Fig. 9. Time courses of the vertical (lift; A) and the horizontal (drag and thrust; B) forces over a flapping cycle. Blue, red and yellow lines represent the measurements of the upper (Exp_u), average (Exp_a) and lower (Exp_l) values obtained by Fry et al. (Fry et al., 2005), respectively; broken line is the computed result (Com_a). T, dimensionless period of one flapping cycle.