It list a .91 for the top end power, BUT I wonder how much 3-d "U-CAN-DO" with a 7+ lb plane with a .91? Probably not as much as you think! I have a 6.5lb G.P. Giles 202 with a strong Saito .91, it will hang, and pull out REAL slow. I cant imagine what it would be like a pound heaver. I'm not saying you can't hover a U-CAN-DO-3D, with a .91, but you aint gona have a whole lot of clicks left to slap the tail around like you'll need to. It looks like a job for a strong 120 size engine to me. Lets face it, hovering is one of the backbone maneuvers for 3-ding. I would have to see one before I bought one.