I was wondering if some one out there could tell me the volume of this air tank I found. I was going to use it
for my onboard air system. It's looks a little small maybe too small, what do you think? The tank is 3.5 in
dia. by 23 in. My math is a little rusty or should I say avaperated.
Thanks

The formula you want is the diameter divided in half (radius), times pi (3.14), times pi again (pi squared (all the pies I've seen are round)), times the length. So, (3.5/2)x3.14x3.14x23 = 397.25 cubic inches./wwwthreads_images/icons/smile.gif

/wwwthreads_images/icons/smile.gif Bore X Bore X .7854 X length all in inches and decimals of inches, then divide by 231 to get gallons. .7854 is a constant that basically converts a 4 X 4 square post to a 4" round post. It is roughly eight tenths, so it is a good number to keep in your head for roughing out volumns of tanks. A ten foot diameter tank ten feet high would be 10 X 10 = 100 then crank it back to 8/10ths which is 80, then ten high = 800 that's 800 cubic feet and we all know that there are 7.48 gals per cu ft.....about 5900 gallons. Well....there's your lesson for today./wwwthreads_images/icons/crazy.gif A kid from a tiny West Virginia town goes away to college, he being the first of his town to ever do so... When the fall break comes he takes the train home, and everyone is there to meet him, including his Pa. "Talk some college talk, Son!" his Pa exclaimed. "Er....Pi R Square." said the kid. "Thet's nice Son." said the dad, "But Son....wheat cakes is square.....pie are round."/wwwthreads_images/icons/crazy.gif

CJDave
Quadra-Trac modified by the crack moonguy/wwwthreads_images/icons/wink.gif/wwwthreads_images/icons/smile.gif/wwwthreads_images/icons/tongue.gif transfer case team.

ummmm.... the formula for the volume of a cylinder is (PI x R^2)x(Length) = (PI x (3.5/2)^2) x (23) = 221 in^3 , which comes out to .958 gal.
To the guy that squared PI, check your units. You'll notice that you come up with in^2 , vol is in^3
It's all good though! /wwwthreads_images/icons/cool.gif

I guess the prize goes to CJDave for being the closest, nice approximation though /wwwthreads_images/icons/smile.gif

/wwwthreads_images/icons/cool.gif Big Ed
'88 YJ, 4" susp,3" body,33's,283 Chevy V8,TH350,4.11's,D30,D35c

OOPS!/wwwthreads_images/icons/blush.gif My degree is in mathematics even./wwwthreads_images/icons/tongue.gif That's what I get for thinking (workin' without tools).

/wwwthreads_images/icons/smile.gif Fergit them pies kid....unless yer workin' in a bakery....Jes' use what I tol' ya, and you'll be ahead of the pack and running away. Square the bore....multiply by .7854...then multiply by the length....that gives it to ya in FOUR decimal places, which I RECOGNIZE is way more significant figures than you got in yer measurements, but well.....it looks good. And jes' remember....231 cubic inches is a ONE GALLON ENGINE. So the 232 AMC was a wisker over a gallon./wwwthreads_images/icons/crazy.gifI like to keep this stuff simple. I CAN make it complicated, but hey....ALL good engineering is simplicity itself. Like an Uzi doesn't even look like it'll work, but it does./wwwthreads_images/icons/crazy.gif
OH YEAH.....by the way....my moonguys/wwwthreads_images/icons/frown.gif/wwwthreads_images/icons/frown.gif/wwwthreads_images/icons/mad.gif/wwwthreads_images/icons/mad.gif/wwwthreads_images/icons/frown.gifare getting real aggravated that you haven't filled out the profile yet/wwwthreads_images/icons/mad.gif
CJDave
Quadra-Trac modified by the crack moonguy/wwwthreads_images/icons/wink.gif/wwwthreads_images/icons/smile.gif/wwwthreads_images/icons/tongue.gif transfer case team.

Whoops, I just did the cubic inch to gallon conversion on the figures Attilla had. So correct me if I'm wrong here, but I just put two air tanks on the jeep trailer. Both are 10" diameter, 28" long (excluding the domed edges). By these formulas, the two tanks together hold 4398.229 cubic inches, or 19.03 gallons...right? Anybody got a guess on how to calculate the internal volume of a tire (until I get that V-8 york bracket from Ozark, I'm stuck with only the tanks and no compressor...)

Evolution of tools: stone, hammer, wrench, socket, impact, really big hammer, blue wrench.

As far as calculating the volume for a tire:
You could do some calculus and integrate the dimensions to get exact or you can use the following rough approximate formula:
Radius of tire(minus 1" or so for rubber thickness) ^2 x PI x tire width(10", 12.5" etc) = vol of tire and rim
Now you need to calculate the vol the rim occupies:
Radius of rim ^2 x PI x rim width = volume of rim

Then the volume of air in the tire = volume of tire and rim - volume of rim

^2 means squared by the way, and you are right on the 19 gal of your tanks. /wwwthreads_images/icons/smile.gif

/wwwthreads_images/icons/cool.gif Big Ed
'88 YJ, 4" susp,3" body,33's,283 Chevy V8,TH350,4.11's,D30,D35c

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