I think I get airplanes until I look at helicopters. The thrust from a helicopter's rotor holds it up. In order to hover, the rotor's thrust must equal the weight of the copter. Requires a big engine. Okay, I get that.An airplane's lift comes from its wings. The prop or jet propels it forward and the wing provides the lift, which I get. A quick lookup shows that an airplane engine's thrust is about one-seventh of the weight of the plane, which is a nice savings. The efficiency is changed but not drastically so whether the plane is flying forward or in a tight circle.
The other thing you notice is that a helicopter's rotor is shaped much like an airplane wing. Really two airplane wings circling tightly around the center point. So if a helicopter is nothing more than an airplane sweeping out a circle, why can't it be held aloft with an engine whose thrust is just one-seventh of its weight?
No comments:
Post a Comment