Dielos Posted June 10, 2012 Share Posted June 10, 2012 Hello,My rocket is losing control after tanks get empty. The problem I have is that fuel consumption is not happening in a logical order. I have a rocket with several engines mounted on the sides and their corresponding fuel tanks, but all engines start consuming only from one (maybe the first placed?) and then they continue with the others.Of course, as soon as this lone side tank gets empty, the ship losses weight from that side and then tips to the other and out of control.Is there any way to reorder how engines choose which fuel tanks to use? Or is the order of placement the only way to do this?Thanks in advance for any possible help! Link to comment Share on other sites More sharing options...
Monkthespy Posted June 10, 2012 Share Posted June 10, 2012 If you are using .15 (which you most likely are), right click the tank and make it not drain, you will have to the fiddle around with the rest, as I don\'t know the specific cause, because I know this is a bug. Link to comment Share on other sites More sharing options...
Dielos Posted June 10, 2012 Author Share Posted June 10, 2012 I am using .15. And thanks for the tip, it makes sense to stop drainage, although a little bit cumbersome in mid flight...I didn\'t think it was a bug, merely something not implemented yet, but you might be right, maybe I should have posted under support?I did find other posts with similar issues, but they were all related to the fuel drainage pipes, with which I have no problems.Boy, do I love this game... Can\'t wait for the next update!!! Link to comment Share on other sites More sharing options...
SteevyT Posted June 10, 2012 Share Posted June 10, 2012 Are you using the pylons as lateral decouplers? I think they have fuel crossfeed enabled. If you are tagging to the side with fuel crossfeed parts, they will draw from the farthest up tank they can. Link to comment Share on other sites More sharing options...
Ziff Posted June 11, 2012 Share Posted June 11, 2012 Either post a picture of the vessel or maybe even upload the .craft file so we can see exactly what the deal is. It could be a number of different reasons. Link to comment Share on other sites More sharing options...
Dielos Posted June 11, 2012 Author Share Posted June 11, 2012 SteevyT,I am using pylons and also fuel pipes. The ship is built around a central fuel tank with an engine attached thought for munar ascent after landing. It has four decoupler pylons attached, each with 2 fuel tanks and one engine. There are also 4 other pylons with one fuel tank and landing gear attached through fuel pipes to the four engines. As per the logic I had applied (could be completely wrong), each engine should be fed by their corresponding fuel tanks and one side tank. But they are all feeding from the same lateral fuel tank at the start, and after that is empty, then they feed homogenous from the rest. But then it\'s too late, the ship tips to the side...Ziff,I\'ll post the ship file as soon as I can access my PC again. I don\'t think that my explanation above is too clear... Link to comment Share on other sites More sharing options...
Ziff Posted June 11, 2012 Share Posted June 11, 2012 It sounds like you may have an issue with one of your fuel lines. Double check your fuel lines and their directional arrows. I had a similar issue in one of my launch stages once. A backwards fuel line was causing one of my internal radial stages to empty too fast, and when the external stage decoupled the next internal tanks were already drained causing an engine to shutdown and the entire ship to tilt to one side as if a drunken Kerbal was piloting it.What I usually do is I connect my external tanks to the internal one, even if there are multiple radial stages. That way the external tanks get used to fuel both the external and internal engines, so that the external tanks drain quickly and can be decoupled while leaving the internal tanks full of fuel. Link to comment Share on other sites More sharing options...
Dielos Posted June 11, 2012 Author Share Posted June 11, 2012 Ok, here is the ship file. The tanks without engines feed the ones to their right with fuel pipes. I placed the fuel pipes with the symmetry tool and their arrows are correct. But all engines feed from the same fuel tank at the start.I start to believe that SteevyT might be right with the Pylon Decouplers. Maybe someone can see something?The center engine is for another stage and doesn\'t fire at the start. This ship is not finished jet, it\'s missing the Kerbin ascent stage, but it\'s good to test what I mean... Link to comment Share on other sites More sharing options...
Ziff Posted June 12, 2012 Share Posted June 12, 2012 Hmm, what mods are you running? Apparently I am missing that command module and the YMASas modules. No idea what pack those are from. Link to comment Share on other sites More sharing options...
Kreuzung Posted June 12, 2012 Share Posted June 12, 2012 YMA could be the Yawmaster from NovaPunch. Link to comment Share on other sites More sharing options...
Dielos Posted June 12, 2012 Author Share Posted June 12, 2012 Really sorry about that...Yes, it is the Yawmaster from NovaPunch. I really like how it looks...I\'ll see if I can recreate the rocket with only stock parts. There\'s no way to change just the command module, right? Would make it much easier... Link to comment Share on other sites More sharing options...
wired2thenet Posted June 12, 2012 Share Posted June 12, 2012 If you edit the craft file, you can switch out the command pod with the default one. Make sure to make a backup first though! Link to comment Share on other sites More sharing options...
Ziff Posted June 13, 2012 Share Posted June 13, 2012 I have the NovaPunch pack though, and I have those parts, but it doesn\'t recognize them for some reason. I think its because the new folder names are like NP_YMA-whatever. Instead of just YMA-whatever. It\'s being a total pain in the arse at the moment. Link to comment Share on other sites More sharing options...
Ziff Posted June 13, 2012 Share Posted June 13, 2012 Ok, I finally got it all figured out. I see a few easy to fix issues with your rocket. The first is your fuel lines. I\'m not sure why, but the game sometimes has issues when you connect fuel lines around from 1 tank to the next in a circle. So instead, just connect each of your fuel supply stacks to one of the engines next to it. (So it would be 4 fuel lines total, instead of the 8 you have now.) This way the fuel will get used up on equal sides at the same rate so it should fix the tipping problem.You can save some weight by dropping those outer ADVSaS units. You only need the one under the command module, the others don\'t help in any way shape or form. You could effectively remove those, and maybe lower those stacks down a little bit so the landing legs can still reach the munar surface. Link to comment Share on other sites More sharing options...
Dielos Posted June 13, 2012 Author Share Posted June 13, 2012 Thanks a lot Ziff,I will try with the four fuel lines as you said. I was sure it was a design problem...About the SAS... I thought that the more SAS you used, the more strength they applied at the cost of more weight. Am I totally wrong here? Just one is more than enough for any rocket size? I really had the feeling that the more SAS I put on a big rocket, the more stable it was.And about the landing legs, I usually have trouble finding good combinations with the engines, as the engines are mostly longer and lower than the landing legs. The landing legs are also quite unstable, so I\'ve learned to secure them with strengthening struts in the meanwhile and use fixed landing gear instead of the deployable.In any case, thank you very much for your time and help and I will try right now your suggestions! Link to comment Share on other sites More sharing options...
Ziff Posted June 14, 2012 Share Posted June 14, 2012 Yes, that is true, but there is a difference between SAS and AdvSAS. With the AdvSAS (which is what you have) you only need 1, as it will actively use the yaw/pitch/roll controls to counter the ships movement if it drifts off course. SAS is useful for ships that tend to spin like a top on takeoff. Your craft is pretty stable as its small and built with symmetry. Honestly,I had the same sort of problem with the landing legs that led me to a redesign. I now use a launch stage that detaches in orbit leaving behind the Munar stage. The Munar stage only has 1 LVT-45 on a center fuel tank, the 3 outer tanks attached are mounted lower, with the small LVT-909 engines. This allows me to use the large engine if I run into some sort of trouble, but once actually in orbit I only need the 3 LV-909\'s for a trans injection burn and for landing. Theyre short enough to allow landing legs to work well on them. Link to comment Share on other sites More sharing options...
Dielos Posted June 14, 2012 Author Share Posted June 14, 2012 Good to know about the SAS...With my fear of fuel shortage, I always tend to overload the ship with fuel tanks, making the designs quite heavy. I\'m going to follow your hints on the munar lander and make it simpler.I really have a lot of problems with munar landings on manual flights. MechJeb does a very good job, and I try to learn from it, but the lateral velocity always kills my manual landings. The legs always bend and I end crashing. I have only managed to set a single craft on the mun yet with the Kerbals intact, but I can\'t take off again, because it\'s landed head under. I can\'t launch back like that... I will have to try to tip the rocket with another ship, which sounds quite complicated for me and having yet little success in the Mun...Attached is an image from my poor stranded lander, a pity, as it has more than enough fuel to return... (I don\'t know how to just display the image, sorry) Link to comment Share on other sites More sharing options...
Ziff Posted June 14, 2012 Share Posted June 14, 2012 .... so this is what happens when you let drunk Kerbals pilot the mun lander. I have to say, this is quite impressive. My flights tend to fall into two categories. Successful, and catastrophic OMFG failures. Link to comment Share on other sites More sharing options...
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