Why Landing Struts overstress when they should resist?

[montferrer]

Hi! I’m using LT-2 Landing Struts to land on Eve, below its tolerance limit of 12 m/s, but they always crash. Maybe I don’t understand how this works, and impact tolerance is not the same as stress tolerance, but when the vessel “lands” it’s going at 9.4 m/s, which I thought was safe. Here are two pics of before landing and after “landing” (all struts explode and then the vessel flips and everything is over:

http://imgur.com/a/6SnKY (pics are from different landings, but both were going at the same speed and ended exploding)

Thank you very much! 

Edited July 1, 2016 by montferrer

[Lunar Sea]

Does the game calculate the weight on the struts? With Eve's higher gravity that might be an issue. Presumably it's not just landing speed since it appears to be well within spec for that. Maybe try playing with the strut lock settings. 

[bewing]

Yeah, it's a weight issue -- or perhaps a "landing impact" issue. What's the mass of all that stuff you're landing? And since it's not a perfectly flat surface, only a couple legs are taking the weight, at first.

I did testing on all the landing legs in 1.1.2, and put the results in the wiki. I tested them by using the .5 meter drop when a vessel is spawned on the launchpad, to see if they could take it. So they are only falling at about 1 m/s when they hit, in Kerbin's gravity. Three LT2 landing legs could handle 32 tonnes, but they could not handle 35 tonnes (so for Eve, divide that by 1.7). They can handle 5 times more once the ship is stationary.

But you would probably do a whole lot better using wing parts as your landing legs, I'd bet.

 

[montferrer]

10 hours ago, bewing said:

Yeah, it's a weight issue -- or perhaps a "landing impact" issue. What's the mass of all that stuff you're landing? And since it's not a perfectly flat surface, only a couple legs are taking the weight, at first.

I did testing on all the landing legs in 1.1.2, and put the results in the wiki. I tested them by using the .5 meter drop when a vessel is spawned on the launchpad, to see if they could take it. So they are only falling at about 1 m/s when they hit, in Kerbin's gravity. Three LT2 landing legs could handle 32 tonnes, but they could not handle 35 tonnes (so for Eve, divide that by 1.7). They can handle 5 times more once the ship is stationary.

But you would probably do a whole lot better using wing parts as your landing legs, I'd bet.

 

Ok, thank you! What do you mean by wing parts? 

[bewing]

"Wing Connector"s or "Structural Wing"s. Type B, maybe.