A standard brushing bearing such as the 40 LA will do great in the Uproar if you're going to do sport/fun flying. Built with an 11-12oz engine/muffler and you're looking at a 3.5-4lb plane. I had a TT GP-42 on mine and it would do almost everything. I have been able to hang the Uproar on the prop, but when it starts falling off, there's little extra power to correct. That being said, a powerful BB 32-39 engine would make the Uproar a much better plane if you wanted to hover a lot and torque roll. I've got a TT Pro-36 in mine now and vertical is unlimited. Even from a hover, hit full throttle and within seconds the Uproar is a dot in the sky...