The 4s configuration requirement of Falcon UAV model is Yu Lang 2820kv800 with 12x8apc paddle. I wonder if it's okay to use 12x6 paddle?

The size of the paddle is related to the motor KV value, battery capacity and discharge C number. Falcon UAV comes standard with 1280 paddle, which uses 4S battery or 1260 paddle, but the efficiency is slightly lower because the size of the paddle is different at the same power consumption and speed. If you use a smaller paddle, you need a slightly larger throttle and a higher speed, so the power consumption will be faster. (The first two digits of the paddle model refer to the size of the paddle, and the last two digits refer to the pitch. )