Tintin rocket CP

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.

Alternatives:

- Find someone who already has a flying version and ask them where to put the CG.

- Swing test it!

I've never heard of this method. Could you give a short description?

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 should have an engine installed as well for a true stability check?? Am I correct?

Richard

Yes.

And, more specifically, a motor that hasn't been fired yet.

Yes.

p.picton wrote: > Has anyone calculated, determined, etc., the Cp for the Tintin rocket? > It is a bit unusual so I am not sure if the usual methods were > accurate.

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:

Oh yeah, but be sure to stick a fuse in it and light, right before you start swinging.

It's much more fun that way.

TBerk

I'm pretty sure it isn't.

You just need really, really Strong string.

TBerk

I'm unconvinced.