Everyone's born with a light bulb hanging in the air over their heads, just like in the cartoons. Except it's not on. That's our normal state, fumbling our way through life mostly in the dark. What turns on the bulb is knowledge -- the stuff you know. Not money. You can spend a ton of money and a lot of years for a fancy diploma and still be a pretty dim bulb. And not the stuff you THINK you know. While Conventional Wisdom is usually based on a kernal of truth, CW itself is usually dead wrong, even though everyone thinks otherwise.
Kid about ten wearing a wrist-watch with more dials than a steam locomotive, probably to convince someone he's worth kidnapping. Little girl orbiting around him like a tearful moth because the catfish ate Nemo. Abandoned in the office to wait for... something. Wandered into the hangar because it belongs to his dad, which means it's okay to pester the hired help.
No, I'm not Santa Claus. To her. Probably because of the beard.
Santa's hangar is north of here and his beard is all white and he's a lot nicer than I am. Older too. Of course I know him; we were in 'nam together. And the catfish didn't really eat Nemo, it's just a game fish play. Why? Because they get bored of being in that tank all the time. How can they breath under water? Because they don't know it's water; they think it's just thick air. Can you see the air? Well, you're swimming in it right now, just like the fish in the tank in the office. This whole hangar is filled with air but you can't see it. And you have to hold on to your brother's hand because I don't want him to get lost.
Air weighs fourteen point seven pounds per square inch. From him, a bit miffed because she had now latched onto his hand.
Yeah, but that's only for a square inch. To make an airplane fly you gotta know how much it weighs by the square foot. Which doesn't shut him up as long as I'd hoped. In less than a minute he says, two thousand one hundred and sixteen pounds per square foot, sounding a bit surprised. He probably figured it out on that watch of his.
That's right, I tell him. Which is more than this airplane weighs. Or would, if it had an engine and fuel and plex in the windows and stuff like that. Air is heavy stuff. More than a ton per square foot and here we are swimming around in it.
But it's... equal, he sez, struggling a bit, although the bulb is starting to glow.
Yeah. Like the fish. So all you gotta do is make it unequal and the plane will fly.
Lift... he starts to chant something else he's memorized without understanding but I shut him up with a wave of my hand. Lift is just the name we give to the amount of the inequality; the difference in pressure.
Lost him.
Basic PA-28, wings got about a hundred and sixty square feet and the plane weighs about a ton, all up. Lift has to equal the weight, I hint. The little fart shakes off his sister, whips out a calculator and starts punching the buttons! And here I thought he was doing it in his head.
He comes up with number that sounds about right -- so many pounds per square foot.
"Now you can do the square inch thing," I tell him. He eventually comes up with a figure that I convert to ounces. It's meaningless to him. I hand him my pouch of Prince Albert. "About that much and we can fly." He weighs it in his hand. The bulb is lighting up the whole hangar.
"If we move the wing fast enough..." he sez.
We...
If we move the wing through the air fast enough to create a mere ounce and a half difference in pressure for each square inch the lift will exceed the weight and that's called 'flying.'
A woman calls out from the door to the office and the little girl drags her brother away, his bulb glowing brightly. The little girl abandons him before they get there, runs ahead saying, "He knows SANTA CLAUS!"
No wave good-bye. No word of thanks. But the 'we' says the brotherhood of airman had just increased by one.
-R.S.Hoover
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