Variable
|
Description
|
Explanation
|
Angle of attack
|
A straight line at less than a
45o angle through 0,0. The lift and angle show +
and - numbers.
|
The straight line shows a steady
increase. If you double the angle, then you double the
lift.
|
Thickness of airfoil
|
A slight upward
curve.
|
The curve shows that as the
thickness increases the lift also increases, but to a lesser
degree.
|
|
At angle = 0.0, there is no line on the
graph.
|
For a symmetric airfoil, a change in thickness
will not change the lift.
|
Camber
|
A straight line at less than a
45o angle through 0,0 with lift being both + and
-.
|
The straight line shows a steady
increase.
|
Airspeed
|
An upward curve where the slope
of the line increases with increased speed.
|
The upward curve shows that lift
increases at a greater rate than the speed
increases.
|
|
At angle = 0.0, there is no line.
|
For a symmetric airfoil, a change in airspeed
does not create lift.
|
Altitude (density)
|
A downward curving line where
the slope decreases with altitude.
|
As altitude increases the lift
that results decreases; but the decrease lessens with
altitude. ( As the altitude increases, the density of the
air decreases. So lift decreases as density
decreases.)
|
Area of airfoil surface
|
A straight line at a
45o angle through 0,0.
|
The lift increases at the same
rate as the area.
|