The one I have had an Gemini II 120 twin on it, so the exhaust came out the sides with the heads, and the cowl was split along the sides, but I may be putting that motor on a SIG 1/5th Biper Cub for the added weight since the Biper needs a lot of forward CG due to the bottom wing being in front of the top wing. It looked really good, on the ground, but was tail heavy like mad in the air, did not figure the MAC out properly on it. I had it at the leading edge of the top wing, but found it more than likely needed to be at the base of the windshield instead. Once I repair the damaged lower wings and make new struts I will try again. I still need to figure out why it kept rolling towards the end, had it not been for that, I would have been able to bring it down in one piece. I was so close to saving it, but some idiot drove across the end of the runway while I was on final. Then the owners dog decided it wanted to get to know me better and was sniffing all around my legs, Way too many distractions when flying a tail heavy plane. I don't know if I had a servo failure, or a radio glitch, or a binding aileron that was causing the roll.
What killed my Ultimate was the throttle screw coming loose and the throttle fully closing just after taking off, making the turn and throttling back a bit. Had a heavy tail wind too, so it dropped like a rock.