Maiden flight yesterday for my new .46 UCD. Perfect. First it lands like a feather, slow, light, and floaty but stable, seems difficult to pull the landing gear out with this type of landing. I have a Magnum 70rfs 4 stroke with a 14x6 prop. On my second flight I hoovered for the first time and (to me) it pulled out of the hoovers (and missed attempts) with ease. I flew it mostly slow as it was intended to be flown, however I did use the throttle straight and level a few times and it flys fast enough to get from one point to the next for the next trick. My tricks were at about 50'. Even when it fully stalled I was easily able to recover with the low trows and this engine. If you want to do acrobatics at 10' or below and are not skilled enough to not make mistakes, I could see wanting a bigger engine. But, on my second day (today) I was hoovering at 20' with no problems. My advise... unless you have alot of experience with 3-D and understand all that the engine size will affect, stay with in the reccomended range. I am not against over powering, I have an Ultra Sport .46 with a .91 in it. I flew it first with a .50. Just know what your getting into before you spend your money, you can always put a larger engine in later.