Drop tank without straps

[Zedn]

HI Guys,

I am making my drop tank next week, and want to make it to mount without straps. It will be 70lt made from 1.6mm stainless.

Has anyone built one in this style? Just after some tips on how to brace it. I think the baffles will be enough to support the bottom of they welded to the bottom and sides. I am using 2 running front to back.

I am thinking just some brackets mounted on the sides incorporating a rubber mount to the chassis.

Anyone got any tips or pics?

Cheers.

[Aussie Mike]

Hi Zedn,

I was thinking about mounting the tank this way as well but I have some reservations. My worry is what happens in the event of a rear end collision. If the tanks is tied directly to the chassis even though isolated by rubber there is a chance the tank could be torn open if the structure around it is badly twisted or bent. Mounting the tank with straps underneath it lets it move independently of the chassis. The tank could be crushed but with nothing anchored to the chassis to pull against it shouldn't tear so easily.

The other thing I was thinking is that there should be as many radiused corners as possible in the construction of the tank. I reckon a radiused corner is more likely to distort and bend than a square welded corner which might split under the same load.

I think tank design is a good topic for discussion and I'm keen to hear others input.

Cheers

[Outwest34au]

Hi guys,
my alloy tank fits sorta cosy in the rear rail section under the boot floor. I initially got some 40 x 40 x 8 mm angle welded to the sides to hold it up under the rhs rails. After needing to revise the angle of it to fit the exhaust I saw the potential for failure in my initial move. I have just finished making a new bracket to support the front of the tank with straps running to the rear to help support it there. The fore mentioned prevent forward and downward movement of the tank. I am now wondering if I should get the angle welded back to the side to prevent upwards (and other) directional movement.
It's taken longer to think about it than to actually do it so far.

[Zedn]

Mike,

Thats a really good point that i hadnt thought of. What do you think about slotting the mounting holes? That might allow enough movement without tearing. My chassis has a bar running along the back, that would probably crush the tank anyway.


This is the sort of brackets if was thinking.
http://www.rollcage.com.au/images/droptank6.jpg

[Aussie Mike]

Slotting the brackets might be a good option. Maybe an open ended slot so if the chassis distorts far enough it will just pull away from the tank.

That tank is also a good example of what I was getting at with the radiused corners. Note how all the corners have been folded and the welds are on the flat rather than the corner.

Cheers