Having produced something that looks aviation related, after cutting a million small, nondescript parts, I feel like I am really building an airplane.
This first rib went together pretty much as expected. I had originally thought I would hold the gussets in place while the glue dried with staples. That did not work out well. Probably because I used birch plywood for my gussets instead of the more usual mahogany. The birch is much harder.
I noticed, wandering the Photos section of the Wagbuilders Yahoo Group, somebody used large bolts placed head down on the gussets as weights. I happened to have a bag full of big bolts (no recollection of where they came from), so gave that method a try. It worked fine in the test runs, so that is the method I used in building this rib. I am pretty sure I will continue this method through the rest of the ribs.
Building the ribs is a fussy job. Some of the EAA information recommends just cutting all the capstrip square and butting it up, counting on the gussets to make the full joint. The plans I am working from show each piece mitered into the adjoining pieces. Mine are all mitered in. It takes some time to get each piece just right, but I am proud of the result, even though you can't see it.
I had originally planned to do most of the fine cutting with an Exacto razor saw. But I found the grain in the spruce to be too open when trying to crosscut. So I unearthed a small table saw (Harbor Freight) that I use in my model building for the rough cuts and do the final trimming with the disk sander. One of the EAA tips is to make a single pencil line where something needs trimming and then just sand the pencil line off, no more. Works great.
There is also some final trimming of some of the gussets, primarily around the spar openings, that needed to be done. That trimming was done on the band saw.
So far I am very pleased with the Titebond III glue. My test joints passed the "break test" with flying colors. The glue joints are way stronger than the wood. One nice attribute is the quick and firm inital grab. Titebond does not tout this feature, but the initial grip is pretty firm. The glue also dries to handling strength in about 30 minutes. I wouldn't put a lot of strain on a 30-minute joint, but it will allow me to flip the rib over and go to work on the obverse side gussets in a reasonable time. I apply the glue with a glue syringe, available from MicroMark. The syringe gives much better control over the amount of glue applied than trying to squirt it from the bottle.
I should be able to complete one rib in an evening and two, maybe even three, when I have full Saturdays available. Today is a slow day because I am not feeling well.
I am labeling each rib and marking them off on the plans to be sure I get everything done and to help me keep track of what I am doing and what needs my attention next. Completed ribs will be stored in my hangar. One of the challenges of a project this large in a single car garage is storage space, or, rather, the lack thereof. This rib is marked "R2", meaning the #2 rib in the right wing.
Why did I start with the #2 rib? Because the #2 is really the only "typical" rib (I know, that sounds strange). The #1 rib is plated on the inboard side with 1/16" ply for its entire length. The #3 rib is plated on the outboard side from the trailing edge to the rear spar. Ribs #4-#9 are "aileron ribs, meaning they end at the aileron well. Rib #10 is plated on the inboard side from the trailing edge to the rear spar. Rib #11 is the "Tip Rib" and is slightly different than all the others. I will need to modify my jig to do the two (left and right) tip ribs.
I like wing ribs. They are pretty (particularly in wood, aluminum not so much) and are an interesting study in basic structural engineering.
I think Holly would be proud.
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