Fig. 17. Comparison of temporal variation in angle of attack, tip velocity and translatory force between modes. Time course of each parameter over the downstroke and upstroke shown along a normalized time axis. Mode 2 strokes are shown in black, and Mode 1 strokes are shown in pink. Mid-stroke was defined as a normalized time of 0.55, indicated by the vertical dotted lines. (A) Angles of attack over the downstroke. (B) Tip velocities over the downstroke. (C) Translatory forces over the downstroke. (D) Angles of attack over the upstroke. (E) Tip velocities over the upstroke. (F) Translatory forces over the upstroke.