Why do my decouplers blow up?

[JackBush]

I was able to move up a level in the tech tree so I've been trying to add 3 BACC "Thumper" solid fuel boosters to my already successful ship. But my "old" TT-38K radial decouplers now just blow up on blast-off. The Boosters don't get blown off but keep powering the ship upwards. But then I'm stuck with them the whole trip. Are my decouplers simply inadequate?

Question 2: where do you place the Inline Reaction wheel? Above or below the engine?

Thanks in advance.

Edited October 11, 2015 by JackBush

[Harry Rhodan]

I was able to move up a level in the tech tree so I've been trying to add 3 BACC "Thumper" solid fuel boosters to my already successful ship. But my "old" TT-38K radial decouplers now just blow up on blast-off. The Boosters don't get blown off but keep powering the ship upwards. But then I'm stuck with them the whole trip. Are my decouplers simply inadequate?

You probably placed them on the tank below the decouplers. There's still a relatively large gap between the boosters and the tank that might make you believe you attached them to the decouplers.

[Red Iron Crown]

Inline reaction wheels can go just about anywhere and still work properly.

[JackBush]

You probably placed them on the tank below the decouplers. There's still a relatively large gap between the boosters and the tank that might make you believe you attached them to the decouplers.

Well, I've fiddled and fiddled with them, moving the decouplers up and down; I don't know how to tell when the boosters are positioned properly beyond when they shine green. I must be missing something. Here's a screen of the ship on the pad.

http://imgur.com/BHHqC6h

There's another question: why don't my Imgur images show up?

[Waxing_Kibbous]

This happened to me also, make sure when you are placing the engines over the decouplers the readout displays the decoupler's name. You will be able to tell they are on right by how it looks when assembled, if it is wrong the engine and decoupler will be intersecting a bit. If they are in a bad position when properly attached you can adjust them using the translate widget.

[Red Iron Crown]

This happened to me also, make sure when you are placing the engines over the decouplers the readout displays the decoupler's name.

That's a Kerbal Engineer Redux feature, and it does not look like JackBush has KER installed in the screenshot.

The most basic thing with attaching parts to radial decouplers: You *must* have your cursor over the decoupler when placing. Anywhere else and it might look like it is attached to the decoupler but it is not.

Edited October 11, 2015 by Red Iron Crown
Fixed misspelled name.

[JackBush]

What is this, please, and where do I find it?

- - - Updated - - -

This! And thanks ever so much. Ship now flies beautifully.

[Gaarst]

The "translate widget", called offset in the game, allows you to move a part without replacing it, it also allows you to clip parts, to make assemblies look better for example.

It is located top left in the VAB/SPH screen (right of the parts menu though): you'll see four squares corresponding to the "building tools" (place, offset, rotate, root). The offset tool is the second one, it can also be used by pressing "2" on your keyboard.

Simply click on a part and drag any of the vectors in the direction you like. Press C for finer controls, and F for switching the position of the axes from absolute to relative to part placement (for rotated or radial attached parts).

When you're done, click on the first "square" or on the "1" key to get back to placing parts.

Edit: read this to learn how to insert an image on your post, and simply click the "Reply with quote" button bottom right of a post to quote it automatically.

Edited October 11, 2015 by Gaarst

[KerikBalm]

The Boosters don't get blown off but keep powering the ship upwards. But then I'm stuck with them the whole trip

From your screenshot, it seems the boosters are attached directly to the core. They must be attached to the decoupler, which detaches to the core.

I notice you use 8 decouplers, for 4 boosters... they don't work like that... You can only have 1 decoupler per attached part.

If you want it attached more firmly, use a strut as an additional connection between the booster and the core. When the decoupler fires, the strut connection will also be terminated.

Question 2: where do you place the Inline Reaction wheel? Above or below the engine?

If you place them directly below the engine, they will block the engine's thrust.

You could put them below a stack decoupler, below an engine, if you want to get rid of the reaction wheel before using the next stage.

In general, it makes very little difference (if any) for rotation of your craft, where you place your reaction wheels.

[JackBush]

when you are placing the engines over the decouplers the readout displays the decoupler's name.

Where is the readout you speak of?

[Skorpychan]

Inline reaction wheels can go just about anywhere and still work properly.

Mass distribution dictates they should be near the top, though. They're relatively light, and shouldn't be forcing CoM upwards by displacing heavier parts up the rocket.

[Red Iron Crown]

The CoM should be as far upward as you can manage in a rocket for better stability and control authority. Which is a bit orthogonal to my point that reaction wheels work equally well wherever they are placed.

[Waxing_Kibbous]

Where is the readout you speak of?

As Red Iron Crown mentioned, it is from an addon called Kerbal Engineer Redux, which I mistakenly thought was stock. I highly recommend KER because it gives a ton of really useful info, especially if you are just starting out.

[Kryxal]

I'd say toss reaction wheels when the craft gets small enough not to need them. It's a pain to have a little tap spin your ship like a top...