RE: Trainer Knife Edge
You can always practice semi-knife edge flying which is also called side slipping. Hold the plane in a 45 degree bank while flying in a straight line. This will require the rudder and ailerons to be cross-controlled which results in a lot of drag, a great way to shave off excess speed and altitude while making a short approach for landing. Good for crosswind landings also. It's a skill that everyone should learn and most trainers can do it.