You can do something similar working from the top view. Using the top view you can place your ribs anywhere, and get accurate dimensions for them by bringing down construction lines. You may want to reposition a rib for a servo box or some such. You can see this in my first and second pictures. The rib center lines are drawn on the 'top' view, and then construction lines are brought down to scale the ribs onto.

For the rib, I exported a mh43 from profili as dxf. Imported it into my drawing. Now I can use that template to make all of my ribs, without having to redraw anything. The align tool is great for this sort of work. It lets you move and scale a part of your drawing at the same time.

In picture 4 I have selected my airfoil, and started the align command.

In picture 5 I pick the first source point. I want the leading edge and the trailing edge to be aligned to the horizontal line I have drawn, so for my first source point I pick the very point on the leading edge of my airfoil.

In picture 6 I pick the destination point. At the end of the command, align will move the source points to the destination points if it can. In this example, I want the destination to be a tthe very front of the horizontal line I have drawn.

In picture 7 it asks for another source point, so I pick the trailing edge.

Picture 8 wants another destination, so I pick the end of my line.

Now, it will ask for more source points. There is no need for more here, and I have rarely needed to use 3 or more. So just hit enter.

Then align will ask if you want to scale you objects. Hit yes here, this will scale your airfoil to touch both destination points. And now you have a prefectly scaled airfoil. Just repeat this process for the rest.

You can see, if you pick destination points that arn't horizontal, align will rotate your object so that your source points will go thru the destination points, or as best it can fit.

Hope I havn't stepped on anyones toes.

Notice that none of these techniques require CAD to use. Its just basic drafting. I would recommend anyone wanting to learn cad, if you don't want to take any CAD courses, at least take a drafting or descriptive geometry course. You can do the exact same process on a drafting table and the use of a photocopier to scale your airfoil sections.