After some work on the house this morning (trim up in family room, prepping the powder room for paint), the girlfriend and I had lunch and then I spent the afternoon in the garage. I could have kept working on the house, but I really wanted to get the wing stands finished.
First thing, I reorganized the garage to make room for the wing stands. Then, I started gathering all of the necessary hardware. Yesterday, I went to the hardware store and started counting out individual pieces that I would need. I quickly realized that I could always use a good inventory of 1/4″ and 3/8″ nuts, bolts, and washers, so I bought the contractor packs.
After all was said and done, I hardly used any of these packs, but I'll have good inventory for the future.
I also bought two 4′ lengths of 1/8″ aluminum angle (2″x2″) as well as a 3′ pieces of 1/8″ aluminum angle (1.5″x1.5″). I did this because I’m going to have 4 main supports for the front spars (2″x2″ angle), some supports for the rear spars (2″x2″ angle), and some smaller angle (1.5″x1.5″) to make the truss system I’m going to use.
(Sidebar: The whole time I was working today I was replaying the mechanical engineering class I took in college about linkages. Read a quick one-page summary of the class at http://en.wikipedia.org/wiki/Linkage_(mechanical). Pretty interesting stuff.)
I know a lot of people have made a lot of different kinds of wing stands, but I saw Ethan’s and decided I wasn’t going to re-invent the wheel. It’s a good, adjustable system. You can find a couple pictures of his stands here and here.
Okay, let’s start making some aluminum shavings…
My 4 main supports, and my 8 small brackets.
I then drilled the holes in the brackets. I’m using 3/8″ threaded rod, which is probably overkill, but I stood in the hardware store with the 1/4″ stuff and it took a considerable force to make it bend (buckling). I picked up the 3/8″ rod and it was rock solid. I figured for a few more cents per rod, I’d rather overdo it. Anyway, the brackets on the right will get the 3/8″ threaded rod and a 3/8″ bolt through the main stand post. The brackets on the left will get the 3/8″ threaded rod and a 1/4″ bolt that will go through the 2″x2″ angle (the smaller bolt for the smaller head so I won’t have any interference). You’ll see.
Holes drilled in the brackets.
Then, I made matching pairs of left and right supports.
(The bigger hole goes through the main post, the smaller hole is for the bolt that will hold the bracket on).
Here are the brackets attached.
Then, I threaded in the 3/8" rod.
Before I can go any further, I need to make sure the spar will be level when they are hung. Since the garage is sloped, I can’t just drill holes 2 inches from the top of each post. (For the record, I think I could build it that way, because the real issue is wing twist, which could still be fixed if the spar wasn’t level, but I would rather have the wing level.)
Me using the laser-level.
This thing is awesome (it’s my girlfriend’s). I held it up against one support and moved it up or down until the level line across the garage was right on the top edge of the post (the picture below shows me about 1/2″ too low). When the level line was even with the very top edge, I marked a line under the laser leveler (it has a little hole for marking), and then I measured down from that line (and the top of the other post) 2 inches to mark a spot for drilling.
Using the laser leveler.
After that, I drilled a 3/8″ hole and measured down 18″ for the bracket hole and drilled another 4 holes.
Then, I assembled all the hardware and…
TADA!!!
Wing stands!!
Here's a closeup of one set.
And an even bigger close-up of the mechanism. Since most of the force will be down, I kept the threaded rod long and mounted the post bracket 18" below the main bracket.
Here's the upper adjustment mechanism.
And the lower adjustment mechanism. Thank you Ethan.
Then, I had to put the spars on the stands. (Making sure to carefully clamp each side.)
Wuhoo! Wing stands.
I need to add some screws into the 45° wooden supports, and tighten up all the hardware. I’ll also probably cut the carpet out from under the stand bases and use some construction adhesive to glue those bases down once I know their final locations.
Still a very good day in the shop, and now the shop is clean and organized for the wing activities that will hopefully take me through summer 2011.
All in all, I think I worked about 3.5 hours on the stands today. Not bad.
Andrew's RV-7 Build Log 