Question: The Derwitzer Glider was a glider that was developed by Otto Lilienthal, a German pioneer of aviation who became known as the "flying man", and on which date, his glider stalled and he was unable to regain control?
Sentence (from "Otto Lilienthal"): On 9 August 1896, his glider stalled and he was unable to regain control.
Relevant evidence: Yes