Leicontis Posted December 16, 2011 Share Posted December 16, 2011 I\'m getting some really odd behavior from my latest design (attached below, built using KSP v0.13x4): Shortly after launch, it begins rolling side to side, as the outer boosters swing wildly (and the struts behave more like rubber bands than structural supports). Once the first trio of boosters jettison, the rolling stops, and all is well for a while.A while after jettisoning the second trio of boosters, I make a low orbit, and start using periapsis burns to increase the apoapsis. That\'s when the second problem manifests, usually when I\'m down to the last set of tanks on the last long booster trio - while I can roll the ship with no trouble, trying to pitch or yaw seems to become intermittently impossible, no matter how much I lean on the controls (and no, I\'m not in precision mode). In fact, even when not under thrust, the ship will start pitching, yawing, and rolling of its own accord. Often, I\'ll be partway through a periapsis burn, and turn off SAS to nose back down to stay pointed parallel to the ground, only to find the ship nosing up instead, and not noticeably responding to SAS or pitch or yaw commands, even when I engage RCS. The ship just slowly tumbles for a while before it lets me get it back under control.Are these problems due to design flaws, poor piloting, and/or one or more bugs? If the answer is 'bug(s)', then could a mod move this to the Development subforum? Link to comment Share on other sites More sharing options...
Ivan Ivanovich Posted December 17, 2011 Share Posted December 17, 2011 Not a bug, just bad placement of struts. Try to connect shorter struts between the trunks adjacent to each other, then it performs actually quite well.I would suggest making the design a bit more compact and either put the rockets 'up inside' the design further down or eliminate them altogether. Plus, remove the SAS modules and replace it with a single ASAS, better control and less weight. Link to comment Share on other sites More sharing options...
Leicontis Posted December 17, 2011 Author Share Posted December 17, 2011 The suggestion of moving the lander portion downward may help solve both problems; I think the bizarre veering off course problem may be caused by the rocket\'s center of mass ending up below the gimballed engines. Basically, if the vectored engine is forward of the center of mass, it\'ll have the opposite of the intended effect if you try to steer while under thrust.I\'ll post again when I\'ve tested the redesign. Link to comment Share on other sites More sharing options...
TheDarkOne Posted December 18, 2011 Share Posted December 18, 2011 Is the rocket under acceleration while this is happening, or are you turning that off for more precision? For me, it seems that I can only direct my spacecraft usefully when a thruster is going, no matter how much. Link to comment Share on other sites More sharing options...
Ivan Ivanovich Posted December 18, 2011 Share Posted December 18, 2011 Whether and how much your rocket can 'turn' depends on a few factors. First of all, size. The bigger, the harder. Especially the taller, the harder. Rotation speed is mostly dependent on its width. Then, whether or not you have wings on it (at least while you\'re in the atmosphere). And finally, whether you use gimbaled engines, which I guess is what lets you turn your rocket if it only turns sensibly under power. Link to comment Share on other sites More sharing options...
Leicontis Posted December 18, 2011 Author Share Posted December 18, 2011 I switched out the gimballed engines for fixed engines, and the problems disappeared. Apparently my computer and/or design philosophy don\'t react well to engine gimballing. Link to comment Share on other sites More sharing options...
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