a weird situation

[putnamto]

so i built a launcher to send some fuel up to my station, got to the part where i decouple the front and back tanks(the ones withought the mainsails) buuut they were still burning, yet the center stack, and the two sides with mainsails on them were not.

what did i accidently click that i shouldnt have? i checked things like fuel priority and crossfeed and nothing seems strange about that.

[Gargamel]

First reaction is that it's a staging error.  

But looking at it closer, I have to ask how much fuel is left in those center tanks?  A fuel flow mess up would drain the center tanks, while fueling the outer, first stage, tanks.  Looking at the MJ readout, (which isn't always accurate, but for asparagus staging I find it pretty reliable),  the next couple stages have 0 dV in them, indicating there is no fuel left.   Same with KER, which is only showing 2 powered stages. 

I'm an old school player who never learned how to do fuel flow priority (just never bothered), so I'd say check your fuel lines.  Make sure they are pointed in the right direction.  If you're using fuel priority, make sure you got that set correctly.  If you didn't mess with that, make sure crossfeed on those radial decouplers is turned off.    

I'm not sure if you meant for this to be an asparagus staged rocket or not.

 

[4x4cheesecake]

Also check the crossfeed options of the radial decouplers. If the first stage keeps burning even though their tanks are empty, it indicates that crossfeed is enabled

[bewing]

It looks like your front and back tanks are not attached to their decouplers. They are attached directly to the main stack and then offset out so that they just look like they are on the decouplers.

You really should put nosecones on all those side tanks too. Each nosecone you attach will add a couple dozen dV to your rocket -- unless you really need the drag back there for aerodynamic stability.

[putnamto]

7 hours ago, Gargamel said:

First reaction is that it's a staging error.  

But looking at it closer, I have to ask how much fuel is left in those center tanks?  A fuel flow mess up would drain the center tanks, while fueling the outer, first stage, tanks.  Looking at the MJ readout, (which isn't always accurate, but for asparagus staging I find it pretty reliable),  the next couple stages have 0 dV in them, indicating there is no fuel left.   Same with KER, which is only showing 2 powered stages. 

I'm an old school player who never learned how to do fuel flow priority (just never bothered), so I'd say check your fuel lines.  Make sure they are pointed in the right direction.  If you're using fuel priority, make sure you got that set correctly.  If you didn't mess with that, make sure crossfeed on those radial decouplers is turned off.    

I'm not sure if you meant for this to be an asparagus staged rocket or not.

 

i did at first but asparagus was making me lose dv for some reason, now that i think about it why do i even have the decouplers. hmm

 

3 hours ago, 4x4cheesecake said:

Also check the crossfeed options of the radial decouplers. If the first stage keeps burning even though their tanks are empty, it indicates that crossfeed is enabled

no crossfeed
 

 

3 hours ago, bewing said:

It looks like your front and back tanks are not attached to their decouplers. They are attached directly to the main stack and then offset out so that they just look like they are on the decouplers.

You really should put nosecones on all those side tanks too. Each nosecone you attach will add a couple dozen dV to your rocket -- unless you really need the drag back there for aerodynamic stability.

that does look like it, but i didnt touchh the offset tool while building it. as for the nosecones i would have put them on there but after playing at 5fps im a bit to paranoid about part count lol.

[Gargamel]

4 hours ago, putnamto said:

i did at first but asparagus was making me lose dv for some reason, now that i think about it why do i even have the decouplers. hmm

Then you either weren't doing it right, or you were putting too much faith in an erroneous readout. 

If your main booster stage with a payload on top has X dV for that stage, and then you add two asparagus stages of similar design, you should expect to at least double your dV for those stages.  (Citation needed, I have no idea what the actually math is, just that is what instinct and experience is telling me). 

But the best way to figure out if a booster will get to orbit?

Launch it and see. 

MJ/KER with asparagus and SRB's is often like a GPS system.  It will give you an estimate as it starts off, but it won't give you an accurate ETA till you get there.

 

4 hours ago, putnamto said:

as for the nosecones i would have put them on there but after playing at 5fps im a bit to paranoid about part count lol.

Well, you're running out of fuel, so reduce drag. 

[Superfluous J]

Could you strip off non-mod parts and post the ship to KerbalX or somewhere?

I can't think of anything already said.

[putnamto]

58 minutes ago, 5thHorseman said:

Could you strip off non-mod parts and post the ship to KerbalX or somewhere?

I can't think of anything already said.

it was the two non mainsail(bollards?) engines, they burn fuel at half the rate of the mainsails roughly, i swapped them out for mainsails and all five burned at the same rate.

speaking of mainsails, with five mainsails and a straight vertical launch i ended up here lol, this feels like an accomplishment, ive barely been able to crash land something on minmus

[Gargamel]

4 minutes ago, putnamto said:

it was the two non mainsail(bollards?) engines, they burn fuel at half the rate of the mainsails roughly, i swapped them out for mainsails and all five burned at the same rate

Just for S&G's, throw those engine back onto the boosters, and then add fuel lines running from each of the boosters to the each of the mainsail boosters.  

[putnamto]

19 minutes ago, Gargamel said:

Just for S&G's, throw those engine back onto the boosters, and then add fuel lines running from each of the boosters to the each of the mainsail boosters.  

weird, maybe i was putting the fuel lines on backwards the first time i tried asparagus with this ship. works perfectly, thanks.

[Gargamel]

3 minutes ago, putnamto said:

weird, maybe i was putting the fuel lines on backwards the first time i tried asparagus with this ship. works perfectly, thanks.

Decent little article on the wiki about asparagus staging.   Or at least the picture of how the fuel flow is supposed to work is there. 

https://wiki.kerbalspaceprogram.com/wiki/Asparagus_staging

[putnamto]

good read, i understood how asparagus worked and had used it many times before, very nice to understand the real world application(or complications) of the same idea.

[putnamto]

stranger things are happening.

loaded up the game about an hour ago, played around in sandbox mode, came back to my career and load the craft in the vab now says its 1000 dv less then it was earlier.

i go to the launchpad and mechjeb then says i actually have 700 dv more than in the screenshot. i do a few launch tests and the ship wants to twist and go north, i do some tweaks and if flies straight but decoupling the boosters causes RUD, i put some tiny engines pointed inward on the boosters, launch again and the game crashed.

as a quick side though, why do my pilots bail in the last minute? they will be assigned in the vab, then when i get to the launch pad they are either gone, or its jeb.

[bewing]

You've either got game or mod corruption.