Had some fun with wool tufts on my Model 2 wing today. I've always been impressed with the stall characteristics of if and wanted to see just how the stall progressed out the wing.
First thing everyone will notice is how the fabric, especially at the root seems loose and does a lot of oil canning. I had no idea this was happening until I saw this vid and quickly checked the fabric tension after this flight. It's nice and tight so I wonder if some of it is due to normal wing flexion and some is due to the violence of the slip stream where the prop wash interacts with the wing. Remember also that this plane was built in 1991 (by me) and at that time, Denney shipped the lightest Stits fabric available (1.7 oz) which I see now is reserved for ultralight use only. All Kitfox's since use the 'medium' weight 2.4 oz fabric. At least I think they do.
Anyway, the 1.75" twist I built into the wing seems to be working and the stall is nice and linear as it spreads from root to tip.
Next step. Vortex generators!
Chris Carlisle
Model 2, Rotax 582
Sioux Falls, SD