hi.. thanks for input..i have had- 4 -y/a A-4..i moved the flap forward on each one, untill it had no pitch change ,and floated like glider.its just closer to C/G. it also angles 7 deg toward the tip.moves air to the tip. this one is a little smaller . it will be covered by the wheel /landging gear/ pod. the aluminum pivot tube is just aft of my flap.the wing gets thin in that area.did not want to get into that mess.. i will beef-up aft area for sure..put servoe pockets in today..so far added ..4oz.. to wing.no gear mount in yet!! what do you think about full intake ducts??