Geezzzz, I hate to ask but what is Crow?

Oldernut

Crow is a method of computer radio mixing on a model with flaps and ailerons using 4 servos, one on each surface. When the programed "Crow" switch is activated both ailerons go up and both flaps go down, Wallah "air brakes". The model I had this set up on (a Dynaflite 80" Chipmunk) would react just like it had hit a stiff head wind, really slowed it down.

Generally it refers to gliders, though any 4 servo wing can do it, its fun to play with on stik's and such.

Both flaps down, both ailerons up and whatever elevator compensation you need in one mix.

Pop crow on my 2m sailplane and it will nearly stop in mid air.

In addition to what others have posted, crow (or butterfly) helps to stabilize the aircraft in roll and reduces elevator dependency when deploying flaps. The raised ailerons help reduce the pitching moment from flaps and change the camber of the wing at the tips to provide washout. This high drag/high stability configuration is good for braking or landing many models. I have used this configuration on everything from funfly planes to jets.