1.5 1.0 0.5 0 5 10 15 20 25 Angle of Attack C$_{L}$ Root at minimum controlled airspeed Tips at minimum controlled airspeed CG CG Arm Pilot induced pitch moments Pilot input force Pilot induced pitch moments Pilot input force Arm 1.5 1.0 0.5 0 5 10 15 20 25 Angle of Attack Root Tip .12 .3 C$_{L}$ Example of Increasing AOA  3 degrees above trim Example of trim AOA Figure 2-28. Example AOA versus C$_{L}$ showing the wing increasing  AOA three degrees with the tip C$_{L}$ increasing more than the root.  Figure 2-26. Example of AOA versus C$_{L}$ for wing at minimum  controlled airspeed.  Figure 2-27. Pilot actuated pitching moment.  of change of the C$_{L}$ is much less at higher AOA at the root  chord. Therefore, an increase in AOA for the wing results in  the tips creating a greater proportion of the lift and moving  the center of lift behind the CG, creating a negative pitching  moment to lower the nose at high AOA.  Based on the same principle, when the wing AOA is lowered  below the trim position, the tip chords’ C$_{L }$decreases more  than the root chord and the center of lift for the wing moves  forward creating a positive moment to raise the nose at  lower AOA. In situations where the pilot is flying in severe/extreme  turbulence, wind sheer, or the pilot is exceeding the limitations  of the aircraft, the WSC aircraft can get into a situation where  the root chord is at a negative AOA and not producing lift.  This could result in an emergency vertical dive situation, as  discussed later in the Whip Stall-Tuck-Tumble section. When  at very low angles or negative angles of attack, the WSC wing  is designed so that the wing has positive stability or a nose- up aerodynamic moment. This is accomplished by a number  of different systems (washout struts, sprogs and refl ex lines)  further explained in chapter 3 that simply keep the trailing  edge of the wing up in an emergency low/negative AOA  dive situation. As shown in  Figure 2-29,  the root area of the  wing has reflex which creates a positive pitching moment  for the root chord to rotate the nose up towards a level fl ying  attitude. At the same time, the tips are at a negative AOA  producing lift in the opposite direction as usual, creating a  moment to bring the nose/root chord up to a positive AOA  to start producing lift and raising the nose to a normal fl ight  condition. The negative lift or downward force as produced  at the tips and root as shown provide a positive moment to  raise the nose back to a normal fl ying attitude. 2-15