Mathematically intelligent wanted.

Submitted: Wednesday, May 10, 2006 at 19:07
ThreadID: 33766 Views:1983 Replies:7 FollowUps:23
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Ok now i have ur attention.....I have been toying with the idea of fitting stormwater pipes under my offraod trailer.Was thinking of a continuous length which worms its way from front to back using U connectors. I would naturally fit a sheet under it that protects the pipes from damage.

My question is....How do you calculate how much water the pipe will hold if i use 100mm pipe. Lets just say for the exercise of this calculation that the total length of the pipe will be 10 mtrs.

Any takers...sorry maths was NOT my fav subject.

P.S. Please dont hit me with the negatives of trying this, I have plenty of room under there even with the extra sheet to protect the pipes. I only use the trailer for family camping weekends, so serious 4wding is not an issue.
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Reply By: Truckster (Vic) - Wednesday, May 10, 2006 at 19:11

Wednesday, May 10, 2006 at 19:11
since you have heaps of room, why not get a tank made up, that will hold a larger capacity, and not get shower smashed with rocks?

As for how much it holds?? NFI, google ;)
AnswerID: 171984

Follow Up By: cokeaddict - Wednesday, May 10, 2006 at 19:14

Wednesday, May 10, 2006 at 19:14
i was waiting for that 1 truckster :-)

Oh and btw very nice GU pic u posted, i like the tyres mate
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Follow Up By: Truckster (Vic) - Wednesday, May 10, 2006 at 19:25

Wednesday, May 10, 2006 at 19:25
serious.. dude we were talkin to at 4b show had that happen to his pipe, dry showers for few nights :(
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Follow Up By: rhino - Sunday, May 14, 2006 at 21:12

Sunday, May 14, 2006 at 21:12
Try filling it up with 2lt bottles (or get the mrs to do it) while u count the bottles. ???
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Reply By: hoyks - Wednesday, May 10, 2006 at 19:15

Wednesday, May 10, 2006 at 19:15
Pi (3.14) x the diameter of the pipe will give the area of the cross section, and times that by the length will give the volume.

So 3.14x 10cm = 31.4 x 1000cm = 31400 which should give you around 31.4L.
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Follow Up By: hoyks - Wednesday, May 10, 2006 at 19:16

Wednesday, May 10, 2006 at 19:16
My mistake Pi R squared...wait one
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Follow Up By: hoyks - Wednesday, May 10, 2006 at 19:19

Wednesday, May 10, 2006 at 19:19
3.14 x 25 (radius squared) x 1000 = 78.5L
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Follow Up By: Member - Reiner G (QLD) 4124 - Wednesday, May 10, 2006 at 19:23

Wednesday, May 10, 2006 at 19:23
rxrx3.14x100 is 78.5litre.......

Reiner
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Follow Up By: Member - Reiner G (QLD) 4124 - Wednesday, May 10, 2006 at 19:24

Wednesday, May 10, 2006 at 19:24
ok.......you win :-)

Reiner
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Follow Up By: cokeaddict - Wednesday, May 10, 2006 at 19:24

Wednesday, May 10, 2006 at 19:24
Well...if your calculations are correct hoyks, 78 ltrs will do just fine. thats quite a few showers to keep the fems happy.

Thanks for taking the time to work that 1 out mate.
Ange.
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Follow Up By: Truckster (Vic) - Wednesday, May 10, 2006 at 19:25

Wednesday, May 10, 2006 at 19:25
78.5litre.......
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Follow Up By: V8Diesel - Wednesday, May 10, 2006 at 19:42

Wednesday, May 10, 2006 at 19:42
Roughly 78,500ml's according to my calculations. Don't know where those other blokes got their numbers from.
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Follow Up By: V8Diesel - Wednesday, May 10, 2006 at 19:44

Wednesday, May 10, 2006 at 19:44
or 5,308 table spoons.
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Follow Up By: RedGibber - Wednesday, May 10, 2006 at 20:15

Wednesday, May 10, 2006 at 20:15
..or 2616 and 2/3 doubles if ya filled it with bourbon!! ;-)
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Follow Up By: V8Diesel - Wednesday, May 10, 2006 at 20:21

Wednesday, May 10, 2006 at 20:21
Now ya talkin'!
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Follow Up By: GaryInOz (Vic) - Wednesday, May 10, 2006 at 23:08

Wednesday, May 10, 2006 at 23:08
area = Pi x r x r

r = d/2

for 100 mm diameter pipe, r = 50 mm

area = 3.14159265 x 50 x 50 = 7854 mm2

for ease of use convert to dm2 -> 0.7854 dm2 (4 decimal places to the left, 100 mm2 to the cm2, and 100 cm2 to the dm2)

so there will be 785 ml per 100 mm of pipe length, or 7.85 litres/metre.

Simple.........................................................
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Follow Up By: Richard Kovac - Wednesday, May 10, 2006 at 23:36

Wednesday, May 10, 2006 at 23:36
Try using dm instead of mm or cm the answer always comes out in litres

Richard

most of as will be old enough to remember
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Reply By: Sand Man (SA) - Wednesday, May 10, 2006 at 20:10

Wednesday, May 10, 2006 at 20:10
Ange,

Don't wish to sound negative mate but why would you opt for a pipe to hold water rather than a purposely designed water tank. The tanks are readily available from Caravan supply outlets and can be located to give you positive, negative, or neutral balance at the tow ball.

I couldn't think of anything worse than 40 odd litres of water surging backwards and forwards along the length of the pipe when it's half empty. (or half full)

I used to transport two or three 20 litre containers of water when I used the off-road 7x4 trailer to travel. There was plenty of room for them.

Bill


I'm diagonally parked in a parallel Universe!

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AnswerID: 171995

Reply By: kesh - Wednesday, May 10, 2006 at 20:14

Wednesday, May 10, 2006 at 20:14
3.142 x r x r x l (centimetres) = vol. in cc's. Divide by 1000 = litres.
where r = radius of pipe diam.in cm (10cm. diam = 5cm r.)
l = length of pipe in cm.
Therefore for 100mm pipe diam = 7.85l/m
150mm = 17.6l/m
200mm = 31.4l/m
There you are, done it for you!
AnswerID: 171999

Follow Up By: Member - Ian W (NSW) - Wednesday, May 10, 2006 at 20:49

Wednesday, May 10, 2006 at 20:49
OK all you smarty pants, while you all have your slide rules out, (remember them), can someone tell me how much my 200Ltr wheely bin holds.

Ian W
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Follow Up By: Jimbo - Wednesday, May 10, 2006 at 20:56

Wednesday, May 10, 2006 at 20:56
That would depend how much Sierra Hotel India Tango you put in it Ian.
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Follow Up By: RosscoH - Wednesday, May 10, 2006 at 21:52

Wednesday, May 10, 2006 at 21:52
Would not the" 200lt" bit tell you something about the volume
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Follow Up By: Member - Ian W (NSW) - Friday, May 12, 2006 at 07:57

Friday, May 12, 2006 at 07:57
Whoosh!
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Reply By: Member - Darren T (VIC) - Wednesday, May 10, 2006 at 22:53

Wednesday, May 10, 2006 at 22:53
Um, I`ll just try and make it sound a bit easier, a cube of 10cm x 10cm x 10cm holds 1 litre of water.
So with the same principle - does this mean a 100mm pipe that is 100mm long will hold slightly less than 1 litre?

I say slightly less because PVC pipe sizes are measured in outside diameters. So obviously if you had a peice of pipe that had a sidewall thickness of 5mm will hold less than a peice with a sidewall thickness of 2mm.

I`m sure if I am wrong someone will tell me in many ways why :).

AnswerID: 172048

Follow Up By: V8 Troopie - Thursday, May 11, 2006 at 01:08

Thursday, May 11, 2006 at 01:08
Darren, a cube is... cubic and a pipe is.... round. Your 10cm long pipe will hold a LOT less than 1 L
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Follow Up By: agsmky - Thursday, May 11, 2006 at 14:27

Thursday, May 11, 2006 at 14:27
Darren, most water pipe is measured with the Internal Diameter (ID), except for Poly (the black stuff) which is measured with OD.

Andrew
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Reply By: Member - Bradley- Thursday, May 11, 2006 at 02:23

Thursday, May 11, 2006 at 02:23
Ange, save the stress of cutting and gluing and supporting all of it, not to mention the cost of all the elbows etc. and install 2 70 lt camec caravan tanks, the ones with all the fittings threaded, to allow proper fill pipes and breathers. put 1 in front and one behind the axle, so as to not affect the balance. i think they are about $ 80-90 each.

Ive got one under our trailer, and it is grouse.
AnswerID: 172071

Follow Up By: V8Diesel - Thursday, May 11, 2006 at 08:09

Thursday, May 11, 2006 at 08:09
Good call Bradley. A mate of mine just fitted two of them in the tray of his Navara too. Works well, looks professional, not too expensive and was available of the shelf from Camec (?) in Welshpool Rd.

I asked the bloke what the difference between an off-road and on-road tank was and he said "a thin strip of rubber between the tank and the strap". Reckons they don't give any problems.
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Reply By: cokeaddict - Thursday, May 11, 2006 at 13:07

Thursday, May 11, 2006 at 13:07
WOW.....some real smart people in here....but i already knew that !!!!

Thanks to everyone who replied. It is very much apreciated.

I will sit down and think it through again. Some very good ideas tossed in too.

Just for those who were suggesting the pipes would break due to stones ....I had a plate designed on paper that was a second floor to protect the pipes. Pipes were not visible at all once the steel plate was in place, and i can get the pipes for nothing. That was my reason for fitting them on.

Ange.
AnswerID: 172131

Follow Up By: gottabjoaken - Thursday, May 11, 2006 at 15:02

Thursday, May 11, 2006 at 15:02
Cokie,

I reckon the water surging back and forwards in a pipe will very quickly rip it from whatever mountings you use, if it doesn't blast the end off the pipe first.

Imagine 50 kg sliding up and down the trailer...

Ken
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