New Landing Legs

[stupid_chris]

The problem will definitely not be in the craft file. I believe it's more in how it's made, and how you use it that will trigger it to happen. It's definitely unreliable, but my guess is that the landing legs absorb shocks but don't push back hard enough. Thanks for the craft file, I'll mess with it when I get some rest.

[Galane]

I wonder if it's possible to edit the legs' cfg to add an extend and lock function which can be added to an action group?

What would be a useful addition is a trigger for self leveling so that when landed on an uneven surface the uphill legs retract and the downhill ones extend to point the vehicle as straight upwards as possible.

Legs that can't hold a ship upright on the perfectly level launchpad are a bit less than useful!

[MalfunctionM1Ke]

I wonder if it's possible to edit the legs' cfg to add an extend and lock function which can be added to an action group?

It is but I cant find the thread anymore where I read about this. You can even stiffen the pistons so that they are not absorbing any shocks anymore.

Let me dig a little.

Edited October 20, 2013 by MalfunctionM1Ke

[Joshington]

I had the same problem. I ended up fixing it by replacing the legs with 1x1 structural panels. Honestly still can't believe they worked.

[MalfunctionM1Ke]

There is the handmade solution:

You can fix this by going to the part.cfg and changing suspensionSpring = 1 to something larger. Or you can disable the suspension effect completely by setting suspensionUpperLimit to 0. This should let you play the game with landing legs again.

[Bill Zarr]

Decided to give this a bit of a methodical test after I discovered how much the LT-2s slump. As a rough figure the legs seem good for about a 25kN loading. So on Kerbin a 10 ton mass needs 4 legs. You just need to multiply the mass of your craft in kg by the surface gravity of the place you wish to land, then divide that by 25000 to get an idea of the minimum number of legs you'll need. - At least in theory, I've not yet tested anything in practice. (They do seem a bit on the weak side now)

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Edited October 20, 2013 by stupid_chris
fixed album

[Hodo]

Decided to give this a bit of a methodical test after I discovered how much the LT-2s slump. As a rough figure the legs seem good for about a 25kN loading. So on Kerbin a 10 ton mass needs 4 legs. You just need to multiply the mass of your craft in kg by the surface gravity of the place you wish to land, then divide that by 25000 to get an idea of the minimum number of legs you'll need. - At least in theory, I've not yet tested anything in practice. (They do seem a bit on the weak side now)

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Great work, love the tests. +1

[Galane]

Compared to landing legs that have been used on real spacecraft, these have far too much travel. The two Mars Viking landers had crushable parts to absorb the last bit of landing force. IIRC the LEM legs had something similar for their one time use.

I think the DC-X experimental rocket had no suspension on its legs, but on its final test one of the legs failed to extend so it fell over and had an explosion event. Something simple for an emergency extender like a shotgun shell blank would've saved it.

Can't tell from the videos whether or not the Space X Grasshopper's legs are fixed or have some sort of suspension. If they do, it'd likely be reusable.

The ideal way for the game legs legs to work would be to automatically rise to their full extension after absorbing impact.

Next on the wish list is a way to have the legs auto-adjust to aim whatever they're attached to as vertical as possible.

There's no way this will work with the new legs. My NEW (Nearly Everything Works) Lander and, well, every lander I've built, won't work.

Can the .21 legs be renamed and added to .22, or rename the .22 legs so they won't affect old ships?

[nismobg]

The new legs outperform the old on sloppes, i started intentionaly to drop faster so i can get a level on slopes with the new legs, it works a treat.

[Oznerol256]

The new legs outperform the old on sloppes, i started intentionaly to drop faster so i can get a level on slopes with the new legs, it works a treat.

I didn't notice that but i also never had a problem with the old landing legs.

While features like that are good and i don't want them to be removed, the legs still need to extend all the way after the landing. The travel should also me lowered or the engines aren't protected properly. I actually think that protecting the engines is the only reason to use legs on most spacecrafts (modular bases being one of the exceptions).

[TheWanderer]

i am glad to see that after 8 pages we have finally come to the point of saying people we just overloading the legs :-)

[Oznerol256]

i am glad to see that after 8 pages we have finally come to the point of saying people we just overloading the legs :-)

Do you really think that kerbals shouldn't be able to build landing legs that are capable of holding more than 250 kg?

Edit: Also, do you really think these legs are overloaded?

Edited October 21, 2013 by Oznerol256

[SteevyT]

There does seem to be something off with the way the landing legs rebound. I mounted an engine pointed downward to increase force on a lander that I knew could sit near full extension. I compressed the legs all the way down and they only rebounded about halfway. Raising and lowering a single leg caused them all to kind of pop back to where they normally were under the weight they were supporting.

[TheWanderer]

Do you really think that kerbals shouldn't be able to build landing legs that are capable of holding more than 250 kg?

Edit: Also, do you really think these legs are overloaded?

its not loaded centred, of course it will lean over. If you put more weight on one side why are you expecting it NOT to lean?

[Oznerol256]

Not centered? What is not centered in that craft? All parts have been attached using symmetry. Download the craft file and take a look at it. Its completly symmetrical.

[SkyRender]

I think part of the problem with the new landing legs is that they do not compensate properly at all for asymmetry of any sort. Even if that asymmetry is actually symmetrical along one axis but not another (ie. a classic two-side-engine lander design). I did some tests, and found that ANY disruption of perfect symmetry from the relative position of the landing legs results in the craft's legs failing to compensate correctly. They will bend towards the discrepancy, and keep bending towards it no matter what. To the point that even a cubic octagonal strut (which weighs all of 0.01T) will knock a 20T vessel askew. This needs to be fixed, to say the least.

[TMS]

Shouldn't this be in the support/bugs forum?

[Brotoro]

Shouldn't this be in the support/bugs forum?

The first thread I posted about this topic got moved there.

[Endet]

I've been experimenting with the new landing leg mechanics for a few hours now. It seems that the LT-1 landing legs act pretty much as they should, even though I'd say they are a bit on the weak side also, but the LT-2 landing legs suffer from weakness, heavily. I've been messing with the spring and damper settings for the LT-2 legs to see the effects of them and I believe the developers have set the settings way too low. Setting the springs to 10 and dampers to 5 seems to give me the similar results I was seeing in 0.21 when under a 40ton load.

The odd behavior of the LT-2 landing legs seems to be a bug also, talking about the part where they compress to one side and even after using engines to level the ship, it will lean back to it's original setting. If the ship is leveled, the load should be balanced on all legs and not on one so I believe this is a bug. Changing the settings in the part.cfg heavily helps with this (it still happens but not on a grand scale and it can be reset with proper landing leg configuration).

Think I'll post a video in a few hours about how the setting changes affect the behavior of the legs and what I've found to be the correct values.

[JumpsterG]

I would wager that the legs are "working as intended" but that they have some gameplay balance yet to be applied. Heavy landers now require a silly amount of landing legs to keep from buckling.

The largest legs will probably need to be beefed up (or a new, even stronger, landing leg introduced) to make heavier landers not require dozens of legs. (Anyone looking for a balanced mod part that fills this niche should check out the largest landing legs in Novapunch: they're heavy, don't have suspension, and are not retractable but are huge, sturdy, and look awesome).

Tests of the new stock legs seem to show predictable behaviour whereby they work just fine up to a threshold weight, above which they buckle. This is good and is another factor we can design our vehicles around. Something that would help greatly would be if we could see load limits in the part descriptions so we know what to expect. Tweakables would also be nice here for balancing spring vs strength on a craft-by-craft basis.

[Edit] All bugs aside, of course. Reports of landers leaning over to one side for no good reason probably need to be addressed.

Edited October 22, 2013 by JumpsterG
Afterthought on bugs

[mastiwawa]

I have found that the legs only compress like this while on the launch pad. if oyu fly away and land anywhere else they work just fine.

[Brofessional]

We simply need an action added to the legs to make them fully extend. Then we can just map the legs to an action group and extend them after landing.

[Scarecrow88]

I have found that the legs only compress like this while on the launch pad. if oyu fly away and land anywhere else they work just fine.

They didn't work just fine for me off the pad. My structure kept falling over because the legs were buckling, and that wasn't on the pad.

[Brotoro]

I have found that the legs only compress like this while on the launch pad. if oyu fly away and land anywhere else they work just fine.

I have found this is not always the case.

[hobbsyoyo]

The first thread I posted about this topic got moved there.

And the developer who answered you more or less said this wasn't a bug, right?

I don't see how anyone thinks it isn't a bug to be honest.