Here is one I sortta invented
. The concept is not new as I found out after I posted it elsewhere seeking an opinion if it could work, I found out there is an ultra light in USA using the “ring wing” approach even plans for huge planes built in this fashion that never were built
. It is made by making an a4 sheet into a cylinder length ways and cutting a section about 45 degrees across. Fold in little vanes at the top and bottom place weight on the bottom vane and test fly, adjust until it glides and there it is
. The bottom on the one in the photo needs some blue tack so I have not flown this one
..no blue tack or paper clips anywhere
.. but with a little trimming they glide very well and flattened it a little more and it will fly upside down as well
…looks very cool upside down
.
Alex