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"): He was the first person to make well-documented, repeated, successful flights with unpowered airplanes.
Relevant evidence: No