Rocksim CP Locations

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Piled Higher and Deeper
TRF Supporter
Jan 26, 2009
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thank u, next
I've noticed lately when I'm designing rockets in RockSim, they sim as "marginally stable" using the Barrowman method. However, from my experience, the designs just *look* like they would be stable. Using the RockSim CP calculation method, they are stable. So how much do you guys trust the Rocksim CP numbers? Are they any more trust-able on unconventional designs than conventional ones? Thanks!
Short answer: Swing test and add nose weight if necessary.

Slightly longer answer: Don't trust either completely, and the more unconventional the design the less I trust either method since they are approximate formulas. See "short answer" for my solution.
On fairly conventional designs, I trust the Rsim numbers 100%. On the more unique designs, I often go for an extra 1/2 caliber of stability from the Barrowman. I swing test when unsure.

Nothing is 100%, I've had swing tests fail also.

PS Check the thrust-to-weight ratio, speed off the rod, etc!
POST 700!

w00t :D

The bird in question is a 6" x 9 foot rocket that's fairly conventional (eNvy, it's a L3 cert bird that'll fly lower than the planned 15K of Fundamental), so swing testing it would be like trying to fling my cousin around my head on a piece of tubular nylon :p The only "non-conventional" thing about it is it's boat tail, which is 6" diameter to 4" diameter... awww what the heck here's the sim file for you guys to check out!

EDIT: OBTW, I plan to fly on either an M1297W, an M1315W, or an M2500T... T/W even on the baby M is 10:1!