I used a simulator and training skids, they come stock with the Hirobo Challenge. They saved my heli from a couple brain freezes that I would have surely crashed with. I did however manage to break the right rear mounting bolt on the heli frame with the skids, I think because of the leverage from the training skid on that side hitting a little hard on a botched landing. Sucked replacing the main frame, but I think the training gear has overall saved me some greenbacks and rebuild time overall.