The Rocketry Forum

Help Support The Rocketry Forum:

Joined
Apr 18, 2019
Messages
2
Reaction score
1
Hey guys, I'm currently into building my own motors and was wondering if anyone else out there currently uses star grains? I currently use a bates grain configuration (basically multiple toilet paper roll shapes stacked together with a slight gap between each) but I end up taking a long time to make each grain and then shape it to get the right geometry. I was wondering how many people out there make star grains and how they do it? Particularly interested in any thrust and pressure calculations that can be done, as my casing is currently designed to handle 1000 psi.

If it helps, the propellant I use is RNX-57 (a Richard Nakka development).

Thanks!
 

Banzai88

Lvl 1,Wallet....Destroyed
TRF Supporter
Joined
Jul 15, 2015
Messages
2,572
Reaction score
741
This thread probably belongs in the Research topic.
 

3stoogesrocketry

Well-Known Member
Joined
Feb 26, 2012
Messages
1,442
Reaction score
254
Hey guys, I'm currently into building my own motors and was wondering if anyone else out there currently uses star grains? I currently use a bates grain configuration (basically multiple toilet paper roll shapes stacked together with a slight gap between each) but I end up taking a long time to make each grain and then shape it to get the right geometry. I was wondering how many people out there make star grains and how they do it? Particularly interested in any thrust and pressure calculations that can be done, as my casing is currently designed to handle 1000 psi.

If it helps, the propellant I use is RNX-57 (a Richard Nakka development).

Thanks!

First do not mention any formulas or ingredients anymore . Second , is there a reason you need a star grain geometry? What are you trying to accomplish?

Eric
 

timbucktoo

Well-Known Member
Staff member
TRF Supporter
Global Mod
Joined
Jun 13, 2014
Messages
8,193
Reaction score
1,324
Location
Cocoa Beach
Contact cwbullet for access to Research Forum. Not much will be discussed here.
 

djs

Well-Known Member
Joined
Jul 27, 2014
Messages
3,369
Reaction score
251
my casing is currently designed to handle 1000 psi.
Not sure how you determined the casing strength, but generally this is too low.

Also, assuming you're in the US, try to find a local Tripoli prefecture and learn from people who are already making motors.

This is assuming you are 18+, of course.
 

heada

Well-Known Member
Joined
Jan 18, 2009
Messages
4,003
Reaction score
1,178
Location
Indianapolis, Indiana
By "star" I assume you mean finocyl, correct? Most core designs, BATES, moon, finocyl, etc. are made using a mandrel and casting or pressing the grain around it. Some grains are harder to make than others. Finocyl are harder for several reasons but I fear I can't go into detail without the thread being removed. As others have said, if possible, join the research sub-forum here and there you can discuss details.
 

G_T

Well-Known Member
Joined
Dec 29, 2011
Messages
2,311
Reaction score
383
Star grain is a little different than finocyl. There are many grain geometries used to essentially keep the burning surface area near constant, beyond just Bates.

Gerald
 

Latest posts

Top