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
Create successful ePaper yourself
Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.
Chapter 6<br />
126<br />
Aero-Structural Twist (deg.)<br />
0.0<br />
-3.0<br />
-6.0<br />
-9.0<br />
Epoxy Large Hub, C l =0.50<br />
Epoxy Small Hub, C l =0.15<br />
30,000 RPM<br />
35,000 RPM<br />
40,620 RPM<br />
46,790 RPM<br />
50,760 RPM<br />
-12.0<br />
0.0 0.2 0.4 0.6 0.8 1.0<br />
r/R<br />
FIGURE 6.27 Predicted torsional deflections <strong>for</strong> large-hub <strong>and</strong> small-hub four-blade rotors.<br />
The deflected geometry <strong>for</strong> each of five operating points have been analyzed using the<br />
rapid analysis method of Chapter 4. The results <strong>for</strong> the aluminum large hub <strong>and</strong> epoxy<br />
small hub rotors are presented in Figures 6.28 <strong>and</strong> 6.29, along with the experimental<br />
results, the original OVERFLOW-D results, <strong>and</strong> the original rapid analysis method<br />
per<strong>for</strong>mance predictions. There is minimal movement in the aluminum rotor case<br />
indicating that this is not the sole source of the typical 10% variation seen between the<br />
rapid analysis method <strong>and</strong> experiment. However, the torsional model clearly captures<br />
the large-scale per<strong>for</strong>mance loss of the small hub rotor, both in power <strong>and</strong> thrust.