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Bolt on wing question

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Old 01-25-2019, 02:55 PM
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TampaRC
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Default Bolt on wing question

I am working on a 1/12 scale corsair originally designed for rubber band on wings. It will be powered with a 015/.20

I want to convert to bolt on wing. Can you get away with a single dowel at the leading edge (vs. the normal 2 dowels) and a single nylon bolt at the trailing edge? Am I asking for trouble with only one dowel?
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Old 01-25-2019, 03:54 PM
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speedracerntrixie
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I really like the idea of having two attachments at one end or the other. However if the wing saddle is a perfect fit to the wing then yes a single attachment on a small model will work just fine. I prefer to use a CF rod over dowel. Wears much better.
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Old 01-25-2019, 06:27 PM
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Heliman4213
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One is plenty. This is not a giant plane there is almost no stress there for that size model.
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Old 01-26-2019, 08:11 AM
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I used that style of wing mount on my 1/12 scale Arsenal VG-33. It worked just fine.
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Old 01-26-2019, 10:14 AM
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A 40 inch Corsair? Should be no problem. We use to fly 60 size warbirds with a single 1/4 inch dowel holding the front of the wing. What size bolt do you intend on using? A single 1/4 x 20 should be fine but if you're using something smaller I might consider going with two.

The advantage of two dowels is it gets the mounting and hence the stress from the center of the fuselage to the sides. There you have more fuselage structure to support things. The 2 bolts is pretty much the same concept.

Going single bolt/dowel be sure the TE is solid the width of the fuselage to support the bolt. And the mounting blocks in the fuselage go from side to side. 1/8 inch ply re-enforcement on the forward bulkhead for the dowel and a 1/4 inch ply plank side to side in the rear threaded for the bolt. I would also fill in some soft balsa between the wing TE and the threaded ply to help support to the wing. But in the end, it's probably not really necessary.

Last edited by Appowner; 01-26-2019 at 10:22 AM.
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Old 01-27-2019, 12:28 PM
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The Guillow's Corsair will be a fast plane with that sort of power. So while the single dowel and single screw will do fine you'll want to ensure a couple of things. First off is make the dowel large enough to do the job. 3/16 hardwood should be fine. Second is that the plate the dowel fits into needs to be plywood and extend far enough over enough of the bulkhead it mounts onto to transfer the load out and into the bulkhead, stringers and sheeting or planking used for the outer skin. 1/16 or even 1/32 would be fine as long as it spreads out the load. And same at the back end for the screw. The threaded block or plate should be glued to the bulkhead there and should spread out to the side skins.

Along the way you'll want to harden the wing's center rib by making it out of at the very least fairly hard balsa or plywood. Or band the center section with a 1" strip of 2oz fiberglass tape and epoxy to give a good strong center line strength. After all the center point of all the pressure is at a line between those two points. It's spread out but still......

It's also not as bad as it sounds since you're not likely to be doing really high G inverted stuff. The positive G loads will be taken by the wing saddle. Only any negative G loads will need to be taken by the dowel and screw.
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