This is the aerodynamic lifting force as shown in figure 3. Drag force is the resistance of the movement of an object through air. There are three primary types of drag that occur when an object travels at low subsonic speeds. These are induced drag, skin friction drag, and pressure drag. Induced drag is a by-product created by the production of lift and is greatest at the lowest speeds.
Pressure drag is due to the disruption of the smooth flow of air over the aerodynamic surface.
Skin friction drag results from friction between the air and the surface over which it flows. At low speeds, the effects of skin friction drag are small compared to the effects of pressure drag. You probably can find a number of different and promising concepts for your GDS by exploring the application of various combinations of the above factors. Don't be afraid to test your team's different concepts. Each member of your team should have a clear idea how your design answers these questions.