AEROFORUM

                                                                       Form Drag Form drag is experienced in the surface of the aircraft when the streamlined airflow separates and becomes turbulent. To experiment form drag keep a flat plate on the streamlined airflow, now the pressure before the plate is atmospheric and the pressure after it is below the atmospheric which results in sucking effect behind the plate and vortices are formed. It is mandatory to delay the separation point of airflow and this is achieved by altering the shape or streamline of the given object. When the airflow changes its direction rapidly form drag experienced is higher. A fairing is fitted around the fixed undercarriage leg to reduce form drag to considerable extent. The resultant form drag depends on the length and maximum thickness of the streamlined object. The ratio of length to maximum thickness is called the fitness ratio. Fitness ratio = a/b At subsonic speeds fitness ratio of streamlined shapes is

                                                                                                    Drag When an aircraft or any other body moves in atmosphere it experiences air resistance which retards its forward motion. This force is called drag. Drag occurs when an aircraft or any other object moves in air and it depends on the shape of the flying object.   Aircrafts and other flying objects are designed in such a manner to reduce the drag, which increases the efficiency of the aircraft. Drag is experienced parallel to relative airflow. Drag is directly balanced by thrust produced by a propeller or an engine. Amount of thrust required to balance the drag depends of amount of drag, more thrust is required to balance a greater drag force produced. If the drag produced by an aircraft is low then the aircraft consumes less fuel and operating costs are also low. The total drag acting on an aircraft includes Profile drag                                         Induced drag Inter