Trim Tab and Electric Trim:
March 5, 2006
First thing I did today was go to Home Depot and buy a 10" drill press. Thanks go out to Jenni's mom for a perfect Birthday present (Home Depot Gift Card)!!
Building the trim tab was a lot easier than I thought it was going to be. I was thinking that with all of these small parts and problems that people have had in the past that I was going to screw it all up and have to start over. To my surprise it came out looking damn good.
Here is my suggestion for building the trim tab. First don’t follow the order in the plans as listed; it will make your life very difficult. READ THE PLANS, but do that to understand the build process – it’s the order that I call into question. Here is what I did.
Clecoed on the E607PP spar to the trim tab skin (either side for now, I think I started with the top). Final drill those holes to #40. Un-cleco and repeat for the other side.
Here is where I drilled the piano hinge for the trim tab. I measured out the 3/8 from the outboard hole as referenced in the plans. I then used several cleco clamps to hold on the piano hinge and still be able to move it around for final measurement check. Once that was held on, I drilled the first hole and immediately clecoed it in place. I used a cleco clamp moving down the line so the hinge would not push out while drilling and elongate my hole. I rechecked everything to be sure that nothing slid around and then moved on to the second hole; again a cleco replaced my drill almost immediately. Re-check as you move on down the line and drill all of the holes each time you drill a hole, cleco it. Once you have the piano hinge drilled you need to mark it where the hinge overlaps the edge so you can cut it off. I marked it with a fine tip sharpie then took it all apart and used the Scotchbrite wheel to cut it to final shape. I then deburred the hinge and set it off to the side.
Now is the time you want to mark your reference lines for the bends in the ends of the tab and get those ready for bending by clamping a piece of wood on the inside 1/32 inside your reference lines.
A triangular shaped piece of wood on the inside works. Believe it or not mine was a 4 sided piece. Clamp that down as tight as you can get it so that it won’t move. Using another piece of reasonable size and shape, get the initial bend in the tab side and use your rivet gun against the block of wood to bang it into shape. It really works and I got some great looking tabs.
Once that is done you can get the attach points for the trim attachment arm (E718 I think). The electric trim is the route I went so I will explain that one. I clecoed on the longer of the two pieces and used that for a reference for the second one as shown in the plans. I then marked and drilled the holes that were not pre drilled. Once I was satisfied that those were good, I used the Scotchbrite wheel to shape the edges so that there was no overhang off the edge of the trim tab.
Now you can final drill the top holes on E718/717 that also intersects the E607PP spar on the bottom. Be sure your spar is in there when you do that. Take it all apart and debur everything. Be sure you are dimpling all the bottom holes ONLY on the spar and machine countersinking the top holes of the spar – when you do this the holes may elongate slightly to accommodate the dimple of the skin. Now you can go through and dimple all of the holes on the trim tab skin. Dimple the holes on all of the E717/718 parts too. The inside of the skin where the 717/718 attach is tricky to dimple so be careful.
With everything dimpled, now you want to prime it all.
Now you want to back-rivet the bottom of the E607PP trim tab spar on to the skin (BE SURE TO LEAVE OUT THE TWO HOLES WHERE 717/718 attaches). Now you can back rivet or squeeze on the trim tab brackets 717/718.
Next, use your bending brake to complete the bend in the trim tab. Be sure your edges are clearing each other beforehand so that you don’t jack them up. I just hung my trim tab brackets off the edge of the bending brake so that it would be flat when bending the trailing edge. Worked out great.
Next I drilled the holes on the inboard edge of the trim tab using the 3 holes there as a reference. Be sure that everything is in place and where the skin is going to be before drilling these holes. I suggest using the bending brake or something similar to hold it into place while you final drill these holes. Debur these as best you can and dimple the holes to accept the CS-4-4.
Be sure to blow out any debris before you go on.
I then clecoed together the trim tab skin, top of E607PP and the E721 hinge. I clecoed every hole so that I could check the fit and make sure there was no twist. Once that was checked, I squeezed on the rivets one at a time. I used a cleco clamp on the ends so that all was squeezed together when hitting the rivet.
The Trim tab inboard end was 3 simple CS blind rivets.
Next you have to attach the trim tab. That is accomplished by putting the hinge together and clamping the trim tab on to the elevator. Use cleco clamps to hold the hinge in place. Check this thing about 10 times before you proceed. You also will want some shims in place to hold the elevator and trim tab trailing edges in exact alignment. I drilled the first hole and clecoed it in, rechecked all of my alignment, and repeated that process for every single hole. It came out looking great.
Took it apart deburred the hinge and cleaned out the E606PP spar channel. I clecoed on the hinge piece again and Jenni and I squeezed those rivets using the same replace a cleco as you go process.
Everything turned out looking really good and the swing appears to be unobstructed. The only thing is that I am likely going to do some filling to make it look a little prettier where the tab on the elevator was bent. Not that looks that bad, it’s just that it could look better.
March 6, 2006
Today was a quick day although I did did get quite a bit done for only an hours work. Today I measured and drilled the access plate for the electric trim. This was just a matter of clecoing on the Ray Allen trim motor on to the brackets that come supplied with it and marking the access plate with the locations of the brackets. I then match drilled the brackets to the access plate and deburred them. Once I was done deburring the parts I dimpled everything and primed the brackets. Once the brackets were primed I hung them to dry and called it a night. I will hit those with a 2nd coat of primer tomorrow and trim the access plate for the perfect fit to cut down on drag. I will also probably rivet the trim motor to the access plate.
March 7, 2006
Today I finished riveting the trim servo brackets to the access plate and ground down some spots on he reinforcement plate to all the servo to get in there. I also mounted the trim servo with some temp bolts to test the movement.
As I was mounting this I opened up the narrow channel in the bottom of the elevator skin to allow clearance of the pushrod. I also slightly bent the pushrod to allow for clearance through its full range of motion. I hooked up a 12v power supply and ran it all the way in both directions. It worked great!
I was excited to see moving parts mounted and moving on our plane!
Tomorrow - Rolling leading edges. UGH!!! I will have to take the trim tab and servo out for that so that I do not damage them while rolling the leading edges.
I am thinking that I want to leave the cotter pins out until I am sure all is good. I still have to measure the trim tabs movement and make sure that its within specs of Vans numbers. BTW - all the dust on there was from using the sander to grind open that channel.
I also put my new drill-press together and test drilled a block of scrap wood that I had laying around. Sweet!
March 8, 2006
Tonight Was leading edge night. First, I had a few minor things to finish up before we tackled those. I torqued on the bolts for the counterbalance E714 and attached the servo with the permanent bolts from the kit. I know that I hate rolling leading edges the most so far, of course I have yet to seal a fuel tank yet.
Jenni was ready to help but I think I may have been procrastinating. We eventually started the task of rolling the leading edges. Starting at the outboard end we rolled the bottom then top section. This time I used the hand seamer to tweak the bottom skin so that it was not pushing up on the top skin. Then we repeated the process for the middle section and then the bottom section. We clecoed everything together and called it a night. Doesn't sound like we were in there too long but it turned out to be 2 hours worth the work. No pictures yet...I will probably take some tonight after we rivet the leading edge.
I am glad I have already started actual wing work because otherwise I would be going out of my mind.
March 9, 2006
"Free at last, thank God almighty I am free at last" - Martin Luther King Jr.
That's how I felt after finishing up the leading edges on the left elevator tonight. Drilled, deburred and riveted those together tonight. I also torqued the bolts on the right elevator for E714 as well. I also re-installed the trim servo and just tucked the wires down in there because I am not ready to wire this stuff up yet. I also verified with the parts that I have in the living room that I do not have to roll the leading edges on the ailerons or flaps. At least I don't have to do the flaps the same way as the rudder and elevators.