30+ years ago, I tried making BP rocket motors. Didn't go too well. Now, I have a son and want to show him this stuff and finally get that job done. I learned a lot in 30 years. I'm making progress. I'd like advice on the final steps, though, please.
I have some BP made up. I used home-made willow charcoal in a 75-15-10 charcoal/KNO3/sulfur. I added 5% dextrin (home made) to some of the BP, but I also have some BP without the dextrin. I have granulated some of the BP with dextrin and lit it. It's darned fast but that's not a quantitative assessment. It was all ball milled (3 ingredients together) and it not only burns fast but it also burns cleanly (for BP). I have some motor tubes (new) and nozzle mix and I've made some tooling to make end burners. I'm using 1/2" ID tubes and I formed a 1/8" nozzle.
Here's what I've gotten so far: I used a mallet and rammed a nozzle and about 12g of powder in 3g increments into a tube, taped a 3/32" aluminum TIG filler rod to the side and lit it. It flew (my first successful BP motor flight ever) but it was lethargic and laid over in flight and dove to the ground. My second attempt was like the first attempt but I used about 8g of powder and I used a shop press and rammed it in stages and lit it upside down on a block. It burned but not well. Those were both with the dextrin BP mix. My third attempt was with 75/15/10 and no dextrin, all rammed with the shop press. As before, I taped a rod to the side and lit it. It flew a little bit more energetically but still not like the commercial motors by any means.
None of the comps have been wetted. This may be a problem. I didn't have a reinforcing liner on the outside of the cardboard tube so I was limited in the force I was able to apply to the comp in the tube with the tooling (it started to bulge the tube). I have built a sleeve for the tube but won't get to use it until tomorrow.
I've read somewhere that someone used mineral oil in their comp for a rocket motor, is that a thing? Should I be using a different ratio for the BP? Will wetting (and then drying) the fuel improve the performance? Anything I'm missing here? I'd like to make end-burners that function well because it would seem that higher flights would be achieved with longer burns (yes, longer burn at less force, so maybe it doesn't matter...but I'd still like to get an end-burner to work well).