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ground spinner fail


insutama

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I have been trying to get a ground spinner to work but basically all that happens is a jet flame shoots out of the hole i drilled in the side of the tube and it doesnt spin. This is how i made it

 

i pluged a 1/4" tube with bentonite then rammed in increments of black powder the same way i would do a rocket then at the end of the tube i rammed a other plug so it goes plug black powder plug then i drilled a 1.8mm hole in the side of the tube on a angle and stuck a fuse it in it.

 

when i light it the tube moves so that the hole i drilled is facing up and then the flames shoot out the hole face up and does not spin can anyone see where im going wrong ?

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From your description, not really. If your hole is at an angle, it should cause it to try and rotate, but it seams your force is to low, so when it starts pushing "down" in to the ground, it stops, and is stuck.

I'm assuming your "at an angel" is the same approach one uses for a stinger.

I used to make ground spinners, but i made them cored straight through, and put a hole at both ends, no angle, only causing them to rotate (or blow up) around the center of the device, and not spin around it's axle.I think this was when i started to use tubes that fit over one and other snuggly, so that i could put a solid cap on both ends, while still having the core go straight through all the composition.

 

I had to experiment a little with roman candle compositions, to tune it back, or they would over-pressurize, and CATO. Somewhat entertaining that to, i admit, but not the intended effect. It's to long ago, and atleast one visit from the cops since, so i might not have my notes left. I'll check in the next few days, i have to head out to my lot anyway.

B!

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I have been trying to get a ground spinner to work but basically all that happens is a jet flame shoots out of the hole i drilled in the side of the tube and it doesnt spin. This is how i made it

 

i pluged a 1/4" tube with bentonite then rammed in increments of black powder the same way i would do a rocket then at the end of the tube i rammed a other plug so it goes plug black powder plug then i drilled a 1.8mm hole in the side of the tube on a angle and stuck a fuse it in it.

 

when i light it the tube moves so that the hole i drilled is facing up and then the flames shoot out the hole face up and does not spin can anyone see where im going wrong ?

 

Your fuel is not burning quick enough.

 

It seems like a reasonable prospect to be able to enjoy a positive reaction from your well thought out experiments. Unfortunately, it doesn't always happen that way, but we learn. In this case, your case, I believe that the fuel is not burning quick enough.

 

Remember that a rocket motor is a "controlled explosion", which is essentially what your "spinner" is, ie. a "sideways rocket". The fun part is finding out the point between not enough and cato, which is what amateur rocketry is about.

 

Stixenfreud says "Lay back on the pyro-couch, and start at the beginning". Ask if, and/or why, the fuel is not burning fast enough.

 

Cheers.

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Thanks for the reply the BP i use should be hot enough its my same fuel i use for my rockets and it works great for them its regualr 75 15 10 ball milled for 4 hours.

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If you'd like to start with spinning fireworks, you may want to look into wheels as a starting point. They're easier to get working in my opinion. There is also less of a chance of them flying off and causing issues as well.

 

As of the last time I checked, you're making bottle rocket sized things. These will accept basically any fuel on earth, so it's not really a good test of quality. If you've gone bigger, are you making core burning rockets? If so, then there is no way your fuel is hot enough. Good quality 75:15:10 would likely blow up even smaller core burners every time.

 

If everything else is fine, using two vent holes can sometime help with spinning. They should be 180 degrees from each other, and on opposite ends. If you really want to learn more about these sorts of things, the Westech Firework Manual is an excellent resource.

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Ya I am basically sticking with smaller stuff for now I make bottle rockets and 1/2" core burners I'm using pine charcoal with my bp I thought it burned pretty quick but I have never had a cato with any of my coreburners so maybe it's not as fast as I thought I guess the only way to speed it up would be to use a softer wood like alder or red cedar because I mill it for 4 hrs until it all clumps into a ball and I live in a semi desert and store all my chemicals in a airtight container with silca packs and calcium chloride so maybe I need to try different charcoal
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Well today i finally tried one of my 1/2" core burner rockets with my black powder and its the first one i have had a chance to light off since i got my tooling from caleb and sure enough it was a cato so i guess my black powder is hot lol how do i avoid this ? do i have to use slower BP ?

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Well today i finally tried one of my 1/2" core burner rockets with my black powder and its the first one i have had a chance to light off since i got my tooling from caleb and sure enough it was a cato so i guess my black powder is hot lol how do i avoid this ? do i have to use slower BP ?

 

Are your bottle rockets nozzled or nozzle-less? I tried to look at some of your previous posts but couldn't find what I was looking for. So I'm assuming "nozzled" hence the cato.

 

It's all well and good that you did that test. Unfortunately it doesn't really prove anything. The reason I say this is that we don't know how much you are compressing the fuel when ramming and therefore how fast the fuel is burning.

 

I look at it this way - a small 1/4 inch tube (end burner) can be compressed much easier than and 1/2 inch core burner. The more compressed, the slower it burns and therefore inversely, the less compressed the faster it will burn, resulting in possible cato. If you've ever made a ground salute with bp, you would have witnessed this.

 

Nevertheless, let's agree that your fuel is indeed "hot". So why didn't it spin? The 1.8mm diam. hole, drilled in the side of a 6mm tube reveals something. Too large of a "nozzle" compared to the rate the fuel is burning. A 1mm hole (If it could be lit) should produce some movement.

 

If you packed the spinner looser then it may well have cato'd, or spun, and spun, so fast you may well have almost pissed your pants laughing about it :).

 

So, I've come full circle - Like I said:

 

Stixenfreud says "Lay back on the pyro-couch, and start at the beginning". Ask if, and/or why, the fuel is not burning fast enough.

 

Cheers.

Edited by stix
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thanks for the reply stix, Yes your right it was a nozzled 1/2" core burner that cato so maybe i added too much fuel increments in between ramming before this i had made a 1/2" end burner with nozzle and a 1/4" core burner nozzelless and i have never had a cato before so it must have to do with the nozzle. I just got this 1/2" coreburner tooling so i haven't really had much time to play around with it maybe next time ill try making it nozzle-less and adding less bp in between increments. also i noticed when i was ramming it that the tube fit quite loose on the spindle and when i was done ramming it my rammers had bp caked to the sides because of the loose fit in the tube could this be what caused it to cato ?

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. . . before this i had made a 1/2" end burner with nozzle and a 1/4" core burner nozzelless and i have never had a cato before so it must have to do with the nozzle . . .

 

I think you've said it right there yourself: Nozzles for end burners, no nozzle for core burners (with bp fuel). I've only ever made end burner bp motors, but not for a long time - I make sugar rockets (semi-bates grains).

 

I couldn't even imagine wanting to make a nozzled core burner with bp - well, I suppose I could imagine it, and that image would be boom booms!! Unless you have really slow fuel. As you suggested, making a nozzle-less version with smaller increments sounds like a good plan.

 

Loose fitting tooling could also cause a problem, but more likely it's the nozzle causing cato. I don't know much about that sort of tooling but there's lots of folk on this forum that do.

 

Hope you get it sorted.

 

Cheers.

Edited by stix
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Thanks for the reply the BP i use should be hot enough its my same fuel i use for my rockets and it works great for them its regualr 75 15 10 ball milled for 4 hours.

Try ball milling milling some BP for 4 hours for your rockets, and other for 8 hours to break shells and make those ground spinners.

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Try ball milling milling some BP for 4 hours for your rockets, and other for 8 hours to break shells and make those ground spinners.

when milling black powder any more than 4 hrs in my mill it doesnt change the performance its as milled as its going to get unlike when im milling mg it takes days

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