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Wingtip stiffness.

p51dplt

Well Known Member
Has anyone built ribs or some other support in their wingtips? I just upgraded from the old flat top style to the newer shear tips from Vans and they are very flimsy. How or what is the best way to add some stiffeners?

Thanks for the input.
 
Wingtip ribs

I used 1/2" pink foam board from Lowes. Peeled off the plastic, glassed both sides, cut to shape, then used 2" fiberglass tape and glassed in place. The tips are quite large and I was concerned they may flex and crack the paint.
 
Strategically placed wood dowel fiberglassed (and pre-stressed) inside the tip will stiffen it right up. Got the idea off here.
 
I just finished the exact same upgrade

I too replaced 7 tips with the older 6 flat tops ones. I too felt they were a bit flimsy so on the inner surfaces of the top and bottom I glassed in a thin foam sandwich. worked great, an I think it is lighter then the rib method.
 
I had some Parabeam 3D cloth I used to reinforce the tips on my rocket. Worked great but the Parabeam cloth is hard to come by. I don't know where one can get it in the USA.
 
Why are you reinforcing your wing tips? Just because they seem flimsy, or is there a history of failures?
 
Why are you reinforcing your wing tips? Just because they seem flimsy, or is there a history of failures?

There is a history of sagging. Lots of Sagging. Particularly with dark colored paints. Also when moving in soft ground, say the grass at AirVenture, grabbing the wingtips is common to move plane forward. The shear tips will fold and crack your paint in the right conditions, about 6" forward of the trailing edge.
I used foam board.
 
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I see. Can I trouble one of you to please post photos of your mod? I'm about a month or two away from installing my wingtips, and I'm having trouble picturing the mods you are describing.
 
I have used 3/8 rope glassed over to make ribs and found that it works great. Use to use rope for ribs making canoes. Cheap and simple.
 
I used 1/4 in square spruce glassed in with very lightweight glass fabric, four in each wingtip. Should have some pics on my KITLOG, link below.

Bird
 
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Thanks for the feedback guys. Now armed with the new ideas, I will get to work to get them stiffened and ready for paint.
 
Pourable Foam

Has anyone considered using pourable boat hull foam? Light, rigid and conforms to any shape.
 
Has anyone considered using pourable boat hull foam? Light, rigid and conforms to any shape.

A few problem I see with that.
1. Cost
2. Complexity
3. Many, like me, have lots of stuff in that tip. Antennas, wire, etc.
4. Weight

A very simple piece of foam board from Lowes. Trace general shape using the wingtip profile. Cut. Sand to fit. Light coat of epoxy on the ends to hold it in place. Really its a 15 min job. I would not try to over think this. The support for sagging only needs to be from the trailing edge fwd, about 22".
 
Article

On the left side of the opening page look under articles. I wrote a step by step on laminating some dowels in the tips.

This method is simple and doesn't add much weight. It's not the only way but works quite well, and, did I mention, it's simple?:)
 
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