I solved my engine power issue by using 30% Nitro instead of 15% Nitro.
My Edge can do inverted flat spin all day long with power issue
In fact, the 30% nitro give me 1000RPM boost ( 13000 RPM on APC 12.25x3.75)
that allow me to CLIMB when doing flat spin inverted!
I burned a glow plug and i have put a new one, set the carb, one flip and go!