[JoeF]

[AWES] Soaring Thermals by Passive Auxetic Control

dave santos [AirborneWindEnergy] <AirborneWindEnergy@yahoogroups.com>
7:20 AM (33 minutes ago)
to Yahoogroups

When a glider encounters a thermal, one or the other wing tends to kick-up first in reaction to the rising air encountered. This passive action tends to bank the glider away from the thermal core. Soaring agents, like birds and glider-pilots, bank against the initial roll signal, and succeeding roll tendency gradient, to stay in the thermal core.

A popular metamaterial property of inverse Poisson Ratio is an Auxetic reaction inverse to simple linear reaction. A soaring wing designed as an Auxetic structure can in principle passively turn into a thermal, much as a classically intelligent soaring agent does.

There are many possible ways to design an Auxetic soaring wing, but a prime idea is to couple Auxetic reaction to ailerons, not necessarily design the reaction monolithically into wing roots or spanwise wing-warping.

It should be simple to design a proof-of-concept Auxetic soaring wing.


Auxetics
Auxetics are structures or materials that have a negative Poisson's ratio. When stretched, they become thicker p...

[JoeF]

dave santos Today at 8:15 AM
Thanks Joe, and Hi to all the Hawks.

Further notes. An auxetic soaring wing needs to tap some flight-energy to reapply as actuation-force. There is a delay relation between input signal and actuation, with a persistence or locking factor to actuation. Actuation should unlock once the input state abates. Slow quasi "memory foam" recovery of the metamaterial seems helpful.