Figure 2-6. Aspect ratio comparisons for wings with similar areas. Figure 2-7. Dynamic pressure.  Figure 2-8. Cell openings and cross-port view.  the wing because the dynamic pressure hitting the  opening is the same for each cell and the speed is  the same. The cross-ports aid the complete wing in  becoming pressurized during inflation and maintain - ing the pressure throughout the wing in turbulence. [Figure 2-8] The inflatable wing airfoil generally remains a consis - tent shape as designed by the manufacturer. However,  pilot control of the wing to make a turn significantly  changes the relative aerodynamic qualities of the PPC  wing by pulling down the trailing edge similar to a  flap on an airplane. [Figure 2-9] Faster speeds from smaller wings or more weight cre- ate a higher pressure in the wing resulting in higher  control forces because of the higher internal pressure. 1. The sum of all upward forces equals the sum of  all downward forces. 2. The sum of all forward forces equals the sum of  all backward forces. Forces in Flight 2-4 Like all aircraft, the  four forces that affect PPC flight  are thrust, drag, lift, and weight. [Figure 2-10] In  steady PPC flight: