All this discussion...

Here is a photo of some that really worked. This is a 15 year old ARF Extra. It was a tip stalling fool. It was so bad my buddy didn't like flying it. Another guy at the field suggested stall strips. These are 1/4 tri stock, faired in with microballoons & Epoxy. He later painted over them and most people didn't even notice they were there. They turned the plane into a nice landing plane that Bob flew for several more years.

Don't let any of the guys who haven't tried them tell you they don't work.