It seems that Strontium Carbonate-based red motors get a bit of a bad rap in the community. The king of these formulations is Pat Gordzelik’s Polish Rojo family of propellants. I originally shied away from making reds, as I believed PR/SPR to be “wimpy” propellants that made a weak red flame, and that real men used Strontium Nitrate to make red motors. But Strontium Nitrate has its problems — it’s highly hygroscopic and needs to be dried and screened before use, and the grains must be kept sealed tightly before flight. I have a few old Kosdon East “Red Rhino” motors that are nitrate based, and though they give a BRILLIANT red flame and a delightful low-thrust, long-burn profile, they are immensely difficult to light due to their age and the amount of moisture collected by the hydrophilic Nitrate groups.

So, I decided to try out Polish Rojo:

Further details on the motor after the jump: (more…)