Theory of Flight Complete Solutions Graded A+

Relative airflow - ANSWER This is the airflow that approaches the wing directly opposite the wing's direction of motion. Angle of Incidence - ANSWER This is the angle at which the wing is mounted to the fuselage. It is measured between the chord line and the aircraft's longitudinal axis or horizontal datum line. With the right angle of incidence (most planes have a + angle of incidence) we can improve flight visibility, enhance takeoff and landing characteristics, and reduce drag in level flight. Pressure distribution around an airfoil - ANSWER The pressure along the surface of an airfoil is not constant. Once could measure the different pressures at point all over an airfoil section. The center of pressure is the "average" of all these pressures. It is the point through which the aerodynamic force exerts itself. Stalling - ANSWER That angle of attack at which any further increase in that angle of attack will result in a decrease in lift. (15-18 degrees). A stalling wing is still generating lift. However the lift that the wing generates is not enough to overcome the weight. An aircraft wing will always stall at the same angle of attack which is determined by the design of the wing. A wing can stall at any airspeed, weight, C of G location, etc. Stagnation point - ANSWER a point where the relative airflow hits the wing and then some wind diverges over the top of the wing and the rest underneath the wing. This small point is called the stagnation point. The build up of wind at this point also results in an increase of lift. There can also be a stagnation point towards the back of the wing. Center of pressure rules - ANSWER 1) As I increase my angle of attach, the center of pressure moves forward. 2) As the aircraft stalls, the center of pressure moves backwards. Change in pressure distribution - ANSWER As the angle of attack increases, the pressure distribution changes and center of pressure moves forward. When a wing stalls the center of pressure moves rearward. Wake turbulence - ANSWER Wake turbulence is produced by the air moving over the wing or airfoil. Aircraft encountering a vortex will tend to roll with it. Wing tip vortices are greatest while developing lift. The vertical guests encountered when crossing through a vortex can impose structural loads as high as 10 G's. Vortices - ANSWER When seen from behind the aircraft, the left wing tip vortex turns clockwise and the right wing tip vortex turns counterclockwise. Both travel downwards and are partly responsible for induced drag. The heavier and slower the plane the greater the vortex. Clean airplane - ANSWER Means that the airplane doesn't not have anything on it that disrupts vortices, such as landing gears. Wake turbulence avoidance - ANSWER On takeoff stay upwind and plan to be airborne before the rotation point of the previous taking off airplane and beyond the touchdown point of the previous landing airplane. When landing plan to touch down before the rotation point of the taking off aircraft and after the touchdown point of the previous landing airplane. Ground effect - ANSWER When an aircraft is flown low to the ground the formation of wingtip vortices is reduced, thus induced drag is reduced. The closer an airfoil is to the ground the greater the performance gained from ground effect. The downwash is also defected more parallel to the surface. If a plane is too heavy, the pilot might not be able to pull it out of ground effect and stall. In short, the vertices hitting the ground create a tiny amount of lift. 4 main forces of flight - ANSWER Thrust, Drag, Lift and Weight. Chord line - ANSWER An imaginary straight line drawn through the airfoil from the leading edge to the trailing edge. Lift - ANSWER Force upward which sustains the airplane in flight. Is the component of aerodynamic forces that is perpendicular to the relative airflow. According to Newton, the downwash is what creates lift. Is when there is a pressure difference between the lower and upper surfaces. Has a vertical and horizontal component. Acts through the center of pressure. Is created by Bernoulli, Newtons, Euler and Navier strokes theories