I flew the Spacewalker with the G38 and the APC 19x8W prop and boy did it make a difference over the ProZinger 18x8. Engine ran good in 95 deg. heat. Prop provided great thrust and good downline breaking. I was able to do big loops from level flight without problem. Stall turns had great vertical. I would like to try a 20x8 Menz S to see how it performs, but I am really happy with the APC. I did not tach it so I do not know what it was turning, but the difference over the ProZinger was amazing, it was like flying a different plane.