Devin W.C. Ryan

Building Aero 3D Day 21: Ribs Glued & Scarf Joints

Today started by reinforcing the scarf joints, seen in the featured image above, using gussets which in this case is made out of wood (filler I believe). The pieces are cut to the width of the sides they are going on (1/4” in this case) and a length that goes a bit past the scarf joint on each end. You can see the glued pieces, using medium CA in the featured image above. In the image at the bottom you can see where weights were left on the spars to keep them flat.

Once that was done we moved on to the wing. Using the big ruler to help keep a straight edge we propped up the trailing edge along it… we started with the ruler at the end closest to us in the picture below (right) and pinned some blocks to support it from the other side.

Starting with the outter rib (W3) on the right we placed the tail end in the slot and the front on the main spar. This gave us the starting point for where the main spar would have to be, so we pinned it into place.

Using a bigger square, placing the bottom along the side of main spar, and the other side of the square along the rib we ensured the rib was perpendicular to the main spar and trailing edge. I then used a smaller square to make sure it was square veritcally as well. Using a pencil I then marked where the rib sat on the main spar. It was at this point I placed a pin between the current and next rib.

Working my way towards the left end of the wing I followed the same procedure for each rib. Where there are two ribs close together they are W2’s and all the others are W1’s. Between the W2’s is where the aileron servos will be placed.

Once that was done I used medium CA to glue each rib into place. Putting glue on the little slot within the trailing edge as well as along the top and two sides of the main spar between my pencil marks. Then quickly placed the rib and held for a few seconds while the glue dried.

Ribs Glued
Ribs Glued

This process wasn’t flawless as due to the fast setting CA glue there were two occurances where we had to cut a rib out because of a mistake. Using CA is allowing us to speed up the process of building the wing; as we’d only be able to do one (maybe two) at a session otherwise. Peter ensured me the wing will be just as capable and that builders have been doing this “forever”. 🙂

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