Robert Biegler: Model junk rig with curved battens

When I saw the Bierig CamberSpar, I thought it could be applied to a junk rig. Let the battens be permanently curved, and let wind pressure flip them around an axis between fore and aft end, about 45 degrees either side of vertical. That worked very nicely on the model sail shown here. When I scaled up to 5 square metres, that didn't work, but because my focus was on other experimental element of the boat, I never worked out why. I suspect that the battens had to flip not between fore and aft ends, but between the aft end and each batten's contact point with the mast. If so, then simply pulling the sail back using the batten parrel might have solved the problem. The gaff-junk or gunter-junk hybrid also shown in this album would also fix the rotation axis to be between fore and aft ends of the batten, giving wind pressure enough lever arm to flip the batten (I hope). Nils Myklebust built a c. 20 square metres sail, and rigged a line to flip the battens by 180 degrees. He got a nicely cambered sail out of that.