I already had my wood base, and that did not change, except that I had to drill a 3/8 inch hole in the base wood to allow the rod to freely rise and fall inside as the nut is adjusted. Here are some pics. The first is of both the old hydraulic (worthless) jacks now sitting on the shelf doing nothing:
When everything is done all you have to do adjust the height is screw or unscrew the nut to raise or lower the threaded rod, which raises or lowers the support wood resting against the rear spar web. No more having to keep re-pumping up the hydraulic jack every time I go out to the garage. SO why did I not do it this way a long time ago? Well, if you look at the drawing from Vans plans that shows this assembly, they show a rather simplistic but OBVIOUS picture of what looks like a bottle jack holding up the middle of the frame while it is on the stand. So I thought OK, I'll do that too. What a crock. Anyway, it's done now, and the left wing assembly was checked for level again by running the fish line across the holes in the main wing spar flange and adjusting the nut until the line runs through the middle of the spar flange rivet holes. Here is the left and right assembly in place:
the next thing I did was take a mirror to check the clearance of the joiner strip and the outboard fuel tank rib. I have reported in several prior posts that my "strip" did not exactly end up being 11/16th of an inch from the LE rib web as called for in the plans. In some places it ended up slightly less, and in others slightly more. This seems to have been confirmed after I was able to set a flashlight inside the new access hole and used my mirror to check the gap between the rib and the joiner plate. On the top side I ended up with more than enough clearance, but on the bottom side the clearance is just barely there, meaning that the joiner plate edge just about touches the fuel tank rib flange.
The reason that this is important is that at some point that fuel tank rib flange is going to be sealed with proseal and riveted in place. A combination of excess proseal in this area where the joiner plate is supposed to be flush with the fuel tank skin might be interfered with from the excess proseal. There is supposed to be a 1/6th inch gap all the way around, but mine obviously are not that way. I don't have pics of it but will try to get some for the next post. it is always interesting trying to use the mirror to check certain things. You could give a demo class on this subject alone, because it is more of an art than a science to figure out how to position the mirror just right so that you can see exactly what you want to see.
My plan for this is to continue with all the other stuff I need to do on the LE, and then when I am ready to take it off the wing again I will leave that LE rib and the plate attached, while I remove the rest of the LE (You know, the way I SHOULD HAVE done it the last time I tried to take it off), so I can more easily check the clearances of the joiner plate with the fuel tank rib. Trimming excess material is never a problem, but I want to better understand the reason why there is such a difference between the top and bottom sections first.
The other reason why it was important to double check this was because this may also have been contributing to the gapping problem between the outer LE and fuel tank skins that was giving me fits the other day. Need to check clearance with skins, ribs, Z brackets, and the baffle plate to make sure nothing is interfering with the fit.
Now that all that madness was done, it as time to remove the blue vinyl from the first bay of the LE so that I could make some final measurements and draw the final lines on the skin that will be used to mark the rivet lines, cut lines, and nut plate lines for this lovely time-consuming mod of mine. taking pics of bare metal is always a challenge, so these dd not come out exactly the way I wanted them to, but they will suffice for now.
Here is the bottom of the LE skin with the basic drawing of the planned cutout. I decided to use .75 inches as the rivet line mark from inside each existing rivet line for the rivets that will attach the ribs to the skin. The next decision was to use 5/16ths of an inch as the edge distance from the new rivet line. This will become clearer when I start drilling the new holes for everything. I decided on 5/16th of an inch because in other areas that could be construed as a "splice joint" per AC 43.13, such as the main wing skin overlap, the vertical edge distance of those wing skin rivets is 5/16ths of an inch. What's good enough for the goose is good enough for the gander, as they say.
I am using a 1/2 inch radius for the rear side of the removable LE, similar to the same radius used for the new access panel cover. In fact, I took one of those covers that already had that radius built in to it to trace it onto the LE skin.
These last couple of pics show a line that drew on the top side of the LE skin between the 5th rivet hole from the front of the LE. After spot checking the rivet hole layout of the LE ribs on the top and bottom flanges, I discovered that the 5th rivet hole on the top is almost directly vertical to the 4th rivet hole on the bottom. The concern about using the 5th rivet hole on the top as the line where I will make the cut, is that there is still a pretty substantial amount of bend in the skin at that point. one of things I need to be careful about is to make sure that the removable part and the remaining LE skins will retain that curvature after they are fastened with screws or rivets to the subskin. I can perform some tricks that will apply a slight curve to the edge of the removable part if I need to, but I was hoping not to have to perform too much of that sort of magic.
The other, much more important concern about this, is if a crack forms or a screw come loose from a nut plate on the top of the LE. If this happens, and the skin is allowed to rise up into the slip stream, it basically turns into a spoiler, that will disrupt flow over the top of the wing, and, at best, will cause me to loose lift. At worst it can cause that part of the wing to stall, or for part of my aileron authority to be lessened, or lost entirely. (THIS is that part of the safety concern about this mod that I have been talking about ever since I thought it up.) Needless to say, my pre-flight inspections will always consist of a significant amount of time devoted to checking ALL of the rivets and screw attach points on the top and bottom of this area, before I even think about getting in the airplane. All screws will be checked for tightness and the overall condition of this area will be scrutinized heavily.
Till next time,
KPR
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