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Thread: The Barn Find Build

  1. #171
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    Default Re: The Barn Find Build

    Boy, it sure is nice to have a friend five minutes away who has a machine shop in his hangar! I went over there this morning and he modified the control column mounting block so that a washer would sit flat against the top surface at the bolt locations.

    IMG_0996.jpg

    Then we scrounged a piece of 4130 tube, drilled the ID to slightly over 3/16", and he parted off two 1/4" spacers for me.

    IMG_0995.jpg

    Back home, I found that the spacers were a tad long, so I held them with needle nose pliers and shortened them on the disc sander. I also ground a chamfer on each one so it would clear the weld bead under each of the mounting tabs on the fuselage.

    IMG_1012.jpg IMG_1013.jpg

    Then I was finally able to reinstall the bracket, with just enough clearance that fabric won't touch the end of the bolt.

    IMG_1014.jpg IMG_1015.jpg

    Now that I look at that last photo up close, it appears the spacer on the aft (left) bolt rotated under the nut; perhaps that one didn't need the chamfer after all...

    I had to use longer bolts to account for the spacers, and the only ones I had are too long, so I'll need to order some. For now, it's a festival of washers!

    IMG_1010.jpg

    I figured I might as well press on, so I installed the control column also. I don't remember how it was done by the first builder, but I do remember it was quite tight, so I presume he didn't fiddle with it to get a smooth action. I found that the plastic bearing block on the left side pulled the column down too far, causing the axle bolt on the right to bind in the bronze bushings. Not wanting the washer festival to end, I put five -10 washers on each bolt between the plastic block and the mounting tabs to get the block high enough that the column rotated fore/aft with just a light touch. Before you shout at your screen, read on...

    [NOTE: The plastic bearing block is installed temporarily for now.]

    IMG_1022.jpg IMG_1023.jpg

    Since I didn't fabricate the plastic bearing block, I don't know what the dimensions of the supplied material were. If someone has one that hasn't been touched yet, could you measure it? I'm curious to know if the first builder cut it down too far, or if it was provided this size.

    It could be that the welded tabs for the aluminum bushing block on the right side cause it to angle upwards slightly. I'm considering putting a -10 washer into the stack-up under the "L" angle so that the whole block is angled downward to the left a few degrees, then I could probably remove two or three washers from under the plastic block at the other end. There's already one washer on the aft tab, as there was a gap to fill. If I move one more washer from each bolt head to the space between the "L" and the tab, I'll only have two under each bolt head. That, I can live with. Thoughts?
    Eric Page
    Building Kitfox 5
    Member: EAA, AOPA, ALPA
    ATP: MEL / Comm: SEL, Glider / ATCS: CTO
    Map of Landings

  2. #172
    Senior Member jrevens's Avatar
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    Default Re: The Barn Find Build

    Quote Originally Posted by Eric Page View Post
    Boy, it sure is nice to have a friend five minutes away who has a machine shop in his hangar! I went over there this morning and he modified the control column mounting block so that a washer would sit flat against the top surface at the bolt locations.

    IMG_0996.jpg
    Glad to see that worked, Eric. That's exactly what I suggested in my reply (#138)... he spot-faced those holes with a counterbore.
    You're gettin' there!
    John Evens
    Arvada, CO
    Kitfox SS7 N27JE

  3. #173
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    Default Re: The Barn Find Build

    Quote Originally Posted by jrevens View Post
    That's exactly what I suggested in my reply (#138)... he spot-faced those holes with a counterbore. You're gettin' there!
    Yep, and I meant to thank you for the idea -- cheers!
    Eric Page
    Building Kitfox 5
    Member: EAA, AOPA, ALPA
    ATP: MEL / Comm: SEL, Glider / ATCS: CTO
    Map of Landings

  4. #174
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    Default Re: The Barn Find Build

    Yesterday I started by tripping over something and hitting my head, so I spent nearly three hours completely rearranging my shop/garage, blowing off all the airplane parts, sweeping out an alarming amount of dust and swapping the wings between the cradle and rotisserie.

    Feeling righteously smug about the shop, I got to work on the actual plane. Since I now had the left wing in the rotisserie, I took a look at how I was going to remove the original pitot tubing (it's being replaced with new tubing from the Dynon installation kit). The first builder routed it through a hole drilled in the aft spar, then encapsulated the pass-through in Scotch-Weld. I got extraordinarily lucky on that mark, as the Scotch-Weld didn't adhere to the plastic tubing. A gentle tug pulled it loose, and I was able to withdraw the entire length through the hole. I also removed the fitting where the pitot tube would have gone, which left me with this.

    IMG_1025.jpg IMG_1026.jpg

    I'm thinking that I should probably cut/grind the Scotch-Weld back a bit, then plug that hole with a good dollop of Hysol. I might as well remove that triangle mounting gusset as well; it's just dead weight.

    Moving to the fuselage, I took the control column out and started over, using the idea I mentioned in my last update about moving washers around to angle the aluminum bushing block down toward the left. With one washer on each of the outer welded mounting tabs, I was able to remove
    six washers from under the plastic bearing block (three forward, three aft). That makes for a much neater looking installation and it resulted in even smoother movement at the sticks. Plus, I no longer have to order longer bolts for the plastic block.

    As soon as that was done I started installing push rods, and ran into a problem. The ears on the control column for the forward elevator push rod were welded about 1/16" too far to the right, so the rod fouled on one of the bars in the truss structure. The only way I could see to solve this was to insert a -416 washer on the control column axle bolt, between the right end of the column and the inner bronze bushing in the aluminum block. That pushed the whole column to the left a tad, which made room for the push rod.

    I also installed the aileron push rod, during which I discovered that I apparently misinterpreted a drawing in the manual and put the wrong shorty rod-end assembly on the 90 pivot arm at the left end of the truss (I confused it with the slightly longer one that goes on the mixer assembly). With that sorted out, I also installed the flap push rod. All of these are temporary for now (I didn't even install nuts on many of them) because I purposely loosened all of the rod end bearings and wound them shorter so I'd be forced to re-rig everything; I'm assuming it was done wrong, because, well, you know why by now...

    IMG_1024.jpg

    That's where my good luck for the day ran out. When I removed the dented rear elevator push pull tube from the fuselage several months ago, it came out through the mid-fuselage bearing ring without removing the rivets. I don't know how that happened, but I didn't note any difficulty that would have given me a clue about building the new one. You probably know what's coming. When I tried to install my new one, the outside diameter of the rivet heads is too large to fit through the bearing ring. AAAAARGH!!

    There's zero chance that bearing is going to come out, so I see two options: 1. grind/sand the bearing back to the steel ring, install the push rod, then fit a new bearing around it; or, 2. drill out the rivets in the aft end of the push rod, install the rod, then pull new rivets. I prefer the latter option, except that it leaves four rivet stems rattling around inside the tube. I think I can solve that by drilling one additional hole just past the end of the reducer bushing, injecting some glue to capture the rivet stems, and plugging the hole with one additional rivet.

    If anyone has another idea, I'd love to hear it!
    Eric Page
    Building Kitfox 5
    Member: EAA, AOPA, ALPA
    ATP: MEL / Comm: SEL, Glider / ATCS: CTO
    Map of Landings

  5. #175
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    Default Re: The Barn Find Build

    Drill out the rivets in the elevator push-pull tube. Install new ones after your tube is in place.

    You won't be able to do anything about the little pieces rattling around inside but at least our planes will match in that regard.
    I suppose you could heat up the Hysol to Tg, remove one end and do the job again if you really want to.
    Kitfox 5 (under construction)
    Citabria (flying)
    Commercial SE/ME, CFII

  6. #176
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    Default Re: The Barn Find Build

    Quote Originally Posted by alexM View Post
    Drill out the rivets in the elevator push-pull tube. Install new ones after your tube is in place.

    You won't be able to do anything about the little pieces rattling around inside...
    Yep, I think that's what I'm going to do. A new #40 hole should be big enough to inject some adhesive that will capture the rivet stems and keep them from rattling around. Shouldn't take much, then the hole can be plugged with a 3/32 rivet.



    Today I got a couple of add-in kits installed, starting with the Trim Assist Kit.

    IMG_1027.jpg

    The instructions mention that in the case of an early Series 5, which I have, the horn on the mixer assembly for the flap push rod doesn't have lightening holes, so you have to enlarge the second hole to 3/16. I drilled it to 0.185 then followed with a 3/16 reamer.

    IMG_1029.jpg

    The other consequence of not having the lightening holes is that later kits can use a supplied nylon bearing on the eye bolt that's mounted in that hole, allowing it to rotate. To achieve more or less the same thing without the bearing, I greased the eye bolt's shaft and both fender washers, tightened the nut just until it began to bind, then backed it off a tiny smidge. The bolt rotates easily with no side-to-side play.

    IMG_1030.jpg

    Next is installing the spring anchor bracket onto the idler bell crank for the elevator push/pull tubes. The instructions show and explain that the bracket has two holes, which are used to adjust the amount of pull force exerted by the spring...

    IMG_1032.jpg

    ...but the bracket that came with mine has only a narrow tab with a single hole. Anyway, installation is pretty straightforward. Rough up the powder coat, clean both surfaces, butter the bracket with Hysol, pre-position the hose clamps (they have to be completely opened to get them on the bell crank; remember to raise one clamp above the bracket before sticking it in place), hold the bracket where you want it and tighten the hose clamps.

    IMG_1031.jpg

    The last step is to install the spring, which is easier said than done. I'm not a physical specimen so I wasn't able to bare-hand the spring, but a pair of pliers helped it into place.

    IMG_1033.jpg

    I'm somewhat surprised at the amount of force that the spring exerts on the controls. I certainly hope that it balances out a lot better when the whole system is installed and rigged, and when the weight of the elevator is acting against it, because it's pretty alarming as it is now.

    Next I wanted to get the Trim Position Sensor Kit brackets installed so I could be sure there wouldn't be any interference with my comm antenna installation (there isn't). That kit is pretty simple and quick as well. Just two brackets to bond in place; one on the aft elevator tube and one on the horizontal frame member that runs fore/aft just above the horizontal stab.

    The first bracket is the one that pushes on the potentiometer's plunger, and it's supposed to be bonded in place so that it's parallel to the chord of the stab. Unfortunately, the half-round part of the bracket is too long on one side, so the bracket is unable to sit parallel due to interference with the welded tube that carries the bushing that mounts the stab.

    IMG_1034.jpg

    A little work on the belt sander removed enough material that it could be rotated forward into the correct orientation, so I roughed up the powder coat, cleaned everything, applied Hysol, and clamped it in place.

    IMG_1036.jpg

    The other bracket holds the potentiometer in a vertical orientation, pointing down. The instructions want the vertical tab to be 1-1/2" forward of the mounting boss for the horizontal stab. The bracket was 1-3/8" on each side of the vertical tab, and the weld bead on the boss occupied about 1/8", so it positioned itself correctly without modification.

    It did require a minor clean-up on the inside of the half-round where the weld penetrated through and left two little bumps. Those came off with a burr in the Dremel.

    IMG_1037.jpg IMG_1038.jpg

    I just had to chip away a few Scotch-Weld drips from the fuselage tube, then roughen, clean and it was ready to Hysol in place.

    IMG_1039.jpg

    While I was looking at the back end of the plane, I recalled that I still needed to reinstall the small section of fiberglass fairing that I cut away prior to having the tail post reinforcement welded.

    IMG_1041.jpg

    I wanted a way to attach it not only to the tail post and the bottom rib, but also to the rest of the fairing above. I had a couple of small pieces of thin wood sitting on the bench that were left over from assembling the pitot mounting plate. They were the perfect size, so I lightly sanded the inside of the fairing on the plane, cleaned the surfaces, smeared the last of my batch of Hysol on them and clamped them in place. The ends sticking out will be bonded to the offcut piece when I reinstall that.

    IMG_1042.jpg

    Last for today, I cleaned up some Hysol squeeze-out under the left wing cap strips on ribs 1, 3, 5, 7 and 9, then match drilled the flaperon hinge bracket reinforcing plates. They can be Alodined and installed tomorrow.

    IMG_1043.jpg
    Eric Page
    Building Kitfox 5
    Member: EAA, AOPA, ALPA
    ATP: MEL / Comm: SEL, Glider / ATCS: CTO
    Map of Landings

  7. #177
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    Default Re: The Barn Find Build

    I started out today doing a little bit more prep work on the pitot tube mounting plate. I made the final cuts to size, and to align the edge that will be against the rib with the fore/aft axis of the Gretz tube. This resulted in one side looking a bit crooked but it's straight when it's held in place in the wing, and crucially, the pitot tube will point straight ahead.

    IMG_1044.jpg IMG_1045.jpg

    I also match drilled the holes for mounting screws and added a thin strip of aluminum to the little stepped edge at the top in the second photo, as I needed to take up a bit more space between the plate and the bottom stringer; I didn't get a picture of that.

    Next up was a bit of work on the bottom mount for the comm antenna, now that I know it won't interfere with the trim position sensor. I found a length of leftover maple trim from my kitchen cabinets, cut about 6" from the end of it, held it up to the fuselage and marked what I needed, then cut it to size and smoothed the corners. It's an oddly shaped piece, but it fits the spot. The black tape under my thumb in the second photo is the bottom of the antenna.

    IMG_1046.jpg IMG_1047.jpg

    I also cut a small block 1-1/2" long that will serve as a clamp. I intend to put two tee nuts into the outside face of the larger block and use a couple of small screws to pull the clamp piece tight against it. I'll bond a strip of rubber to the inner face of both parts so there's plenty of friction to hold the antenna in place. To remove the horizontal stab, I'll just have to back off the screws and the end of the antenna will slide out. I finished that for today by painting the parts black to match the frame.

    IMG_1048.jpg

    I put the flaperon hinge reinforcement brackets through Alodine, then bonded and riveted them in place in the left wing. My luck with Hysol ran out, and I ended up with it all over my hands and even on the garage floor.

    IMG_1056.jpg

    In between batches in the Alodine tank, I started test fitting the rudder pedal assembly. I can see now why this task is such a notorious pain. Stupidly, I put it in directly on the frame at first, then wasted half an hour fiddling with it before it occurred to me that nothing I was doing mattered one bit since the final fitment had to include the floor board.

    IMG_1050.jpg

    It's just as well I had to take it all out and start over, as the pilot's left pedal would only rotate smoothly with three washers worth of shim under the left-hand bracket.

    IMG_1051.jpg

    I started planning a wooden spacer in my head when I finally woke up and decided to test it with the floor board. Lo and behold, it works fine without any shimming at all. Unfortunately, I'm not out of the woods, as the lateral fit isn't working.

    With the right bracket centered over its C-channel in the fuselage...

    IMG_1055.jpg

    ...the middle bracket (its sidewall is highlighted in red) is pushed about 1/8" too far to the left...

    IMG_1053.jpg

    ...and the left bracket is pushed about 3/16" too far to the left.

    IMG_1054.jpg

    I might be able to gain 1/16" by sanding a couple of the plastic bearing flanges a bit thinner, but it's not going to be enough. The only other way I can see to get the brackets lined up over the C-channels is to shorten the right side torque tube by about 1/8" and the left side torque tube by about 1/16". What have others done in this situation?
    Eric Page
    Building Kitfox 5
    Member: EAA, AOPA, ALPA
    ATP: MEL / Comm: SEL, Glider / ATCS: CTO
    Map of Landings

  8. #178
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    Default Re: The Barn Find Build

    I started today's effort by mixing up some Hysol (I'm still using the 50 ml cartridges but for larger amounts I find it easier to dispense what I need into a cup, mix it by hand and spread it with the stir stick).

    First to get glued was the fiberglass fairing at the base of the tail post. It was a bear to fixture due to its odd shape and flexibility, but I think I got enough tape on it to hold it in place. It'll need a couple small beads on the inside where it meets the bottom rib, but I can do that another day, when I'm using a mixing nozzle.

    IMG_1057.jpg IMG_1058.jpg

    Next was the pitot tube mounting plate, which went in easily and was a cinch to clamp. I decided to leave the triangular gusset where the old pitot would have mounted. It's negligible weight and it'll strengthen the rib where my new pitot is mounted. I will clean up all the old glue and Poly-Brush.

    IMG_1059.jpg

    I had just enough Hysol left to re-glue the end of an aluminum angle behind the left door where my clamping failed last time. I drew a thin hacksaw blade through the opening to remove the last batch of Hysol, followed by the acetone-soaked edge of a rag to clean out the dust. I used the stir stick as a spatula to apply some Hysol into the void, then clamped it with a block of wood and two lengths of duct tape. Tomorrow will tell whether I've glued a 2x3 block of 3/4" maple to the side of my plane.

    IMG_1060.jpg IMG_1061.jpg

    Frankly I'm sick and tired of fixing problems and I wanted to do something with the flavor of a new kit, so I put some fresh Kraft paper on my table and unwrapped my new elevator (there's nothing unairworthy about the old one; I just wanted to switch to the longer Series 7 surface). First I put the 3/16" reamer to work again opening up the mounting lugs and control horn, which went surprisingly easy.

    I was mildly amazed to find that the hinge lugs on my 2020-built elevator match perfectly with the bushing bosses on my 1994-built horizontal stab. I had visions of 1/16" misalignment and another trip to the welder.

    IMG_1062.jpg

    I found that the Series 5 manual and my 2006 Series 7 manual both show ten ribs in each side of the horizontal stab, but only six in each side of the elevator, while the current Series 7 manual on the Kitfox website shows ten and eight, respectively. Since I bought a new elevator, I have eight, but there's one spot on each side, at the outboard ends, where there's a rib in the stab but none behind it in the elevator (the -302 rib in this image).

    Tail Ribs.jpg

    This offends my sense of order, and I imagine it will be noticeable after covering, so I elected to make two more ribs. I traced the profile of the small end onto the table, measured the required distance between tubes, traced the large end at that distance, then connected the dots. Confident that it would work, I copied the layout onto plywood and cut the blank with my miter saw (right at the limit of its reach!).

    IMG_1063.jpg

    I used the belt sander to bring the width down to the line, then a sanding drum in the drill press to shape the large end and a tiny burr in the Dremel (held in the bench vise) for the small end.

    IMG_1066.jpg IMG_1069.jpg

    After a little back-and-forth to dial in the fit, I had a new rib.

    IMG_1064.jpg

    Flush with the glow of success, I traced that shape onto the plywood and cut another blank, repeated the shaping process and ended up with a pair.

    IMG_1068.jpg

    I still need to adjust fit on the factory ribs, but the sanding drum makes it a pretty quick process, so it shouldn't take too long. I should also mention that my rib locations bear almost no relation to the measurements shown in the manual. I laid it out on the Kraft paper as shown in the manual, then held my horizontal stab up to the elevator and realized that none of the ribs match those locations (here we go again...). So, I'm just going to roll my eyes and match the horizontal stab locations. Thank goodness they're not structural.

    IMG_1070.jpg
    Eric Page
    Building Kitfox 5
    Member: EAA, AOPA, ALPA
    ATP: MEL / Comm: SEL, Glider / ATCS: CTO
    Map of Landings

  9. #179
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    Default Re: The Barn Find Build

    Just a short update for today, starting with yesterday. All I managed to do on Wed was pick up my doors from the welder. I ended up having him just close the holes that would be visible after mounting the new bubble acrylic, which eliminated any concerns about warping the doors by welding many holes on one side. I didn't take any photos. The welder gave me a line on a local powder coater he uses, so that'll be their next stop.

    Today I removed the clamps from all of Tuesday's glue-ups, with good results. The tail post fairing will still need a couple small beads of Hysol at the bottom inside edges, the wood reinforcements will need varnish, and some gaps need filled with Poly-whatever-it-is, but it feels good and solid even now.

    IMG_1074.jpg

    The left door trim glued down the way I wanted it to this time, so it'll just need some body work with Poly-blue-goo to make it disappear.

    IMG_1075.jpg

    My fabricated pitot mounting plate is very solidly glued in place, and I cleaned up the old gusset of glue and Poly-Brush. This still needs a stabilizing brace on the lower right corner of the first photo, which I'll install next time I'm playing with Hysol.

    IMG_1076.jpg IMG_1077.jpg

    Most of today's effort was directed at fitting the ribs to the new elevator. I got them all done, and I think they fit pretty well. I gone one about 1/32" too short, but it's nothing a bit of extra Hysol won't solve. Since these ribs don't match the factory-specified locations, many don't lay beside tubes, so they'll need narrow chord-wise braces glued to them for stiffness. I'll probably apply those separately, out of the structure, then install them in the elevator. For now, it looks pretty good!

    IMG_1073.jpg
    Eric Page
    Building Kitfox 5
    Member: EAA, AOPA, ALPA
    ATP: MEL / Comm: SEL, Glider / ATCS: CTO
    Map of Landings

  10. #180
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    Default Re: The Barn Find Build

    Today I started out with more woodworking. Since my elevator ribs don't follow the factory spacing, only two on each side are adjacent to steel tubes. As a result the rest are a bit floppy, so I fabricated stiffeners for them from 1/8" plywood, which I attached to the ribs with a bead of Hysol.

    IMG_1083.jpg IMG_1081.jpg

    While I had some Hysol mixed, I permanently attached the top anchor block for the comm antenna. It moved a bit on me while I was taping it in place, which explains the smear of Hysol behind it in the photo. Oops.

    IMG_1082.jpg

    Next to get Hysol was a reinforcing piece for the previously unsupported corner of the pitot tube mounting plate. (Yes, there's still room for the pitot tube's base flange.)

    IMG_1079.jpg IMG_1080.jpg

    After lunch I re-attacked the rudder torque tube assembly mounting. Having heard no complaints about my plan to shorten the tubes slightly, that's what I did. I ended up only having to take a bit less than 1/8" from the inside end of the right-hand tube, which made each bracket line up perfectly over its respective C-channel. This photo is the left bracket.

    IMG_1085.jpg

    Some of the existing holes in the floor board don't line up with the new bracket positions, but they'll all be hidden under the brackets. I drilled new holes, but it took some considerable effort. Apparently Harbor Freight drill bits aren't the best for drilling through weld-hardened steel. I got it done, but I'll definitely be stopping in town for some good bits before I try to drill the holes for the brake master cylinder brackets.

    Taking an idea from alexM, I drilled the holes oversize, and I intend to use floating nut plates to secure the brackets with screws from above. My effort to get the brackets centered will pay dividends when I mount those in the C-channels.

    IMG_1086.jpg

    With everything tightened down I had some tightness return to the torque tubes, but I used a suggestion from the forum (I'm sorry, I can't remember who suggested it) to sand the bearings in a slight barrel shape to allow some wiggle for misalignment. That worked beautifully, and I've got almost no drag on their movement at all now. It feels really good to have that bug-bear behind me and know that they're ready to be greased, installed and rigged.

    IMG_1087.jpg
    Eric Page
    Building Kitfox 5
    Member: EAA, AOPA, ALPA
    ATP: MEL / Comm: SEL, Glider / ATCS: CTO
    Map of Landings

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