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Old 05-31-2012, 05:33 PM
  #22  
da Rock
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Default RE: Sailplane Wing Design Round II


ORIGINAL: Nodd

Spar Confusion
It took me a little while to realize there's two ways to go about building my new spar...

Continuous Webbing - Split Ribs (top cap strip not shown)
[img][/img]
In this technique, the spar is completed first using a strip of continus shear web material. This is ideal for constructing spars wrapped with 45° bias fiberglass or various tube/sock wraps. The advantage is the ribs don't get in the way while you're doing the wrapping, they're attached afterwards.

Bay Webbing - Full Ribs (top cap strip not shown)
[img][/img]
Using this technique the ribs & webbing are added in alternating order to the bottom cap strip. The advantage here is you can use full ribs, which on non-flat bottomed airfoils like the SD 7037, helps assure things stay aligned. Obviously trying to slip a tube wrap over the spar with all those ribs in the way isn't an option. However you can still wrap it using Kevlar thread or ribbon (tow).

I like both techniques but I think I'm going to go with the second. Seeing as this is a tapered wing, I'll need to construct a jig to accurately cut the shear webs but that sounds like a fun challenge. I'll be doing the same thing for the outer panels but with thinner/narrower CF. Will likely ease up on the Kevlar wrap out there too. Anyway I'm liking the direction this is going.

Both are excellent designs.

Do you have a drawing that shows how the design of the wing joiners lays out? ....how the joiner rods are tied to and supported by the center section?