Starting into end burners

[Uarbor]

I got the new version of the fire Smith 1 lb end burner. I cranked out a few Motors they fly pretty good with just a stick of course. I set up a test rig to check the thrust. Seems like they do pretty good A nice steady 1 lb for about 4 seconds with my Willow black powder. I hear these things fly well with a header that is about half of the thrust minus the weight of the rocket of course. Rocket with stick weighs about 125 grams a lb of thrust is about 454 G cut that in half and subtract the weight of rocket and stick and it looks like my header should be 100 G with no problem. Do you guys think this sounds okay and reasonable? What kind of headers do you guys use on your 1 lb end burners? And finally do you guys think my thrust is good enough or should I work on it?

I have some Benny whistle that I will eventually use to make composite fuel for this tool set. But I just want to get a feel for black powder first

 

 

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[SharkWhisperer]

All good cept that tube "dispersion" at the end. That needs to be solved or your header will possibly go its own way. For comparison, here's the Estes chart of their BP endburner motors. https://estesrockets.com/wp-content/uploads/Educator/Estes_Engine_Chart.pdf . Test with a dummy header (after cato issue solved) to see how much you can lift. I'd trust that more than a postal/kitchen scale, though your set-up was interesting. Big difference between peak thrust and average thrust in determining how much your motor can lift off the ground. Is that full-strength 75% oxidizer in your BP? 4 s seem like a long burn time even for 3/4" 7.5" endburners. That's pretty much an F-impulse motor in dimensions (how much BP mass in total?).

[Uarbor]

All good cept that tube "dispersion" at the end. That needs to be solved or your header will possibly go its own way. For comparison, here's the Estes chart of their BP endburner motors. https://estesrockets.com/wp-content/uploads/Educator/Estes_Engine_Chart.pdf . Test with a dummy header (after cato issue solved) to see how much you can lift. I'd trust that more than a postal/kitchen scale, though your set-up was interesting. Big difference between peak thrust and average thrust in determining how much your motor can lift off the ground. Is that full-strength 75% oxidizer in your BP? 4 s seem like a long burn time even for 3/4" 7.5" endburners. That's pretty much an F-impulse motor in dimensions (how much BP mass in total?).

that was not so much a Cato as it is the fact that I forgot to ram a bulkhead because I wasn't really planning on testing that motor on the stand. I recovered the tube and it was undamaged. It just got to the end of its propellant and still had high pressure inside. I will definitely add some delay once I start putting headers on. I would imagine I would need more than with a core burner. I do have a bulkhead maker that leaves a pass fire I might start using it I guess for something other than making gerbs. There is 60 G. Of 75 15 10 milled black powder in each motor. I do believe the charcoal was Willow . The propellant is loaded at 5600 PSI. Edited May 21, 2022 by Uarbor

[Uarbor]

Also the tubes are waxed and I did not dampen the propellent this time I wanted to see what would happen. I think I'll just put a dummy head on one with some vitamin f in the tube and see what kind of height they're going to pop at. My ultimate goal would be a crackling parachute flare (try to imagine my crackling waterfall hanging from a parachute LOL) I have quite a few steps to go before accomplishing that Edited May 21, 2022 by Uarbor

[Uarbor]

Well I just launched one with a dummy header. It seemed rather underpowered I'm starting to think I got my charcoal mixed up. That's what I get for labeling the lids rather than the containers LOL I just got some good news though my sister told me the power company cut down the rest of that willow tree that made the nice powder. So by next year I'll have an endless supply of Willow