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PSA: Struts actually have weight now


zarakon

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KSP is not supposed to be realistic!

It kinda is. That's kinda the thing that makes it stand out from so many other games about space travel.

Not 100% realistic, but close enough that we get a feel for what real space travel is sort of like.

It is a good thing the physicsless parts have mass now. Bit of a hindrance for glitch exploit vessels, but worth it.

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Tw1 is correct. The incorporation of approximations to real rocket science and orbital mechanics makes KSP special.

- - - Updated - - -

Whackjob probably has a tic in his eye from this. He better not let it discourage him.

Then you economize and strategically place said struts. I've been doing that long before, being careful to place them as symmetrically as possible and as few as necessary(especially with career and parts costs).

Struts are not a game-only implementation. They see plenty of use in the space program, or did at least when the shuttle fleet was in operation, and they do see use on the ISS. They just weren't used as visibly or generously as they are used in KSP. If you do have to use more struts because of a crazy build...then use more boosters. That is our mantra, after all.

Of course there are struts in real life. That isn't the point. In KSP we have to use struts where you don't need them in real life because of the weak joints and wobbly structures. I've had a couple rockets that couldn't make it through boost in 1.0.2 because the bending of the rocket was placing parts near the nose of the rocket at a higher angle of attack, making the rocket flip. When I added stiffening struts, the rocket made it through boost. Also, i had a long spaceplane that was wobbly...but when I added struts to make it more rigid, the extra drag made the plane incapable of reaching space. In real life, such reinforcing should be inside the plane's structure, not hanging out in the breeze.

So I think Squad should cut us some slack on the struts, since we need to add them at times to overcome deficiencies in the program.

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Yeah, I've done a series of in-vacuum tests (plus a teeter-totter test on the launchpad) and massless components all do assign mass to their IMMEDIATE parent object (not the root object or something), including struts and fuel lines.
Actually, that's still possible because physicsless parts mounted on physicsless parts are still massless.

Neither of these statements are completely accurate. Physicsless parts mounted on physicsless parts are *not* massless. Their mass is added to the parent as usual but if the parent is physicsless then the whole of that part's mass (including the mass of any physicsless children) is added to its parent, and so on up the part tree until the root is reached.

Demo.craft

This craft demonstrates this. The COM is in the center of the probe core and when it is launched it doesn't fall over but if you detach half of the cubic struts and the battery then the mass of the vessel does change.

Edited by Padishar
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Neither of these statements are completely accurate. Physicsless parts mounted on physicsless parts are *not* massless. Their mass is added to the parent as usual but if the parent is physicsless then the whole of that part's mass (including the mass of any physicsless children) is added to its parent, and so on up the part tree until the root is reached.

Demo.craft

This craft demonstrates this. The COM is in the center of the probe core and when it is launched it doesn't fall over but if you detach half of the cubic struts and the battery then the mass of the vessel does change.

I'm pretty sure they actually are massless when placed on other "no physics" parts based on my tests.

Make a vessel that just barely lifts off with one cubic strut attached. Easy enough to do using the thrust limiter. Then add a bunch more cubic struts and a bunch of regular struts between those. The listed mass (both in the VAB and the map info panel) will show the mass go up, but it won't actually affect the craft's ability to fly. If you put the roots of those struts on the main body of the craft instead, then it won't be able to move.

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I'm pretty sure they actually are massless when placed on other "no physics" parts based on my tests.

Make a vessel that just barely lifts off with one cubic strut attached. Easy enough to do using the thrust limiter. Then add a bunch more cubic struts and a bunch of regular struts between those. The listed mass (both in the VAB and the map info panel) will show the mass go up, but it won't actually affect the craft's ability to fly. If you put the roots of those struts on the main body of the craft instead, then it won't be able to move.

Indeed, I stand corrected. I was under the mistaken impression that Squad had fixed the in-VAB mass readout to actually be accurate but that isn't the case. I have run some lift-off tests and confirm this behaviour. Hopefully Squad won't change it again without letting it be known...

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