Using tri- and quad-adapters both ways

[allmhuran]

Sure, because they make more point connections, therefore there are fewer degrees of freedom and tensile strength will increase. But I'm referring to transfer of "shennanigan" forces through coupled ports that originate from say, wobbly bits at the front.

[allmhuran]

Actually, this would probably all be in unity itself rather than in KSP code...

[sojourner]

That's true.

[KerbMav]

Probably what you could do is go ahead and build the bottom part first - the adapter with the ports - then take it off your stack, flip it over and set it aside. Go ahead then and build the upper part - adapter, engine, decoupler, port - then grab the bottom part and stick it on.

something - n-adaptor - engines - decouplers - docks - docks - n-adaptor - something else

The problem with taking off and setting aside anything is, it will leave you with a component that only has the connector node it was attached with before you took it off (yellow ball) - so you cant take it off and flip it, because it will not have a node on that end.

Solution:

Prepare the craft with the engines, decouplers, docking ports downwards and only ONE port upwards.

Rotate the n-adapter the way you want it to be attached.

Connect it with only one of its n ports under the craft to this one upwards docking port.

Add the missing upwards docking ports to the n-adapter, then take it off and rotate the ports under their counter parts, attach.

[Tiron]

I skimmed the thread honestly, so if I repeat something I missed, I apologize in advance.

KSP Uses a tree structure to represent a craft. There's a 'root part' (the first one placed), and every other part is ultimately attached to that part via a parent<->child relationship. The key thing is that each part can only have ONE parent, but a practically unlimited number of children. One of the effects of this is that it's impossible to build a structure that leads to one part via another by more than one 'path'. No loops, and no single->multi->single. This includes Bi/Tri/Quad Adapters/Couplers.

There are exactly two ways to get around this limitation, both use the ability to form a physical connection without forming a link in the actual craft tree. The first, most direct method is struts. The second is multidocking.

Multidocking still has to follow the tree: There can only be one parent<->child link, and that one link is the first port pair that connects. The subsequent pairs use a physical connection functionally identical to a strut connection between the two ports. This is why the magnetic attraction stops working the instant the first two ports connect.

You're also limited to one 'parent' port connection in the VAB, but if you set up port pairs so that they're facing each other in the VAB, they'll auto-multidock when the physics loads in on the pad:

Note the parent port pair is the set on the BOTTOM, the two upper pairs are physically connected only. This is showcased when you fire the decouplers:

You'll note that the bottom, fully connected port pair stayed connected, while the top two pairs lost their physical connection when they were decoupled (They lost their parent links, so the physical connection wasn't valid anymore.) They got pushed around quite hard by the engine exhaust firing into them, hard enough to cause some explosions when they hit the ports and tri-coupler (the one on the left lost its port but not the fairing, which hooked around the port on the second tricoupler, which I found slightly hilarious.)

Edit: Note for the multidocking to work you have to connect the lower ports to the adapter/coupler, and not the port attached to the engine: This means they have to be placed individually.

Edited August 30, 2013 by Tiron

[Gijs]

I think I found the solution to this problem. Well, I'm not taking the credit. But docking isn't necessary, that's what I have found out.

See this thread: http://forum.kerbalspaceprogram.com/showthread.php/48147-Nuclear-engines-and-tri-adapters?p=624153&viewfull=1#post624153

As you can see, I had the same problem. I explained here how I solved it:

Well, the way I have it now (exactly the same as in the pic, but with three blue seperators instead of three yellow/red ones, and, as you suggested, the engines turned 90 degrees), it works perfectly fine. First I detach the big orange tank with the big seperator. Then I activate the engines, and then lastly I detach the seperators.

I could upload the .craft file for that other thread.

And here is the picture (note that the craft in the picture does NOT work. Please refer to the quote):

Again, it works fine. No exploding engines. They are all attached.

If you guys want, I can upload the .craft file. But I think the picture + quote speaks for itself.

[Tiron]

I think I found the solution to this problem. Well, I'm not taking the credit. But docking isn't necessary, that's what I have found out.

See this thread: http://forum.kerbalspaceprogram.com/showthread.php/48147-Nuclear-engines-and-tri-adapters?p=624153&viewfull=1#post624153

As you can see, I had the same problem. I explained here how I solved it:

And here is the picture (note that the craft in the picture does NOT work. Please refer to the quote):

*Snip*

Again, it works fine. No exploding engines. They are all attached.

If you guys want, I can upload the .craft file. But I think the picture + quote speaks for itself.

If all you did was swap the decouplers for stack separators, no, it's not attached, at least on the bottom. You could in fact remove all but one of the stack separators and it would work exactly the same way it is now: The only thing keeping it together is the struts from the top section to the orange tank. This accomplishes essentially the same thing as using docking ports would.

[Gijs]

If all you did was swap the decouplers for stack separators, no, it's not attached, at least on the bottom. You could in fact remove all but one of the stack separators and it would work exactly the same way it is now: The only thing keeping it together is the struts from the top section to the orange tank. This accomplishes essentially the same thing as using docking ports would.

You sure? Because I have tried it without struts. It just wobbled too much. I figured the struts would stabilize it. But I could get into orbit without the struts.

And the struts get deleted the moment I detach the orange tanker anyway.

[Tiron]

You sure? Because I have tried it without struts. It just wobbled too much. I figured the struts would stabilize it. But I could get into orbit without the struts.

And the struts get deleted the moment I detach the orange tanker anyway.

Yeah. The game's not capable of doing node-to-node connections with multiple parent parts. Two of the stack separators aren't actually attached to the tri-adapter at all. They look like they are because of physical proximity, but there's no actual connection. That's why it flopped without the struts.

The struts form a physical connection that prevents it from moving. Docking ports like in my screenshots would do the same thing, although probably a tiny bit floppier than the struts.

[Gijs]

Oh alright, nevermind then.

I'll try it with docking ports, see what works better.

[Tiron]

Oh alright, nevermind then.

I'll try it with docking ports, see what works better.

I'd wager the struts: The docking port bit really works better when you're trying to build circular structures or something.

If that turns out to the be the case you can probably use just ONE decoupler, use the struts to keep it from flopping, and save a bit of weight. It'll unbalance the weight and drag very slightly, but the SAS should be able to cope with it. It'd also give you only one set of fairings instead of three, so you'd have six fewer pieces flying around at decouple.

If the mass/drag is a problem you could get the same effect with balanced mass/drag by placing the decouplers individually, on the tri-adapter instead of on the bottom of the engines(Except the first one, which the tri-adapter is itself attached to). That way they don't detach when you stage it.

Edited August 30, 2013 by Tiron

[bwheatley]

Another cheat...

Warning: Current version are really NOT supported the tri-to tri both ways. Do this and you will damage your craft file, and make it unusable.

It actually does work. You just need the decouplers...and the biggest thing is you *MUST* have your engines at thurst 0 when you power them up. If you decouple w/ full power the fairings destroy 1 of the engines and then the ship is totally off balance.

I did this a lot last night so it was fun to get it to work.

[bwheatley]

The really funny thing was i spent 2 hours trying to figure it out and found this thread while looking for a solution

[sojourner]

It actually does work. You just need the decouplers...and the biggest thing is you *MUST* have your engines at thurst 0 when you power them up. If you decouple w/ full power the fairings destroy 1 of the engines and then the ship is totally off balance.

I did this a lot last night so it was fun to get it to work.

]

Nope, you only have one connected there. It only looks like you have 3 connections. as for the fairings, rotate the engines until the fairing face to the sides, then they won't hit the other engines.

There are more detailed explanations in this thread, you need to read more of it.

[Tiron]

It actually does work. You just need the decouplers...

If it's connected, why do you have that big ring fairing with a bunch of quantum struts in there to hold the joint together?

Because the joint was floppy, due to only one of the stack separators being attached to the bottom tri-adapter.

Again, it's the struts holding it together, and two of those stack separators are just extra debris.

I swear, I'm gonna see if I can't make a video just to demonstrate once and for all, single multi single is NOT possible.

Edited September 8, 2013 by Tiron

[Tiron]

Okay. Here we are. Starting in the VAB with the first part of the setup put together. My mockup here has a Okto2 on top of a Rockomax x200-16, with a PB-NUK on top of the Okto2. On bottom of the -16 are 3 LV-Ns.

I first place a small stack separator on bottom of the LV-Ns, using symmetry to put it on all three. I then attach another tri-adapter in such a way that it appears to be connected to all three of them.

I then spend some time mousing over all the engines and the decouplers. There's a reason for this: When you mouse over a part, not only is it highlighted, but all of its 'child' parts are as well. Every part connected to it, and every part connected to those...and so on, as far down the tree as it needs to go. At least it's supposed to do that, it wasn't when I was hovering over the stack separators for whatever reason.

First thing you'll note, if you watch carefully, is that the only things that cause the bottom tri-adapter to be highlighted is hovering over it, or hovering over a specific one of the LV-Ns. Hovering over the other two does not highlight it. This an indication right in the VAB that it's not connected to those two, but I took it a bit further just to make it explicitly clear.

Having used that method to determine which of the stack separators the tri-adapter is attached to, I mark it by placing a linear RCS port on it. I could've also just split it out into its own stage, but decided it'd be clearer what I was doing if I didn't, thus the marking.

I then 'launch' the craft. While sitting on the launchpad, I right click the marked stack separator and select 'decouple', which causes only the selected stack separator to decouple. Predictably, the Tri-Adapter falls off as well, leaving the other two Stack Separators attached to the bottom of the other two LV-Ns and demonstrating that they were never attached to the Tri-Adapter in the first place.

This test can be duplicated by anyone that thinks they've found a way to make this 'work'. When you decouple the singular decoupler that's actually attached, the entire bottom part will be disconnected. Any struts stabilizing the connection should break automatically when it disconnects.

I don't use quantum struts, so I'm unsure if they will disconnect or not. I've heard tales of them grabbing onto debris before, so it's possible they might re-grab the bottom half and hold it in place physically, even though the two parts are now separate craft. I would hope that's not the case however, as it seems like it could make the quantum struts hard to use.

[bwheatley]

Nope, you only have one connected there. It only looks like you have 3 connections. as for the fairings, rotate the engines until the fairing face to the sides, then they won't hit the other engines.

There are more detailed explanations in this thread, you need to read more of it.

Oh no i wasn't saying anything about multiple engines actually being connected. I was just saying you could get 3 in line w/o them blowing up 1 of the engines. I just fix the wobble with strutting the crap out of it. Yea not perfect but for now it works.

[bwheatley]

If it's connected, why do you have that big ring fairing with a bunch of quantum struts in there to hold the joint together?

Because the joint was floppy, due to only one of the stack separators being attached to the bottom tri-adapter.

Again, it's the struts holding it together, and two of those stack separators are just extra debris.

I swear, I'm gonna see if I can't make a video just to demonstrate once and for all, single multi single is NOT possible.

Like i said I wasn't debating it's one connection. Just that you could break 3 up w/o blowing the other 2 engines. It works it's not as nice as it should be. And those were not quantum struts they were the procedural fairings i just hadn't added the fairings yet. It's pretty obvious it's 1 with how it did the fairing coverings. <3

[sojourner]

Oh no i wasn't saying anything about multiple engines actually being connected. I was just saying you could get 3 in line w/o them blowing up 1 of the engines. I just fix the wobble with strutting the crap out of it. Yea not perfect but for now it works.

Yeah, as noted, to avoid destroying other engines when placing multiple atomics, just rotate the part so the fairings aren't facing each other before you place them. no need to edit files.

[bwheatley]

Yeah, as noted, to avoid destroying other engines when placing multiple atomics, just rotate the part so the fairings aren't facing each other before you place them. no need to edit files.

Thanks. Yea that will be a lot easier then making sure you cut the engines before you blow the fairings.

[Linventor]

On 8/28/2013 at 10:04 PM, Sirine said:

And here is my solution...

The main problem = The Bi-Tri-Qu-coupler-adapter, they only go in 1 direction. Put something in between them which support bi-direction, like fuel tank. and make the fuel flow "down" by connecting the "fuel pipe" downward, and problem solve.

That was really useful, up until I realized that allowing the fuel flow caused a major loss of ▲v, namely going from around 11 km/s of ▲v to around 3k. Still really useful though!

[Kerbal101]

Any news??    This issue is still not solved in 1.1.3.

@PetWolverine has nailed it very exact:

Not allowed:

       Bicoupler (/Tri,/Quad etc)
        /     \
       /       \
      Part   Part
       \       /
        \     /
       Bicoupler (/Tri,/Quad etc)

 

Allowed:

       Bicoupler (/Tri,/Quad etc)
        /     \
       /       \
      Part   Part
               /
              /
       Bicoupler (/Tri,/Quad etc)

 

 

You connect:

       Root part
           |
       Bicoupler (/Tri,/Quad etc)
        /     \
       /       \
      Part   Part
       |       |
      Part   Part
       |       |
      Part   Part
       \       /
        \     /
       Bicoupler (/Tri,/Quad etc)
           |
       tail part

But game does this actual connection:

       Root part
           |
       Bicoupler (/Tri,/Quad etc)
        /     \
       /       \
      Part   Part
       |       |
      Part   Part
       |       |
      Part   Part
       \               <<<< missing link! 
        \     
       Bicoupler (/Tri,/Quad etc)
           |
       tail part

 

Proof:

 

 

[Tarheel1999]

@Kerbal101 This has always been how multicouplers work. This is less a "bug" that needs to be fixed and more a limitation of the game engine.

[Red Iron Crown]

Tree structure of craft hasn't changed since this thread was started three years ago, it's too fundamental a change to the game.

One change coming in 1.2 for multicouplers is they now permit flow in both directions; in 1.1.3 and previous flow was only permitted from single side to multiple side.

[Kerbal101]

@Tarheel1999 I don't think so