Re: CAD programs

Hi Robert,

I recently drew up the plans to a stick flyer that I will build this 
year. I used a free copy of Intellicad that I have had for many years.

I got the coordinates for the airfoil from the web, then set up a 
spreadsheet that added the horizontal and vertical position offsets to 
the airfoil coordinates.

I just plotted the final numbers directly into the drawing, starting at 
the leading edge (could have used the trailing edge just as easily) 
drawing a line from point to point. The precision was good enough and 
when I form the ribs by hand I will end up smoothing the minor 
variations as I sand.

For real accuracy (such as you might want for selling plans), break up 
the airfoil into smaller sections, then select that section and convert 
it to a spline, then reconnect it to the larger sections and you are 
done. Well, maybe a bit more complicated than that.

Most all medium to high end drafting programs will do this easily, even 
many low end programs will too.

Draw in full scale and plot in full scale.

Best of luck to you.

George