How many landing legs

[Spyros]

Is there any way to determine the optimal (or an approximate good range of the) number of landing legs that you need according to your ship's weight and the target planet? I am trying to land on Eve. 

[radonek]

Eve surface gravity is slightly higher then kerbin (1.7g) so I'd say  that anything that works well for you on kerbin should be at least acceptable on Eve. Or attach a big fuel tank and fill it to make whole  craft weigh1.7x as much.

[Xd the great]

Well, 3 is the minimum.

Jokes aside, double the amount of legs that you would use on kerbin.

[swjr-swis]

1 hour ago, Spyros said:

Is there any way to determine the optimal (or an approximate good range of the) number of landing legs that you need according to your ship's weight and the target planet? I am trying to land on Eve.

Landing legs have been... let's put it mildly... a bit 'touchy' for a few versions of KSP now. Regardless of what you do, there will be spontaneous explosions at touchdown. Eve is especially prone to cause such explosions, because the gravity is significantly higher, which exacerbates the problem.

Theoretically, and logically, the answer should be that you look at the 'Stress Tolerance' value of the parts, and compare that to the weight of your craft (adjusted for local gravity). This number should indicate how much weight they can handle, or how many legs you need for the calculated weight. But as you can quickly notice, that value has already been raised to an absurd number in the stock game, and legs still explode anyway.

So the most practical answers are:

• If you still want to use legs anyway: however many legs you use on Kerbin, times 1.7x, plus a safety margin of about 25-50% to allow for a few legs to explode. Legs are going to explode no matter what you do, so try to think in terms of 'how many legs do I need to have left after the inevitable explosions for my craft to remain stable'... and go with it.
• Use something other than legs. Ironically, just about any part not meant to be a landing leg is more reliable to land on than landing legs. The whole concept of 'suspension' is practically useless at the moment with how buggy it is, and KSP physics do not penalize sudden stops, so you may as well just pick parts with the highest crash tolerance (other than actual legs) that look like they'd make pretty legs and use those. Just keep your velocity under their crash tolerance and your craft will be fine.

 

[Laie]

8 hours ago, Spyros said:

Is there any way to determine the optimal (or an approximate good range of the) number of landing legs that you need according to your ship's weight and the target planet? I am trying to land on Eve. 

My suggestion: don't use any legs, land her on the engine bells. I can assure you that this works very well with Mammoths and Twin-Boars, but I don't know about Mainsails.

[Spyros]

12 hours ago, swjr-swis said:

 

• If you still want to use legs anyway: however many legs you use on Kerbin, times 1.7x, plus a safety margin of about 25-50% to allow for a few legs to explode. Legs are going to explode no matter what you do, so try to think in terms of 'how many legs do I need to have left after the inevitable explosions for my craft to remain stable'... and go with it.

 

True, I tried to land with multiple legs and I noticed that some of them exploded! I tried again and eventually I tried to land with 0 explotions, but I had to burn a bit of extra fuel for that.

12 hours ago, swjr-swis said:

 

• Use something other than legs. Ironically, just about any part not meant to be a landing leg is more reliable to land on than landing legs. The whole concept of 'suspension' is practically useless at the moment with how buggy it is, and KSP physics do not penalize sudden stops, so you may as well just pick parts with the highest crash tolerance (other than actual legs) that look like they'd make pretty legs and use those. Just keep your velocity under their crash tolerance and your craft will be fine.

 

Lol, most interesting thing I learnt today XD   (as I am still relatively new to KSP).  Nevertheless, I suppose that they plan to hopefully fix the issue of the landing legs in the future, so perhaps there are going to be days when using landings legs would be more useful than landing on the engine bells? 

[swjr-swis]

17 minutes ago, Spyros said:

I suppose that they plan to hopefully fix the issue of the landing legs in the future, so perhaps there are going to be days when using landings legs would be more useful than landing on the engine bells? 

Unknown, because Squad is annoyingly silent on the issue. This last 1.6 patch they decided to increase the range of the suspension/damper sliders, apparently as a workaround. They haven't explained how that is supposed to help though, and it contradicts earlier statements that extreme values for those sliders would make matters worse. So hopefully there's still some actual fixes in the works for the intrinsic problems with the wheel system (legs in KSP are internally handled as a type of 'wheels').

A small source of hope is that it didn't use to be this way. Landing legs were once very useful - pretty reliable and actual shock-dampening suspensions and all that, and we used to be able to 'lock' their suspension too for more stability once landed. There's also mods that replace the wheel code with something that works. So the possibility for a fix exists. We're just waiting for it to actually happen.

[magnemoe]

On 12/24/2018 at 7:17 PM, Laie said:

My suggestion: don't use any legs, land her on the engine bells. I can assure you that this works very well with Mammoths and Twin-Boars, but I don't know about Mainsails.

Better to use some sort of beams on decoplers obviously so you can decople them on takeoff. Using the large grinder boxes or the H beams you can take pretty rough landings you can also put stuff as ladders, science gear or solar panels on the beams. 
Put them as you put legs, you can not retract them but that is an minor issue for an Eve rocket.