Hi Sponge,
thanks for the pictures. It's nice to see different ways to do things. You do like your saw. Most of that could be done more easily by using a drawing knife and plane and carving down to the lines.
You had a problem with the line delimiting the thickness at the trailing edge. I think that's what you wanted to ask about in your post. A lot of people get puzzled by that. My latest plans have better diagrams of how to do this.
The line actually hits the edge/corner of the wood before it gets to the first (widest) station where the drop is largest. You should not bring the thickness line right in alongside the trailing edge line the way you have done because then the blade will be too thin.
When the guide line hits the corner of the wood, run it across the back of the wood after that until it meets the pencil line on the other side at the other corner at a point near the root. Then when you are carving, keep the back face parallel to the front face so the thickness is constant at any station.
The pencil lines are just to guide you. Check the thickness with calipers as you carve it down. In the end all that matters is that the blade should be the right thickness at a certain point about 30% of the width back from the leading edge. And it also matters that the back face is parallel at that point. All the rest of the back will be curved away later so it doesn't matter if that is not the right thickness and smooth etcetera.
Try not to weaken the blade by sharp notches near the root. You need to ramp it up to full section rectangular shape smoothly in a triangular ramp when the aerodynamic part runs out at the root.
I hope this helps.
