You are better off using the gear switch because it is a on/off type function. If you are using a drop box type, the wind pressure will help keep the door up after release until you land, just make sure the hindge line is at the leading edge of the airflow. If you want to get creative you could hook the door up to the servo like a gear door so that the door will open and close like real bomb doors. It would be really easy as long as the load is not too heavy. [8D]