Technical Notes

摘要

Okamoto et al. [1] recently analyzed the flight stability of the lateral-directional motion of a swallowtail butterfly Pupilio xuthus. Their analysis showed that a swallowtail glides with a high dihedral angle due to the stability of the spiral mode and that the relation between a dihedral angle arid the stability of the Dutch roll mode is strongly affected by Re. In the present analysis, the flight stability of the longitudinal motion of the same swallowtail is analyzed to investigate the stability of the longitudinal motion at a high dihedral angle'. Furthermore, the flight stability of the lateral-directional motion of the same swallowtail will be analyzed again. A main improvement from the previous analysis is the measurement of the pitching moment with high accuracy. The effects of Re on all the modes of the longitudinal and the lateral-directional motions will be investigated.