I have a North Star (kit from Balsa USA: http://www.balsausa.com). I like to fly it but I have notice that when I perform a low pass at low speed and then I go to full throttle, the airplane nose goes down and I have to pull Up the elevator. This is appening only when I go from Idle to full Throttle. I guest this is appening because of the special configuration of that aircraft. I haven't install an elevator like the original plan I have preferred using delta wing mixing. Should I add DOWN or UP thrust to the engine mount to correct the situation?