BTW, the term "washout" often is used with modifiers. You might see "aerodynamic washout" used. And sometimes you see "physical washout" and such.

A lot of people think that washout just means the wing is twisted. But aero washout is a wing with it's airfoil changing from root to tip. The idea is to do what twisting the wing to get washout does without the problems that causes. So how does that work? Great..... and what's the theory of it? If the airfoils are symmetrical then it calms the wing's tip stall potential. And it does it right side up and upside down. If you were to twist the symmetrical wing to get some washout, you'd be screwing the airplane's performance when inverted or when doing outside maneuvers. So what about cambered wings.....

Most designs that choose cambered are for airplanes that won't be doing maneuvers where inverted performance is paramount. However, there are cambered airfoils that don't kill the airplane when upside down, and there are lots of aerobatic airplanes that have cambered wings. And there are pairs of cambered that do pretty good outside and inverted. You just don't expect to need cambered and inverted with models thanks to their light wing loadings and high power loadings. So you don't often hear much aero washout talked about for the model designs that employ cambered wings. And after all, if you're using a cambered wing, what 'cha gonna lose if you twist the sucker. It's already not symmetrical.