# Center of pressure problem

1. Feb 12, 2006

### ranger1716

I have some intro aeronautical class homework problem that is giving me difficulty.

I need to find the center of pressure for the upper surface of an airfoil in terms of percent chord from the leading edge. I know that the chord lenth is 1m. The pressure from the top surface of the airfoil starting at the chord is 3N/m. The pressure from the bottom surface of the airfoil starting at the chord is 1N/m. There is no angle of attack and I do not know the velocity of the incoming air.

Do I need to use the equation Cp=Pt-P/1/2pv^2 ?

I can't understand how to use this equation in the context of this problem.

Any help pointing me in the right direction would be appreciated

2. Feb 12, 2006

### Staff: Mentor

3. Feb 12, 2006

### ranger1716

I've looked at methods similiar to what was on that page, however I don't think I have enough information from that problem to use this method.

Do I have to know the velocity of the incoming flow in order to determine the center of pressure? I have a sort of triangle made for determining the center of the triangle. However, I only know the length of one side-the base is 1m. I know the pressure acting on another side, but that's all.

4. Feb 13, 2006

### enigma

Staff Emeritus
Can you give the exact wording of the problem?

5. Feb 13, 2006

### ranger1716

"Find the center of pressure for the upper surface of the airfoil (in terms of %chord from the leading edge)."

I was trying to get the picture from the problem posted up here, but I haven't been able to so far.