bradbamstl Posted April 5, 2012 Share Posted April 5, 2012 I\'ve been getting to the moon lately on a 2 meter liquid core first stage, with big pad lit solid booster, and four in flight boosters. I like it, but I want to use only controllable liquid motors. I built a new rocket using a 2 meter TLI booster, a 3 meter second stage booster to earth orbit, and a first stage with the 4X-800 engine cluster. Basically the Saturn V. The only problem i have with 3 meter is that every time I use it it shakes and shimmies a couple meters in each direction, which doesn\'t help much with guidance. Any advice on making the structure more rigid? The decoupler between stage one and two is held on only at the center engine, which I know is most of the problem, but I can\'t find a solution. Link to comment Share on other sites More sharing options...
sjwt Posted April 5, 2012 Share Posted April 5, 2012 I\'ve been getting to the moon lately on a 2 meter liquid core first stage, with big pad lit solid booster, and four in flight boosters. I like it, but I want to use only controllable liquid motors. I built a new rocket using a 2 meter TLI booster, a 3 meter second stage booster to earth orbit, and a first stage with the 4X-800 engine cluster. Basically the Saturn V. The only problem i have with 3 meter is that every time I use it it shakes and shimmies a couple meters in each direction, which doesn\'t help much with guidance. Any advice on making the structure more rigid? The decoupler between stage one and two is held on only at the center engine, which I know is most of the problem, but I can\'t find a solution.Have you tried strutting the tank to the decoupler? Its easer to do if you zoom right in, put the first part of the strut on the lowest part of the fuel tank, then connect it to the decoupler. Picture provided below.Though If you can post a craft file or a picture, that would help. Link to comment Share on other sites More sharing options...
FourTee2 Posted April 5, 2012 Share Posted April 5, 2012 Are you using Mechjeb? I\'ve tried essentially the same configuration, and have found through some experimentation that Mechjeb HATES large ships with thrust-vectoring engines. It can\'t help but overcorrect, even if you\'re just using the Smart A.S.S. for some stabilization. I\'ve yet to find a heavy rocket configuration that won\'t cause Mechjeb to do a backflip... or shake itself apart. Link to comment Share on other sites More sharing options...
Twinky827 Posted April 7, 2012 Share Posted April 7, 2012 Smart ASS? XD Link to comment Share on other sites More sharing options...
E. F. Kranz Posted April 7, 2012 Share Posted April 7, 2012 Yeah, you need to strut the heck out of that thing. Link to comment Share on other sites More sharing options...
Tiberion Posted April 7, 2012 Share Posted April 7, 2012 Sounds like you\'re using Novapunch (or maybe the older SIDR or Sundaypunch) - If you have the latest version (1.1a) there is an example craft named NPSuperHeavy that sounds a lot like what you want; you can use it as an example.It likes to wobble with ASAS on because ASAS flails on the controls, but if you fly the 1st stage manually it flies fine; If we can ever get some control management that doesn\'t flail like that, things would work a lot better Link to comment Share on other sites More sharing options...
Cthulufaic Posted April 7, 2012 Share Posted April 7, 2012 Sometimes, the controllable winglets are BAD with 'Instant' control on. The ASAS overcorrects a lot, so it wobbles. Link to comment Share on other sites More sharing options...
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