Chapter 4 - Aerodynamic Force Flashcards
What is form/finesse drag
Pressure differential between the two stagnation points
What is the difference between a symmetrical and Biconvex aerofoil
Symmetrical is only same upper and lower
Biconvex is the same forward, back, upper and lower
What happens at the stagnation point
no dynamic pressure as the air is brought to a complete stop. only static pressure.
How do we get total reaction
using lift vector (perpendicular to airflow) and drag vector (parallel to the RAF)
Where does the total reaction point originate from
Centre of pressure
What is the camber
the distance between chord line and the mean camber line
What is the Chord/Fineness ratio
Chord divided by max thickness = %
How do we get AOA in 2D
RAF and Chord Line
How do we create an unbalanced force
By producing an static pressure differential above and below an aerofoil
What are key parts to creating an unbalanced force on an aerofoil
Rounded LE
Sharp TE
Curved shape
Low AOA
What causes the static pressure to be lower on top of the wing?
The bend in the aerofoil causes an acceleration which in turn raises q and reduces Static px
What does viscosity do to the air over an aerofoil
Slow it down because of the air molecules having to pass the ones already there
What do we call where the volume of air that has been slowed compared to the free streaming air because of viscosity?
Boundary layer
Where does skin friction occur?
Within the boundary layer
Viscosity causes what behind the aerofoil
wake
