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Stabilizer position
Everybody has their own favorite way of making sure wings, fin and stab are all square. Usually I measure corner-to-corner and eyeball it from there, at least on the stab. For the Toni, I wanted to get the stab lined up just right so did a little extra setup. At the end of the day, though, I eyeball everything very carefully. The eye can catch some tiny differences that are sometimes hard to measure.
First, incidence... I made sure the stab slot was cut at 0 degrees incidence to the wing. The 0 degree line on this airplane runs from the prop shaft to 5/16" below the leading edge of the stab. I marked the line and ensured the stab cutout was parallel. And, frankly, Terry makes things pretty brainless by molding in a small dot right at the leading edge of the stab on each side, and another right at the trailiing edge, which form another 0 degree incidence line. That was the easy part.
Next, I put the stab in loosely in its slot along with the elevator joiner connected to its pushrod. I bolted in the wing. I had to wait to set the stab until after I finished doing the wing saddle a week or two back, as that cements the relationship of wing to fuselage. Also, I had already established during the wing mount phase that the leading edge of the wing is exactly square to the centerline of the fuselage -- e.g. measuring from wingtip to tail end of fuselage is exactly the same both sides.
I put the airplane on a glass table -- something big enough to hold the whole airplane and perfectly flat. I blocked up the low wing until both wingtips, measured at the trailing edge (which is a sharp point and thus easy to measure accurately) were exactly the same height above the table.
I use some combination of an 18" metal ruler, 1 meter metal ruler, and 12" square for all the various measurements. When measuring distance back from the table edge or distance off the table, I make sure I'm always at 90 degrees in all dimensions.
I also squared the leading edge of the wing relative to one side of the table, by measuring from the leading edge to the table edge both wingtips. I then taped the tail skid down to the table to help prevent any movement.
Finally, I squared up the stab with three measurements: First, centering the stab in the fuselage by measuring from fuselage side to stab tip along its trailing edige and making left and right the same; second, by measuring wingtip trailing edge to stab trailing edge both sides; and third, by measuring the distance of each stab tip off the glass table. As any adjustment in any direction affects all measurements, I repeated each measurement if I made an adjustment. I used some blue painter's tape in a couple of spots on the stab to keep it in place once I got close, and then could just press a bit in one direction or the other for fine adjustments. Oh, I also double-checked squareness by measuring the distance from the edge of the table to the trailing edge of the stab both sides, just to make sure the stab was also exactly square to the centerline of the fuse when viewed from above.
After all that, I double-checked by eyeballing from about five feet directly behind the airplane. I've always found this to be the most accurate measurement of them all!
I was lucky this time, as I did not need to make any further adjustment on the stab relative to the wing (the stab tip height was exactly the same each side) -- otherwise I would put a little block under the low tip to prop it into the right position.
Now the tricky part: The stab is in, there's tape everywhere, but no glue! I knew I couldn't just coat this thing in glue and slide it in, so went with this dry-fit method. Instead, I used a toothpick to place a thin line of epoxy inside the fuselage along the top of the stab, where I have access from the vertical stabilizer cutout. This is just enough to keep it in place. As a next step, I'll come in later, mask off the stab and fuse and leave only a 1/16" or so line along the mounting line top and bottom, and squeeze in plenty of epoxy -- especially to fully cover that plywood plate just underneath the stab.
A side note on epoxies... I almost never use anything faster than 45 minute epoxy because I've found that the faster the epoxy, the sooner it turns into gummy rubber and starts disintegrating. I will rarely if ever touch the 5 minute stuff as in my experience it starts changing color and going soft within just a few months, at least in warmer climates. I also tend to mix at least 1/8 ounce or so at a minimum, even for small jobs, just to help increase my accuracy in getting the epoxy and catalyst measured out in the correct ratio... if you have even a little too much of one or the other, you're again going to face decreased lifetime of the finished product. I've occasionally weighed out each component (by keeping the mixing cup on a gram scale) for the most important jobs.
Next up... I have some final fitting and sizing of the vertical stabilizer to do... as right now with the rudder attached to the vertical stab, the bottom edge of the rudder doesn't reach all the way down to the bottom of the fuselage. I'll have to shorten the vertical stab (by trimming its base, where it fits against the horizontal stabilizer) just a little bit. I still have to trim the wheel pants too. Then it's on to more primer!!
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