Efficient cruising is a function of low frictional drag and low wetted surface WS. WS가 낮을수록 더 적은 노력으로 더 빠른 순항 속도를 의미하며, 여기서는 평방피트 단위로 표시됩니다. ft. For example, the shorter Arctic Tern cruises with less effort than the longer AT until the AT reaches.mph.