Wing Building: Roger is at it again - How he makes aluminum ribs.

Well Roger did it again. He went ahead and detailed how he built the aluminum ribs for his plane. The process seems very similar to how the hummelbird people do it, and given the success of that plane, that's nothing but a compliment.

I'll annotate the pictures he posted, but here's his letter to the group:

"I'm back by request of one or two interested people on how I made my wing ribs. I posted a few photos again on cheapaircraft2 - Rogers (Kenneth formally Jims)photos.

It really is easy to make them this way. They are attached with rivits. That part goes fast. I put a wide cap strip on either end. To cut them out, You lock the piece up between the forms with bolts, The thin one on top to hold it down tight and the thick one on the bottom to guide the router. You need to make sure the bolt head on the top is flush or below the surface of the jig so the router can pass over it without dragging. I used toilet flange bolts because they have a flat head.

For the holes, you simply plunge the bit through the middle of the hole some where and cut it out fast and easy. Then cut around the outside. In less than a minute it is done. It takes more time to put it in the form than to cut it by far.

Next you lock it in the bending form and tap it over with a mallet. remember to make half each direction. The outside ribs do not have the lighting holes cut out. When you take them out of the form they will bend because of the curve of the air foil. You will have to flute them about every 2 inches to straighten them. I made a fluting tool out of a pair of vice gripes with a rod welded in the middle of one jaw and two on the outsides of the other by passing outside of the other to bend the aluminum to a controlled amount by adjusting the vice gripe closing screw. You then have to flange the holes to stiffen them. that is also quick with the home made flangers. With that you are finished. If your bit is sharp and cutting well which is normally not a problem, you will not even need to deburr the edges.

I made the aileron ribs the same way. It was quick and easy also. If this doesn't make sense shoot me a message and I will try to explain it better.

Warning, do not try to cut more that one at a time or you will have that many pieces welded together. I speak from experience.
Good luck and keep building. Roger."

How about lets follow along in pictures. First, he made his ribs from aluminum flashing from the hardware store. It typically comes in a 2' by 50' roll.

Step one is to make some cutting guides. You should make four without holes in them for the end ribs.

You can see the bolt holes in them, that you use for locking the aluminum in between the cutting guides. After you cut out each rib, you'll then need to fold the edges over. This provides a wide attachment point for the fabric, and prevents a sharp aluminum edge from slicing open your wing from the inside. These forms get banged on quite heavily, so they're made of much thicker material than the cutting guides. You'll want to make sure you make "left" and "right" sided ones. Which you decide is which doesn't matter, so long as you mirror the left and right sides.

Now the bit you folded over is longer than the outer surface of the airfoil. Which means you now have a pleasantly pringle shaped rib. On some planes they have cuts in the flange to do this, But seeing how those lead to more sharp edges I think the following method is better.

To straighten them out, you'll need to crimp, or flute, the flange you folded over. The flutes will take up the excess metal, without leaving sharp edges. An easy way to make a fluting tool, is to weld two pieces of welding wire to the top jaw of a pair of vice grips, then weld a single wire to the bottom jaw. It will take you a few attempts, but you should be able to figure out a pattern which leaves you with a very, very straight rib.

Also to improve the stiffness of the ribs, the cutout holes should also be flanged. That's best done using some blocks of wood that have been routed out. These are then pressed together over the opening in the ribs. Here's a couple pictures of the tooling that Roger made:

And here's a grandkid using the tooling:

Isn't it nice to call it tooling? It sounds so professional.

He also used the same techniques to build his ailerons.

Not bad eh?