Stablizing rockets.

I just remembered that I ran onto this when I was packing up the rocket stuff.
I was frustrated with how to figure out just where the center of gravity should be, without doing complicated drawings or math. This page explains why you want the center of gravity in front of the center of pressure:http://www.midsouthrockets.com/tech_004.php but it doesn't provide any easy answers.
There is this option: Buy a copy of RockSim from Apogee Components and "build" your rocket there.

But looking at the basic Estes rocket info that came with an Estes' kit I found their easy answer.
The swing test.
Put a string around the rocket at the point that it balances (with everything in place, including an unused engine) and swing it around your head. If it goes straight, you're good. If it doesn't, put some weight in the nose cone (or take some out) and adjust until it does swing straight.

So there you go for next time.