Composite Throught dia?

ddun · Post by **ddun** » Mon Dec 01, 2003 11:44 pm

Hello,

I have been making various rocket motors for some time now and I have been doing alot of calculations and one thing keeps coming up when with composite engins and that is the throught dia is 12.5% of the motors ID. This seems to go agianst my common sence and experience but the number do not seem to lye so I thought I would ask and see what other people do. The formula that I have been experimenting with is the popular composite used on the shuttles SRB's. I have made several grains with great sucsess and am now working on the motor body and nozzle design. I realy do not want to KATO so for a 1" ID motor I get a throught diameter of 0.125". I realize I need this much restriction for the "k" factor, but ...... is this right?
Please confirm for me,
Thank You,
Dwight Duncan

Joe · Post by **Joe** » Tue Dec 02, 2003 5:29 am

It depends on how long your motor, or at least your propellant grain, is. Of course, it also depends on the grain design itself; if you're using an end- burner, then the Kn probably won't be too bad.
What exactly is your composite formula?