egg changed the topic of #principia to: Logs: https://esper.irclog.whitequark.org/principia | <scott_manley> anyone that doubts the wisdom of retrograde bop needs to get the hell out | https://xkcd.com/323/ | <egg> calculating the influence of lamont on Pluto is a bit silly…
raptop has quit [Read error: Connection reset by peer]
raptop has joined #principia
_whitelogger has joined #principia
<queqiao-> ⟨PrinceZola⟩ does the physics of spinning objects still break with principia?
<queqiao-> ⟨PrinceZola⟩ honestly im just having that old issue of spin stabilization again
<queqiao-> ⟨PrinceZola⟩ the "amplitude of nutation" or whatever it is correctly called, just keeps growing as the rocket goes on
<queqiao-> ⟨PrinceZola⟩ does even the smallest nudge during separation completely ruins your spin stabilization? can anyone show me a 3000km downrange RD-100/aerobee rocket that doesnt start spinning madly soon after separation?
<queqiao-> ⟨Kirk (He/Him)⟩ ⟪PrinceZola⟫ does the physics of spinning objects […] ⮪ The physics of spinning objects works perfectly with Principia. It’s stock KSP behavior that’s broken
<queqiao-> ⟨itsRyan⟩ Since Principia correctly models angular momentum including the intermediate axis (aka tennis racket) effect, it can be more challenging for some designs, but it's actually stock that's "broken"
<queqiao-> ⟨PrinceZola⟩ this rocket has no intermediate axis
<queqiao-> ⟨itsRyan⟩ It also has no fins. Most likely it's just aerodynamically unstable.
<queqiao-> ⟨PrinceZola⟩ at 100km altitude? lol
<queqiao-> ⟨Kirk (He/Him)⟩ Yeah
<queqiao-> ⟨Kirk (He/Him)⟩ Aerodynamics do matter at 100 I’m
<queqiao-> ⟨Kirk (He/Him)⟩ * km
<queqiao-> ⟨PrinceZola⟩ im not even going that fast aaaaaaa
<queqiao-> ⟨test_account⟩ Are you using phydics warp? Rotation does work poorly in physics warp for me.
<queqiao-> ⟨test_account⟩ * physics
<queqiao-> ⟨PrinceZola⟩ nope
<queqiao-> ⟨test_account⟩ Then maybe just make it short and wide, it tends to help
<queqiao-> ⟨itsRyan⟩ A primary axis spin rocket is going to be pretty un-aero for a 3K downrange rocket. That's better for in-space stages.
<queqiao-> ⟨test_account⟩ Coasting helps
<queqiao-> ⟨test_account⟩ And I suppose "primary axis spin rocket" means the same as "short and wide", right?
<queqiao-> ⟨itsRyan⟩ But you have to be careful, in between what is shown and short and wide there be secondary axis of angular momentum dragons.
<queqiao-> ⟨PrinceZola⟩ fins helped a little bit
<queqiao-> ⟨PrinceZola⟩ or it was just blind luck idk anymore
<queqiao-> ⟨PrinceZola⟩ either that, or the wings increased the momentum of that spinning attitude idk
<raptop> Ah, yes, the tennis racket dragon
<queqiao-> ⟨PrinceZola⟩ how is the sensitivity of pertubations about a rotation axis estimated?
<queqiao-> ⟨PrinceZola⟩ like, how do we know that spinning a long slender rocket will be stable as well as spinning a short stubby one?
<queqiao-> ⟨egg⟩ I suspect the whole tennis racket/intermediate axis discussion is a distraction here, rather you are merely seeing that if you sufficiently molest a regularly spinning object (either aerodynamically, or by a rough separation), its rotation starts regularly precessing.
<queqiao-> ⟨egg⟩ I believe I have said so earlier.
<queqiao-> ⟨sichelgaita⟩ It would also be better for my blood pressure if every post on that topic didn't start with "physics break in Principia".
<queqiao-> ⟨Bluef16⟩ Where can i find the version which supports 1.12.3?
<queqiao-> ⟨egg⟩ I recommend reading the README: https://github.com/mockingbirdnest/Principia#principia.
<_whitenotifier-1adf> [Principia] eggrobin opened pull request #3673: Factor the barycentre calculations between the BarycentricRotating and RotatingPulsating frames - https://github.com/mockingbirdnest/Principia/pull/3673