Asparagus staging is not working

[justanotherdude]

I recently decided to play KSP again, after taking a break. When i wanted to fly to the mun, my asparagus staging was not working. After doing some research and testing of my own, i found nothing wrong with my design. I have reason to believe that the fuel lines are not working and are bugged. 

The last time i played KSP was version 1.4.1, and i did not install any additional mods since 1.3 (only updated them). back in version 1.4.1, my asparagus worked. I have no idea how to fix this, if anyone has any ideas on what is going on i would be very happy. 

Here are the images from my rocket.

https://imgur.com/a/AKet8iX

If there is any more information needed, just let me know. Thanks

Edited June 5, 2018 by justanotherdude

[Gargamel]

Mod list would help.  While you might not have changed any of your mods, the behavior of a mod could change.

You also need to define what you mean by not working? 

The most likely cause is a design flaw in your rocket (as is usually the cause for asparagus staging problems).  Do you have fuel flow priorities set? Is crossfeed disabled (or enabled, per design requirements) as needed? 

And finally is your staging set correctly?

Looking at the pics, I have no idea what's going on with all those inline decouplers, but those really don't matter (I think).  I see 1 set of 4 SRB boosters, and 2 sets of 2 LFO Asparagus boosters, yet I only see 2 sets of 4 Radial Decouplers in the staging tree.    Based on what I think your intended fuel flow is (fuel lines are notoriously hard to read), you need to separate those 4  LFO decouplers into 2 stacks of 2.    As your staging is currently set, it seems when you fire off the radial decouplers, all the LFO boosters will separate, and not just the outer 2.  If you are using an autostaging auto pilot, it will not fire the stage until all the fuel is drained from both sets of LFO boosters, which means you will end up carrying dead weight with you. 

Either that, or you intend to carry spent SRB boosters to orbit. 

 

 

Edited June 5, 2018 by Gargamel

[justanotherdude]

26 minutes ago, Gargamel said:

You also need to define what you mean by not working? 

 

I mean that all the 4 outside boosters (not the SRBs) are draining at the same rate.

27 minutes ago, Gargamel said:

The most likely cause is a design flaw in your rocket (as is usually the cause for asparagus staging problems).  Do you have fuel flow priorities set? Is crossfeed disabled (or enabled, per design requirements) as needed? 

The fuel ducts are in the right setup, fuel flow priorities are at the default. (could you maybe elaborate on this?) and i did not change the crossfeed settings. 

28 minutes ago, Gargamel said:

And finally is your staging set correctly?

yes, the 4 boosters are decoupled the way that they are set up with the fuel ducts. (in sets of 2, first 2, then the next 2, leaving the central booster to circulize)

30 minutes ago, Gargamel said:

Looking at the pics, I have no idea what's going on with all those inline decouplers, but those really don't matter (I think).  I see 1 set of 4 SRB boosters, and 2 sets of 2 LFO Asparagus boosters, yet I only see 2 sets of 4 Radial Decouplers in the staging tree.   

the decouplers are doing what they are supposed to do, the way that the rocket is built is that the asparagus setup is not connected radially, but vertically to the transfer stage. They don't matter. 

 

33 minutes ago, Gargamel said:

Based on what I think your intended fuel flow is (fuel lines are notoriously hard to read), you need to separate those 4  LFO decouplers into 2 stacks of 2.    As your staging is currently set, it seems when you fire off the radial decouplers, all the LFO boosters will separate, and not just the outer 2.  If you are using an autostaging auto pilot, it will not fire the stage until all the fuel is drained from both sets of LFO boosters, which means you will end up carrying dead weight with you. 

Either that, or you intend to carry spent SRB boosters to orbit. 

I set it up that the SRBs will be drained, and the main rocket is still running. They are there to just give the rocket a little boost when taking off. (usually, when the SRBs are separated, the main rocket asparagus setup is half full.)

 

Thanks for the quick reply, and hope that this clarifies some details. 

[4x4cheesecake]

You can right-click each of your engines and enable 'Fuel Flow Overlay'. This allows you to see, which tanks provides the fuel for your engines. On the first aspargus stage, you should have something like this:

Just 2 lines, nothing else.

Second stage should be similar but with additional lines inside the second stage tank. The core stage should be connected with every tank.

If you have any other results, it is caused by some wrong crossfeed settings. So, even if you haven't changed something, check it and maybe take a look how the fuel flow overlay changes when trying other crossfeed settings.

Flow priority should not have any influence, afaik the fluel lines 'overrides' flow priority. But just to be sure: the first aspargus stage should have the highest value, second stage a bit lower and the core stage the lowest value.

[Xd the great]

Well, i would suggest rebuilding a new rocket. Plus asparagus staging isn't necessary when you have vector and mammoth engines. Are you absolutely sure you have set up the fuel lines? I think you should read the part descriptions.

[Gargamel]

2 hours ago, Xd the great said:

Plus asparagus staging isn't necessary when you have vector and mammoth engines

It all depends on the payload, just because an engine can do X, doesn't mean he doesn't need the engines to do Z.  I love asparagus staging, and build them all the time, usually using engines more powerful than vectors.   I've been tempted to do a 7.5m core 8 stage asparagus just cause.   

 

21 hours ago, justanotherdude said:

the decouplers are doing what they are supposed to do, the way that the rocket is built is that the asparagus setup is not connected radially, but vertically to the transfer stage. They don't matter.  

Well, they can't be, or else it's not asparagus staging.  You might have set up an asparagus / bamboo hybrid, which is overly complicated for just about any task.   

You haven't said if you have run some tests. 

Build a simple rocket that never launches.  Three identical fuel tanks, three identical engines, two tanks radially attached (by decouplers) to the core tank, fuel lines both feeding in.  Attach that to a launch clamp, and fire it off without leaving the ground.  Prove that this is a bug.  Let's build a basic asparagus launcher and see if that works, then we can add more parts and maybe recreate the issue.  The other thread you bumped seems to also have a similar design to yours, with a asparagus/bamboo hybrid, so there may be something.  Since I'm an asparagus fan (Until I recently discovered grilled asparagus, I never liked the vegetable though), I'm on board trying to help figure this out. 

If this test case works (and it seems to with every version I've tried), then it's down to this wonky design you got.   I might be more on board with the design if you possibly highlight what decoupler is where, so I can read along and understand your thought process ( I like new ways of doing things, even if it's weird :D).  So maybe some more description to the pics?

 

 

 

Edited June 6, 2018 by Gargamel

[justanotherdude]

3 hours ago, Gargamel said:

Build a simple rocket that never launches.  Three identical fuel tanks, three identical engines, two tanks radially attached (by decouplers) to the core tank, fuel lines both feeding in.  Attach that to a launch clamp, and fire it off without leaving the ground.  Prove that this is a bug.  Let's build a basic asparagus launcher and see if that works, then we can add more parts and maybe recreate the issue.  The other thread you bumped seems to also have a similar design to yours, with a asparagus/bamboo hybrid, so there may be something.  Since I'm an asparagus fan (Until I recently discovered grilled asparagus, I never liked the vegetable though), I'm on board trying to help figure this out. 

the problem is that i used the most simple design, and the asparagus did not work. this is the reason why i think that this is a bug with my installation of kerbal space program. 

 

here is my craft file so you can try it out and check the design.

http://www.mediafire.com/file/3rx8ijykf00ipkk/%230005_Mun_transport.craft/file

[mystifeid]

4 hours ago, Gargamel said:

I love asparagus staging, and build them all the time

Me too.

Anyway, try reversing the order of the decouplers in stages 5 and 6 - ie make stage 5 stage 6 and make stage 6 stage5. You have the tanks that are supposed to empty last staging first. Well, it works for me.

[4x4cheesecake]

38 minutes ago, justanotherdude said:

here is my craft file so you can try it out and check the design.

The file is very helpful

You have some flow priority problems....the first stage got a lower value then the second stage and this cannot be changed. Reducing the value of the second stage will also reduce the value of the first stage, probably duo the fuel lines( I guess you have used 2x radial symmetry to build the aspargus staging?). The simple solution: switch the first and second aspargus stages. You just need to rearrange the fuel lines.

Edited June 6, 2018 by 4x4cheesecake

[mystifeid]

7 minutes ago, 4x4cheesecake said:

You just need to rearrange the fuel lines

Or reverse the staging

And the boosters are still burning long after the first tanks have run dry but maybe you're not running them at full throttle.

Edited June 6, 2018 by mystifeid

[4x4cheesecake]

6 minutes ago, mystifeid said:

Or reverse the staging

Hehe, haven't noticed this one ^^

It is not just the thr wrong order, it is also the reason for the wrong flow priorities. I've never noticed that the priority is defined by the staging, always thought it is defined by the placing order.

[mystifeid]

4 minutes ago, 4x4cheesecake said:

I've never noticed that the priority is defined by the staging,

I have a 61 engine booster and I notice it because I do this all the time in the process of making it.

[Gargamel]

Thanks guys for finding that!  Hope that helps @justanotherdude