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Thread: Repairs for oversize holes? Other ideas?

  1. #11

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    Default Re: Repairs for oversize holes? Other ideas?

    As I said in one of my earlier posts, one of the aileron spars was showing signs of trouble at one of the hinge points where the steel fitting is riveted. The picture below shows the view of the trouble spot as seen from the trailing edge. The picture was taken AFTER I removed the steel fitting from the other side, so the crack was not there. You could see the dull grey area that there might be some corrosion there.

    IMG_0203.jpg

    Here is a pictured of the other side of the same location with the fitting removed...
    IMG_0202.jpg

    Yikes! ... and here's some photos of the steel hinge fitting, one taken with different lighting. What's that? Powdered aluminum?
    IMG_0205.jpgIMG_0206.jpg

    Okay, if one is THAT bad, the rest of them are probably not very good, so I drilled some more of them apart and here's what I found...
    IMG_0228.jpgIMG_0229.jpgIMG_0310.jpgIMG_0311.jpgIMG_0318.jpgIMG_0320.jpg Well, by now you are getting the idea.

    So, I started drilling all of the ailerons and flaps apart one at a time, and wound up with a pile of parts to reassemble each time.
    60643537473__27E53B9E-8832-446D-980B-EEE9B73F03EA.JPGIMG_0321.jpg I was able to sand blast most of the steel fittings and reuse them, but some of them had to be replaced due to previous attempts at repairs with oversize holes that I didn't want. For the most part, they tried to get the fittings out and succeeded in some cases. You could still see where they scraped a little bit with a screwdriver or something then just bashed some new (oversize) rivets in place... All cleverly disguised with a brush coat of zinc chromate over the outside. Even when they were successful at removing the fitting there was no primer or chromate or anything between the steel and aluminum parts except the remaining corrosion.

    So with new spars from Univair, an assortment of new bulkheads for the leading edge skins, a few new ribs, a few new steel fittings and a bunch of other little pieces of sheet metal and a bunch of rivets (AN456) I started putting things back together. I was trying to figure out how to match drill the new spars so I asked my IA for his advice. He suggested using match drilling strips of plexiglass cut to the width of the spar which worked beautifully!
    IMG_0237.jpg I hope you can see this. I tried to put in a couple more pictures but I hit the limit for this post.

    I'll try to put another post up tomorrow with some more info on the flap and aileron assembly process.
    Attached Images Attached Images

  2. #12

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    Default Re: Repairs for oversize holes? Other ideas?

    Hey everyone, it's been a while again, but here are some more photos/info on my project.

    As I was saying in my last post, I used plexiglass to match drill the new spars and it worked beautifully.
    60643534201__D7B759F3-CA2D-4ED7-833A-61C26CE50796.JPGIMG_0262.jpg
    After application of some epoxy primer I was ready to begin reassembly.
    IMG_0266.jpgIMG_0283.jpg
    Next, I needed to install the bulkheads in the new leading edge blanks that I ordered from Univair (originals were all dented up). Here's the problem with those blanks... They were fabricated from .032-T3 aluminum and the originals were .025-O. That might have been okay but they weren't shaped very well at all so the didn't really fit the bulkheads (nose ribs) satisfactorily. I used the leading edge blanks that I ordered on the ailerons, but it was after I spent a whole day trying to re-radius them to fit. Needless to say that was a major pain! Fortunately they were slightly oversize so I was able to install the bulkheads, then trim the trailing edges after they had been clecoed the spar and marked for trimming.
    IMG_0246.jpg
    I needed more leading edge blanks for the flaps too after I had used the Univair blanks, however, I decided to try making my own out of .020-O like the originals. For some people that would be easy but for a beginner like me it was a head scratcher. What I came up with was to cut a channel into a 2X4 and then use a dowel that I taped to the edge of a piece of plywood to press the aluminum into the channel. I used a piece of 5/8" dowel pressed into a 3/4 inch channel and the radius was perfect. It was much better and much easier to work with than the Univair parts.
    IMG_0313.jpgIMG_0314.jpgIMG_0315.jpg
    You can see from the pictures how it worked. I used the pictured clamps to push the aluminum into the channel. Pretty sweet!

    Now that all the pieces are ready for final assembly, I needed a fixture of some kind to hold it all with the proper twist (per Piper drawings from SWPC). More to come on that. I'll post again soon.

  3. #13
    Administrator Steve Pierce's Avatar
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    Default Re: Repairs for oversize holes? Other ideas?

    Hmm, I looked at the drawing and then went and measured the leading edges I have and both the drawing and my stock ar .016". How did you get the roll in the top of the skin?
    Here are some pictures of my jigs. https://www.shortwingpipers.org/foru...-jig&styleid=5

  4. #14

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    Default Re: Repairs for oversize holes? Other ideas?

    Hi Steve,
    Every time I get on this site I wind up surging around and looking at all kinks of stuff and run out of time to post a reply. So much useful information!!! I've been meaning to reply to your post for some time now so here goes.

    In that last post I wrote that the leading edge skins were .025 in one paragraph and .020 in another. I meant to say .020 in both cases. Anyway when I get back to my hangar in a week or so I'll double check the thickness of the originals which I still have. I used a thickness gauge to check them so I could have been mistaken. I'll check with a micrometer or caliper next time. Anyway, I used .020 for the replacements...

    I'm trying to remember how I put the roll in the top of those skins for sure, but i think I just formed them (gently) over the edge of my workbench by hand. It was pretty easy since they were soft aluminum as I recall.

    I saw some pictures of your jigs and also looked at what Jason Perkins did. I started out trying to do it Jason's way and gave up of it later, I think because it wasn't going to work after I installed the hinge fittings. I was seriously considering welding up my own fixture like yours but started brainstorming for something I could do quicker. After noodling around on it for a few days I came up with something I though would work. By the way, I had not seen the post about the Javron wing build. Had I have seen that I probably would have done it that way, with the plywood and shims,

    I did the initial assembly of the ailerons and flaps just by riveting all the steel fittings and ribs in place. Then I clamped everything down to a couple of 2X4s to get to assembled -minus the leading edges.
    IMG_0267.jpg
    IMG_0283.jpg

    For the final assembly here's what I came up with. I have this workbench that a Sherman Tank couldn't hurt and it's about the same length as one of our ailerons. I bought a few pieces of steel angle. I cut some pieces a couple of feel long or so and clamped them to the ends of the workbench in the vertical and made sure they were perfectly upright (in the same plane) with the aid of some fishing line and a level. Then I bolted a couple of pieces horizontally in the correct position so that I could clamp the aileron or flap to it with some pieces of rubber tubing slit lengthwise for cushions. So that I could get the correct twist, I simply put washers in one end or the other I turned out the the same spacer work for both the aileron and flap on the same side. I had to get creative on the clamps. I used tape, clamps zip ties, you name it, but it worked.
    IMG_0284.jpg
    IMG_0285.jpg

    I see now in looking at these pictures again, I just used some small pieces of angle at the bottom (near the spar area), but I had to use a bar across the bottom for the flaps.

    Gotta run for now.
    Pat

  5. #15

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    Default Re: Repairs for oversize holes? Other ideas?

    Hi Folks,
    I find myself in the same situation as avspecguy in the beginning of this thread. I have oversize and snowman looking holes in my horizontal stabs that I need to address. Steve stating they are drilled at assembly and are a match set explains why sometime in the past they ended up it his way. A couple questions though for which I’m looking for some advice. I do plan on welding my the holes up horizontals. My question is do the bolts have to be in the vertical plane or can drill the new holes slightly off vertical to avoid drilling through the weld? Also I need to replace the short tube that passes through the fuselage, but the longer tube (and some how I’ve acquired 2 of them) seems to be in good shape. Would it be ok to rotate the tube 90 degrees and redrill new holes through it at assembly? If there’s a strength or fatigue issue I can just spend the 100 dollars and buy a new one.

    Thank you,

    Pat

    224455A5-964A-4A73-9125-64CC925977B9.jpeg22C11E04-268C-404D-889D-01A02D75AA31.jpeg

  6. #16

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    Default Re: Repairs for oversize holes? Other ideas?

    Welding up the holes in the stabilizer will be OK, biggest issue will be cleaning out the ID for the cross tube to slide in. I don’t think drilling a few degrees off vertical will be a problem. I wouldn’t drill a second set of holes in the cross tube. I think it would remove too much material as it is only .049 tubing. Do not weld those holes as the tube is chrome plated, and you would be introducing chrome into the weld puddle, making that portion of the tube very brittle.

    Go spend some money with Univair on some new tubes! $66.66 for the rear one, and $104.25 for the front one.


    Sent from my iPad using Tapatalk

  7. #17
    Administrator Steve Pierce's Avatar
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    Default Re: Repairs for oversize holes? Other ideas?

    You could drill the new holes inboard of the figure eight you have now. If you do not drill vertical you will be pushing the fabric down ever so slightly either on the top or the bottom. It is not recommended to add another set of holes 90 degrees in the liner tubes. Charlie Center, Cross Wind STOL tells a story about one that broke that was drilled that way.

  8. #18

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    Default Re: Repairs for oversize holes? Other ideas?

    Thanks for the input gentlemen. I will order new tubes and after the horizontals are welded, drill them vertical slightly inboard. I see the print gives a range of 1/2 to 1 inch for that hole location from the end of the tube.

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