ORIGINAL: ARUP
I have drawn a set of 1/4 plans for this bird but haven't built it. I think I would build the wing with the trailing edge in a jig. The TE would be a laminate to help ribs hold TE 'droop'. I was thinking of using Spectra line as cross bracing. I did that for some scale CL racers and both RC Bleriots I have built. Indestructible and weighs 'zip'! Good luck! ARUP
Hi Arup - close to what I was thinking.... I was going to block the tips - front and back, and a few locations along the TE, then glue top/bottom TE pieces to the ribs, forming a lamination. An alternative would be to prelaminate the TE under some cawls. Actually as I think about it, there's another factor to consider - I was going to prebuild the box spar. But pushing the TE down will cause the LE to curve up. Seems like the spars would need some sag too, if the point is to have the LE straight. Either that, or the ribs need to be shaped differently. Think I need to look at the photos more closely[sm=confused.gif]
Anyone want to speculate on the aerodynamics of the droopy TE? This is what I was thinking for incidence:
Top wing: Root: +2 (deg), Mid-panel: +1, tip: 0 (i.e., about .5 inch washout)
Bottom: Root: +2, Mid-panel: +5, Tip: 0
I scaled the +5 degrees (droop) from a photo. I usually set up bipes with equal incidence top & bottom but I know some folks like a little convergence (e.g., lower incidence on top). This design will have convergence with more positive on the bottom. 5 sounds high at first glance but the average for the panel is about half that. So long as the washout is there, I think it should be fine.
I didn't think of using spectra - funny since I've used spectra core lines on my sailboats for years! Spectra (a HMWPE) is known for strength and lubricity, whereas Kevlar (an aromatic polyamide) is known for strength and abrasion resistance). I would have thought Spectra would not glue very well, but be less likely to chaffe against itself than Kevlar. I'll have to fish some of it out of my lines and play around with it. Thanks!