# When calculating lift, using the the NASA lift equation, can any value be increased, ie. velocity or surface area, for increased lift?

I am trying to understand the breakdown of the NASA lift formula, which is written as such

$$L = C_L \frac{\rho v^2}{2}A$$

If I take for example CL=0.87, v=20m/s, ρ=1.22kg/m3, and A=9.02m2, my equation looks like this so far: Lift = (1/2) * 0.87 * 1.22 * 20^2 * 9.02. Can any one of those values be increased for greater lift? If I doubled my velocity would I double the lift that the velocity provides? But if I added 25% to the surface area of the wing, my drag also increases. How does that factor into lift? By decreasing velocity?

Does this equation scale in that way? I apologize if it doesn't make sense, I am not sure how to word the question well.

Can any one of those values be increased for greater lift?

Certainly. But increased lift will not be the only effect.

If I doubled my velocity would I double the lift that the velocity provides? But if I added 25% to the surface area of the wing, my drag also increases. How does that factor into lift? By decreasing velocity?

It doesn't directly factor. The formula gives you the approximate lift given certain conditions. It doesn't tell you if those conditions are reasonable or achievable.

You're correct that increasing the wing area or speed will increase drag. But this equation doesn't tell you how much. You'd need to look elsewhere to find out the specifics. The drag increase will not be linear with either one.

• Thanks for your reply. I am trying to make sense of building a model of a cargo plane and need to redesign the wing a bit. My best option to increase lift overall would probably be increase wing surface area and velocity, even if drag increases as well? Also, do you know what it is called when things like air and water don't scale? – Derrick Dec 19 '18 at 19:05
• @Derrick You're looking for the Reynolds number with regard to scaling. If you're interested in designing a model aircraft that will fly, you should get an introductory textbook for aerodynamics. You can change any property of the wing, but it will have other effects besides just increasing lift. – zaen Dec 19 '18 at 21:25
• @zaen Thank you! I'll look into it. – Derrick Dec 19 '18 at 22:51