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Old Feb 06, 2012, 07:38 PM
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Help!

Lil Bird 2M: sheeting and leading edge mystery


I need some help again. I'm about the glue the top sheeting on the wing's inner panel. After I'll be done building the other wing and join the two together, the instructions specify to sand the excess wing sheeting that is protuding past the front of the ribs - that's a width of about 1/4 of an ninch.

2 questions arise now:

1- Should I trim the botton and top sheeting right away using an X-acto to make sure it's about flush with the ribs (and straight!) or should I do that after the sheeting is glued? (black lines on picture)

2- Is the leading edge properly positioned on the picture below? The thickness seems right but it looks way too large. I'll have to sand that much off after it's glued? It seems like I should split it in two but I have no means to do that properly...

Thanks for your help, I don't know what I'd do without rcgroups!
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Old Feb 06, 2012, 09:46 PM
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Proceeding...


O.k., I've looked at many pictures of 2M Lil Bird build logs and found out people cut the excess before carrying on.

I'm now stuck with "Will I glue the leading edge on its 1/4 inch side (wich fits the ribs front edge but is way too long) or on its 1/2 inch side? (wich is way too high, but seems to be of the appropriate lenght to fit airfoil)"

Next step is to light a votive to Saint Joseph of Cupertino.

Thanks!
Old Feb 06, 2012, 11:05 PM
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Did you account for the thickness of the sheeting? I bet you have glue the half inch side on. Don't overdo it on the glue, and you might want to use Ambroid or Duco so your carving and sanding will be easier. If you use a slow glue like these, or some carpenter's wood glue, you will have time to reposition if you goof.

You might want to trim the sheeting just barely oversized and sand back flush with the front of the ribs so that it will sit nicely against the l.e.

If you use a plane (small carpenter's plane would be good, or maybe a razor plane), you can carve a lot of the excess l.e. edge off first.

If there's any curve on the underside of the front of the ribs, be sure to shim up the bottom sheeting when you glue it on so that it doesn't leave a space.

A useful trick for applying the top sheeting is to paint some slightly thinned yellow carpenter's glue (such as Titebond) to the ribs. Immediately apply the sheeting, and then remove it. You'll see where the glue goes on the sheeting. Brush it down flat and make sure there aren't any dry spots where it will meet the rib. After the glue dries it will act as an iron on adhesive. I did a glider like this back in 1990 or so. After many years and a few crashes it's still holding together nicely.

I'm not sure if this works with the new, water resistant carpenter's glues. You might want to test. It definitely works with the old yellow carpenter's glues.
Old Feb 07, 2012, 10:38 PM
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kurt:

What lincoln advised is exactly how I'd do it. I haven't built one of these, but others go together in the same way.

Yours, Greg
Old Feb 08, 2012, 07:00 AM
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I need some help again. I'm about the glue the top sheeting on the wing's inner panel. After I'll be done building the other wing and join the two together, the instructions specify to sand the excess wing sheeting that is protuding past the front of the ribs - that's a width of about 1/4 of an ninch.


Does this mean you are planning to sheet the top of the wing panels before joining the four panels together ?

The answer to the leading edge question is on the construction plan. It shows the width of the LE to be 1/4".

Build instructions with photos are also on my Web.

Ray
Sky Bench ... Woodys forever
http://www.skybench.com
Old Feb 08, 2012, 05:01 PM
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Does this mean you are planning to sheet the top of the wing panels before joining the four panels together ?
The answer to the leading edge question is on the construction plan. It shows the width of the LE to be 1/4".

Build instructions with photos are also on my Web.

Ray
Sky Bench ... Woodys forever
http://www.skybench.com[/QUOTE]

Well... it seems to me that the instructions specify to do so! That is, to sheet the first top inner panel, then join the two wing halves, to cover the other inner panel and then to cover both outer panels. Hope I didn't do anything wrong... a quarter of the wing is now sheeted. I saw the pictures on the web site but am closely following instructions!
Last edited by kurtenstein; Feb 08, 2012 at 05:08 PM.
Old Feb 08, 2012, 05:43 PM
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The instructions don't say sheet the tops of the wings before joining the wing halves together. Where are the plywood center dihedral braces at this stage of construction on your wing ?

My web site has this link that may be helpful to you. "Assembly Tips" link is located on the 2M Lil Bird description page. I tried coping the hyper link and pasting here ,,, but no go on that idea.

I'll not be available on RC Groups for a couple of days.


Ray
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Old Feb 08, 2012, 06:28 PM
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????


The plywood center dihedral braces are glued to one half of the wing. I scanned the instructions and underlined the steps that seem crucial to me... I can't understand where I've done wrong!
Old Feb 08, 2012, 06:42 PM
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I forgot...


And thank you Mister Hayes for your help! You're the absolute authority on the matter!
Old Feb 08, 2012, 07:14 PM
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Quote:
Originally Posted by kurtenstein View Post
The plywood center dihedral braces are glued to one half of the wing. I scanned the instructions and underlined the steps that seem crucial to me... I can't understand where I've done wrong!
Well,maybe you haven't gone wrong, without seeing a larger view of your wing parts, it is not conclusive, but you you seem to be at the step when the right inner wing panel is joined to the already top sheeted left inner panel. ??.
Old Feb 08, 2012, 08:08 PM
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The wing as it is...


Here's the wing:


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