Mass / Load Rating

[CheftonUTD]

Just wondering if anyone has any figures or guides to the load rating of lander legs?

For a specific scenario, what I'm planning on doing is making a large Kethane lander/orbiter/fuel-station/driller/storage/refining vessel all in 1 ship - it's target is Minmus, so I think it may be possible with the low gravity.

I'm still early in the design phase but I was hoping for a configuration including; 1 orange L-fuel tank, 4 16,000L Kethane tanks, plus all accessories needed. It's already about 60t, and its 'wet' mass would be about 188t.

Anyway back to the question, any idea how many lander legs I would need to stop it from collapsing (while landed on Minmus) as it becomes a nearly 200t 'base'?

Edited August 18, 2013 by CheftonUTD

[ThatDebri]

Can you post a pic of the lander, i like to place the landing legs symmetrically according to the design.

[CheftonUTD]

Yeah sure, I kept working on it and I think this should do it:

The goal is for it to land on Minmus, extract Kethane, take-off and orbit/travel, refine it and transfer fuel to other vessels (looking at KAS docked with another ship in orbit), then get back on Minmus and repeat.

Specs:

Mass - 83.5t / ~212t fully loaded

Legs - 3 on each Kethane tank, 4 on orange tank (LT-2)

Prop - 5 x Poodle engines

Misc - RCS, 4 x gigantor panels, 4 x small drill, 1 x heavy converter, 2 x KAS winch + connector, etc

Batt - 8000 capacity

Crew - Up to 3

I'm thinking this thing might actually work as intended, looking pretty good so far, the legs can extend and support its 83.5t on Kerbin.

But if anyone does know a guideline for mass/lander-leg ratio that would be helpful for the future.

[Bean]

Well I did some testing: 8T/leg is too much for the mid size, 7.5T/leg is ok.

Large legs: 54T/leg is fine, my test rig bounces a hell of a lot though, I'll try to break them. Up to 85T/leg and they still won't break from a 5+m/s drop at kerbin grav. Just broke them at 88T/leg.

So there you have it, as long as you land at less than 5ms at kerbin grav or less.

[CheftonUTD]

Thanks that should save me a bit of trial and error in the future