallbach landed an Ilyushin Il-62 airliner near the place where Lilienthal had fallen. Named Lady Agnes after Lilienthal’s wife, Agnes Fischer (1857–1920), it became a museum commemorating this great pioneer of human flight.
Original gliders from his time later entered museum collections: the Deutsches Museum, the Otto Lilienthal Museum, Vienna’s Technical Museum, the National Air and Space Museum in Washington, the Sukhoi Museum in Moscow and the Science Museum in London, among others.
Figure 15: The glider damaged in the fatal crash, 1896
Figure 16: Lady Agnes
A close look reveals how different it was from today’s hang gliders, particularly in its controls. According to Professor Raffel, the pilot supports the wings with his upper arms and steers mainly by swinging his lower body and legs sideways: legs left to fly right, legs right to fly left.
As for the experience of flying it, Raffel said:
“A fantastic feeling. I shouted for joy; I could hardly believe it. It’s as though the wings belong to your body,” the scientist enthused.
Figure 17: An original Lilienthal glider in a museum
Figure 18: An original Lilienthal glider in a museum
DLR scientists even put Raffel’s replica into a modern wind tunnel to examine its aerodynamics. It withstood an airflow of ten metres per second. The tests supplied further performance data, which the researchers also used to investigate Lilienthal’s fatal accident.
Figure 19: An original Lilienthal glider in a Washington museum
Figure 20: Wind-tunnel testing of a Lilienthal glider
These systematic wind-tunnel tests dispelled the last doubts about the glider’s flying capabilities. Andreas Dillmann, head of DLR’s Institute of Aerodynamics and Flow Technology, put it this way:
“One can only take one’s hat off to him: he built a fully fledged aircraft.”
It was a resounding endorsement of Lilienthal’s work by modern science.
Figure 21: Wind-tunnel testing of a Lilienthal glider
Lilienthal was gone, but his discoveries and influence endured. Inspired by him, the Wright brothers began in 1896 to develop a controllable, powered, heavier-than-air machine. On 17 December 1903, their own Flyer I achieved humanity’s first sustained, controlled, powered flight in a heavier-than-air aircraft.
He also left a precious legacy of spirit. Before dying, he said:
“Small sacrifices must be made!”
He was buried in Berlin’s historic Lankwitz cemetery, where graves of honour commemorate people of outstanding achievement. His last words were inscribed on his gravestone.
Attentive readers may notice that the gravestone omits the first word, kleine—“small”. It reads simply, “Sacrifices must be made.” Perhaps to Lilienthal an individual sacrifice seemed small beside humanity’s progress towards flight. To those who came after him, his sacrifice was anything but small.
Memorials were erected throughout Germany. Berlin Tegel Airport received the additional name Otto Lilienthal. Outside it, Rolf Scholz’s sculpture Daedalus and the Fall of Icarus recalls the Greek myth while also suggesting Lilienthal’s own death—a remembrance of the pioneer.
Figure 22: Lilienthal’s grave. Inscription: “Sacrifices must be made.”
Figure 23: Daedalus and the Fall of Icarus at Berlin Tegel Airport, by Rolf Scholz
Figure 24: Otto Lilienthal memorials around Germany
Today, with aviation so well developed, an aeroplane may seem merely a means of transport. But when we fly away on holiday, or soar beneath our hang gliders and paragliders, we should remember Lilienthal’s enormous contribution. And we should remember the spirit he left us: the perseverance, courage and ambition with which he pursued his dream.
This essay is dedicated to all the pioneers who helped humanity take flight.
Figure 25: German commemorative stamps and coins featuring Lilienthal
Figure 26: Lufthansa magazine