BP core burner rocket CATO

[SharkWhisperer]

Update

I built 2 more 3lb. motors, first was nozzle-less coreburner with the 75/15/10 BP, second was nozzled with 75/15/10 BP altered w/ addition of 5% airflot charcoal screened in. Both had clay bulkheads on top, both J-hooked fused at bottom and both Cato'd.. I need to make a new batch of BP and get some smaller tubes and tooling. I would like to make the largest size motors that have good chances of success. Would .75" id be a safe step down with reliable success rate?

I don't hand-ram anything above 1lb motors (0.75" ID) because I'd expect them to cato. You just cannot get reliable grain compaction in that fat of a tube with a hammer. At least I can't. Screening in +5% charcoal effectively makes your BP 71.4/19/4.8, which really is not much of an oxidizer reduction...

 

So yes, try a smaller tube. Starting to learn BP rockets by ramming 3-pounders is predictably self-defeating.

[Arthur]

There is little chance that a beginner will completely learn all about all sizes of rockets. The first rule of rocket fuel is to make it cato then back the power off til it doesn't cato and is swift and high flying.

 

What this means is that a 1/4" bore rocket will likely need hot BP well pressed, also that a 1" bore rocket will need something MUCH slower. The problem with cato's is that they make noise and annoy the neighbours, better to make a rocket that limps away from the tube and make if faster next time

[tld6008]

I don't hand-ram anything above 1lb motors (0.75" ID) because I'd expect them to cato. You just cannot get reliable grain compaction in that fat of a tube with a hammer. At least I can't. Screening in +5% charcoal effectively makes your BP 71.4/19/4.8, which really is not much of an oxidizer reduction...

 

So yes, try a smaller tube. Starting to learn BP rockets by ramming 3-pounders is predictably self-defeating.

I had not thoroughly inspected the tubes after my last pair Cato'd. They were still attached to their sticks and seeing the first one split i jut put them in the corner of the garage. Today I went to remove the tubes and save the sticks and noticed that the one that I had made with the slower BP (5% added charcoal) still that the clay nozzle intact and the tube was not split just the upper bulkhead blew out. Don't know if this was an aberration but I'm thinking of making a batch of 65/25/10 w/out milling all components together and try again. Also I'm shopping for a 3/4" tool kit

Edited August 8, 2023 by tld6008