Sunday, July 28
Finally, back to work! Today, I started back on the trim tab. I put it in the bending brake last session and I went too far. I tried carefully to bend it back out, no easy task. I managed though. There are a total of 4 tabs (2 on each end) that require bending 91°. Make sure you pay close attention here. The lower tab is bent FIRST, then the upper tab. This way, you won't get water leaking or draining into the tab in the rain. When you start this process, the plans show you starting with the whole trim tab upside down. It makes it a little confusing. In this case, you bend the top tab (lower) down first, then the bottom (upper) tab up second. You'll get the picture with the inboard section as there are 3 rivet holes on one tab that need to be on the outside when finished bending. Do both ends the same. I read of many builders ordering an extra trim tab set just because most use the first one as practice and aren't happy with the outcome. C'mon! It's just a trim tab. Once it gets sanded, cleaned, primed and painted, I don't think they really turn out that bad. I know, there are some perfectionists out there. I'm one too. You can always order a kit later and do it again if it's really that bad. I think mine turned out pretty well. I may have bent a little too much of the tabs on one end, but I think it'll be fine.
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| Outboard End of Trim Tab, Decent Bending |
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| Inboard End of Trim Tab. A Little Too Much Metal Bent |
Basically, I took a piece of 1/2" particle board about 7"x3", figured the angle of my trim tab with the spar in place, which is right about 10°. Then I cut it at that angle. I'm not too fond of my small, cheap, name-brand band saw's ability to cut a nice, straight line. So, I used a piece of 1/4" metal, used for my dimpling in tight spaces, and clamped it to the board on the angle of my cut and used a small hand saw against the edge of the metal and made a real nice cut. In retrospect, it doesn't matter what angle it's cut. Basically, it just needs to be greater than 10° but less than that which would open the trim tab up too far. You can use the distance that when the end tabs are bent, they're separated by 1/8" to 1/4". If you follow the 10° method, make sure to leave a small enough angle at the trailing edge to fit into the space of the trim tab. I used double-sided Scotch tape on both sides of the inside block and a strip on the outside for the outer block. This keeps things mostly in place. I should have put the whole assembly on a non-slip piece of mat on top of the work surface to prevent slipping but it "slipped" my mind. Haha, bad joke. Another thought would also be to use some tape on the work surface to hold the entire trim tab in place. I clamped the whole block assembly to the bench with ratchet clamps as well as clamping the trim tab on the leading edge to the edge of the work bench. Let the bending commence. You want to turn your pressure down on your rivet gun so you don't go too wild and bend the crap out of the tabs. Use a block of wood to get started on the bend, per the plans. Once you get the tab closer to its final position, you can use just your gun to flatten it out pretty nicely, all along the edge, back and forth until you're satisfied. Yes, you'll notice here that this is the same exercise used on the left elevator. I previously used foam tape. BAD idea. Don't go this route. It's is too thick and gives too much and is a royal pain to remove from your jig parts. It was a bit overkill. Just follow the directions for preparing and you should do fine.
Next, I cleco'd the trim tab spar (E-607PP) to the bottom surface of the tab skin. Then I got the electric trim tab motor trim tab horns (E-617EEPP-1 and E-618EEPP-1), clamped them together, used a clevis pin in the holes for alignment and clecoed them as a whole part to the skin. Needed are a couple holes drilled for one of the horn parts as the skin is without. That's why it's necessary to clamp the 2 horn parts together, using them as a template, of sorts. Pretty simple here. After fitting the parts in place, I match drilled the holes through the trim tab horns.
Tuesday, July 30
Tonight, I started working on a few bends and dings that mysteriously showed up on the leading edge of the left elevator. Okay, I'll confess. I had put the elevator up out of the way, hanging the counterweight end on one of the rafters. I had the garage door open half way for air and later decided to open the door all the way. I wasn't paying attention and the door pushed the elevator off the rafter and bent a couple of areas along the leading edge. So, I took a little time to straighten them out. The edge hasn't been rolled yet, making it pretty easy to ding the edges up a bit. I was able to straighten the worst offenders pretty well. There were only about 3 or 4 issues. The elevator itself looks pretty straight and true so I don't anticipate any issues with it later. It'll be interesting to see the leading edge after it's rolled and riveted. I'll try to post a couple pictures after the roll.
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| The Smallest of All Dings. Needs a Bit More Work |
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| Ding #2. I Hope This Cleans Up Better After Edge Rolling |
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| Ding #3 More Outboard of #2 |
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| The Top of Ding #3. I Hope This Ends Up Rolling Ok |
Next on the list was to work the hinge for the trim tab. I checked a couple other builder logs for info. Interestingly, the few I looked at didn't have much in the way of information. So I decided to follow Van's plans the best I could. Sometimes they can be a bit confusing. I have a habit of over-thinking things at times. It took me a while to comprehend that the hinge DOES NOT go between the skin and spars. I don't know why I had this in my head, but once things "clicked", it was much easier to move forward. Over-thinking I guess! The hinge rivets to the innermost area to the skin and spars.
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| Hinge Measured, Marked & Clamped in Place |
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| Showing 3/8" From Rivet to Inboard Hinge Edge |
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| Trim Tab Hinge Drilled & Cleco'd in Place |
I started by marking the hinge at 1/4" in from the trailing edge of the trim tab side of the hinge the length of the hinge. I did the same for the elevator side as well. This line is used as a site line through the rivet holes for alignment and distance. Then, I made a mark on the hinge for the area that would be removed (waste) on the inboard edge. That distance is 3/8" from the left-most rivet hole to the end of the hinge on the trim tab side, per the plans. After trimming the hinge, I clamped it in place on the bottom of the trim tab spar, making sure the site line is centered in the rivet line. Then I match drilled the holes starting with the inboard hole first, clecoing it then drilling every other hole and clecoing while removing the clamps along the way. Then I went back to finish the rest of the holes. I then put the other half of the hinge back together with its mate. The next step is to take apart the trim tab assembly, machine countersink the spar and dimple the trim tab upper holes and work more on the control horns. Stopping here tonight.
Day Total: 2.0 HOBBS Meter - 134.2
Wednesday, July 31
Tonight saw drilling the rest of the holes in the trim tab, countersinking and dimpling the trim tab spar. Next was to disassemble and the usual "Lather, Rinse, Repeat" with deburring, dimpling and priming. Not too much tonight, just enough to keep busy on the project, KPR! (Keep Pounding Rivets), and... edge finishing, deburring, dimpling and priming. KPR for short. =8^)
That's all for now. Take Care & Thanks For Reading!
Day Total: 1.7 HOBBS Meter - 135.9
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