I'm not a sailplane enthusiast, but my understanding of crow that it is a mix of flap and aileron positions used in landing. In crow, when flaps are down, both ailerons are up. It is a complicated mixing function requiring a computer transmitter. I use a MicroPro8000 transmitter and on it to set up crow, you need a 4 servo wing. The flaps are plugged into the throttle channed and channel 5. The ailerons are plugged into the aileron channel and channel 7. When you go to low throttle position, the mixer on that channel makes the flaps drop and both ailerons go up, as well as mix in some elevator to compensate in pitch changes. When ailerons have this crow mix on, they must still be set up to operate as ailerons while in the crow position. So it takes a high end computer to accomplish all this.

I would also be interested in a treatise on the subject from someone with some indepth knowledge of the subject.