Saucer secrets - stability & simulation?

[cls]

OK TRF - I am looking for rules of thumb and design tricks for saucers. I would guess the CG/CP relationship is the same as for a "regular" (3FNC) rocket. is there anything special about drag stabilized models? are they more or less forgiving for balance?

any thoughts about flying payloads in saucers?

any ideas about accurately modeling saucers & other drag stabilized craft in Rocksim?

... this is for our Lander Challenge entry.

thanks a bunch!!!

 

[Justy]

All I know about stable saucers is that an Estes Snitch with 30-or-so BP motors crammed under the hood, isn't.

 

[powderburner]

Originally posted by cls
I would guess the CG/CP relationship is the same as for a "regular" (3FNC) rocket.

I think the interaction of aerodynamics, thrust, and center-of-gravity gets a bit more complicated. The attached site shows a design that is not a saucer, but definitely illustrates that being 'stable' is a complicated thing.

https://www.rocketreviews.com/reviews/descon9/anfscd.html

 

[cls]

my son loves his snitch, I think because the prep is so easy. I've heard you can chad stage them and they are still stable.

re: descon 9: yeah, that's cool! that's been on my try-it list for a while.

along the same lines, someone flew a Centuri Satellite Killer at last weekend's launch.

 

[rocwizard]

A Snitch may not work with 30 some estes motors, but i do know that they do work with a Kosdon J450 hanging a foot out the forward end <properly reinforced of course>

here's me with my beasty snitch last year at BALLS

 

[teflonrocketry1]

I am working on this problem but I don't have a good answer for you yet. One of the weak points of the RockSim program is that it doesn't take body lift or base drag into account. I am looking for a way to make the program do this anyway. I can model Spunik's, spools, disks and cones but none of these fly the way I think they should!

Attached is my best attempt to date to simulate a disk with a motor at its center. The base drag is simulated as four triangular fins with a root cord three times the diameter of the disk. I hope
to find a way to prove this concept, that I can not yet explain.

Bruce S. Levison, NAR #69055

 

[daveyfire]

Originally posted by rocwizard
Here's me with my beasty snitch last year at BALLS

It flew like snot, too... Kos Fast is cool stuff!