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How does the maximum coefficient of lift for an airfoil behave?
The angle at which maximum lift coefficient occurs is the stall angle of the airfoil, which is approximately 10 to 15 degrees on a typical airfoil. That is, the angle at which cl = 0 is negative. On such airfoils at zero angle of attack the pressures on the upper surface are lower than on the lower surface.
Why does coefficient of lift increase with Reynolds number?
The lift-to-drag ratio increases as Reynolds number increases for both the airfoils without and with GF. This drag penalty increases with Reynolds number. At higher lift coefficients, the lift-to-drag ratio increased. Hence the lift coefficient increases for a given lift-to-drag ratio.
How does the lift of an airfoil change?
We know how the flight stuff changes : Lift (flight) = constant x density x velocity squared The geometric stuff (thickness and camber) will not change when we change flight conditions–it will still be the same shaped airfoil regardless of altitude or speed.
How does the lift coefficient change with altitude?
The geometric stuff (thickness and camber) will not change when we change flight conditions–it will still be the same shaped airfoil regardless of altitude or speed. So let’s combine the geometric stuff and the angle of attack term into a new variable called the lift coefficient –> Cl. The original equation then looks like:
How does angle of attack affect airfoil thickness?
The geometric stuff (thickness and camber) will not change when we change flight conditions–it will still be the same shaped airfoil regardless of altitude or speed. So let’s combine the geometric stuff and the angle of attack term into a new variable called the lift coefficient –> Cl.
The thickness and camber are geometric properties of the airfoil cross-section, the area depends on the geometric chord and the span of the wing, the airspeed and density (altitude) depend on flight conditions, and the angle of attack sort of connects the airfoil geometry to the flight conditions.