The rivet backing washer idea worked out nicely. I ended up not coming up with any slick way to cut the slot in the thin plywood rib plate. Just drilled three holes in a row and shaved out the slot with a knife. The next task after mounting all the ribs was to install the internal diagonal strut which requires you to hold it in place over the #2 rib and "eyeball" the location of the hole you need to cut through the center of the foam in that rib. I tried but didn't get close enough and had to elongate the first attempt to get the strut to fit through. This strut was also raw stock so had to be wet sanded with 400 grit and treated (oxidized) with chromic acid solution same as the new LE and TE sections.
Had to fabricate a missing gusset for the internal diagonal strut (thanks Ron Enck!). Don't recall what alloy we ended up using but it wasn't 6061. I am certain it will be plenty tough for the job at this joint, it took quite a bit to form it around the TE using a broom handle as a mandrel.
I set the LE gusset and put a few rivets in to hold it at the set distance from the end of the LE at the root called for in the plans but let the TE position float a bit inboard of the set dimension indicated in the plans because it would have required me to file out the end of the strut significantly to fit at the spec dimension.
I can't rivet the other side yet since the wing is mounted to the floor frame. Recheck that all the rivets on the top side of the wing are in and then remove the wing panel from the frame and flip it, laying it right back down on the frame with the LE tip section now up on the 2 1/2" block. It should lay nicely on the frame with the ribs off the floor.
I show the wing flipped here as I begin to complete the rivet installation on the bottom of the wing. I have place one of the new aluminum stamped ribs next to the old, original wood/foam ribs to show the difference. Just for fun, I weighed them prior to install. The aluminum rib came in at 132g and the wood rib weighed 88g. For 7 ribs per upper wing panel, that's 308g's more for those fancy aluminum ribs which I really doubt are any stronger than the wood/foam ones I'm using. There are 26 ribs in the glider so that's over 2.5 lbs additional weight for those aluminum ribs. I'm sure the reason they started using them was to offer a significant time saving in construction. Myself, I will do whatever I can to keep the weight down. Looking back at original Easy Riser glider specs, says the glider alone should weigh in at only 50lbs (that's using dope to treat the 1.4oz Dacron cloth). A 50lb glider is good, especially when I think about being able to only have to carry one side at a time over to where I will set up (that's 25lbs). The idea here is to be able to still be doing this when I'm 80+.....I think it's realistic. I am now looking to find a source for the foam they used in the event I ever need to fabricate new ribs. Attended my first local chapter meeting of the EAA (Experimental Aircraft Association) and within an hour after getting back home, had successfully joined the national association and sent in my check for the local chapter dues. What a gold mine of resources!
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