TR-18A Stack Decoupler: I don't have one

[MetricKerbalist]

Hi Kerbal colleagues,

A number of rockets that I have built according to specifications have called for the use of a TR-18A Stack Decoupler.

Unfortunately, I don't have that component in my Kerbal Space Program bundle.  I had a nice, successful install of the program from Steam, but I don't have that.  I don't know why not.

Here is what I do have:

• TD-06 Decoupler
• TD-12 Decoupler
• TD-25 Decoupler
• TD-37 Decoupler
• TS-06 Stack Separator
• TS-12 Stack Separator
• TS-25 Stack Separator
• TS-37 Stack Separator

Therefore, I have these two questions, please:

• Is there a way I could get the TR-18A Stack Decoupler?  But I can't see how.
• Of the components that I do have listed, is any one of them a close enough substitute for the TR-18A Stack Decoupler?

Thank you.

Stanley

[Serenity]

7 minutes ago, MetricKerbalist said:

• Is there a way I could get the TR-18A Stack Decoupler?  But I can't see how.
• Of the components that I do have listed, is any one of them a close enough substitute for the TR-18A Stack Decoupler?

I think this is right, replaced when Making History dropped:

The decoupler is replaced by the new TD-12 Decoupler. The TR-18A Stack Decoupler is a Decoupler that allows for staging rockets vertically and in sequence.

If you need to complete a contract then the Alt+F12->Contrats debug menu can help you complete it.

[18Watt]

I believe that part is in the Making History expansion pack.   

[MetricKerbalist]

Hi Serenity and 18Watt,

Thank you for your answers.

So Serenity, you are saying to use the TD-12 Decoupler in place of the TR-18A Stack Decoupler.  OK.  I will do that.  That is very useful information.

I assume that you are aware of this, but I just do want to point out that the specifications of these two components differ to some extent:

• Physically, they seem to be the same size, so that is good.
• The TD-12 weighs 0.04 t versus the TR-18A, which weighs 0.05 t.  Not too much of a difference there.
• The TD-12 has a tolerance of only 6.0 m/s impact versus the TR-18A, whose impact tolerance is 9.0 m/s.  This worries me somewhat.
• What especially concerns me, however, is that the TD-12 has an ejection force of 100.0 versus the TR-18A, whose ejection force is 250.0.

Well, it is what it is.  But there are these differences.

Stanley

[Rhomphaia]

22 minutes ago, 18Watt said:

I believe that part is in the Making History expansion pack.   

Nope, Serenity has it right, the TR_18A is the old 1.25 m decoupler, the TD-12 is the one you want.

 

 

[MetricKerbalist]

Hi Rhomphaia,

Oh, I wasn't disputing the accuracy of Serenity's message.  She clearly knows what she is talking about, and I am grateful for her answer.  I just wanted to bring to everyone's attention that the two components do not have identical characteristics.

Stanley

Edited June 9, 2021 by MetricKerbalist
Typo

[Rhomphaia]

4 minutes ago, MetricKerbalist said:

Hi Rhomphala,

Oh, I wasn't disputing the accuracy of Serenity's message.  She clearly knows what she is talking about, and I am grateful for her answer.  I just wanted to bring to everyone's attention that the two components do not have identical characteristics.

Stanley

Yeah, It was in response to 18Watt, the 1.8 m size was added by Making history and the old name looks similar to those. 

the old decouplers can still be found in game in \GameData\Squad\zDeprecated\Parts\Utility, they are hidden from being able access normally in the editor, just kept around for people running old saves that have ships still using them.  

[MetricKerbalist]

Hi Rhomphaia,

Wow!  That is interesting information!

So out of curiosity, let me ask this, please.  Let's say that I wanted to put the TR-18A back into use.  How would I do that?  In other words, how do I move it out of storage, so to speak, and put it back into an active area.  I am not planning on doing this.  But knowing how to do it would teach me something more about KSP.

Thank you.

Stanley

[bewing]

If you go into the Advanced Search options in the VAB or SPH, you can probably still find all the old parts. They are "deprecated", but not deleted.

[MetricKerbalist]

Hi bewing,

I can see the part mentioned in my directory tree.  I just don't know how to activate it.

But I don't really need to either.  I have got so many things to learn.

Thank you for your contribution.

Stanley

[bewing]

1 hour ago, MetricKerbalist said:

I just don't know how to activate it.

Like I said, it's already active. All you have to do is click the "Advanced Search" button when you are building your rocket.

The button looks like three bars with an arrow in the upper left corner of your VAB window.

[MetricKerbalist]

Hi bewing,

OK.  I understand.  Thank you.

Stanley

[Zhetaan]

15 hours ago, MetricKerbalist said:

• The TD-12 has a tolerance of only 6.0 m/s impact versus the TR-18A, whose impact tolerance is 9.0 m/s.  This worries me somewhat.
• What especially concerns me, however, is that the TD-12 has an ejection force of 100.0 versus the TR-18A, whose ejection force is 250.0.

The impact tolerance won't be an issue unless you try to land on it or decide to play bumper ships in orbit.  Generally, you want to land with less than 6.0 m/s anyway.

The ejection force isn't a problem; it's not a terribly useful form of propulsion, so the force that you need is only that which pushes the separated stages apart in a reasonable amount of time.

One thing to note about the new versus the old decouplers is that the new ones have names with systematic relationships to their size.  The TD-12 is the 1.25 metre decoupler.  The TD-06 is the 0.625 metre decoupler.  Similarly, the TD-25 and TD-37 are the 2.50 metre and 3.75 metre decouplers.  The old decouplers usually had random numbers or no numbers at all (the 2.5 metre decoupler used to be called the Rockomax Brand Decoupler, which told you nothing about its size unless you knew ahead of time that Rockomax parts tended to be 2.5 metres).  This is still the case with the radial decouplers:  the 38 in TT-38K means nothing that I can determine, and Hydraulic Detachment Manifold is practically technobabble.

[MetricKerbalist]

Hi Zhetaan,

Thank you very much for your highly informative post.

Stanley

 

11 hours ago, bewing said:

Like I said, it's already active. All you have to do is click the "Advanced Search" button when you are building your rocket.

The button looks like three bars with an arrow in the upper left corner of your VAB window.

Hi bewing,

Thank you for that information.

Now, I am going to start using the TD-12 because you nice, helpful KSP colleagues are advising me to do so.  However, just because I want to learn as much as I can about KSP, I would like to understand how to find the TR-18A.  I followed your instructions, and thus I was able to find the button to which you referred.  But I still cannot locate the TR-18A.  Would you mind going a little bit further and telling me what options I should then choose.

Thank you for your consideration.

Stanley

[bewing]

Ah well. That used to work in previous versions, but I just tried it and it doesn't work anymore.