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

Chapter 3.0 Vehicle Design
3.2 Wing Motion and Structure Analysis
Table 3-4: Wing Geometry and Mass
Thickness (m)
(Root to Tip) 0.026 to 0.026 0.024 to 0.005 0.019 to 0.019 0.0165 to 0.005
Interior Ellipse as a
Percent of Outer
Wing Dimensions
Solid: a = 0%,
b = 0%
Solid: a - 0%,
b = 0%
a = 90%
b = 80%
a = 95%
b = 85%
Total Wing Section
Mass (kg) 2.46 1.52 0.51 0.214
Maximum Tip
Deflection (m) 0.015 0.015 0.015 0.015
The tapering of the wing also had an effect but it wasn't as dramatic. The maximum loading
point on the wing, used to generate the results given above, occurs when the wing is at its maximum
downward position. In this position the wing sees both a maximum acceleration load as
well as the gravitational load both working in the downward direction. This maximum loading
profile along the wing is shown in Figure 3-18 for the base flight conditions given in Table 3-3
and the hollow tapered wing geometry shown in Table 3-4. The radial loading profile is shown
in Figure 3-19. Structurally the radial loading is not significant and does not affect the wing
structural design. The structural geometry will not effect the maximum loading point for the
wing. It will however have an effect on the absolute value of the loading experienced. Therefore
the loading profile and point of maximum loading will be consistent for each structural geometry
considered.
The hollow tapered geometry produced the lightest wing for a given amount of deflection. Based
on these results this geometry configuration will be the baseline geometry for the wing. This
baseline, as listed in Table 3-4, consists of a wing taper from 0.0165 m at the root to 0.005 m at
the tip and an inner ellipse length “a” equal to 95% and thickness “b” equal to 85% of the outer
ellipse dimensions respectively. For this hollow tapered geometry, the loading profile along the
wing length is shown in Figure 3-20. Also shown in this figure are the subsequent shear loading
and bending moment curves for this wing geometry.
Variations in the wing structural geometry from the baseline values were also examined. This
was done to determine what effect each of the parameters had on the wing mass and tip deflection.
The results of these variations are shown in Figures 3-21 through 3-24. Figures 3-21 and 3-
22 show the effect changing the dimensions of the hollow elliptical core of the wing has on the
wing section mass and wing tip deflection. As the hollow core dimensions are increased the
wing section mass decreases linearly with both dimensions (a and b) as should be expected. The
tip deflection is greatly effected by variations in the thickness (b) of the core ellipse. This is
because the moment of inertia for the wing is greatly dependent on the ellipse thickness. From
this curve it can be seen that a minimum tip deflection occurs at a hollow core thickness of
approximately 85% of the overall wing thickness. This is consistent with the design point that
was chosen.
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