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proppastie

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Is there an equation/method to determine maximum aileron hinge moment
Faa Glider Criteria (google) has a chart for limit load on ailerons based on speed.....my limit load for the Aluminum Dragon is 9 PSF (pound/sq ft) which is also the lowest setting on the chart.

note edit of load
 

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TFF

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Are the aileron ribs bonded to the torque tube only, or is there an anchor like a pin or a screw to back up the bond, if splits loose?

No , you don’t need to glue fabric to false ribs.
 

proppastie

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seems to me I remember the load distribution was triangular .....I loaded the ailerons at 1/3 the height of the triangle.....
1613739637354.jpeg
 
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Rudy Lee

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Are the aileron ribs bonded to the torque tube only, or is there an anchor like a pin or a screw to back up the bond, if splits loose?
The current design is just bonding aileron ribs to torque tube. Once I run the numbers, if it turns out that they need extra support, we were thinking of 3d printing nylon flange rings that we would epoxy on to increase surface area in contact with the tube.

Also thanks for the gluing tip :)
 

Rudy Lee

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Hi all, another question about fabric covering. We are using poly-fiber systems and found some differing explanations on how to prepare our fiberglass rib caps for poly tak gluing. Stits website seems to infer that we can just sand the top with sandpaper (FAQ's, How do I paint over composites or fiberglass?) but the systems manual says we need all sorts of chemicals that I thought were only used for finishing the fabric, not preparing surfaces for adhesion. (https://drive.google.com/file/d/1y1sh0X7FNZOEB0nxC7_jQAyu2e3HPQ0G/view?usp=sharing page 10, pdf page 21 on fiberglass). Do we really need to use all of these coats or can we just sand the fiberglass as preparation?
 

Dana

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An aluminum cap strip on the ribs could rivet to the aileron spar and the trailing edge, that's what I was planning for my ultralight biplane design.
 

Rudy Lee

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Is the foam safe with the Polyfiber? It would not be my pick for foam ribs.
the foam will melt when in contact with polytak. However, our fiberglass rib caps are fine when in contact and we will be taping over all exposed foam. The main question is how to prepare the fiberglass for proper adhesion
 

TFF

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The problem is vapors and the MEK based paints as much as contact directly. I am a fan of Polyfiber. I used it to cover my plane. Lots of work can be lost with an accident like a spill, and damaged will be hard to inspect if fumes do attack. I would go get a $5 can of MEK at the hardware store and see what the foam can tolerate.
I would be using 3M UF30 glue. Next plane I cover even if Polyfiber will use that glue. Probably would use Latex house paint if I was not going waterborne airplane paint.
 

pwood66889

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Good luck on getting the MEK, Rudy! I had found a MEK-a-like substance that I could Not Use because the PolyFibre manual I was using called out MEK (the real stuff) and I have a certificated airplane!
 

TFF

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When I was covering mine there was a shortage. They make the stuff here too, they make TP here too and there was a shortage of that too. None at Home Depot or others although they do now. Went to a regular house paint store and asked. They said how much do you want? I do think they do not want to sell it at box stores anymore and limit it.
 

Rudy Lee

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Good luck on getting the MEK, Rudy! I had found a MEK-a-like substance that I could Not Use because the PolyFibre manual I was using called out MEK (the real stuff) and I have a certificated airplane!
We have poly systems MEK just in case we need it
 

proppastie

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I got a quart of the real stuff from McMaster Carr.....that size they said no hasmat fee.
 

proppastie

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the foam will melt when in contact with polytak
I think all the poly-fiber stuff you thin with MEK. .......one possible solution is to use that 3m water base glue and consider latex as others have said..... or even "no finish" (if you keep it inside)
 
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