Commercial Pilot Operations- Aerodynamics & Principles of Flight 100% Correct

Commercial Pilot Operations- Aerodynamics & Principles of Flight 100% Correct 4 forces of flight Lift, Weight, Thrust & Drag. Accelerated flight Thrust exceeds Drag. Decelerated flight Drag exceeds Thrust. Lift Provides the upward which sustains the aircraft in flight. It is perpendicular to the relative wind. Lift Equation Coefficient of Lift * Wing Area * Air Density/2 * Velocity Four ways to control lift - Change the shape of the airfoil. - Increase airspeed. - Change the angle of attack. - Change the area of the wing. Wing types -Elliptical wing. -Tapered wing. - Swiped back wing. - Rectangular wing. Elliptical Wing - Most efficient design. - Low induced drag. - Little stall warning. Rectangular Wing - Poor performance. - Good stall characteristic and training. Sweep Back Wing - Very good high speed performance. - Good lateral stability. Tapered Wing - Most expensive to construct. - Lighter. Effects of High Aspect Ratio - Decreased induced drag. - Good gliding distance. - Less maneuverable. -Efficient cruise. Effects of Low Aspect Ratio - Greatest lift at high Angle of Attack. - Poor cruise. - Maneuverable Flaps Increase the camber of the wing. Increased wing area and increased coefficient of lift. Flap use - Become airborne sooner. - Minimize ground roll. - Steeper descent without increasing airspeed. Leading Edge Devices Slots, slats and leading edge flaps. Greatest Coefficient of Lift Critical Angle of Attack Stall An airfoil stalls once the critical angle of attack is exceeded. When an airfoil stalls, airflow over the wing becomes turbulent and separates from the wing. At that point, there is not sufficient lift being produced which leads to a loss of altitude. Vortex Generators Often placed on lifting surfaces to energize the boundary layer and prevent airflow separation. Drag The force opposing thrust and parallel to the relative wind. Parasite Drag Results of aircraft interference with smooth flow of air about the aircraft. Types of Parasite Drag 1- Skin Friction. Ex: Dirt, and rivets. 2- Form Drag. Ex: Shape of aircraft. 3- Interference Drag. Ex: Attachment points, struts, etc. Induced Drag A byproduct of lift. High pressure below trying to reach the low pressure above creates wing tip vortices disrupting lift. Devices contributing drag Spoilers and speed brakes. Spoilers - Rapid descent without reducing power, engine stays warm. - Maintain normal descent speed. - Help slow to landing gear extension speed. - Descent rapidly through icing. - Stay at high altitudes longer. Weight Force resulting from gravity and acts directly towards the center of the Earth at all times. It also acts at the aircraft center of gravity. Ground Effect When the airplane is flying within a distance equal or less than its wingspan, induced drag is decreased. Aircraft Stability The characteristic of an airplane in flight that causes it to return to a condition of equilibrium, or steady flight, after it is disturbed. Static Stability Immediate initial tendency of an aircraft when displaced. Dynamic Stability The tendency of an aircraft over time (oscillations). Positive Static Stability The initial tendency of an aircraft to return to its original position. Positive Dynamic Stability The tendency of an oscillating airplane (with positive static stability) to return to its original position relative to time. Neutral Dynamic Stability The overall tendency of the airplane to attempt to return to its original attitude, but the oscillations do not increase or decrease in magnitude as time passes. Neutral Static Stability The initial tendency of the airplane to remain in a new condition after its equilibrium has been disturbed. Negative Dynamic Stability Oscillations increase in amplitude with time following a displacement. Negative Static Stability The initial tendency of the airplane to continue away from the original equilibrium (attitude) after being disturbed. Longitudinal Stability Stability of the longitudinal axis around the lateral (pitch). Depends on the CG location. Lateral Stability Stability of the lateral axis around the longitudinal axis (roll). Design characteristics: Dihedral and Sweep Back. Directional Stability The stability of the longitudinal axis around the vertical axis (yaw). Keel Effect The flat surfaces located behind the center of gravity tend to weather-vane with the wind. Related with directional stability. Factors Affecting Stall Speed - Flaps - Power/Thrust - Frost/Snow/Ice -Turbulence Spin A spin is an uncoordinated stall. The aircraft rotates around the aircraft's center of gravity. Maneuvering Speed It's the speed above which full or abrupt control movements in one axis can result in structural damage to the aircraft.