Fuel tank strap tension

[haribole]

Trying to figure out how to measure the tension of the fuel tank straps. any help would be highly appreciated. Thanks

[Battson]

Trying to figure out how to measure the tension of the fuel tank straps. any help would be highly appreciated. Thanks

The amount of force (weight will do) required to deflect the straps by a known distance. Hook a tension scale up to the strap and pull 20lbs, see how far it lifts off it's resting position. Hard to know what the tension is exactly, but at least you can make sure it's the same all around.

[swpilot3]

I'm not certain of the correct tension, but here was my experience. I didn't want to over tension my tanks. So, I set the tension to what seemed appropriate. After filling the tanks completely full for the first time, the tanks slid back a little bit (in the 3-point attitude) making the filler neck not centered in the hole anymore.

So I'd go for somewhere between not bending the spars and not letting the tank slide around. :-) In all seriousness, I'd make sure they're very snug.

[svyolo]

My first tank is sitting on the top straps, but haven't made the bottoms yet. I will hopefully make them today. It seems to me that how the tensioners apply tension makes the whole thing a bit indeterminate about how secure the tanks are for and aft. I think the bends on the fore and aft edge need to be, if anything, made such that the strap length over the top and bottom of the tank is the exact length (impossible), or very slightly short. I believe that will keep the tanks more secure for and aft.

Tension from tightening the tensioners needs to be transferred to the top part of the strap. If the bend are such that they make the top and bottom of the straps even slightly longer, I think the tension won't be adaquately applied for and aft.

At least that is what I think. Could be wrong.