Aerodynamics Flashcards
What is an Aero Foil.
A aero foil is a structure designed to generate lift from the passing airflow
What is the Chord Line.
Imaginary straight line joining the leading and trailing edge.
What is the Mean Camber Line.
Line at equal distances from the upper and lower surface.
What is the Camber.
Distance between the Chord Line and Mean Camber Line
What is the Angle of Incidence.
Angle between the chord line and longitudinal axis of the aero plane.
What is the Angle of Attack.
Angle between the chord line and the relative airflow.
What is the Wingspan.
Distance from wing tip to wing tip.
What is the Wing Taper.
Wing that has a smaller chord line at the tip than at the root.
What is the Sweepback.
The wing tip is behind the wing root.
What is the Mean Aerodynamic Chord.
Chord of an imaginary rectangular wing, used to do calculations for aircraft performance.
What is the Aspect Ratio.
Ratio of the wing span to the chord = Span2 / Area.
What is the Wing Dihedral.
Wing tips are higher than wing roots, assists lateral stability of the aero plane.
What is the Wing Anhedral.
Wing tips are lower than wing roots.
What is the Wash-out.
Wings are twisted so that the Angle of Incidence at the tip is less than at the wing root.
What is the top of the aero foil called.
Upper Surface.
What is the bottom of the aero foil called.
Lower Surface.
What is the front of the aero foil called.
Leading Edge.
What is the back of the aero foil called.
Trailing Edge.
What is the Wing Root.
The base of the wing.
What is the Wing Tip.
The tip of the wing.
How do you calculate Wing Area.
Span X Chord.
How to calculate Wing Loading.
Weight/Wind Area.
How to calculate Aspect Ratio.
Span/Chord.
What direction does Relative Airflow go in relation to the plane.
Backwards.
What direction does Flight Path go in relation to the plane.
Forward.
What three things does the size of the Total Reaction depend on.
Airspeed.
Size.
Angle.
What is the Centre of Pressure.
The position at which the average resultant force acts.
This is the point about which all of the pressures are evenly distributed
It is NOT a fixed point
It changes position as the pressure distribution changes in response to changes in AoA.
What are four factors that affect lift.
Airspeed.
Size.
Angle.
Camber.
How do you calculate Angle of Attack.
The AOA is measured by using the pressure difference between the two orifices. The magnitude of the pressure difference depends on the shape of the nose of the tube and the angular position of the orifices.
How do yo calculate Lift.
Lift = Coefficient of Lift(CL) X 1/2 Air Density(P) X Velocity of Aircraft(V)^2 X Surface area of the wing(S).
How do you calculate Drag.
Drag = Thrust = Coefficient of Drag(CD) X 1/2 Air Density(P) X Velocity of Aircraft^2 X Surface area of the wing(S).
How does drag move compared with relative airflow.
In parallels.
How many categories of drag are there and how many types of drag are there.
2 Categories.
4 Types.
What drag increases as Angle of Attack Increases.
Induced drag.
What drag increases as airspeed increases.
Parasite drag.
What drag increases as airspeed deacreases.
Induced drag.
How do winglets work.
Winglets increase an aircraft’s operating efficiency by reducing what is called induced drag at the tips of the wings. An aircraft’s wing is shaped to generate negative pressure on the upper surface and positive pressure on the lower surface as the aircraft moves forward.
How do winglets work in relation to Bernoulli’s principle.
In general, the wing’s upper surface is curved so that the air rushing over the top of the wing speeds up and stretches out, which decreases the air pressure above the wing. In contrast, the air flowing below the wing moves in a straighter line, thus its speed and pressure remain about the same.
What does positive dynamic stability mean for an aircraft.
Positive dynamic stability is the tendency of an aircraft to dampen toward original position once disturbed.
What are the 2 categories of drag.
Induced drag.
Parasitic drag.
What are the 4 main types of drag.
Induced drag.
Skin friction drag.
Form drag.
Interference drag.
What is induced drag.
Induced drag is affected by lift more accuratly the angle of attack.
What is Skin friction drag.
Results from frictional forces existing between an object and the air through which it is moving.
What is Form drag.
Caused when airflow separates from the surface, forming eddies which disturb the streamline flow
What is Interference drag.
Caused by mixing or “interference” of converging airflow at the junctions of various surfaces (wings to fuselage)
