•  Shifting weight to one side of the wing, thus warping  the wing to aerodynamically change the lift on each  side, as in airplane roll control.  [Figure 2-31] CG Arm Pilot input roll moments Pilot input force Resultant roll moments about CG Smaller area creating loss of drag Larger area creating more drag Yawed to the left, the wing  automatically rotates  into the relative wind Relative Wind Flightpath Figure 2-32. Yaw correction about the vertical axis.  Figure 2-31. Pilot induced moments about wing/carriage hang point  and resultant CG rolling moment.  Figure 2-33. Keel pockets and vertical stabilizers are additional  tools designers use for yaw stability on the wing.   Carriage Moments  Roll Stability Summary  Yaw Stability and Moments  Carriage Moments Carriage weight and resultant CG are the main factors that  contribute toward increasing the roll moment for the carriage.  Carriage aerodynamic forces are not typically a factor for  rolling moments. Overall, roll stability and moments are a manufacturer/ make/model balance between dihedral/anhedral, wing twist,  nose angle, airfoil shape from root to tip, and leading edge  stiffness. Some designs are stable, others neutral, and others  can be designed to be slightly unstable for quick side-to-side  rolling. There is no significant turning about the vertical axis because  the WSC wing is designed to fly directly into the relative  wind. Any sideways skidding or yaw is automatically  corrected to fly straight with the swept wing design. An  airplane uses the vertical tail to stabilize it to fly directly into  the relative wind like a dart. The unique design of the WSC  aircraft performs the same function through the swept wing  design, but also the wing twist and airfoil shape from root to  tip assists in the correction about the vertical axis. A simple  way to understand the yaw stability is to see that any yawing  motion is reduced simply through the increased area of the  wing as it rotates about its vertical axis.  [Figure 2-32] There is a slight amount of adverse yaw similar to an  airplane that can be noticed when a roll is fi rst initiated.  The amount varies with the specifi c manufacturer’s design  and make/model. In addition, the wing can yaw side to side  to some degree, with some different manufacturer’s make/ The wing is a significant factor in the design of yaw stability,  but the carriage can be a large factor also. If the area in front  of the CG is greater than the area in back of the CG, and  the wing yaws to the side, then the front would have more  model more than others. The higher performance wings  with less twist and a greater nose angle are noted for less  yaw stability to gain performance. These wings also require  more pilot input and skill to minimize yaw instability through  pitch input. An addition to the wing planform, twist, and  airfoil shapes to minimize yaw, some wings utilize vertical  stabilizers similar to these in airplanes and others use tip fi ns.  [Figure 2-33]  Generally, the WSC wing is yaw stable with  minor variations that are different for each wing and can be  controlled by pilot input, if needed.  2-17