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when looking at a cross-section. A wing possesses upper camber on its top surface and lower camber on its bottom surface. WSC airfoils can be single surface, with one piece of fabric for most of the airfoil, for slower wings. Faster airfoils have two surfaces and are called double surface wings, which are more like an airplane wing. [Figure 2-1] This double 

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surface allows the wing structure to be enclosed inside the wing, similar to an airplane wing, reducing drag and allowing for faster speeds for the same thrust. The leading edge is the forward edge of the airfoil, and the rear edge of the airfoil is called the trailing edge. The chord line is an imaginary straight line drawn from the leading edge to the trailing edge. The WSC airfoil typically uses a different camber with the airfoil high point farther forward than the airplane airfoil, creating a more stable airfoil. [Figure 2-2] 

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The WSC wing is a unique design of airfoils that differ throughout the wing span. Looking at a top view of the wing, in the center is the wing root and on each end is the wingtip.  Wing chord is any section of the wing parallel to the wing root. [Figures 2-3 and  2-4] The wingtip chord is the chord where the trailing edge is furthest to the rear of the wing. This can be inboard of the tip (as shown) and can vary depending on the specific wing design. The nose angle is the angle made by the leading edges, typically ranging from 120° to 130°. Sweep is the angle measured between the quarter chord line (line of 25 percent chords) and a line perpendicular to the root chord.  [Figure 2-3] 

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