# Intro/ Question

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#### drewbuildsstuff

##### New Member
Hey Guys!

I'm fairly new to the rocket game, I have launched a couple store bought ones but never built one from scratch. I recently did a youtube video on one that I powered with co2 cartridges. I ran into a problem with it tumbling in the air after take off. Due to the power of the cartridge's weight is the biggest concern so I don't have a lot of room to add pieces or weights.

It was a lot of fun and I want to build another to see how high it will go if I can get it to go straight. Video is below if that helps give you an idea of what is happening. Any suggestions would be awesome!

#### prfesser

Is there a particular reason for using CO2 cartridges? First, on TRF this would be considered "research rocketry", using other than certified motors, and that sort of stuff is relegated to the Research forum; access requires L2 certification from TRA/NAR/CAR.

Certified motors would provide considerably greater thrust as well as a means of activating a recovery system.

That was a darned good representation of a Saturn V, for a freehand effort!

Best -- Terry

#### Grog6

##### Well-Known Member
That's a cp violation, lol.

#### kalsow

##### Well-Known Member
I'd guess your rocket's center-of-pressure (CP) is ahead of its center-of-gravity (CG). For stable flight (without vectored thrust) you need the CG to be ahead of the CP. A foam rocket with four heavy CO2 cartridges in the rear and smallish Saturn V-like fins is almost certainly going to tumble.

If you really want to design rockets, use OpenRocket(free) or RockSim() before you light'er up.

#### tsmith1315

##### Well-Known Member
The marketing dept appears to have a bigger budget than the research team.

#### Grog6

##### Well-Known Member
This is a good start:

#### Scott_650

##### Well-Known Member
It’s always fascinating watching someone come up with a more complicated and less successful method to do a fairly simple task

#### Grog6

##### Well-Known Member
A culture of safety is the first step toward safe conduct; always think "What's the worst thing that could happen?"
When that involves other people, said action is a bad idea, and could end you up in jail, if you hurt someone.

#### Grog6

##### Well-Known Member
One of my friends saw me write this; he mentioned that we rarely took that advice; and that was how we ended up telling Atlanta's finest "No, I haven't seen two guys with parachutes!" while stuffing said parachutes into the back seat of the subaru.
He was looking right at us, so IDK why we didn't get arrested. : )
People apparently get mad when you jump off their buildings, lol.