Scott wondered why our gliders don't have tips like this:

Steven Pearson <<Steve>>
wrote back:

Already tried that in 1977. Wills Wing had an SST proto called the
‘sawtooth’ with overlapping panels that were somewhat free like feathers.
There’s been more research done over the years (see
http://bamlab.mechse.illinois.edu/barbule/) but we don’t have anywhere near
the time and money to pursue a small fraction of the promising ideas.
Realistically, it could improve Cl max by 10% which would be about 1 mph stall
speed reduction.