Jun 26 -- Install Trim Tab Hinge & Threaded Rod

Short session today, because it was a spectacular Sunday in Western Washington so Michael Beare and I went flying in his Luscombe.

In order to insert the servo into the access opening, you need to power it up to move the screw to the extreme "trim up" position. Great, except that I forgot about this (a day passed), so I cut the stainless 8/32" threaded rod to the wrong length.

Picked up a new threaded rod for the trim servo, installed that, and trimmed the edge of the trim tab (is that recursive?) where it was hitting the elevator when positioned at an extreme "down" angle. Also bent the hinge pin per the photo below, in order that it can be safety-wired to the elevator. The safety wire will be installed later.

Total Time: 1.5 hours

Jun 24 -- Work on Electric Trim Servo

Tonight it was time to assemble the parts that were primed last night, and to see how everything fits. Thanks to clearance issues it was not really possible to use clecos during try-fit.

Three things needed resolution:

• The servo is a really tight fit in the access hole. (WHY? another 1/8" clearance would have been wonderful and would not cause structural issues.) The edges of the nutplates needed to be filed down so that they did not protrude into the opening.
• In a similar manner the edges of the access opening needed to be relieved near the throat, because the clevis pin on the servo was binding on the edge of the opening.
• Finally, one corner of the servo was hard to insert into the hole. So I drilled a new hole and installed a rivet there. That made room to relieve the corner, as shown in the photo below.

Total Time: 1.5 Hours

Jun 23 -- Start Work on Electric Trim

Relatively short session this evening. Set up the mounting brackets for the electric trim servo on the elevator. The trim is mounted in the elevator and positions the trim tab via a control rod.

So tonight it was a matter of laying out the bracket holes, drilling, deburring, dimpling, and priming. This is the reason that God invented Lilac Bushes: to hang airplane parts from.

Total Time: 1.5 Hours

Jun 22 -- Install Trim Tab

I didn't post Sunday's work on the elevator, where I redrilled one rivet twenty times. In the end I stuck a pop rivet in the hole :(

Tonight was different. Attached the trim tab to the elevator and am pleased with how it came out, per the photos below.

Some tips for others:

• I left extra material on the left end of the half of the hinge that attaches to the elevator. That way right-left adjustment could be controlled by jamming the end against the corner of the trim tab cutout on the elevator, and I simply sanded it down to get the exact spacing that I wanted. This eliminated trying to control two dimensions at once as I clamped things up.
• Others started drilling holes at one end and working their way along the hinge, with a cleco in each hole that they drilled. I carefully drilled one hole in from each end, and then drilled a couple in the middle before splitting the difference on the rest of the holes. Kept the trim tab in place the entire time, in order to prevent the half that I was working on from sagging.

Time Sunday: 5 hours
Time Today: 2.5 hours

Jun 18 -- Trim Tab & Left Elevator

What you don't read here is also an important part of the project. Everything has been on hold because the drill press needed repairs (the chuck kept falling off). Took the spindle to a local machine shop; however when I got the part back the chuck wobbled slightly. Not good! EBay solved the problem after some off-EBay dickering with a dealer.

Per an earlier post, the first run at a trim tab hinge was all boogered up. So this time I used a #41 drill bit and a rivet fan to carefully lay out and drill the hinge holes. At least with this rivet fan a #41 bit is perfect in the rivet fan holes, as you can see in the photo below. Using the rivet fan really helped clean up "eyeball" variances from hole to hole. Simply clecoed then ends, then drilled holes in between, using the rivet fan to guide the drill press directly.

Used ProSeal to glue some foam ribs inside, and also carefully riveted the tab together. It's sitting in a corner for a week or so while the ProSeal sets up.

Next I closed up more of the left elevator and also glued up the apex wedge in its trailing edge. Hard to believe how much day all of this ate up, but a great way to spend a rainy Saturday.

Total Time: 5 Hours

May 30 -- Left Elevator and Trim Tab

Been forever since I worked on the project. The Luscombe annual, followed by a trip to Europe for close to a month conspired... And now a deck refinishing project lurks. Couldn't finish it last summer thanks to neck surgery. Not to mention that the drill press is in pieces for a long-overdue overhaul.

At any rate some modest progress.

On the elevator, I drilled the trailing edge wedge, also known as the apex wedge. Learned a lot on previous attempts, so this time I used angle iron for the trailing edge to keep everything lined up. Also used the new battery-operated drill for countersinking. Slow speeds really help with control.

The trim tab is starting to come together, although I did have some issues thanks to dimpling. See the photos for where the dimple die interfered with the bent tab at the end of the trim tab. Had to do some repairs, so back into the clamping blocks...

I also went off plans with standard rivets in place of the pop rivets on the plans. Hoping that there are no issues when it comes time to squeeze them (doubt there will be as long as I perform this operation before inserting some internal foam ribs). Also dimpled and primed the forward trim tab spar.

Hard to believe; however this was:

Total Time Today: 5 hours

April 12 -- Elevator Trim Tab

Posts have been sparse lately, thanks to work. Silence cloaked what activity did occur, and perhaps that is just as well.

Picked up a spare elevator trim tab skin while at Vans to get the wings. At the time it looked to be wasted money; however statistically an extra skin is a good investment.

Sure enough, the first attempt was a fiasco when I bent the tabs at the end. Issue was that I pranged the aluminum in every conceivable way while bending. Some (OK a LOT of) research online turned up that (a) the block recommended for forming the bend should be harder than pine, and (b) there is no such thing as "tight enough" when clamping the block down.

Fortunately(?) the mess known as our garage has some hard maple stock in it. Karin's childhood bed frame, to be precise. A piece of that maple made a great forming block, with more maple affixed to the sides of the wood to keep everything aligned. Then three screws in the bottom of the block served to clamp the assembly, and a humongous C Clamp worked on the other end. The genesis of this approach came from this page -- about halfway down.

That's a 10 degree angle in the maple, and I used a jointer to make certain all was super smooth. (The jointer is another bit of clutter in the garage.) The pieces tacked on the side don't quite touch the bottom of the block, in order to ensure that there was not any tilt induced by alignment issues. This setup took me 4+ hours to build, including time spent on some bad tries.

Some thoughts for others who may be reading this blog post as they consider their own construction project.

• Make certain that you clamp tightly and precisely. Bend the bottom tab first, then the top tab over the bottom. It's easy to miss in the instructions; however the bend line should intersect the middle of those "u" notches on the aluminum. Consider that the top bend will be over the bottom one, so make certain that the first one is spot on.
• Vans says to use a rivet gun to finish off the bend. I found that was a way to scar the aluminum. Besides, a block of maple and a hammer are all that are required.
• My bending brake (per Vans instructions) was made with wood from Home Depot. It was wet, green, and warped. Stuck it thru a planer to true it up, then left it on top of the table saw for a week. Result was a rusted table saw top, and wood that warped again. You can draw your own conclusion...
• That same brake will be used later for (longer) ailerons. Word is that I should have purchased wood long enough for a six-foot brake. I didn't, which is either good or bad, depending on your thoughts about the previous point.

Total Time: 10 hours (includes the bad trim tab not shown here)

Click on photos for a close-up view.

Mar 5 -- Elevator Trim Tab

Lots of "enabling" work today.

Started by melting plastic off the outside skin of the elevator, then drilling and deburring both the skin and trim tab rib. Didn't even bother with clecos before match drilling, because when I lined parts up it was obvious that once again CNC had everything spot on.

But most of the time was a matter of cutting foam for ribs and also some wood for forming blocks. Once again the miter saw came in handy with its clean cuts. So did the table saw.

Total Time: Can you believe that I burned over 4 hours on this?