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Balancing Ailerons

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  • Balancing Ailerons

    Just seeing of anyone has a suggestion here. Made my ailerons and loaded balance tube with about 4.5 lbs of lead, round mold that was almost tight in aluminum tube. Have about 8" of tube remaining. Covered and painted and need about another pound to balance. Tube filled with fine shot and is about 5.7 oz short.

    Steve P203

  • #2
    Depleted uranium. ;>) actually tungsten's about the same density which is about 70% greater than lead.

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    • #3
      You will need to open a hole at the side of the tube (its not an easy area to see on a finished plane) and melt about 1.1 lbs of lead, then pour it into the tube. You'll have to pour fast.

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      • #4
        you can avoid the heat if you mix the lead shot with epoxy and pour it in the tube.

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        • #5
          I am afraid the heat would ruin your fabric/paint. The way I read your post, the tube is full but short of the required weight. If that is correct you can add loose shot to one or both ends of the aileron leading edge by drilling a #10 hole in the aluminum skin just in front of the spar. Pour in the required amount of shot. Position the aileron so that all shot is in the nose and use a syringe to add enough T-88 to hold the shot in place. Use a pan head screw to close the hole. Ask me how I know this works.

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          • #6
            Thanks guys. I left the end of the tube open knowing I was going to add more weight but thought I had the room. I filled it with fine shot and epoxy yesterday and will check it again for the necessary weight needed for balance. On one of the ends, I will open a hole for another tube to be inserted at the end nose rib to the inside rib at the hinge bay. I can use the tooling holes to secure it at least on one end. I will have to create something on the one end to bolt to the rib flange. I think with the resin added, I will only need a few ounces to balance. I think a slightly larger tube initially would have been the answer. A buddy building a 4 place used a heavy wall 7/8" aluminum tube which will work if he needs the room. His logic was you have to add the weight anyway so why not use a heavy tube.

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            • #7
              Thinking out loud here....Cerrobend melts at 158 degrees. Is a combination of 50% bismuth, 26% lead, 13.3 tin and 10% cadmium.
              If the builder feels 158 degree melting point is low? Adding lead shot will increase the melting point. Use a stainless bowl on a gas cook top on low heat. Melt the cerrobend then add lead shot say 10-15% by weight...bring up the heat as needed to liquify. Cool then use a double boiler and candy thermometer to find the new higher melting point. Use cooking oil instead of water...cooking oil will not begin to burn/smoke until the temperature is greater than 350 degrees. Just googled Rose metal....is an alternative....melts at 208 degrees..bismuth melts at 212 degrees.
              Last edited by Mark Moyle; 10-11-2018, 12:32 PM.

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              • #8
                If you can take the tube back out of the aileron without too much trouble (ours is held in place with a few pull rivets}, then you might be able to get the lead to settle into the voids in the tube by heating it with a torch. We used a weed burner type torch to get the lead to settle when pouring it and a 3/4 inch tube held enough weight. The lead melts at a much lower temperature than the aluminum but certainly care is in order.

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                • #9
                  I needed just about 100g a side to balance or even slightly nose heavy. I opened up the front 3/16" tooling hole on the outer end nose rib one and poured in about 80g of fine lead shot. Shook it into the front corner. With a syringe I put in about 30cc of epoxy resin and shook it again until I couldn't hear any of the shot moving inside. I do and don't like this idea. It is a very simple fix which I like. Was thinking what if it every came loose?? If the resin works its way into the voids and flanges, it shouldn't come loose and move out of position. Anyways, another thing crossed off the "to do" list.
                  Thanks for everyone's ideas

                  Steve

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