Aluminium fuselage flex

Hey guys, I’m currently working on a foil design and instead of using a carbon or fiberglass fuselage I tried to use aluminum and because of that there is some flex. I was wondering if you guys could let me know if this is too much because I tested it just by holding down in the water off of our boat and it produced a ton of lift at low speed so I dont want to entirely scrap it.

Video: https://photos.app.goo.gl/z8U5Dboxz9Vg1D9aA

In my opinion this is way to much flex. You can’t have a stable ride like this. The foils with aluminium fuselage that I have don’t flex. The fuselage part is massive. Yours is hollow I gues?

Yeah mine is a U channel, I think I might get a square channel to eliminate some flex if you think that is too much and it should also slightly improve drag on my design.

It’s too small, it must bigger…
Greetings Frank

The aluminum on my commerical fuselages is solid with little to no flex.

I use Gong foil now but I have designed my own, and you must use a Big Aluminium fuselage, no tube, only full aluminium. 20mm is a minimum.

What thickness rod/pipe enough for DIY aluminium fuselage?

Is it enough 35mm aluminium solid rod to make CNC milled fuselage from it?
Or better 40-50mm 2-3mm wall thickness pipe?

35mm rod - 2.6kg/m
40mm *2mm pipe - 0.65kg/m
50mm *2mm pipe - 0.85kg/m

Price for rod is *5 than 50mm pipe

PS:

The section stifness is dependent on the moment of inertia, comparing solid 30x30 vs 36x36 3mm thick tube then tube is already stiffer than the solid profile at a third of the weight. there is a lot to be gained by a larger hollow profile (at increased drag).

But it’s been discussed regarding the interfaces from mast to fuselage and board. If this is not totally gap free then the mast stifness is secondary.

when I searching aluminium profile I found non standard profile which used in smoking meat production. There are profiles with size near 30mm and I think it could be inserted to the tube, to make it more solid. And the weight for such profile is only 350g per meter.

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