More info on throat dia of composite

[ddun]

Thanks for the replys,

I plan on useing three segments of a BATES grain 2" in length, OD 1", ID .375" using the NASA SRB formula of :
Ammonium Perchlorate, Al, Ferric Oxide (red), HTPB,HDI. I have tested this formula before with a 30% throat restriction and burned steady but slowly. It was clear that there was considerable potential there once all of the variables were tunned in.
As I stated before, my calculation indicate I will need a 12.5% restriction to achieve max Isp but my experience tells me this may be too much and may KATO. I just wanted to know if others that make these motors also come up with small throat restictions, wrt 30%.
Once I fly the 29 mm version I plan to move directly to the 38mm which is my end goal and have the parts for all ready.

Thanks for the input
Dwight D

[Stephen H]

sounds interesting!!