Aerodynamics and Design for Ultra-Low Reynolds Number Flight
Aerodynamics and Design for Ultra-Low Reynolds Number Flight
Aerodynamics and Design for Ultra-Low Reynolds Number Flight
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Chapter 8<br />
further investigation, but do not significantly diminish the utility of the rapid analysis<br />
<strong>and</strong> design method.<br />
Experimental testing has also served to both validate the method <strong>and</strong> expose another<br />
potential problem that strongly influences micro-rotor per<strong>for</strong>mance. Certain designs,<br />
having small hub diameters or high local solidities, exhibited thrust <strong>and</strong> power levels<br />
significantly below predicted values. The two-dimensional aerodynamic studies have<br />
demonstrated the strong need to minimize airfoil thickness at ultra-low <strong>Reynolds</strong><br />
numbers, but the derivation of an aero-structural model <strong>for</strong> torsional deflections reveals<br />
that one consequence of reduced airfoil thickness is a disproportionate increase in<br />
torsional deflections due to rotational effects. Failure to account <strong>for</strong> this in a design can<br />
result in reduced incidence <strong>and</strong> aerodynamic unloading of the rotor.<br />
Finally, this progression of work has led to the design <strong>and</strong> fabrication of prototype<br />
micro-rotorcraft. The largest design brings together current existing technologies into a<br />
flight-vehicle that could provide a valuable test-bed <strong>for</strong> further research. Full realization<br />
of the smallest of these designs appears to be beyond the state of the art, but it sets the<br />
bar <strong>for</strong> the future. Any complex device requires a convergence of necessary<br />
technologies <strong>for</strong> it to come into existence. Motors, batteries, microelectronics, <strong>and</strong> many<br />
other necessary components are progressing at accelerated rates, driven by the wants <strong>and</strong><br />
needs of society. The aerodynamics are still in their infancy <strong>and</strong> progressing slowly.<br />
Even if the end product is not viable now, the research must still continue in order to be<br />
ready at the point that it all comes together - to do anything else is simply short-sighted.<br />
8.3 Consideration of Future Work<br />
This work was not envisioned as all-encompassing, <strong>and</strong> in that regard it has been an<br />
overwhelming success. There are many possible avenues <strong>for</strong> continued ef<strong>for</strong>t. Much can<br />
be done to improve <strong>and</strong> exp<strong>and</strong> upon the methods <strong>and</strong> analysis completed here, but there<br />
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