RE: Why???
Some Peter Miller designs can KE with rudd only, Toot Sweet and Fire Drake.
They are sport planes though, and plan builds, but some charactaristic of them must make them KE with no problems.
The Toot Sweet is a bi plane with with a straight wing with no taper, same chord and section all the way. No dihedral too. Lots of side area, its a box fuz but does taper to the back, Im not sure.