It will use all of the digits. The spline approximation is very weird. Turn on curvature combs to see the crazy wiggles. Airfoils are sensitive to curvature and rate of change of curvature. I get the best results using le, te and two or three points in between. Then draw a spline that snaps to these points and adjust curvature combs manually. Alternatively you can use geometric formula for NACA four digit airfoils.
Adjust your decimal settings to five or six places in "document properties" for the file containing the curve. The "curve file" dialog displays the coordinates according to this setting.
Also, I have imported this same data file and the trailing edge of the foil is open as reflected in the first line"Y" (0.001260 ) point for the upper surface and the last line "Y" (-0.001260 ) point for the lower surface. Select the "close trailing edge" check box for the adjusted data points.
Steven Trvalik wrote:
...The problem with this is that the majority of the points for the airfoil are only different from the thousandths place on.
What is the precision of your manufacturing system?
Just because you (or your computer) can calculate out to x number of digits - doesn't make them significant.