How to use ullage motors?

[eygc]

When I put them on my SRB's and fire them during decoupling, they blow up my primary rocket. I have no idea how you are supposed to use them. Anybody have a quick how-to? Thank you in advance.

Edited August 30, 2014 by eygc

[DeMatt]

1. KSP rockets do not need ullage motors, as their fuel does not need to be "pushed" into the pump intakes as it does in real life.
   
2. Expended SRBs are usually light enough that the decoupler alone can push them clear of your rocket, so no need for the Separatrons.
   
3. Try "duck-footing" the Separatrons. Instead of aiming them straight outwards, aim them at an angle so their exhaust doesn't hit your central rocket.
   

[Reactordrone]

I've had success with mounting a single one on each booster near the decoupler, angled outwards slightly. The boosters just spin away cleanly.

[Boomerang]

You can also put them on the outside of your SRBs, towards the bottom, facing down. Keeps the SRB more upright after detachment, rather than spinning about, and no exhaust near the parent craft.

[eygc]

I've been using 4-6 Separatrons angled towards my primary rocket on each side of each SRB to get the SRBs off cleanly. I'll try those tips for the Ullage motors. Just to be clear, I want cool looking and clean separations if possible. Thanks for answers.