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The lift coefficient C L is defined by [2] [3] = =, where is the lift force, is the relevant surface area and is the fluid dynamic pressure, in turn linked to the fluid density, and to the flow speed.
Lift is proportional to the density of the air and approximately proportional to the square of the flow speed. Lift also depends on the size of the wing, being generally proportional to the wing's area projected in the lift direction. In calculations it is convenient to quantify lift in terms of a lift coefficient based on these factors.
For small angle of attack starting flow, the vortex sheet follows a planar path, and the curve of the lift coefficient as function of time is given by the Wagner function. [9] In this case the initial lift is one half of the final lift given by the Kutta–Joukowski formula. [10]
Lifting line theory supposes wings that are long and thin with negligible fuselage, akin to a thin bar (the eponymous "lifting line") of span 2s driven through the fluid. . From the Kutta–Joukowski theorem, the lift L(y) on a 2-dimensional segment of the wing at distance y from the fuselage is proportional to the circulation Γ(y) about the bar a
The coefficient of lift for a two-dimensional airfoil section with strictly horizontal surfaces can be calculated from the coefficient of pressure distribution by integration, or calculating the area between the lines on the distribution. This expression is not suitable for direct numeric integration using the panel method of lift approximation ...
The aerodynamic center is the point at which the pitching moment coefficient for the airfoil does not vary with lift coefficient (i.e. angle of attack), making analysis simpler. [ 1 ] d C m d C L = 0 {\displaystyle {dC_{m} \over dC_{L}}=0} where C L {\displaystyle C_{L}} is the aircraft lift coefficient .
The lift force L on a wing of area A, traveling at true airspeed v is given by =, where ρ is the density of air, and C L is the lift coefficient. The lift coefficient is a dimensionless number that depends on the wing cross-sectional profile and the angle of attack. [12] At steady flight, neither climbing nor diving, the lift force and the ...
Platform angle of attack Coefficients of drag and lift versus angle of attack. Stall speed corresponds to the angle of attack at the maximum coefficient of lift (C LMAX) A typical lift coefficient curve for an airfoil at a given airspeed. The lift coefficient of a fixed-wing aircraft varies with angle of attack. Increasing angle of attack is ...