Some aeroplanes have stall strips just to give stall warning, by make the
h-tail vibrate from the turbulence.
some Hershey-bar wings have twist to improve its handling.
most all taper wing have some washout in form of twist or aerodynamically or
a combination of the two.
aerodynamic washout can be achieved by using an airfoil at the tip with more
camber, or more nose camber (drop nose)
Messersmith was probably one of the first to use a combination of twist and
a more cambered tip airfoil, it is made so the zero-lift line at tip have a
small amount of twist compered to the root airfoils zero-lift line, the cord
line have then a larger amount of twist. At high speed the tip will not
produce negative lift due to the small difference in zero-lift line.
Jan Carlsson
www.jcpropellerdesign.com