[mazhar16823]

Hi,



I have noticed that most of the airfoil coordinates borrowed from online websites or from the companies they always miss some x,y coordinates along the trailing edge and eventually one needs to create an additional part to fill up the trailing edge. Why is that so?

[aero_head]

Originally Posted by mazhar16823

Hi,



I have noticed that most of the airfoil coordinates borrowed from online websites or from the companies they always miss some x,y coordinates along the trailing edge

Hello,

Could you provide an image to clarify your question?

[aerosayan]

Originally Posted by mazhar16823

Hi,



I have noticed that most of the airfoil coordinates borrowed from online websites or from the companies they always miss some x,y coordinates along the trailing edge and eventually one needs to create an additional part to fill up the trailing edge. Why is that so?

Do you mean, when the curve starts at the trailing edge, then doesn't end at the exact same point, and there is a gap between the first point and the last point? In such cases there will be a gap at the trailing edge.



That is actually an option given by airfoil databases. Some users don't want the last point in the list to be a duplicate of the first point in the list. If you're writing a CFD solver, you don't want a duplicate point.


That's one reason.


Another more advanced reason is that the CFD engineers actually like to decide how they will close the gap at the trailng edge. Engineers will most probably decide to either fill up the gap using a straight line, or they'll use a semi circle/arc.