180-degree Turn Maneuver

Is there a way to program a maneuver triggered by radio switch, where a forward-flying copter dumps all kinetic energy into potential energy (climb), spins 180 degrees around at near zero or low velocity, and drops back down to starting height to recover some of original forward kinetic energy?

I am looking for an energy-efficient 180-degree-turn maneuver.

Unless it’s a traditional helo or a multi copter with some sort of aerodynamic lifting surfaces, there won’t be much energy saved in a “whifferdill” maneuver as you describe (and it may well cost energy to achieve the pitch/roll/yaw angles).

You could check out scripted aerobatics if you’re very interested in attempting such a thing.

oh yes of course. the copter has a wing. without a wing i agree no energy could possibly be saved.