Why do hang gliders have (broadly) neutral roll stability?
It has always struck me as fortuitous that differential airspeed and differential angle of attack in a turn produce balancing roll forces. I am sure hang glider designers can fine tune that balance, but even before anyone designed anything (in the early gliders) they still pretty much balanced. Hell, even slow-flying rigids with huge spans (sailplanes) do not normally need much ‘high stick’ or low stick to keep a steady bank angle, as far as I am aware.
