# What is area in equation of lift?Does it remain constant during flight? [duplicate]

I am beginner & learning aerodynamics concept. What is area in equation of lift(L) =Coffecient of lift x area x density x square of velocity/2. Does increase in angle of attack increases the area & thus increasing lift?

• This area is called a reference area, and for serving as a reference it is helpful that it doesn't change. Here and here are answers which you should find helpful. – Peter Kämpf Jun 1 at 11:07
• This really is two separate questions also. – Ryan Mortensen Jun 1 at 15:52

The área $$A$$ in lift equation $$L=\frac{1}{2} \rho AV^{2}C_{L}$$ is a reference area, so you can choose the one you prefer, but some election can be more apropiate than others depending on what you want to compute. For example if you are going to relate lift coefficient with drag one, the reference area should be the same, in this case a good selection will be the projected area in lift direction (aka planform area). It has the drawback that it depends on angle of attack/incidence since the true area is the same but lift vector changes. Another well selected area could be the true area (aka wetted) when working with drag, specially when friction drag is dominant considering that viscous stresses are proporcional to this area.