hebertjj

I'm building and old kit, a Marks Models Bushwacker; 69"WS sholderwing and I don't want to use the dowel and rubberband wing hold down method shown on the plans. The wing sits on top of the fuselage with no former in front of it, and the top of the wing has a fairing on it to blend it into the turtle deck and canopy.

I've thought of gluing and glassing 3/4" dowel pieces vertically, one front center LE and two in the TE, drilling holes vertically down thru the dowels then use 1/4-20 nylon bolts going down into plywood plates I put into the fuselage under the LE and TE. Probably use 1/4" ply plates glued to the fuse ply doublers and braced with tri stock. Does this sound adequate and/or does anyone have any better ideas.

Thanks,
Joel

MinnFlyer

My Feedback: (4)

Instead of 3/4" dowels, I would use a 1/4" plywood plate in the front. It should go out at least 2 ribs from center in each direction and in the center area, it should go from the LE to the spar. Then just a strip of 1/8 across the TE

hebertjj

Mike,

Looks like a neat installation. I do understand the need to put the stress over a couple of rib bays or more and I was assuming on glassing the center section to do this (should have specified that) and incorporating the dowel sections in the rear. One of the reasons for the dowel was that the center of the wing has a fairing on top of it and the bolts would have to go thru that to press against the wing surface and be deeply countersunk; I'd have to build some kind of tube from the surface of the fairing down to the wing, kind of like a retract wheel well.

Your drawing (picture?) does give me something to think about though; I may do the ply Tee from LE to spar and less glassing. Whadayuh think?

Thanks,
Joel

MinnFlyer

My Feedback: (4)

As long as you're glassing, and adding a fairing to the top, why not just add 1/4" dowels to the back of the wing going into a plywood plate behind the wing? (similar to the dowels that usually go in the front of the wing.)

hebertjj

Mike,

Sorry, there's just not that much of a turtle deck behind and above the wing. I think I'm gonna have to go with the three verticle screws. I also think I'll do some kind of ply crutch like you show between the LE and spar.

I guess my question now is how much of an anchor plate do I need under the LE and TE. Will a couple of say, 3/16 ply, 1" wide plates glued across (about 4") the top of the fuse to the inside fuse side ply doubler, reinforced with 3/8 tri stock be sufficient? This is a .20 size plane with a 69", semi- symetrical, sorta glider (hi aspect) type wing.

Thanks,
Joel