RE: 3D Trainer...
You might want to get a foam one before you get a mini katana, it is a lot cheaper to replace. Also the mini katana needs a runway to land, grass will rip off the gear every time. So some of this depends on if there is a good spot to land. For foamies I like the Shockflyer F3A. Put a CDR brushless in it with a CC 10 amp esc and TP 910 3S battery. Fly it with no gear of course.