Today I finished up the upright project.
I'm hoping to run some straight-line tests later this month if I can get a half a day to sneak out to the Mojave in the car.
I've already documented making uprights a couple of times in this thread. But in case you missed it, I'm going to do it one more time. If nothing else, it gives me a reference to come back to if it turns out these new uprights fail.
This (in the center) is the initial design I cut out of plywood. It's a two part thing. The 'shoe' up at the top is what attaches to the wing. I've combined the rear wing mounting point with the rear shoe-to-upright junction because I think it's a stronger way to go. In front, the wing attaches to the shoe, and then the shoe attaches to the upright through one of four holes. Each hole gives me a slightly different angle of attack for the wing, with the shoe-and-wing-assembly pivoting on the rear mounts.
That lump in the shoe is necessary for the row of holes for changing the angle of the wing. But in looking at the plywood version, I came up with another place for the lump which I thought would be a little better looking. I also decided to make the junction points in the upright a little beefier -- to not have the angles on the two triangles not be so sharply cut.
So here (to the right of the old, failed upright) is my revision of the new design, cut into particle board instead of plywood (hey, you use what you've got sitting around). Now the lump is part of the lower piece, and it looks like it's part of the upper triangle of the design. Why am I worrying about aesthetics on something that will always be ugly? I don't know, but I am.
These are the pieces traced out on the 7075 aluminum. You can see I was stingy in purchasing the stuff. It's expensive.
And here's the cutting. The idea is to cut outside of the lines, so there's extra material that can be taken away for the finishing cuts.
Here's the guy doing the cutting. With the router, I'll wear a full face shield. But for this part, I've got eye protection, hearing protection, and a headlamp. I'm hooked on the headlamp, these days.
Quick and dirty. Here's the roughly-cut upright.
This is a picture from the last set of uprights I made, but it gives you the idea. You adhere the rough-cut aluminum to the more-accurately-cut plywood, and then use the wood as a guide for an ordinary router to trim the rough cut piece to the same shape as the plywood.
Nice and smooth. I wouldn't be able to do that with my skills and a jig saw.
Here's a routered one on the left and a ready-for-the-router piece on the right.
A step back. I've got holes in the fold-down table that keep the router in a fixed place. There's sawdust and metal shavings everywhere, but it still looks pretty clean, doesn't it?
Here's what the router leaves behind. You have to wear a face shield, because these things shoot off the router blade at a pretty good clip.
These are the marks for the angles I'm using for the mounting holes. I later added one more below the two on the left. There are two mounting holes on the corresponding piece, which is why I didn't have to put all four holes in a row.
This is the test fitting of the new setup. I get the car perfectly level, and then I can measure and re-check everything before drilling the mounting holes.
There's the allthread diagonal -- no steel sheath covering it yet. I used to run a horizontal piece between the bottom end of the uprights, but decided it was unnecessary this time. (I hope I'm right.) On the right side of the picture, you can see that there's still a sharp edge to the upright.
Here are the two 'shoe' pieces. The one on the right still has the sharp edge and the one on the left has had that edge rounded off. No more cuts to my hands and fingers.
Here's one of the uprights, painted and reinstalled. If you look for it, you can see the way all the edges are rounded off, now.
This is the whole thing put together. The diagonal has the aerodynamic sleeve on it now.
This is a closer look at how the adjustment holes work.
And here's a final look at it.
Next up? Testing to see how the downforce changes at each angle-of-attack setting, with a simultaneous look at whether there's any flexing when the thing is running at triple-digit speeds.
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