its a water fall.....
with rc planes i was told to clim like you are going to do a flatspin or whatever..just get enough hieght
use full down elevator when plane gets to invertstall add power(alot)when upright andlevel no power..waterfall needs lots of elevator and elev is full the hole time power gets it to flip it around..when you manage the power right it should be a constant speed up and down..you will need the ailiron and rudder to make correction during move.to get out flip to low rates and netrual..i will see if i can find the site that show some 3d moves with vid..