This is the cargo extraction system used on our C-130. its purpose is to push cargo out of cargo models in flight, it could be used on other models as well. This kit comes with the laser cut parts needed to complete the system and a plastic formed gear cover. What is not included is the standard servo used as the systems gear box and the switches and wiring used to control it.
There is a video demo here. http://www.youtube.com/watch?v=aN0A7O81RCc