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-   -   how do you sand wing ribs?? (http://www.rcuniverse.com/forum/questions-answers-154/3528361-how-do-you-sand-wing-ribs.html)

99GrandTouring 11-07-2005 01:18 AM

how do you sand wing ribs??
 
Hey guys, I'm working on my second kit and although its about 99% done, now in hindsite I should have asked this.
How do you sand wing ribs to "even them up" when its a tapered wing?
I'm almost done building a bob martin *****cat Glider, the leading edge is just a dowel and in some spots it doesn't contact a rib, if I were to force it then the leading edge wouldn't be "flat" it would be rippled.
Now the spars lined up ok.
So how would you stack wing ribs on a tapered wing to sand them before assembling the wing?
Thanks!

R8893 11-07-2005 08:38 AM

RE: how do you sand wing ribs??
 
Typically the "truing up" is done after the wing is assembled. I don't know how this could be done before. A long sanding block that spans over several ribs is used. This method assumes that the ribs are accurately cut by the kit manufacturer; that is not always the case and problems like the LE not fitting occur. In this case you can sand everything down to the smallest part or add shims to the undersize parts. With the dowel stock LE I assume the rib has a half round cutout at the LE. I would take a piece of balsa sheet the same thickness as your ribs and file a half round cutout. Then glue this new piece to the side of the short rib so the new piece contacts the dowel. Then us the long sanding block to shape the new piece to the proper airfoil.
Chuck

99GrandTouring 11-07-2005 01:27 PM

RE: how do you sand wing ribs??
 
I see... so basically your just doubling up the balsa and the doubled part is finishing up contacting the LE...

what would you do about turbulators and spars not fiting exactly or to snug of a fit, should the ribs be lined up before hand and sanded for the spars?
Thanks!

MinnFlyer 11-07-2005 02:01 PM

RE: how do you sand wing ribs??
 
You could do it that way.

Something else you can do is to line up all of the ribs from one side of the wing and hold them in place with the spars. Then sand them until they are all even. It may even be a good idea to make a plywood template of the tip and root ribs to act as sanding guides.

kdheath 11-07-2005 04:04 PM

RE: how do you sand wing ribs??
 

ORIGINAL: 99GrandTouring
what would you do about turbulators and spars not fiting exactly or to snug of a fit, should the ribs be lined up before hand and sanded for the spars?
Thanks!
I will notch ribs beforehand, but only if I cut the ribs myself, while they are still clamped in a stack. Then you can use a razor saw and/or a sanding tool to notch them. Fuselage formers are notched after assembly.
If the kit is die-cut, work the notches after the parts are assembled. Single edge razor blades are the tool to use. A thin, flexible metal ruler can be very helpful keeping things straight. Die cut parts seldom have accurate notches. Laser parts should fit better.


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