Haven't done it for that particular rocket, but the later versions of
RockSim will make a reasonable job of estimating the CP of this style
(pods, curved bodies, etc) of rocket.
- Find someone who already has a flying version and ask them where to
put the CG.
- Swing test it!
Sure, you tie string around the body of the rocket at the CG. Then you
swing the rocket around your head at the end of the string. If it
points forward, it's stable. Doesn't work for very big rockets, or
very long rockets.
I assume you mean the Tintin Moon Rocket.
I modeled it in RockSim and got the following CP values:
Barrowman .68 (.86)
RockSim .70 (.88)
Cutout .60 (.75)
The first number in each row is the CP location as a fraction of the
overall length; the second number, in parentheses, is the CP as a
fraction of the airframe length. The CP is measured from the tip of the
nose (NOT the tip of the nose antenna).
My model is based on the drawing in Spaceship Handbook. I didn't model
the fin tip pods, except as profiles included in the fin shapes.
Here's the model if you're interested: