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Wingtip Fit

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  • Wingtip Fit

    I'm not entirely thrilled with the fit of these wingtips. I have to extend the tail about 1/2in so the aileron lines up. That's a pain, but relatively easy to fix. I do have a "pooch" near the tip though. It measures about 1/4 inch. I can slit it and patch it, but I'm not sure what would look worse...the pooch or the patch. I suppose if I go out far enough it would feather out. Any creative ideas on how to fix it?

  • #2
    I fiddled with the tips for too long before giving up and just going with them. If I had done that sooner, they would have looked the same but I would have been flying a few weeks earlier. In the years years since, I may or may not have hit the hangar door with one, providing further relief that I had not strived for perfection.


    • #3
      It looks like your screw spacing is on the long side. I actually modified to make a flush fit but my spacing was around 3". Even then, I got a little pillowing.


      • #4
        I drilled out every third rivet and replaced it with a nutplate. The fiberglass is just the wrong shape for the airfoil.


        • #5
          I had the same issue. The fiberglass wingtips just don't really fit the airfoil. I've got the same "pooch" as you and just went with it until I get around to making a pair of my own.


          • #6
            I don't grind fiberglass indoors so I would leave it until it is outdoors/already flying.

            When i did fix it I would slide some sheetmetal under the affected area to protect the wing sking, leave all fasteners in place, and I would grind all the affected area away, plus put a bevel in the adjoining fiberglass that is remaining, probably at least a 3/4" wide bevel. I would then remove the sheet metal, replace it with waxed paper, and apply new fiberglass. Fair the new glass in.

            I think if you remove the tip to fix the problem, you will never get the shape correct. The fasteners are stressing the tip into place, I would grind away the offending material, in place, and re-glass in place.


            • #7
              Every BH I’ve seen in person has that same fit of the tips. Most older certified planes do too. I’m not sayil Sds ng you should leave it but I do agree with Jared.
              Scratch Built 4-place Bearhawk. Continental IO-360, 88” C203 McCauley prop.


              • #8
                I've never seen another bearhawk out and about flying, but when I did my wingtips, they were too short. I slotted them up the trailing edge, made up a template of MDF based on drawing #7, and gave the whole lot to a boat builder with some money. The wingtips came back the right length. Keep in mind when drilling out the rivets for the nutplates that you can obtain more even a spacing by aligning the existing rivet hole with either the centre hole or the leg holes of the nutplate. Also, use mini-pitch nutplates if you get cramped near the wing spars. I used NAS1169-6L countersunk washers, and there's hardly any pillowing. Countersink the fibreglass after installing the nutplate with a #30 100degree countersink bit mounted in a drill - it auto-centres in the nutplate and won't bottom out! :-)

                Because they are so heavy and easy to take off, the wingtips might be part of the aircraft I look at modding down the track, maybe some of those fancy carbon fibre stol wing tips :-)
                The Barrows Bearhawk: Who knew my wife could get jealous of a plane?


                • #9
                  I took the time to make a flush fit by adding a strip of 025 under the skin on the outboard rib. Got a nice fit. Probably a day's work but well worth it. Bit late now for you as you've already fitted the nutplates to the rib but I would recommend it to other builders.