A search for blended winglets produced this link and this blog entry. Aviation Partners, the same folks who pioneered blended winglets and spiroid winglets are testing split blended winglets with scimitar tips. I thought I could reproduce split blended winglets, but didn’t feel the scimitar tips were necessary in the Reynolds environment of a butterfly.
The design uses the barnaby platform, with the tapered-fold leading edge to thin out the tips of the wings. The taper fold was made using a traditional fold of half in each direction, then, unfolded, I folded in the corners at the front, cut them off, and tucked them in when folding up the leading edge, to get the weight up front. The wing is thick in the middle and thins toward the end. The inital flight went about 25 feet ruler-straight down a back hallway. The second flight was equally straight. This looks like a win.