First , engineers could develop low-turbulence rotors .
一是工程师可以研制低紊流转子。
Commander , we 've lost power to the forward rotors . We 're losing altitude .
指挥官，我们旋翼失去动力，正失去高度。
Heavy-transport helicopters , such as the mil mi-26 or sikorsky s-64 skycrane , address some of these difficulties , but their payloads are limited to 20 and nine tonnes respectively , and their huge rotors create a powerful downdraft that makes handling that payload rather tricky .
