Early in May 1910, Sikorsky wheeled the B.I.S.I out of its hangar on a windy day, turned it into the wind and opened the throttle of the tiny 15hp Anzani engine. Encouraged by a hop of 0.5 or 1 meter into the air for a few seconds, he tried several times to repeat it before realizing that it was made possible only by a sudden gust of wind.