哇，窗口太小啦
请调整浏览器窗口大小或者请使用手机查看！
S2 E3 Going Vertical: Piasecki's Machine
本集简介
Frank Piasecki was a pioneer of rotorcraft and his groundbreaking tandem rotor design brought the helicopter into the modern age; the iconic Chinook helicopter and it's many uses from combat to humanitarian aid is his legacy.
当前季
