Ideally, bi-directional pump only is best,if you have electronic recovery system to prevent loss of radio contact OR you only run in swimming pool where you can see the sub & recover it OR you have a powerful reliable RC system that losing control would never happen. In my case I have NONE of above ! :) What I am trying to do is simple. Use pump to go only to snorkel depth & use diving plane to go deeper down. Losing control = re-surfacing to snorkel depth. It's still being tested. |