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Old Feb 15, 2012, 07:35 AM
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Scratch Built Balsa Wing (Build Log)

Hello everyone, I thought I'd like to try building a balsa wing.
I chose a Sipkill 1.7/10B foil.

Ive got the planform drawn out, ribs cut and starting on assembling the wing .
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Old Feb 15, 2012, 08:46 AM
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Are you building without a jig? It's hard to get all the ribs aligned vertically without one. Could cause some control problems.

--Norm
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Old Feb 17, 2012, 05:58 AM
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Are you building without a jig? It's hard to get all the ribs aligned vertically without one. Could cause some control problems.

--Norm
The notches in the ribs are nice and firm when the strips and slotted in,
I then use a square angle to adjust each one while putting a little glue on to lock it and stop it from moving.
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Old Feb 17, 2012, 11:13 PM
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You are doing fine, don't let the ney-sayers stop you. It is nice to see someone taking up the challenge/fun of an old school build. The rib alignment is not that critical, good tight glue joints are. Do not compensate for a poor fit with glue, it just adds weight and very little strength. Looks like a decent amount of wing area for a nice stable flyer.

Best of luck.

Peace, Wolf
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Old Feb 18, 2012, 11:47 AM
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Originally Posted by bd5wingnut View Post
You are doing fine, don't let the ney-sayers stop you. It is nice to see someone taking up the challenge/fun of an old school build. The rib alignment is not that critical, good tight glue joints are. Do not compensate for a poor fit with glue, it just adds weight and very little strength. Looks like a decent amount of wing area for a nice stable flyer.

Best of luck.

Peace, Wolf
I'm not sure if you are saying that Norm is a ney-sayers. I can tell you first hand that is definitely not the case. I can also tell you first hand that rib alignment can be very critical on swept flying wings. Not trying to pick a fight just adding my two cents.

I too like the "old school" wood build. Take a look at some of my build and you'll see that's the case.

Cheers!
Brian
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Last edited by cpdude; Feb 18, 2012 at 02:06 PM. Reason: Typo
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Old Feb 18, 2012, 12:32 PM
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sure you may already know this ,but what Norm is referring to is the dihedral/ anhedral as well as and twist that should be there.I have played with this airfoil a long time ago and it does very well with symmetric profile. it doesn't need twist if using winglet's,but twist may not be a bad thing ether.
Not sure how this would do built flat.
Good luck,glad to see the old school balsa as well.
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Old Feb 19, 2012, 01:39 AM
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Someone (Norm) said he would need a jig to get the ribs aligned correctly, that is just plain bull... Yes, the leading and trailing edges need to be aligned properly but that does not require anything more than simple blocks placed under either the leading or trailing edge. I built for decades without a jig for the rib placement. matters not whether the wing is straight, swept, tailless, etc.. If they are eyeball straight then go for it, if they look crooked then adjust till they look right. The important thing is tight glue joints.

A warp free wing is simple and does not require anything complicated to achieve. Just knowledge.

Proper washout? Peice-o-cake, no rib jig in sight.
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Old Feb 19, 2012, 08:38 AM
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I too like the "old school" wood build. Cheers!
Brian
Yea I know what you mean.
To many people will buy a radian ( Or whatever ) slot the wing halves in place, then slide the tail in while they proceede to tell everyone that it was
an "Easy Build" despite the fact that they didn't actually build anything!

Planes like this get alot more attention at the field than store purchaced ones.



One thing that I've found is that the glue can warp the frame when its drying, so I always pin it in place.

Next step is the Winglets!
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Old Feb 19, 2012, 09:16 PM
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Pins are a good idea for sure, but if the glue joints are free of slop then there should not be any movement. Are you using aliphatic resin or...? CA's will help speed things along.

I agree that true "builds" do garner more attention, especially from those who have never done one.
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Old Feb 20, 2012, 01:50 AM
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Originally Posted by bd5wingnut View Post
Pins are a good idea for sure, but if the glue joints are free of slop then there should not be any movement. Are you using aliphatic resin or...? CA's will help speed things along.

I agree that true "builds" do garner more attention, especially from those who have never done one.

As I mentioned in an pervious post, the joints are tight.
When your joining 2mm balsa, even a tight joint will still let it "pivot".

Im not sure what type of glue it is that I'm using ( Its not here with me)
but its called C23 Balsa Cement.
Ive used it on 4 scratch builds Ive done in the past and its been good.
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Old Feb 20, 2012, 05:42 PM
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C23 is the good stuff
looking good so far.
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Old Feb 20, 2012, 10:18 PM
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Do you have a copy of the plans for this? I would be interested in a build of this nature.
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Old Feb 21, 2012, 12:12 AM
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looking good.

But if I may give some advice, you got a little overboard on the amount of glue around the center section. In the close-up, there are some very large glue fillets and the glue covering the aluminum stiffener is just adding weight without any additional strength. Large glue fillets just add weight and very little strength. Adhesives are there to bond two surfaces together and by themselves have no inherent strength.

Rock on.

A thin CA would work much better for most of your work, nice attention to detail on the joints.
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Old Feb 21, 2012, 05:34 AM
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Do you have a copy of the plans for this? I would be interested in a build of this nature.
No plans exist sorry, its a true Scratch Build!

The closest thing to plans would be the Planform I Used to line the ribs up
which can be seen in the first photo.
you will see that the wing size was actually dictated by the size of paper
that I had to draw on.
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Old Feb 21, 2012, 05:42 AM
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Originally Posted by bd5wingnut View Post
looking good.

But if I may give some advice, you got a little overboard on the amount of glue around the center section. In the close-up, there are some very large glue fillets and the glue covering the aluminum stiffener is just adding weight without any additional strength. Large glue fillets just add weight and very little strength. Adhesives are there to bond two surfaces together and by themselves have no inherent strength.

Rock on.

A thin CA would work much better for most of your work, nice attention to detail on the joints.
I used a 5 min epoxy that I don't normally use for the alloy stiffener, it started setting before I was fully ready to apply it so I just slapped it on
as quick as I could!
I prefer the gel epoxys because they don't flow.

You might have noticed the notches in the ribs, thats for when I run the
servo leads.

You may also notice some of the ribs have been sanded incorrectly by
mistake, this has been fixed.
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