Trim Tab Complete!

Okay, okay. I may have been a little harsh in my previous post regarding builders being overly picky and meticulous when it comes to the trim tab. I know that I'd like the perfect plane, in every aspect. Those little blemishes that occur along the way are what make our planes ours and very unique to us. I had much more difficulty with my trim tab than I'd expected. I think the issue is that the directions could be written a bit better with regular updates. Maybe this isn't the most cost effective way to do things at Van's, but it would help builders who succeed us with less headache. For instance, particularly on the trim tab, noting what areas should be dimpled and countersink BEFORE even bending the trim tab would be MOST beneficial and save on some time and aggravation. I know it would have for me. Ask me how I know this. Maybe I should start reading the sections entirely before embarking on a part. At times this isn't feasible, such as when you read before you build, sometimes it doesn't make sense as you're reading.

Masking for Priming Before Riveting Horns

Notice Anything? Yep, I Forgot to DIMPLE!
This Also Shows Rivet Sizes for Different Holes

Previously, I deburred, dimpled, countersunk and primed all the trim tab parts. I started with clecoing the trim tab back together. The directions tell you this then to rivet the bottom of the skin to the bottom of the flange and the trim tab horns. Well, you can't entirely cleco the trim tab and accomplish this. I needed to leave the upper skin unfastened to get either a squeezer or a bucking bar in the space. I riveted the horns and flange all in place and only had to rework 3 rivets.

I don't think I followed the directions in the right order but I basically got the hinge positioned in the previous steps, drilled and clecoed to the trim tab. Next, I positioned the trim tab on the elevator and marked the hinge position on the elevator laterally, figuring about 1/8" between the bent tabs areas. Next, I removed the forward part of the hinge and clamped it in place on the elevator. I started drilling on the outboard hole, then cleco, then drill every other hole, cleco then went back and finished drilling the rest of the holes. Next was marking the inboard skin edge on the hinge then trimming that area to match the skin when installed into position. I clecoed the forward part of the hinge back on the elevator and connected the trim tab with the hinge rod. Once this is in position, I used a small squeeze clamp to hold the trim tab in line with the elevator. This step is where alignment is needed to get the tab to follow the line of the trailing edge of the elevator and to tweak the tab to get it straight and follow the same line on the up and down axis. Per the directions, I clamped a piece of angel aluminum to the trailing edge of the elevator and aligned the tab to follow the same line and angle. Once it was straight, I put the clamp in position to hold it to the elevator then drilled the three #30 holes for the pull rivets on the bent tabs and put a couple clecos in. Next, I carefully removed the hinge rod and riveted the top of the tab with the hinge in place. After that, I put the pull rivets (CS4-4) into the bent tabs. Then I needed to figure where the rivets would go on the other end of the trim tab so as not to interfere with the rivets needed on the elevators bent tabs. I put the trim tab back on to mark where I would put those rivet so they were offset from each other.

Setting Position for Tweaking the Trim Tab

Marking Bent Tab Area for Pull Rivets

Next, I riveted the forward part of the hinge elevator and VIOLA! The trim tab is is done!!! Directions tell you that the pin/rod for the hinge is not long enough and that you'll get one that fits the way it should for bending and positioning in place to be wire tied to the elevator. That one will come with the fuselage kit. I need to make a punch list of things I need to go back an complete. Up to this point, there hasn't been much. Things like this hinge rod, torque sealing certain nuts and bolts as well as any other things that don't get checked off the direction list right away.

Trim Tab Complete, Except for the Hinge Rod

Another Shot of the Completed Trim Tab

I agree that the trim tab is very small, but a major pain in the @$$! It does take patience. If you're getting frustrated, STEP BACK, TAKE A BREATH! Just go slow. This thing doesn't and WON'T be done tomorrow, at least not at this stage. While riveting my hinge to the trim tab, I didn't have my squeeze set right and bent one of the hinge sleeves. That took 10 minutes or so to get worked out. But turned out fine. I put another marred spot in the skin while bucking one of the hard-to-get-to rivets. The bar was set funny inside and I didn't have the rivet gun on very well. Needless to say, the skin is quite ugly in that spot.

The Marred Area From the Bucking Bar

The Same Area, Different Angle. It Has A
Tin Can Effect if Pushed From Both Sides

If it turns out that I'm just not that happy with it, maybe I'll make another later. It's pretty straight and true. I saw another builder talk about the flange inside not being very well fabricated and it causing one side of the skin to bow when pulled into position. Mine is doing that as well. There's a bit of a bow on one side and pretty straight on the other. I'm going to leave it alone for now.

I semi-installed the trim tab motor to get a feel for how the push rod will be positioned when it's in it's final position. There will be some trimming needed for clearance where the rod exits the elevator skin. It shouldn't be a big issue, a little fine trimming, filing and cleaning. I'll probably work the fiberglass tips later with the other fiberglass. I want/need to take the fabrication course that the EAA offers (SportAir Workshops) before I venture into uncharted territory. I'm not sure if I'm going with the seamless look or screwing the tips on. The latter gives better accessibility for any fixes, changes or repairs. The seamless gives a nicer look as well as better waterproofing for the inside of the wings and empennage. I'm going to weigh the options and read what VAF members and other bloggers have done to see what the consensus is. Next will be rolling the leading edges of the left and right elevators. Fun stuff... NOT! Well, it kinda is. =8^P

That's all for now. Take Care & Thanks For Reading!

Day Total: 5.9  HOBBS Meter - 141.8