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

Planetary Exploration Using Biomimetics
An Entomopter for Flight on Mars
Figure 3-9: Entomopter Landing Approach
In this landing sequence the Entomopter would slow by flaring upward as it approaches the
landing site. This would cause the vehicle to slow as well as lose lift. The Entomopter would
then descend to the landing site. To ease the descent the engine would be overpowered for a
short period of time to increase the flapping frequency of the wings as much as possible. This
would produce extra lift and help slow the vehicle’s descent. The over-speeding of the engine
would occur for a very short amount of time (1 to 2 seconds) and therefore should have little
effect on the engine. The main effect on the engine from running at these increased output power
levels would be an increase in temperature. Because the engine would run in this condition only
for a short period of time, the temperature rise would be absorbed by the thermal mass of the
engine. While the Entomopter is on the surface the engine would need to cool down to its normal
operational temperature before the Entomopter could take off again. In addition to providing
increased power, over-speeding the engine will also consume more fuel, which will produce
more exhaust gases. This increase in exhaust gas can be used to further augment the vortex formation
and attachment to the wing, thereby temporarily increasing the lift coefficient of the
wing. Some additional flight energy can be absorbed by spring mechanisms in the legs of the
Entomopter. These springs act as shock absorbers and to lock into a compressed state upon landing.
Releasing the leg springs can be used to push the Entomopter into the air and assist with
takeoff. The combination of the over-speeding of the engine, increased gas production, and leg
spring energy absorption should be sufficient to allow the Entomopter to safely land on the surface.
3.2 Wing Motion and Structure Analysis
The structural analysis for the Entomopter wing is an important part of the overall vehicle
design. Even though the gravitational force on Mars is only roughly a third of Earth’s, significant
forces can still affect the wing structure. The bulk of the force the wing will see comes from
the motion of the wing. The operation of the Entomopter entails the rapid motion of the wings.
Caused by the acceleration and deceleration of the wing on each beat, this motion imparts a significant
loading on the wing structure.
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Phase II Final Report