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Building Tips and technical articles. => Building techniques => Topic started by: Peter Walker on March 07, 2015, 05:30:37 PM
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Hello everyone
I have decided to scratch build an old Envoy. However, I seem to be having a problem with the wing assembly. No matter what technique I try with it I cant seem to get the ribs to line up on either the LE or TE. I checked that the material is all straight and true and that all my ribs are exact according to the rib patterns on the plan. It's all 100% straight and true.
I have tried setting it up with wing jigs, but cant see to get all the ribs exactly level with the top of both the leading edge and trailing edge.
I am really open to any and all suggestions please. ???
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This Envoy? http://www.outerzone.co.uk/plan_details.asp?ID=4787 (http://www.outerzone.co.uk/plan_details.asp?ID=4787)
How did you cut the ribs? From the plans, it seems to be a fairly straightforward build, except that it's not terribly "jiggable".
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Yes Tim, that is the one.
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If I understand your problem, some of the ribs protrude from either the top or bottom of the leading and trailing edges? Or, the ribs do not even reach the top or bottom of the leading or trailing edge, therefore leaving a gap (hole?) that then has to be filled.
And, you say all parts are true an straight? The only thing I can come up with right now is that maybe the rib profiles on the plans are not drawn perfectly symmetrical. That might account for not being able to get the ends of the ribs to match the leading and trailing edges.
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the ribs drawn on the plan are NOT accurate - take the root rib and tip rib and make your own set using those as a template - I had the same issue until I measured all the ribs and found the error
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Wynn beat me to it. If you make the root rib and tip rib out of plywood you can then make as many rib sets as you want. Also if lined up right, depending on straight leading or trailing edge, you make the jig holes.
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Thanks a lot for the advice guys. Will most certainly follow that bit of advice. One tends to take for granted that if its on a printed plan that its automatically correct. And so we learn I guess. Will keep you all posted on the results.
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The joys of CAD and laser cut ribs. At least you know they are correct - if the CAD drawing was anyway.
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The joys of CAD and laser cut ribs. At least you know they are correct - if the CAD drawing was anyway.
Go review my Legacy wing build!
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All it takes is a long sanding bar to sand down the high spots, some glue and 1/16 balsa slivers to build up the low points, and lots of patience. Cover with cap strips, check for accuracy, repeat if necessary and move on. 8)
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or you could just do a foam core wing:D
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All it takes is a long sanding bar to sand down the high spots, some glue and 1/16 balsa slivers to build up the low points, and lots of patience. Cover with cap strips, check for accuracy, repeat if necessary and move on. 8)
not in this case - the ribs are not the right length either
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Lengthen 'em then---CA glue and balsa scraps to the rescue, foam wing?, what?, and miss out on all this fun? That's one way. Actually, if faced with this many discrepancies I would make a good pattern out of plywood of the R-1 and end rib and carve/sand using the stack method. 8)
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BUT THATS TOO EASY!
There must be a way to complicate this more!
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Thank you all for the input. I have taken a bit of everyone's advice and managed to get the wings together relatively straight. %^@
You guys have been a great help, and I have really enjoyed the humor. Thanks again. Will post some pics when it looks a tad more like a plane. n~
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All it takes is a long sanding bar to sand down the high spots, some glue and 1/16 balsa slivers to build up the low points, and lots of patience. Cover with cap strips, check for accuracy, repeat if necessary and move on. 8)
Good one Pete! This is what I do too! y1
Jerry.
PS: Will I see you on April 18 TH?