Thursday, November 07, 2013

[Science] If the Plane Flies, You're an Idiot

If the Plane Flies, You're an Idiot: Once again, the nonsense about a plane taking off from a treadmill has popped up around the web. Very few things can rustle my jimmies more than this. Let's go over it one last time.

For a plane to take off it needs a massive rush of wind from the front, a headwind. A plane's wings are designed so the wind from the front will push harder on the bottom of the wings than the top. This is what causes the plane to leave the ground. (Technically, it is coriolis force creating lift.) That's why they build those long, expensive runways for a plane to go barreling down at insane speeds before taking off. It's not just because it's cool. You need to create enough headwind pressure to lift the plane off the ground.

Now, some clown comes along and glibly asks "If you put a plane on a treadmill, would it take off?" The answer is obviously no. On a treadmill, like the ones you see at the gym, you exert energy to move your legs but you do not move forward relative to the air around you. In other words, you never generate a headwind on a treadmill. So, by extension, if you put a plane on such a treadmill, it would not move forward, no headwind would be generated, and it would not take off. Ipso facto.

But then clown smugly "proves" you wrong. He says, yes it could because there is no treadmill a plane couldn't overpower and you couldn't build such a treadmill and Mythbusters proved it...blah, blah, blah.

Really? Really?

So when you said "plane on a treadmill," we weren't supposed to imagine a treadmill like we are all familiar with, the kind we use in the gym. Apparently, we were supposed to imagine a treadmill that wasn't strong and efficient enough to hold a plane steady. We were supposed to imagine a treadmill that a plane would just blast right over. We were supposed to picture a 747 placed on top of a $500 treadmill you can buy at Sears.

Well, then I suppose you're right. If the question has become, "If you put a plane on a treadmill that is not capable of stopping it from taking off, could it take off?" then the answer is yes. Yes, it could.

Also, you're an idiot.