I have 3 nextars did you add flaps? if you did .use meteric the us measurement is wrong in the manual also also disconnect the anti crash prob that can give you problems like you are saying no matter who flys I did not get off the ground with it on .2nd take the speed brakes off its the reason that your plane kept climbing.this happens when the engine is going fast DO you have flaps? with the speed brakes? the nextar is a great plane !!!