Is there a way to set the DJI Go app to save the 720p video that is captured while piloting to the SD card, and not the internal memory?  TY

it's saved on the GO app so that may be the only place to save it unless there's a setting somewhere on your Android device that will let you do that.
You can try asking on an Android forum, here's a few links.
http://forums.androidcentral.com/
http://androidforums.com/