TVR-400L Stack Quad Adapter wont attach all 4 Points??

[BloodyAxe]

Ive made a Heavy Lifter works great until last stage when I Separate to fire the 4 engines the stack only seems to recognize ONE Booster as connected. and it drifts apart in space.

Ive inverted a TRV-400L stack Quad Adapter and build 4 boosters then rejoined the Stack.

Ive rebuilt the same design over 10 time thinking I miss clicked.

Stack is VERY stable and suffers NO damage on decouple even tried low power decoupler with no boost on when I decouple.

ANY IDEA what I'm doing wrong?

Edited September 24, 2013 by BloodyAxe

[Tripod27]

I'm guessing you built from the bottom up, so you had the 4 fuel tanks above the nukes, then attached the quad adapter and put the capsule on top

The issue is, currently KSP lets you attach multiple parts to one part, but not one part to multiple parts, so the quad adapter you're placing is really only attaching to one fuel tank

The only way to "fix" this, is to attach a docking port to the top of each fuel tank facing up, then attach another docking port to one of those docking ports facing down (like they would if they were actually docked) then attach the quad adapter to that docking port. Then you add three more downward facing docking ports to the adapter so they touch the three other upward facing ports.

Only the first port you put down will be "actually" attached (like you can see in your screenshot) but the other ports will dock with the ports below them as soon as the game starts, causing them to attach

this takes up a lot of space, but if you need the stability, it's worth it

Edited September 24, 2013 by Tripod27

[Kasuha]

VAB does not support "cycles", i.e. parts branching out and later connecting together again. Therefore out of your four engine stacks only one can be attached at both ends, the rest is only attached at one end. To fix that, you can use docking ports, attaching parts where they should hold and putting docking ports to face each other where they will clamp together on ramp when physics start.

Or you can just strut it together. If it held together all the way to the orbit, you may just attach the other end and be a bit careful to not break it.

[Specialist290]

It's due to the way KSP's vehicle designs reads connections. The game only recognizes connections between two nodes at a time -- you can't just invert a 3-way or 4-way adapter and connect it to multiple nodes at once unless you're prepared to get a little creative.

I've noticed you're using LV-Ns as well. They have shrouds which fire out to the side instead of decoupling from the bottom when you jettison them, unlike every other engine in the game. When these shrouds hit your engines, they're probably knocking them off the bottom of the fuel tanks. You want to rotate them when you attach them in the VAB using Shift + Q or E so that the seams are facing diagonally, like in this post.

[Tripod27]

one thing you have to watch out for, I generally rotate the coupler out of the way so the nodes of the coupler and the docking ports below it arent close

if you don't do this you have a chance of attaching the docking port to the docking port under it instead of the coupler, so then it won't be attached to the coupler

if you're too lazy to do this, just pick up the coupler every time you place another port and see if the port moves away with it. if it doesn't you attached it to the docking port below it instead

WARNING: I just tested your design with the docking ports set up. The way the nuclear engines are set up means that when you undock, their protective covers will shoot out to the side, hitting the other nuclear engines right beside them and ripping them off anyway

Edited September 24, 2013 by Tripod27

[Starwaster]

Put another way, once you branch out, the branches (children) can't merge into a single point again.

[Monkeh]

You don't have to use docking ports. Attach 4 mini girders just above the engines and then 4 just below, pointing outwards and lined up with each other. Strut between them. Sorted.

You'll still need to spin the engines around until the seams of the pairings all point outwards though.

Didn't give the nukes any fuel but you can see it works fine. Now, must go to work and not play KSP... :/

Edit: (made from work... :/ ) Also, don't bother with 4 nukes. For the best efficiency you want the low thrust to weight only 1 or 2 will provide. My own recent interplanetary stage had around 7,000 delta v in just the nuke stage. It pushed at around 0.2 thrust to weight so it meant 16 minute burns or so to go to Jool, but it's the most efficient way of doing things.

Also also, if those are mainsails at the bottom of those orange tanks you could afford a hell of a lot more fuel in those stacks. Increase that total delta v a lot with a couple of grey tanks shoved on the bottom. I've had a double orange tank stack with an extra grey tank, to reduce overheating, and still pushed off with a decent thrust to weight ratio. More fuel means more delta v means further travel.

Also also also, those cones might look quite nice but they just add weight right now and don't help with the aerodynamics at all.

Edited September 24, 2013 by Monkeh