Pre-requisites:
 - transitions intro
 - collective management training

nose-in backflips (+ elongation): fly to nose-in hover. Pull back elevator and begin backflips (manage the collective). After a few times, try elongated the maneuver by Increasing the amount of collective while slowing down the rate of pulling the elevator. The model will look like it's going into a loop. Once the model is vertical, begin transitioning the collective to negative in order to "catch" the model and not lose altitude. Perform the same input to bring the model back to upright. This is the beginnings of both the inverted tail-first loop as well as backwards inverted flight.