lander leg strength

[Hatsune]

I am working on my reusable first stage, I name them rage rockets, because it's difficult to accomplish and would cause rage moments. I found that as my rocket gets heavier, the lander leg explodes during touchdown. Is there a way to strengthen the legs? 

[Superfluous J]

No you need bigger legs or more of them.

I bring extra legs to Eve every time because I know I'll lose a couple at landing.

[Foxster]

Lateral thought - don't use landing struts at all. They are buggy and feeble for their weight. 

Some of the relatively new panel structural parts have very high impact tolerance and low weight. They make very good landing surfaces and your craft won't pogo after landing. 

[Xurkitree]

The best solution for heavy duty Landing Legs is Landing Gear. They are very sturdy, having 50m/s imapct tolerances or more, flex very little and don't get stressed, and can support very large loads.

But seriously, KSP needs vastly improved landing gear. the LT-2 Landing Strut is basically space toothpicks which is not properly angled.

[Snark]

Moving to Gameplay Questions.

[Aeroboi]

On 4/16/2019 at 6:15 AM, Hatsune said:

I am working on my reusable first stage, I name them rage rockets, because it's difficult to accomplish and would cause rage moments. I found that as my rocket gets heavier, the lander leg explodes during touchdown. Is there a way to strengthen the legs? 

I almost never use lander legs unless the lander is lightweight.

Remember that you can land on anything else other then landing legs as long as you don't exceed the "impact tolerance" of the part that impacts. Vector engines and Mammoths have impact tolerances of 20m/s so you have to land unsafely hard to brake them, and let's not forget you should have quiksaved to try again
For reusable rockets I never use convential legs, sometimes landing legs who are wider and stronger especially the heavy landing gears.

Alternatively you can make a construction. On the following vessel I used a construction of Adjustable Ramp Intakes with landing gears put underneath. Remember, both landing gear and the intakes are very aerodynamic so you won't lose much due to drag and wont have your rocket flip over to easily using other parts.

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[Snark]

On 4/17/2019 at 3:54 AM, Aeroboi said:

I almost never use lander legs unless the lander is lightweight.

Remember that you can land on anything else other then landing legs as long as you don't exceed the "impact tolerance" of the part that impacts. Vector engines and Mammoths have impact tolerances of 20m/s so you have to land unsafely hard to brake them, and let's not forget you should have quiksaved to try again

That certainly works!

Though it's worth bearing in mind that lander legs also provide another useful trait:  abnormally high friction.  They get a lot of traction from their feet.

This becomes relevant if you land on a slope-- using non-landing-legs as your "landing gear" means that your ship is more prone to slide downhill, whereas the legs can handle a surprisingly steep slope before they start skidding.

There's also the "tip over on landing" problem-- legs provide a wider "stance" for the lander, so it's less likely to tip.

One technique that I've found that can help provide the best of both worlds (legs' wide stance and high friction; other structural parts' impact tolerance and ability to withstand the shock of landing) is to do both.  What I mean by that is:  go ahead and put legs on the lander... but carefully position them so that, when deployed, the feet are just slightly below the lowermost point of your engines or whatever.

Specifically:  make it so that the "protrusion distance" (i.e. the vertical distance by which the legs extend farther than the engines) is less than the suspension "travel distance" of the legs.

Why this works:  Legs rely on the shock absorbers in their suspension.  As long as the ship's descent stops before hitting the limit of the suspension's maximum travel distance, then the leg will generally be fine.  What snaps the legs is generally when you touch down, the leg suspensions compress to the max, but you've still got enough downward inertia on the ship body that it tries to compress the legs past that travel distance.  That's when things snap.

So if the bottom of the engines is lower than the travel distance of the legs, then that provides a useful "safety bumper".  The descending ship has its feet touch down first, and then a split second later the engines go thump on the surface, before the legs hit max compression limit.  Presto, your legs are saved!

After the initial shock of landing, then depending on how heavy your ship is, it might then rise up on the leg suspensions (so that the ship is resting merely on the legs), or you might end up with the engines still resting on the surface.  But even in that latter case, the legs are still firmly planted on the surface, with enough suspension travel that they've got their feet securely planted and providing plenty of friction-- not to mention tip-over protection.