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

Planetary Exploration Using Biomimetics
An Entomopter for Flight on Mars
for future study. The purpose of legs on Mars would be to position sensors after landing, reposition
the Entomopter for a more favorable launch, and grapple with ground-based rovers during
refueling operations. The primary form of locomotion is intended to be flight; the legs are for
limited surface mobility, not extended ambulation.
The Entomopter wing is a thin air foil with a sharp leading edge and moderate camber. The leading
edge of the wing is sharp to improve creation of the lift-enhancing leading edge vortex during
flapping. The separation location for this leading edge vortex is controllable and is used to
modulate the lift of the wing on a beat-to-beat basis. Because the coefficient of lift of each wing
section is thus controllable, the wings need not beat at varying rates or angles of attack to maintain
attitude and heading of the vehicle. Thus, the Entomopter is designed to flap its wings autonomically
at a single optimal wing beat frequency. This feature facilitates the incorporation of
resonance into the wing beating kinematics. In fact, this resonance is essential for any flapping
wing device to operate efficiently. The flapping mechanism for the Entomopter provides a resonant
single-piece construction that takes advantage of torsional resonance in the Entomopter
fuselage to recover flapping energy as is common to flying insects that temporarily store potential
energy in either muscles or resilin.
The Entomopter wing will be designed to produce lift on both the downstroke and the upstroke.
Instead of relying on wing twist under muscular control (a complex action requiring an extra
degree of freedom in the wing hinge), the wings will be stiffened with materials that react differently
to opposite aerodynamic loads. Flexure of the wing structure will cause it to deform relative
to the leading edge spar (which drives the wing up and down) such that it maintains an angle
of attack and camber that provides positive lift on the downstroke.
Figure 2-2: ABS Plastic Wing Ribs from Fused Deposition Modeling Machine
Upon the upstroke, the wing structure will deform under an opposite aerodynamic load to create
an angle of attack and camber relative to the leading edge spar, which also has an upward lift
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Phase II Final Report