First flight on mine today. The book says 115mm from the LE. I set mine up there. OS 40LA mounted at 90 degrees, APC 10-6, Slimline Pitts muffler, Sullivan 8oz. Flex tank, JR 1100ma battery, Futaba 7 channel Rx and S3001 servo's all around. The fish scale puts it on the light side of 4 pounds. (bouncing numbers, windy today) I didn't experiment with any equipment swapping today, just getting the feel for it. At 115mm it is very stable. I'll start moving it back after I get the "right" prop on it. I love doing figure 8's at 10 feet AGL with 4 clicks of throttle! Slow can be a ton of fun!