long range fuel tank,,,,,,,,

[choppa]

i've been tinkering with an idea for a few months now of building a LRFT for the truck,, and the more i think about it,, the more i like it,,,which normally means DISASTER if i think its easy

my plan,,,

i'm making a false floor on the tray of the truck,, to accomadate a few draws etc etc,,to replace the trailer when we go on short overniters etc,,

my intention is to lay a 2 1/2"-3" pipe around the tray,,and have ""crossmembers"" in place to hold the new floor on top,, i say pipe is to be used,, cause thats what i intend to use as the auxillary tank once in place,,, with a direct feed to existing tank,,(ball valve in between junctions),,,and its own filler,,air vents,,

the plan is simple,,,thats why i'm worried,,

the truck is diesel,,,no major concern,,,and the pipe will be ally,,(lightweight),, and i'm no rocket scientist,, but it would have to hold adequate fuel to keep me in the straight and narrow,,,(theres a formula to convert area inside pipe to litres in my library,,,havent pulled it out yet)

now this may sound dumb,,but the more i think about it,,the more i like it,,,(again thats why i'm worried more)

has anyone don this before,,,(and lived),,,or know of anyone who's done it,,,(and lived)?????????

choppa

[Brett1907]

Choppa, a couple of things.

Is the it registered in QLD?? If so it will need to be inspected & Mod plated. To comply you will need to go to the transport dept. and get whatever info they have available. Or contact an engineer who may be able to help.

As to design, I don't have much of an idea really. Best bet would be to have an electric fuel pump to transfer fuel from the auxiliary to the main tank. This means modifying you MAIN TANK as well!! I personally wouldn't try as cutting/welding a fuel tank that has had fuel in it is dangerous.

Would you need baffles in the aux. to prevent fuel from sloshing around?

My mate had an auxilliary tank fitted to his new patrol. It has an electric pump to trnsfer the fuel, but he has calculated the time to pump all fuel over to the main tank will be 37 minutes.

Formula to calculate volume in a pipe is

pi*d*d/4 * length

that is

3.14 x diameter squared / 4 (gives area)
than multiply all by length of pipe to give volume.

Brett

[SeaHunt]

Your an Ideas man Choppa

?? Not a maths expert or anything but I thought the area of a circle was
pi x radius squared.
And the volume of a cylinder was the are of the base (circle) by height or length.

Work in centimetres or decimals of a centimetre is best.
Then 1000 cubic centimetres is one litre.
So if inside daimeter of pipe is 50 mm (about 2 inches)
You will get just under 2 litres per metre of pipe.
1.9625 to be precise.
Doesn't sound like its going to hold a lot, might be a short range fuel tank.
What happens when you go up (or down) a hill and its half full ?
Its all going to be at one end

[Brett1907]

SeaHunt,

3.14 x diameter squared / 4
is the same as
pi x radius squared

using the diameter instead of radius used to make it easier at uni. One less calc to worry about as all pipes were given in diameter.

Don't forget that you need to calculate the internal diameter. It may sound pedantic, but over say 4m of pipe it can create a bit of a difference in volume. Especially using a thick walled pipe.

Brett

[choppa]

dunno if this will work,,, but i'll post a pic

the idea as such is as an auxillary tank only,,,,not direct feed to existing tank,,,ie, auxillary piping will have its own filler,,,and will join to existing main tank via a ""t"" piece in the hosing from the inlet to tank,,,and will be controlled via a ball valve,,,, as such,,when main tank is low,,swing ball valve to open and refill main tank,,,

i don't think DMR will need to be involved,,,as such it would be the same as carrying jerry cans,,, but the piping serves as a 2 fold avenue,,,allowing fuel storage inside,,,and clearance for drawers to be built

the attached ""plan"" is rough ,,,,i'm no computor whiz,,,but if you picture the diagram without a full length of pipe down each side,,,(like a H so to speak),,this is where drawers could go etc etc

slop,,,pipe can be filled to maxx,,,,and emptied in one hit,,,,no slop

anyway,,,just an idea,,,,,i think it should be a goer,,,but as stated above,,,thats what worry's me

[SeaHunt]

SeaHunt,

3.14 x diameter squared / 4
is the same as
pi x radius squared

using the diameter instead of radius used to make it easier at uni.
Brett

I told you I was not a maths expert, otherwise I would have realised that.

[SeaHunt]

Choppa that is still only going to be about 35 litres with 2 inch inside diameter pipe.
Better than running out of course.
How would the filler work?
I can imagine a lot of air getting trapped in there if it was at even the slightest angle when filling.
My brother made one up for his ute that he could just fill the "real" tank from, he bought a tank from some sort of army disposal place in Melbourne.
Rectangular in shape same width as the tray, just bolted it to the front of the tray, held 160 litres, he lost a bit of tray realestate but that didn't bother him with a 10 foot tray on a 6 wheeler landcruiser.

[bungie]

i don't think DMR will need to be involved,,,as such it would be the same as carrying jerry cans,,, but the piping serves as a 2 fold avenue,,,allowing fuel storage inside,,,and clearance for drawers to be built

DMR will need to be included in it. You have a prang and the police are involved, they check the vehicle and find illegal mods especially to the fuel system and your insurance will tell you to get stuffed, and be within their rights too as well

[choppa]

thinking around 3" pipe,, with filler as a direct line from the top rh corner on a 5-7.5degree radiant from the bottom lh corner,,,5 breathers fitted,,each being flush mount,,dump pipe to be welded at closest possible point to existing fuel filler,,closed off via a ball valve,,

frame will sit into tray,, and hence will olny have lugs attached to points where i require to screw false floor to the top,,,drawer sections will have rails/stoppers welded to fix drawer runners too,,

insurance,,,, spoke to our dealer representative already,,,,came back with no probs based on there is no structural changes made,,,and hence why i stated as above,,there is really no difference in this and carrying jerry cans,,as nothing is fixed

the whole shebang would be able to be lifted on tray and off again,,,but i am for leaving it on,,

correct measurements will follow,,i thought i would get more than 40-50 litres though based on the amount of pipework,,,but if thats on 2 inch,,then there'd be a bit more in 3 anyway

as i asked,,,i was more curious to see if anyone else has done this before,,,i know of a heap of guys who use underfloor style LRFT that they have taking out of boats,,,and just laid a floor directly over the top,,,,but these are generally fixed in place,,

i'll keep thinking

choppa

[Brett1907]

Nothing wrong with thinking outside the square!!

It is a good idea and sounds like you have thought it out pretty well.
I'd be interested to see the finished product. Good luck.

Brett

[SeaHunt]

Me too.
3 inch, 2.5mm thick will give you a tad over 65 litres.
Thats a fair bit, my Hilux tank only holds that.

[jimbamb]

CHOPPA.
another thouht.
B...C..F have alloy tanks in various sizes could be worth a look
.deisel is very hard to keep in a container.it will find the smallest hole and u could end up with a tray full of smelly deisel.
I.m gettin one to fit under the tray. so it can leak if it so desires..

[choppa]

Nothing wrong with thinking outside the square!!

It is a good idea and sounds like you have thought it out pretty well.
I'd be interested to see the finished product. Good luck.

Brett

thanks brett,,,,you just saved me about 100-200 bucks,,,

plan has changed (slightly),,

just got back from local ally supplier,,,have ordered a 6.5 mtr length of 80mm x 80mm BOX tubing,,,2.5 mm wall

this will give me a ""square hole"" of 75mm x 75mm,, and will allow the fitment of cupboards more easily,,once i sort out what i want,,,

i have spoken to dmr today,,, (to double check),,, they have confirmed that a removable floor frame that is not fixed to existing tray or chassis is allowed,,,and have no regulation against it,,,,Suncorp,,,Swann,,,Allianz have all come back with no problems,,, OTHER THAN ,,,, for peace of mind a pressure test certificate may be worthwhile having on board,,, which is what i was going to do any way,,

Jim,,,, i was thinking about an under floor tank initially,,,then with the false floor,,,i thought why not kill 2 birds with 1 stone,,,hence this idea was born,,,,it was going to happen one way or the other and with the frame for the floor to be made,,,i may as well use it,,,,,

COST you all yell,,,,,,box ally,,,quoted at $130.00 length,,,,,welding,,(still shopping here) at $66/hr,,approx 2-3 hours work involved,,,total,,,,,$330.00 and i have what i want with drawers,,cupboards,,,and 1 or 2 hidey holes in the floor,,

i'll keep you all posted

[jimbamb]

Good thinkin choppa. my calculations 6.5m of pipe will give u 38.5litres.Is that all u need?maybee you can make a series if pipes(Like Rafters) to get more quantity.
Let us know how it turns out..Good Luck..

[choppa]

got that covered jim with regard to additional ribs to be included,,,but wont know until i decide on drawers or cubby holes,,i think i've created a monster

to include tracks to accomadate drawer runners on side of box is easy,,,,and to make drawers is cheap from the recycle bin at ally supplier,,, i picked up enough stuff there when i visited to do 4 drawers to size,,for $20,,

say a couple of hours work,,,pop rivets,,,,chopjr,,,,scotch or 2,,,still works out cheap,,

the decision that i'm now toying with is to have either access drawers from the sides,,,or cubby holes in floor panel, i'm not to overconcerned with either,,,i'm thinking more of weight and ease of handling,,,still playing here,,,i'll keep ya posted