Whats the best way of copying the rib outline from plans to the wood ? Can you make photo copy of rib from plan and turn upside down on wood and use iron to transf ink to wood or is there an easier way of doing it

Another method
Take photo copies of all your ribs from the plans, go to one of the large copying
stores they use the "good" ink, once you have the copied rib shapes , place
copies "upside" down on your balsa blanks and "rub" along the outlines with
MEK solvent, you then get a perfect print outline on each of your balsa blanks.

*ps while we are on the "ribs" topic I'm still searching for that "ultimate"
rib "sandwich" method, in which the final result is a perfect stack of tapered
ribs

I have an old slide viewer or re-viewer that has a light under the surface.  I lay the plans on it with a piece of paper and trace it onto the paper.  I have also taken plans to Kinkos or some copy place and had copies made to could cut them up.  DOC Holliday

I have heard  that if you place the face of the plan on the wood(face down) and heat the plan with an iron (temp unknown) the ink will transfer to the wood.
I was also told that in most cases it will only work once.
I never have tried this so it would be interesting to find out if it really works.

I use SeeTemp (See Through Template material).
It's a thin red plastic that my LHS sells. Tom Morris also sells it.  You might be able to pick some up at an art supply store.
You simply place it directly on top of the plan and then score the outline of the rib with your Exacto knife.  Then bend the SeeTemp on the score line and the rib template will pop out.  You then have a perfect template to use over and over again.  Great stuff!