I used only 1 20x30" foam board. I used 4x 9 gram servos. 2832 1200kv Brushless motor with 30amp ESC. Spektrum AR620 6-channel receiver. 2200mAh 3S battery with T-60.
If you fly a drone or RC plane then you will really want to build or buy one of these devices because it can make a huge difference to the safety of your flying