Is the force which opposes to the thrust. D The drag acts always parallel to the relative wind and opposite to the flight path It is caused by the airplane's movement , and its direction will be always opposite to itself. The Total Drag (TD), application’s point is the Aerodynamic Center. Aerodynamic Center: Imaginary point where all the axis meet. 100% of Drag 80% of Drag 60% of Drag 50% of Drag 30% of Drag 10% of Drag Magnus Effect Let's suppose there is a cylinder immersed on a fluid and it turns around on its own axis. The gyratory movement of the cylinder will cause, for rubbing, a circular movement of the fluid which is pulled on the same direction of the cylinder. Boundary Layer Is a thin layer of air next to the surface of an airfoil ( zero speed) which shows a reduction in speed due to the air’s viscosity or stickiness until reach the 99% o the air’s free speed. Boundary Layer Inversion Point Detaching Point RELATIVE WIND Types of Drags Total Drag D Parasite Dp Wing's Parasite (Airfoil) Induced Di Airplane’s Parasite (structural) Friction Friction Form Form Interference Total Drag: Is the adding of all of the Drags. DT = DP + DI Parasite Drag: Is caused by any interference between the aircraft's area and any free air stream. Briefly, is caused by any element that does not produces lift. Parasite Drag of the Wing or Airfoil. Is caused by the leading edge “effort” when facing up the air particles. Structural Parasite Drag: Is caused by the entire airplane's structure (with exception of the wings) when facing up air particles. Interference Drag: Occurs when varied currents of air over an airplane meet and interact. Friction Drag Is caused by the roughness of the airplane's surfaces. Even though these surfaces may appear smooth, under a microscope they may be quite rough. Resistencia por Forma Se origina por la forma de cualquier elemento del avión y se puede disminuir carenando o fuselando dichos elementos. Induced Drag. Is generated by the airflow circulation around the wing as it creates lift. The high pressure air beneath the wing joins the low pressure air above the wing at the trailing edge and wingtips. Reducing drag Devices They are aerodynamic devices that face up the free air stream, and its aim is to imprint energy to the boundary layer, retarding the separation point and decreasing drag. Vortex Generators Wing Fence Dog Tooth Trailing Edge Vortex Generators Carenas NACA Air Entries Fuselage Vortex Generators Wing Lets Wing Tip Tanks
