How to attach wings to two surfaces

[Nivalis]

(Windows version 0.9, non-Steam, no mods)

I'm struggling with a plane design I'm working on. Basically I'm trying to build a plane with the fuel tanks/engine build on the wings. It's a big plane, so the engine assembly has two fuel tanks attached together.

The issue is the the wing connectors won't join to the second fuel tank if I attach it to the back of the first fuel tank. Even if they are phased through there is no connection and the tanks "flop" because it's only being held from the front. Likewise, if I attempt to attach the fuel tank to the wing I can't get it to connect to the other fuel tank's node.

What's more annoying about it is that my first, quick prototype concept did join properly with all wing connector pieces attached to both the plane's core and the fuel tanks (multiple pieces). It ended up being one very solid wing (no symmetry build) despite having the weight in the middle. It didn't flop or wiggle.

I don't understand why it worked once but now I can't get it to cooperate with me. Does anyone have any insight on what I might have done differently or a know-how on a way to get the wings to connect to both surfaces?

So far it doesn't matter if I build the fuel tanks first and then put the wing connectors in between or if I build the wing then add the fuel tanks.

Here's a quick snap of the wing assembly in attempted function:

As you might be able to see, only the front wing connector and fuel tank are connected. The other tank and connectors are not joined, causing it to hang down.

[purpletarget]

Mostly this is probably due to the Tree Structure that KSP uses for constructing vehicles. Everything starts with a root part, and each new part attaches only at one point, and they all branch out from there.

Thus, many parts can be connected to a part already on the ship, but each of those parts is only connected to one parent part. You can't have parts connecting around in a circle, or looping back on each other, since that would involve making a child trying to become a parent.

The workaround would be to use struts to staple wing parts together, or reinforce the heavy parts that are loading the structure.

[eddiew]

The workaround would be to use struts to staple wing parts together, or reinforce the heavy parts that are loading the structure.

Exactly that. You can only place a part connected to one other part. You can however move your camera inside some of the pieces (even wings) and use internal struts to stitch them together, so that you don't see the resultant mess of spacetape

[Alshain]

For modular wings, attach in rows, strut in columns.

[KerbMav]

There was something that liftforces only act from the position the wings are attached ... or something ... ?

[Alshain]

There was something that liftforces only act from the position the wings are attached ... or something ... ?

Not exactly, in stock there is a defined "Front" of the wing. It must be facing front. It should be pretty obvious by the way it attaches, don't try to rotate it. That is why there are often two wing pieces of the same shape but different orientation like the Wing Connector Type A and Wing Connector Type B or the Wing Strake and Structural Wing Type C.

In FAR, the shape of the craft is all that matters, you can rotate them all you want.

[Pecan]

... I'm struggling with a plane design I'm working on ... a plane with the fuel tanks/engine build on the wings. It's a big plane ...

You don't sound completely new to KSP but, you know, March forum-join date and one post; sorry if this is teaching you to suck eggs.

Spaceplanes in KSP are hard, big spaceplanes are very hard, spaceplanes with MK3 parts are pointlessly hard (as in, there is no point in using them as there's always an easier way to do whatever you're trying to do).

Start with rockets, start small and achieve success by progressing in small steps.

It's a lot less frustrating than just failing in a big way.

[FlyingPete]

Spaceplanes in KSP are hard, big spaceplanes are very hard, spaceplanes with MK3 parts are pointlessly hard (as in, there is no point in using them as there's always an easier way to do whatever you're trying to do).

This. All those huge cargo bays and cockpits look tempting, but it's not worth it for the use that they get. Crew transport? No need to send 16 kerbals into orbit at once- make multiple trips. Need to launch a Big Orange Tank to orbit? Send it up empty on top of a rocket, then refuel it later with smaller tanker aircraft. At best, I might consider building a Mk2 twin-fuselage design with the cargo slung between them, but I'm not very good at building planes so haven't tried that yet.

[FleshJeb]

Not exactly, in stock there is a defined "Front" of the wing. It must be facing front. It should be pretty obvious by the way it attaches, don't try to rotate it. That is why there are often two wing pieces of the same shape but different orientation like the Wing Connector Type A and Wing Connector Type B or the Wing Strake and Structural Wing Type C.

In FAR, the shape of the craft is all that matters, you can rotate them all you want.

They WILL work in the 180 position, correct? Just not the +90 or -90.

[KerbMav]

.

Let me (try to) rephrase that. My mind tells me that someone mentioned (Scott?) that the position a wing assembly is attached to the plane matters, e.g. if we have a wing made up of three wing parts, it would make a difference if all of them are directly attached to the plane or the part in the front/middle/aft is attached to the plane and the other two attached to the first wing part.

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