Nozzle less rockets

[Jimjimboom]

So im pretty green to this hobby but i have been getting alot of catos, like more than 50% i found that the same fuel works well for stinger missile stlye rockets, i assume the fuel is too hot, and that is why it cato's on a nozzeld end burner and a core burner? I have made a few last night with sorbitol and kno3 +2% FeO2 i havent launched them yet but im interested to know as much as i can, trying to get good reliable rockets befor i start putting anything on top, as the 1 heading i have tried worked well, unfortunatly the rocket didnt and it sent it flying up from the cato about 50m then it fell (all the way to the ground) and the heading went bang! I was quite confident that the rocket was going to work, hence the heading! No one was hurt i try to follow strict safty and that is why i want to make sure it dont happen again! If i can get good reliable rockets i dont care if they are nozzeless or not but need to be reliable!

[justvisiting]

I've had good luck with reliability by carefully applying a thin wax coating to my rocket tubes, top to bottom. This simple hack is not a replacement for skill, but it helps keep folks from getting too discouraged as they learn the finer points of rocket-making.

[Bigmark]

Jimjimboom the most reliable rocket I've built was a nozzles rocket. Fuel was 75/15/10 milled. Then added 1% to 2% water and either hand rammed our pressed both worked. You can fire them as soon as you make them. The water does nothing to the power of the fuel that you will notice besides make it easier to work with. And consolidate better.

[Bourbon]

Does the water of 1-2% apply to all BP motors regardless of construction? Can they all be flown straight away, no wait time?

[Bigmark]

Bourbon I would like to say so but can't. It works on my traditional nozzless Black powder motors 75/15/10 fuel. I have not tried it on a nozzled motor so i can't say how it would work all you can do is try it out.

[Mumbles]

Justvisiting would be the guy to ask, but I think it should work fine on nozzled motors as well. You'll want to use a different base formula than 75/15/10 of course for them.

[justvisiting]

Does the water of 1-2% apply to all BP motors regardless of construction? Can they all be flown straight away, no wait time?

 

Bourbon, I described my results testing a bunch of 3lb rockets made using water, but I can't find where I posted! Anyway, I used 2 1/2% water for the nozzleless 75-15-10 rockets and 3% for the nozzled 60-30-10 rockets. They were stored for a few weeks. I used waxed tubes. When I pressed motors with damp propellant in unwaxed tubes, I got tube compression. With waxed tubes, the consolidation was perfect. The rockets can be flown right away. It was very interesting to me that after 3 or 4 weeks of storage, less than a gram of water was lost from each motor. Black powder has a tendency to absorb moisture if it is perfectly dry. It seems that deliberately adding the water stabilized the propellant so that it would neither absorb or shed water.

 

One thing I like to do is to 'pre-densify' my rocket propellant by making the dampened propellant into soft 'pucks', which I break down by forcing through a heavy screen. The propellant can be stored for over a month in a tightly sealed container, and used as needed. Once I tried water in my BP rockets, I was hooked. I'll never go back to dry pressing again.

[Bourbon]

Thanks for the input guys. I'll definitely try this in the near (real near) future. Just for clarity, this is 3% water right before pressing or ramming? Not thee initial wetting just before forming pucks or granulating right? I'll be using nozzle cored 60/30/10. To start anyway.

[justvisiting]

Yes, 3% water added, with no (intentional) drying. I screen the dampened mix a couple of times, and hand mix. Then I let it rest for a little while, covered. I make a puck, and immediately granulate it through (let's say) 10 mesh. If it is too soft and crumbles back to dust, I press the next one a bit harder. If it's too hard, I back off. Then I process the batch. The dampened, crumbled propellant is a pleasure to use. There's no dust, and each increment has less volume than loosely granulated propellant would have. So, the tube is less likely to pull down when pressing. For me, waxing the tube is important too. I don't worry about wax in the nozzle area, since I apply it very thinly. I don't get blowouts or blowthroughs. Using water and wax gives me reliability in my rockets, and I don't mind a little extra work to achieve it. I would highly recommend dampened propellant for hand-ramming if dry propellant won't work.

[Bourbon]

Yes, 3% water added, with no (intentional) drying. I screen the dampened mix a couple of times, and hand mix. Then I let it rest for a little while, covered. I make a puck, and immediately granulate it through (let's say) 10 mesh. If it is too soft and crumbles back to dust, I press the next one a bit harder. If it's too hard, I back off. Then I process the batch. The dampened, crumbled propellant is a pleasure to use. There's no dust, and each increment has less volume than loosely granulated propellant would have. So, the tube is less likely to pull down when pressing. For me, waxing the tube is important too. I don't worry about wax in the nozzle area, since I apply it very thinly. I don't get blowouts or blowthroughs. Using water and wax gives me reliability in my rockets, and I don't mind a little extra work to achieve it. I would highly recommend dampened propellant for hand-ramming if dry propellant won't work.

Right on. Thanks!

[royster]

Can bp be too fast for nozzleless rockets? I tried 2 4oz nozzleless darts last night with the same fuel i use for my endburners and they shot up so fast it made me wonder if i should use slower fuel. I hand rammed them with 4oz universal tooling from Woodysrocks.

 

They were very cool shooting up so fast but i have a great fear of cored rockets blowing up, that happened once next to me and my ear was ringing for 15 minutes.

 

I would like to gain confidence in my rockets and not plug my ears all the time 😆

[Bourbon]

WOOOOOSH. That sucker was gone!

Edited August 30, 2020 by Bourbon

[justvisiting]

Universal tooling makes a nozzleless rocket with about half the thrust of standard BP tooling. With good, hot BP, I've used that tooling to lift 3" ball shells to a decent display height. Testing your rockets with a dummy shell will give an idea what yours can do.

 

I've made BP that was too fast for ideal performance in a nozzleless rocket, but it's not likely to happen by accident. With super hot milled ERC BP (ERC also pre-milled), I was able to make a rocket with such a short flight time that the drag caused a reduction in projected height, according to Acme. The same propellant with a little less milling actually gave a rocket that was projected to go higher, all other things being equal. I was quite surprised. Apparently, drag increases exponentially with high speeds.

[dlking59]

@ royster that was fast

[royster]

I launched 5 more, amazingly all of them took off, my main concern was catos. I think if i use good tubes and ram them properly these could be a quick and reliable 4ozrs.

 

2 of them had a 30gram header and they lifted to a good height in the direction they were aimed. I think they can lift a little more and still be spicy.

 

The weight really balanced them in a good way.

[dangerousamateur]

 

One thing I like to do is to 'pre-densify' my rocket propellant by making the dampened propellant into soft 'pucks', which I break down by forcing through a heavy screen

 

Justvisiting, how hard do you press these "pucks"? All at once, like a comet?

[justvisiting]

I press them to a density of about 1.3, if that helps. I crumble them through a 10 mesh screen with heavy wires, which is well supported. I try one, and adjust pressing force as necessary.

[dangerousamateur]

Thanks. Well I rather measured pressing forces, never the resulting densities.

Less work

 

Roughly how much PSI did you use, just to get an impression?

Can one get away without an hydraulic press on reasonable sized pucks?

Edited September 2, 2020 by dangerousamateur

[royster]

Tried to edit my previous reply but wasn't able to find the edit button. Anyhow im up 80 gram payload with those 4oz nozzleless universal tooling rocket, and i think Thats the max, it went up but not to a spectacular height. I probably won't go over 70 gram in the future.

 

What amazing is i haven't had 1 cato with over 20 rockets. I think its the lack of nozzle, the consistency of the nept tubes and my new mullet.

 

Can anyone recommend good 1lb tooling for nozzleless bp rockets?

[justvisiting]

I like Woody's because their tooling and service are both good. Personally, I wouldn't buy nozzleless tooling. I'd buy standard BP tooling. Nozzleless tooling has a flat-ended first rammer, so it's not the right shape for making a nozzle, if you wanted to use one. With standard BP tooling, it doesn't matter, and you can do both.

[Bensmith]

You can use just about any core burn tooling to make a nozzleless rocket. In fact, before I developed nozzleless specific tooling, I used my Super BP set to make all sorts of whistle, strobe and nozzleless BP motors. Since I've gotten away from building BP motors with a clay nozzle I use the nozzleless specific set exclusively anymore. It's a bit more user friendly (since the geometry for the nozzle isn't on the spindle or #1 rammer) and it has a spindle that is a bit taller and fatter than the BP set. This produces a core with more surface area to produce a bit more power than the BP setup. It's really apparent when building strobe rockets.

[justvisiting]

I'd like to see (and hear) a video of a strobe rocket made with that super BP tooling.

 

The fatter spindle gives more surface area and initial thrust, yes. But there's less propellant to provide the thrust. The slight length increase would probably offset that for a net gain of... ?

[Bensmith]

Here ya go (my 14 y.o. built this one

 

https://m.youtube.com/watch?v=8QlybUIpI50

 

Really, any core burn spindle will be fine. I have noticed the nozzle less specific set allows me to pack more strobe around the spindle. That creates a better popping in my opinion. But, they all work.

 

Theres a few more videos here (the cato always makes me laugh)

 

https://m.youtube.com/channel/UC0pogucUHyqf7WZjepZM3fA