Simviation Forum - Hot or high?

Reply #15 - Dec 14^th, 2006 at 8:11pm

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Brett_Henderson wrote on Dec 12^th, 2006 at 9:02pm:

Has anybody ever figured out how much more a 172 weighs, when it's soaking wet ? It's got to be at least 10, if not 20 lbs.

Depends on how badly it leaks... Grin

But seriously, seeing as how aluminum isn't very absorbent, I'd imagine if you left a Skyhawk in the rain for a while, then rolled it into the hangar, squeegee'd every last drop off it and collected all of that in a bucket, you'd barely have a quart, if that. And in flight, who knows how long the raindrops actually stay put, and what the rate of replacement is... LOL!
Hey, let's get started on the "do you hit more or less raindrops when moving faster" debate!!! ; Cheesy

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Reply #16 - Dec 14^th, 2006 at 8:15pm

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Mobius wrote on Dec 12^th, 2006 at 8:02pm:

What if it rained so hard that the force of all the raindrops pushed you out of the sky....? Huh

Maybe not... Grin

Hmmmm... it stands to reason that a cohesive stream of water could force an airplane down (say, if you flew under a waterfall or something), but I dunno about even very heavy rain... never heard of such a thing happening, and planes have been flying in very heavy rain for ages. In that scenario, what usually gets 'em is downdrafts.

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Reply #17 - Dec 14^th, 2006 at 9:17pm

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I was thinking it would take at least 4, one quart cans of spray paint to paint the whole plane.. and water's surface tension would no doubt make a coating of water WAY thicker than a coat of wet paint.. so we're talking a gallon or more of water (that's how I came up with 10-20 lbs)..

I'll have to research this..

Remember why they don't paint the shuttle's external tank ? A coat of paint is HEAVY...

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Reply #18 - Dec 14^th, 2006 at 9:44pm

beaky Offline
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Brett_Henderson wrote on Dec 14^th, 2006 at 9:17pm:

I was thinking it would take at least 4, one quart cans of spray paint to paint the whole plane.. and water's surface tension would no doubt make a coating of water WAY thicker than a coat of wet paint.. so we're talking a gallon or more of water (that's how I came up with 10-20 lbs)..

I'll have to research this..

Remember why they don't paint the shuttle's external tank ? A coat of paint is HEAVY...

You may be onto something with the paint analogy...
but then again, you may be on something pondering this in the first place... Grin

I am actually curious as to what the actual amount would be, but I think (just guessing) that a typical aircraft paint would be heavier per unit of volume than water. I know water is way dense (the oxygen atom is a real fatso), but I dunno... the pigments are probably pretty heavy with oxygen and metals. The enamel would weigh less than water, especially after it dries, but my gut feeling is that paint weighs more.

And water tends to bead up and drip off an airplane, even a dirty one. Hell, probably beads up more on a dirty plane, what with all the oil, etc. so we're not really talking about a nice even coating of water.

But ... eh, I'm bored. How about the "can a plane take off from a conveyor belt" debate? Cheesy

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Reply #19 - Dec 14^th, 2006 at 9:48pm

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LOL (this is fun)..

Obviously it's of little concern or they woulda drilled rain flying weight allowance into our beans when we were studying for that first written.

Anyway.. I wasn't comparing the weight of paint and water.. just the volume of fluid needed to cover the whole plane..

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Reply #20 - Dec 14^th, 2006 at 9:56pm

Brett_Henderson Offline
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And the beading is what I meant by surface tension. I buncch big beads is probably larger, volumetrically, than a very thin coat of paint.. And let's not forget water accumulations where surfaces meet rather sharply..

Even if it IS a whole 20 lbs (more likely 5-10), it's not worth worrying about...

ALTHOUGH.. there is that theoretical weight where you get into trouble.. and plus/minus ten pound when you're near it, might make a difference..

(how bored am I ?)

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