context: The Model 299 was first launched into the air on July 28, 1935 by test pilot Les Tower [English: Les Tower] [4]. Richard Williams, a Seattle Times reporter, coined the name Flying Fortress when the Model 299 left the hangar, bristling with machine guns [5]. Boeing quickly realized the value of the nickname and registered it as a trademark. On August 20, the prototype flew from Seattle to the Wright airfield in 9 hours and 3 minutes at an average speed of 378 km / h (235 mph), much faster than competitors [2].
question: When did the Boeing B-17 Flying Fortress make its first flight?
answers.text: July 28, 1935