Help with decouplers and Liquid Fuel Engines

[Beadon]

Hello all and thank you for visiting!

I've just started to play KSP in the last week or so and I've really just begun to enjoy the game! However, with the way I like to design my crafts, I'm having some trouble doing so through either a bug or just lacking knowledge as what to do. So, let me start by explaining my problem!

Lately, I've been trying to use a decoupler or adapter underneath Liquid Fuel Engines to attach booster rockets or to have more stages. Unfortunately, when this happens, the Engine will prove absolutely 0 thrust, even though it looks as if the engine is operating as it should. Am I missing something here? I've been looking for the last day or so and only finally decided to make a thread.

Any help is much appreciated! Thank you!!

Edited November 27, 2013 by Beadon

[Vanamonde]

Can you post pics of your ship? The game does take into account that the *net* thrust will be zero if an engine's exhaust is hitting another part of the same ship.

[Kasuha]

The decoupler looks like an empty ring but in fact it is solid inpenetrable object and it blocks any thrust from an engine nozzle to which it is attached. To get thrust from engine above it, you need to decouple it from the engine first. That is done through staging - the decoupler is marked as two horizontal lines in the staging column.

Each decoupler has arrow marks on sides. These arrows are supposed to point at the engine from which you want to decouple it. It will not decouple by its other end.

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[J.Random]

Each decoupler has arrow marks on sides.

Blue ones don't: they either decouple from both sides (small one) or simply explode on decouple.

[Monkeh]

Decouplers are also not fuel cross feed capable, this means fuel from above them cannot get to an engine below.

[Kasuha]

Blue ones don't: they either decouple from both sides (small one) or simply explode on decouple.

These are not decouplers. They're separators.

[Beadon]

Precisely what Kasuha said, except I'm not playing in sandbox mode, so the only decouplers I have is the starter one and I believe that big ass one. No matter which way the arrows on them are pointing, the decoupler itself never comes off so the engine still never produces thrust.

[Kasuha]

When you place a decoupler on the ship, an icon with two vertical bars appears in staging column (on the right in VAB, on the left in flight; you may notice it in my images, too). You activate (decouple) it by pressing Space. You may drag its icon up/down between stages to get it activated at the right point.

[Taki117]

Alternatively you can also RMB it and select Decouple from the pop-up. (This should only be done in instances where your staging is off because of something, like a Kerpollo mission)

[SRV Ron]

Here is an example of a SRB under a liquid engine.

[Sirrobert]

Can you show us a screenshot of the craft you are trying? I'm a little confused off what you mean with a seperator under an engine and than firing the engine. I'll try to guess it though

The idea of stages is that you first fire the lowest stage, than seperate, and than start up the stage above it. The seperator should be gone when you fire the engine above it.

In the case of the seperator still being there when you fire the engine, flip the seperator around. It's pointing the wrong way, and thus sticking to the engine, instead of sticking to the spent stage (that is now falling down to Kerbin) as it should