pull the control bar in to control pitch. This wing attachment  is different for each manufacturer, but all designs have this  hang point wing attachment so the control bar is always  perpendicular to the longitudinal axis of the aircraft. This  raising and lowering of the nose is the pitch control system  for the WSC aircraft.  [Figures 2-7  and  3-19] Control bar movement from side to side controls the roll about  the longitudinal axis. The wing attachment hang point allows  the carriage to roll around the wing keel. Thus, it can also be  looked at from the carriage point of view, when the control  bar is moved side to side, the wing rotates around the wing  keel relative to the carriage.  [Figures 2-31  and  3-19] It would first appear that moving the control bar to one side,  thus shifting weight to the opposite side, could alone bank  the aircraft. It is true that shifting weight to the right would  naturally bank the aircraft to the right and put it into a right  hand turn. However, the weight alone is not enough to provide  adequate roll control for practical fl ight.  As weight is moved to one side, the keel is pulled closer to  that side’s leading edge. The actual keel movement is limited  to only 1 to 2 inches each side of center. However, this limited  keel movement is sufficient to warp the wing, changing the  twist side to side (as discussed earlier in the aerodynamics  section) to roll the aircraft  [Figure 2-24]  by changing the  lift side to side. Simply, the shifting of weight from side to  side pulls the keel toward the leading edge on that side and  warps the wing to roll the aircraft.  Besides the keel shifting relative to the leading edges and  crossbar, overall roll control is adjusted by the designers to  fit the mission of the wing through sail material/stiffness,  leading edge stiffness/flexibility, amount of twist, amount  of travel the keel is allowed, airfoil shape, and the planform  of the wing.  [Figures 3-20  and  3-21] The most common ground adjustable trim system, and typical  of most aircraft, is moving the wing attachment hang point  forward for faster trim speeds and aft for slower trim speeds.  Each manufacturer has different hardware, but the basics of  sliding the carriage wing hang point forward and backward  on the keel is similar for all. As an example, moving the  hang point at the furthest aft position to the furthest forward  position could speed the wing up 20 knots. This in turn  moves the control bar position back to a new “hands off”  trim speed.  There are a number of trim systems to relieve the control  pressures for pilots to fly at different “hands off” trim speeds.  Ground adjustable trim allows the pilot to adjust the trim  speed of the wing on the ground and remain at one speed  during flight, while flight adjustable trim systems can change  the trim speed in fl ight.  Strap attached to crossbar  that goes around wing keel,  limiting its travel side to side. Far Back View Top View Figure 3-20.  Shifting weight to the right pulls the keel to the right  (or lets the crossbar shift to the left) and increases twist on the right  side for roll control. Figure 3-19.  Hang point wing attachment. Figure 3-21.  Crossbar travel limiter.  Trim Systems  Roll Control System   Ground Adjustable Trim Systems  3-9