Phase II Final Report - NASA's Institute for Advanced Concepts

Planetary Exploration Using Biomimetics
An Entomopter for Flight on Mars
Figure 3-78: Lift Coefficient for the Oscillating Wing Case
Figure 3-79: Drag Coefficient for the Oscillating Wing Case
3.3.1.4.2.2 Thin 3D Wing Geometry
To further investigate the low Reynolds number high-α behavior, a thin 3D wing was modeled
after the North American cicada wing (Figure 3-80). The planform was approximated as a semiellipse
with an aspect ratio of 3. Even though the cicada has hind wings (the right one is shown
in Figure 3-80), the CFD model used only the forewing. The wing is thin (thickness-to-maximum
chord ratio ~ 0.02), has a slight camber, and a slight curvature in the span wise direction.
The hind wing can rotate about the leading edge, which forms a common line of contact with the
forewing trailing edge. It appears that one of the functions of the hind wing is to act as a control
surface to control camber during the stroke cycle. As discussed by Dickinson, et al. [57, 58, 56],
the wing undergoes large changes in orientation during pronation and supination in order to provided
optimum lift and thrust during the entire stroke cycle. The other interesting feature to note
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Phase II Final Report