Unable to consistently attach SRBs to radial decouplers

[macbates]

I’m a new KSP user, and am having a problem using the radial decoupler. After placing the decoupler on the rocket body (anywhere from 1 to 6 of them), attaching the SRBs to the decoupler seems to be a matter of hit or miss. With 6 decouplers on the rocket body, placing the SRBs on the decouplers seems to attach the SRB directly to the rocket body instead of the decouplers. Sometimes it works, but a lot of the times the attachment isn’t correct, resulting in a “click” when I decouple in flight, but the SRBs remain attached (with an attendant disaster!).

Using the move tool to reposition the SRB doesn’t seem to help, since correct positioning of the SRB on the decoupler requires both lateral and rotational movement, and seeing what’s happening is nearly impossible, especially when you get to 6 SRBs.

This seems to be a known problem since I’ve seen references to it dating back to 2015, but I’m hoping that there is a relatively simple solution since all I want to do is add 6 radial decouples and attach a corresponding 6 SRBs. If it matters, I’m running the latest Steam version on a Mac.

Thanks in advance for and advice.

[OrdinaryKerman]

Are you sure you actually attached the boosters to the decoupler? The relatively small size of radial decouplers makes it easy to miss and accidentally attach your boosters directly to the core stage and not to the decoupler. The Move tool just offsets the location of the part, it doesn't change what part it's really attached to. If you move the decouplers after 'attaching' the boosters, do the boosters stay with the decoupler or the core stage?

[OHara]

It is important, as you noticed, to initially place the SRB on the decoupler, and moving it later does not change the part it is connected to according to the game's logic.

The only way I know to do that correctly, is to rotate the view (with right-mouse button or arrow keys) so you are looking straight at the decoupler, remember where it is, and when placing the SRB click to place it when your mouse is directly over the decoupler.

The fact that the SRB obscures you view makes this difficult, but it gets much easier very quickly with practice.

For a while, I was always swinging my view around immediately after placing SRBs, to check that they really sit on the decoupler.

Then later, as Kerbart, says, you can use the move tool to slide them up and down.

[modus]

Also, placing just one decoupler, attach booster, then select the decoupler and use the correct symmetry, helps me a lot to see if I attached the booster correctly, but maybe that's just me.

[18Watt]

As you’ve discovered, it can be difficult determining wether the booster is attached to the decoupler or not.  If you are having a really hard time, here’s a tip-

• Attach a long, skinny part to the core rocket, such as a structural beam, or structural panel.  Attach it so it is sticking straight out (radially) from the core tank.
• Attach the decoupler to that skinny part.
• With the view set to directly look at the decoupler, attach the booster to the decoupler.
• Because the decoupler is now offset considerably from the core, it becomes much more obvious wether the booster is attached to the decoupler or not.
• Finally, grab the decoupler (with booster attached) and set it to the side.  Remove the I-beam or panels, and then re-attach the decoupler (with booster) to the core stage.

Another way is to just use the offset tool to temporarily offset the decoupler(s) away from the core stage, then once the boosters are correctly attached, offset the decouplers back to their position against the ship.

[Kryxal]

One other thing, if you have a booster you like to use a lot, consider making a subassembly of decoupler, booster, maybe nose cap, possibly separatron if needed.

[James Kerman]

Welcome to the forum @macbates, your question has been moved from Welcome Aboard to our Gameplay section.

[Kerbart]

Attach to the center of the booster, not the top or bottom. Then use the move tool to position it correctly.

[macbates]

Thanks for the info! Taking lots of care per OHara's suggestion, followed by symmetry per modus' tip worked great. In the future I'll have to remember to take extra care placing the SRB and check after attaching it to make sure it's attached correctly. Once that's done I'm good to go. Well, good to go for the next challenge, that is...

Thanks again!

 

[Vanamonde]

To clarify or maybe you already know this: the move tool does not change the attachment point. It moves the body of the part but doesn't change its behavior. 

[AlpacaMall]

Adding my two cents, for what it's worth: Personally, I like to place boosters on radial decouplers by:

1. Place the decoupler on the rocket body
2. Pick up the booster, and move your mouse so that the booster is aligned on the rocket body, below the decoupler.
3. Slowly slide your mouse up. Eventually, you'll see the booster do a small "jump" outwards; this means that the booster is now lined up on the decoupler, instead of on the rocket body.
4. Place the booster

As others have said, picking up the decoupler afterward is a great way to verify that the booster is actually attached to it