To get the desired effect of an arrow - something pointy stuck into someone that you don't like - all you need is a pointed stick and something to launch it. So what are all those feathers doing on the back end of an arrow. We'll tell you the simple physics reason why arrows are plumed.
Arrow is coming up on the CW, as part of their line shows about Superheroes who look like they're posing for a commercial about a triple-bladed shaving razor. (I know the Green Arrow has stubble in the ads. I'm not saying that he shaved his face.) To the untrained eye, arrows always seem to have an extra part. The pointed end and the shaft are fine, sure, but then at the end they look like they're suddenly trying to grow wings. This is the fletching. Modern feathers have synthetic fletching, but before that people used goose feathers.
But why use anything at all? They may be feathers, but they still weigh something, and it's important to get rid of all possible weight when you have to speed something through the air. They aren't making the arrow more aerodynamic, either. That's actually the point of them. They are a minor drag on the arrow when it's flying straight. They're a major drag on it when it's not flying straight.
If the tip of a non-fletched arrow wobbles out of line with the arrow's flight path, the entire arrow can go off course, and may even start spinning like a cheerleader's baton. When the arrow flies straight, the narrow part of the fletching on the back is in line with the flight path and provides very little resistance. It's like a feather being dragged through the air by its point. Flip the arrow so it's broad side is moving through the air, and the resistance increases considerably, to the point where it takes effort to drag it through the air. When the point of an arrow wobbles, the fletching on the end is turned so that it gets a considerable push of resistance. That push is directly opposite to the way the arrow turned, and so it puts the arrow back in line with its flight path.
On this week's show, Annalee and I analyse the upcoming show, Arrow, mostly from a perspective of the amount of abs shown, as well as talking about all the other sci-fi and fantasy tv coming out this fall. We also make a pyrex dish disappear. Take a look at this week's We Come From the Future.