How To Balance RCS On Your Payload

[NeoMorph]

I've posted this in another thread but I realised it would be hard to find if others need it so here it is...

NeoMorph's Balancing RCS System Mk1

Now here is a VERY good way to learn how to balance your RCS is to use the built in debugger. Yes, it is a cheat in a way but it DOES help you to balance your final capsule without flying it up into orbit. It's a bit like a simulation system for your design.

1. Build your final payload but don't add on the boosters just yet. You want just the parts you will have in orbit and want to dock. Bit like the Command and Service module of the Apollo era.
   
2. Add on your RCS... Add a ring of "Place Anywhere" RCS pods around the Centre of Mass (you can find the CoM by pressing the little weight icon at the bottom left of your VAB screen). These will be used for translating... ie up,down,left and right. Use 4 for small ships, 6 for medium ships and 8 for large ships.
   
3. Now add a ring of RCS Quad pods around the ship, a third of the way from the top. 4 is fine for a small to large ship as all they are used for is turning the ship.
   
4. Now here is the trick... Go into Action Groups and select one of the Custom slots. For this example we are going to use Custom10. Select one of the RCS Quads on your payload and then you should see it appear in the action group menu as "Toggle RCS Thrust" Click on this and it will now be allocated to Custom10.
   
5. NOW SAVE YOUR SHIP. So many times I have got to launch and the game crashes so I always save before testing a new ship.
   
6. Now that you have saved, add a couple of launch clamps to support your ship. These are just so it doesn't go boom if it falls over.
   
7. Now go to the launch pad.
   
8. Here is the trick. Hit ALT-F12 and a menu will appear. Hit the "Hack Gravity" button.
   
9. Launch your ship... You will now be able to test your RCS without going into orbit. Turn on the RCS by hitting R and you can turn the ship with the WASD buttons and rotate with the Q and E buttons. For translating we need to do a little trick.
   
10. To enter our translation mode hit the custom10 button (which is usually 0). This will turn our quad pods off and on.
    
11. With the quad pods off you can now use the JKLI buttons to move left, down, right and up.
    
12. To move forward and back hit the custom10 button again to turn the quad pods back on and use H and N.
    
13. Testing the ship will probably show you some problems. If the ship turns when you are translating you may have to move the ring or place anywhere pods up and down the body of the payload. If the ship isn't turning fast enough when you are using the WASD buttons you can move quad pods closer to the end of the payload which will speed up the rotation.
    
14. Here ends the balancing RCS tutorial.
    
15. 
    

This technique was given to me by others on this board. It works well and I've just added the fine tuning ideas myself because I either had extra twitchy small craft going crazy or big craft that just wouldn't turn. You don't need two lots of RCS rings like a lot of people use (just look at the Apollo CSM if you don't believe me). I used to use way too many quad pods before I realised this.

[Specialist290]

Nice writeup. Adding this to the Drawing Board

[Tristavius]

Very nice writeup... I've had very successful RCS usage but you've added two things to my own knowledge... firstly adding the translation-only ring along the middle and secondly the gravity hack for testing!

[NeoMorph]

Nice writeup. Adding this to the Drawing Board

Cheers... It's the one thing that REALLY used to bug the hell out of me. Having to launch to orbit just to test the balance of your ship RCS was a timewasting pain, especially as the parallax view in the VAB makes it soooo hard to figure out if you really do have your translation ring in the right place. Then someone mentioned the debug hack and I was like WHOA... Then I looked at the Apollo setup and the light bulb went DING in my head. Hence what I use now and I haven't had a bad docking since.

[Deadweasel]

Awesome write-up! I was struggling with a simple ship (basically an automated orange tank) that was going crazy with the RCS freakout dance.

Found your article, followed the advice, (forgot all about hack gravity!) and got it sorted in minutes.

THANK YOU!

[NeoMorph]

This really should be moved to tutorials... (thx Kasper)

Edited June 22, 2013 by NeoMorph