CPAER General Knowledge - Sharper Edge Questions with complete Solutions!!

Chord - Answer-Straight line joining leading edge to the trailing edge Camber line - Answer-Line which runs midway between upper and lower surfaces of the airfoil joint the trailing and leading edge. Camber - Answer-The measure of the curvature of the airfoil. Expressed as a percentage Angle of attack - Answer-The angle between the chord of the wing and the relative airflow Centre of pressure - Answer-Lift and drag act through the centre of pressure of the wing. The centre of pressure moves with a change in the angle of attack. Centre of gravity - Answer-The point through which the resultant of the weight of all of the components on the aircraft can be considered to act. The centre of ____ is ahead of the centre of _____. - Answer-Gravity, pressure. Axes of rotation - Answer-Three axes which rotate about the aircrafts centre of gravity Lateral axis associated with... - Answer-Pitch Longitudinal axis associated with... - Answer-Roll Vertical axis associated with.... - Answer-YawLift acts... - Answer-Perpendicular to relative airflow Weight acts... - Answer-Towards the centre of earth (gravity) Thrust acts... - Answer-Along the longitudinal axis in the direction of motion Drag acts... - Answer-Parallel to relative airflow Aspect ratio - Answer-The measure of the slenderness of a wing. The ratio of the wing span to the wing chord. Wings with a ___ aspect ratio are more efficient and aerodynamic. Why? - Answer-High because they produce less induced drag. Laminar flow wings - Answer-Keep the airflow laminar much further back along the wing reducing drag. Maximum thickness of the wing occurs much further back. Disadvantage of laminar flow wings? - Answer-Abrupt stall behaviour Substantial drag increase when contaminated. Angle of incidence - Answer-The angle between the chord of the wing and the longitudinal axis of the airplane. Dihedral - Answer-Angle which the wing makes wig the horizontal running from wingtip to fuselage. (Wings angled up)What kind of wing will produce more lift? - Answer-Cambered What kind of wing has a slower stall speed? - Answer-Cambered Lift equation - Answer-Lift = 1/2 p V2 s cL p = air density V = TAS S = size of the wing (surface area) cL = lift coefficient (shape of wing and angle of attack) Drag - Answer-The resistance of an airplane to moving through the air. Parasite drag - Answer-Cause by all parts of the aircraft not producing lift. Parasite drags 3 components - Answer-Form drag Interference drag Skin friction Form drag - Answer-(Shape drag) Results for the air moving over a particular shape. Interference drag - Answer-The additional drag which results when two or more objects are joined together (i.e fuselage and wings) Parasite drag depends on the following - Answer-Air density (greater), surface area, and velocity. Induced drag - Answer-The by-product of producing lift.Wing greats and equal and opposite force upwards and downwards, the downwash is known as induced drag. How does a wing create lift? - Answer-Creating a low pressure above the wing (air has to move faster above the wing) and a high pressure below the wing. (High moves toward the low creating lift. What kind of wings produce more induced drag? - Answer-Low aspect ratio wings. Induced drag is increased by... - Answer-Increase in aeroplane weight, decreasing air density, and increasing true airspeed. Lower air density requires a... - Answer-Higher angle of attack What reduces induced drag? - Answer-High aspect ratios and winglets. What type of drag is associated with high speeds? Low speeds? - Answer-Parasite drag at high speeds. Induced at low. When is drag the least? - Answer-Middle of the speed range. This is known as Vmd (minimum drag speed) Which type of drag changes with angle of attack? - Answer-Induced. Drag and an increase in altitude... - Answer-Induced drag increases. Parasite drag decreases. Drag and aircraft weight... - Answer-Induced drag increases.Parasite remains the same. Drag and speeds... - Answer-Induced is highest at low speed and lowest at high speeds. Parasite is lowest at low speeds and highest at high speeds, Ground effect - Answer-Induced drag is significantly reduced. Wing tip vortices are also greatly reduced. Ground effect will be greater on aircraft with... - Answer-Low wings and short landing gear. ____ acts through the centre of gravity and ____ acts through the centre of pressure. - Answer-Weight. Lift.