某螺旋槳半徑為2m,在其中一槳葉上0.3R、0.6R、0.9R處各旋轉(zhuǎn)36°時分別測得量桿的升程為256mm、252mm、260mm,請問
A.260mm B.2600mm C.252mm D.2520mm
A.252mm B.2520mm C.178mm D.1780mm
A.254 B.2540 C.256 D.2560