well for this engine 10% (with castor) was recommended cause it protects better in lean runs... I am gonna richen it to around 8500 RPM on ground then and see if it finally wants to get into the air... but just a question... what is the difference of me holding it back at 45 degree angle in the air and revving it for 30s full throttle or so to make sure it doesn't cut out on me and the difference when I actually try and launch after I have reached full throttle and I have my speed to launch? cause I feel its the same... and also I hold it in a hover position and rev it to make sure also it doesn't die... these are all my checks before I try and launch... launch(takeoff)... but I will definitely richen it 800RPMS at least to see if it will finally launch...