120 years ago: Aviation Pioneer Otto Lilienthal crashes

Lilienthal was the first man to describe the physical laws at work in aviation - be it the flying by birds or airplanes. He validated his theories in numerous flights. It is perhaps ironic, thus, that he broke those laws and crashed to his death just northeast of Berlin 120 years ago. But today, we know well what led to the crash, and let it be known it was not a faulty construction.

"Lilienthal should not have flown on the day of his crash," said Andreas Dillman, head of the Institute of Aerodynamics and Flow Technology of the German Aerospace Center (DLR). The weather on August 9, 1896 wasn't feasible for his glider, and it was most likely an error by the pilot that brought him down.

The Lilienthal glider was well prepared to fly in calm winds or with moderate headwind but not in more complicated windy conditions, such as those on the day of the crash.

It appears that an upwind lifted the nose of the glider, causing an aerodynamic stall of the wing. "If this happens too sharply, the plane will get out of control," Dillmann said.

Dillmann and his colleagues from the DLR have studied a remake of the original Lilienthal glider. At their headquarters in Göttingen, they conducted tests to determine the threshold of controlling the plane. The plane was also tested in a wind tunnel across the Dutch border in Marknesse, as well as in Braunschweig using computer simulation.

It turns out the plane was perfectly robust. "From the perspective of aerodynamics, it was an absolutely clean construction," Dillmann says.

"Lilienthal knew what was of the essence," said Rolf Henke, of the DLR executive board.

"It is amazing what a good plane he built 100 years ago - without any of the means we have today; he simply knew what was important for flying."

Before ever building a glider, Lilienthal had studied bird flight and discovered the advantages of a curved wing. To this day, airplanes are constructed using the lift-to-drag ratio that he helped develop. "Lilienthal was the first aviation researcher, and we remain his heirs," Henke concluded.

At the age of 48, Otto crashed during a flight from Göllenberg near Stölln in Brandenburg. A day later, he died of his injuries at Berlin's university hospital. The epitaph on his headstone reads: "Sacrifices must be made."

fs/glb (AFP, dpa)