Slight warp in wing?

[Mike K]

Am working on building a new wing for my Drifter II. This is using D-tube construction, details are:
1/8th x 1/4th spruce spars, 3/32" webbing, with .007 carbon strip on top and bottom, with a little bit of kevlar tow wrapping. Expecting to use 1/16" sheeting for top and bottom of front.

I just realized after doing the kevlar tow that one area has a slight warp in it.
Warp is actually probably the wrong word, but this is difficult to explain. The wing panel is flat, until you get to the root rib. When I get to the root rib, the rear of the rib is a bit more than a 1/16th of an inch off the flat glass. Less than 3/32"...

I think that when I do the 1/16th sheeting, I can take out this misalignment.
But I am not 100% sure as this is the first time I am using this technique.

Thoughts?

Regards.
Mike K.

[Sparky Paul]

You might soak the structure with something like Windex, and weight the whole thing to be flat on the board.
When it dries out, it -should- be flatter.

[Mike K]

You might soak the structure with something like Windex, and weight the whole thing to be flat on the board.
When it dries out, it -should- be flatter.

Ok, will try that tonight.

Thanks, wouldn't have thought of that...

Regards.
Mike K.

[bobby legue]

When you add the 1/16th sheeting be sure to weigh the wing down securely and let it dry completely before removing it from the board. You can get into a building frenzy and pull it to soon and the wing will warp a little as the glue dries. Guess how I know?
Bob

[rogerflies]

The procedure suggested above might work, but why take a chance? Make a razor saw cut 1/4" behind the spar. Cut from the bottom up. Weight the panel down flat, and laminate a piece of ply on the outboard side of the rib over the saw cut. Use slow-cure epoxy or carpenter's glue.

If necessary, do the same thing in front of the spar, cutting from the top down.

You'll have everything in the right place when you're putting on the sheeting, and you won't have to worry about the out-of-position rib messing things up.

Roger

[arukum17]

with the slight warp you mention it should still fly and handle OK...fix it if its easy to the best of your building ability but i wouldn't loose any sleep over it...

the beauty of aeromodelling is - if you build it it will fly :)

[Mike K]

with the slight warp you mention it should still fly and handle OK...fix it if its easy to the best of your building ability but i wouldn't loose any sleep over it...

Too late... Already hit with Windex and weighted down and drying as I type...

As it would likely be about 1-2 degrees of washout on the entire panel, I thought it would be best to fix it...

Anyone have a good plan for a dihedral jig? {grin}
That's what I think I need to make up next...

Regards.
Mike K.

[Mike K]

You might soak the structure with something like Windex, and weight the whole thing to be flat on the board.
When it dries out, it -should- be flatter.

24 hours later and it *IS* flatter.

Thanks for the tip!

Regards.
Mike K.

[TomO]

I'm currently suffering the same fate in a wing I'm building (see my Windfree thread).

Today it's drying after a Windex(tm) misting, but I'm wondering what qualities Windex(tm) has that works better than just plain old water? I used the glass cleaner because I've read here and elsewhere that it is the right thing to do - just wondering why.

-TomO

[Mike K]

I'm currently suffering the same fate in a wing I'm building (see my Windfree thread).

Today it's drying after a Windex(tm) misting, but I'm wondering what qualities Windex(tm) has that works better than just plain old water? I used the glass cleaner because I've read here and elsewhere that it is the right thing to do - just wondering why.

-TomO

I'm guessing the ammonia in the solution soaks the wood better.
I could tell that the Titebond I used softened up really quickly.
Nothing else to add, it is cheap and it worked.

What I realized a couple of days ago is that my original Drifter II wing has a far, far larger warp in it. No wonder it is so skittish when turning to the right versus the left... {grin} I was going to peel off some Monokote tonight to try to fix it using the Windex method before the weekend.

Regards.
Mike K.