Most people often underestimate what a trainer can actually do. They will say that trainers aren't capable of doing aerobatics when in reality they can do a suprising amount of them. I often take my own trainer back up and fly it to just have some fun flying aerobatics with it. One thing that will make a world of difference is to seal the hinge gaps on your trainer. When I did this to mine it flew like a completely different plane. You will be suprised at how much of a difference this will make in the way it flies, and it will perform aerobatics much better when you have done this.

Hope this helps

Ken