Billy Buckner

I'm scratch building a low wing plane with slightly swept back wings and would like some advice on how to install the wing joiner.
Thanks for any input.

Ed_Moorman

My Feedback: (1)

Some people use straight hardwood spars across the center sections on both sides.

I have also used a laminated dihedral brace with a bend in the middle. 1/16 aircraft ply bent to match the sweep and laminated (4 pieces) with epoxy works well.

I have also built many planes without a dihedral joiner. I used 6 ounce fiberglass cloth and 30-minute epoxy to join the panels. The largest plane I did this on was a 90" span, 60cc powered giant acro plane. I used to snap the heck out of it and never had a problem.

Billy Buckner

Thanks Ed. I like all the ways you mentioned. Do you have a preference for a 2 stroke .75 powered low wing plane set up?

KitBuilder

Fashion one out of aluminum stock... my sailplanes would have an aluminum joiner with a coiuple holes sandwiched between ply... the holes allowed expoy to tie the ply together.. you could put a slight bend in the joiner and retain all the strenfth of the aluminum.
Mike

MinnFlyer

My Feedback: (4)

If you scratch-built it, you should have designed it with a straight spar. Too late for that now, but something to consider in the future.

What I would do is to use thin plywood - Like 1/16" - and epoxy it in place with the necessary bend.

Clamp it, and let the epoxy set.

Then add a second, a third, even a forth if you think it needs it. Or maybe 2 layers on each side of the spar.

Billy Buckner

Many thanks. I like the idea of an aliminum center between plies. BVB

Billy Buckner

Thank you. Since the wing isn't built you gave me two more options which I appreciate. BVB

AAbdu

My Feedback: (18)

I swept back the wing on an ARF Avistar that, ultimately became a YS 60 pwered bipe, and I used an aluminum spar that worked perfectly. Just bend it to the right angle and install it with epoxy.

Billy Buckner

Thanks. I'm wondering what size aluminum spar you used. Your plane looks great! BVB

AAbdu

My Feedback: (18)

I actually used several (six I think) solid aluminum rods 3/8 in diameter if my memory serves me correctly. Each one was carefully bent to shape and the final resulting spar was epoxied into the existing dihedral slot. I had to sand the center section to have the right angle but it wasn't that bad.

PM me if you need closer pictures or further explanation.
Anthony