Black Powder Rockets

[BPinthemorning]

I'm using them because I have tons, and they are not to big to make my parents mad, but large enough that I don't get bored.

[lnstantkarma]

Have you looked at dowel rods? Those tubes probably won't be strong enough for ramming with a mallet even. It's going to be hard to make a good nozzle too, you could go nozzle less like a bottle rocket they seem about the same size.

[BPinthemorning]

Whatever. I made some good tooling, and they are working perfectly. I don't ram, I press.

[ActionTekJackson]

Whatever. I made some good tooling, and they are working perfectly. I don't ram, I press.

Eh, sweet, sorry for the skepticism, was just trying to help. No one likes wasted chems.

[BPinthemorning]

Ya, I understand. My tight budget makes it all to easy... Ill load some vids.

[moonshot]

Hey BP. You can always reinforce those tubes by rolling a few turns of kraft or paper bag weted out with white glue around them. If the ID is 3/8 to 1/2" go with a 4" length that's what I've found optimum for these smaller motors. 3mm core diameter with a core length of 2 or 2 1/4". Here is a shot of my latest batch of rockets.

http://i107.photobucket.com/albums/m314/di.../Picture177.jpg

Use a comp mix of 60:30:10 propellant to start and speed it up if necessary.

[Apollofrost]

Hmm... yesterday was interesting.

 

On a whim I made a 1" diameter core burner. It went up a good fifty feet then arced back to the ground. It apparently burned through the side of the tube and when it hit the ground the stick broke because it had been partially burned. From this Ive learned that the mix could be burning through the tubes and it could be burning off the sticks.

 

Next time I'll have to try a wider nozzle.

 

But on a bright note my BP is hot enough for a 1" end burner, so if I'm not mistaken that means it's at least decent.

[FrankRizzo]

Apollo, What type of tooling are you using? Is there a cone-shape to the inner portion of the nozzle, or is it flat?

[Apollofrost]

It's flat as can be. Hmm... I think I see what you're getting at.

 

My tooling consists of dowels cut to size and I do my nozzles/cores with a drill bit turned by hand.

 

For a while I experimented with a brass screw embedded in a piece of wood for use as a spindle and it worked decently enough. Just twist off the rocket when you're done. But this one was not made that way.

[Yankie]

I have made a few 5cm by 1cm cored rockets and used both 5 hour pine and 6 hour willow, the pine was fairly slow and limited power, yet the willow rocket (which I expected a CATO) was unbeleivably fast and powerful. maybe my nozzle are too big. the nozzles are 3-4mm. what should I do to acheive a powerful pine bp rocket?

[pa_pyro]

Moonshot, how long on average(if at all) do you mill your 60:30:10 mix? I can't seem to get the right mix, meal burns to slowly, and my fast BP usually CATO's. Also, I have been using 3/8" tooling with 1-1/2" core length, and the casing are just above 2" in length, should I use a longer case length?(4" like you use?)

[moonshot]

Hey pa_pyro. I actually use a 71:24:5 mix for my propellant. I mix 200 gram batches at a time so 142 grams KNO3, 48 grams charcoal and 10 grams sulfur. I mill this in a cheap loretone rock tumbler with brass media for 8-10 hours. The comp will be air float out of the mill so I put it in a ziplock bag and add small amounts of 70% H20 30% alcohol solution and knead it until it just sticks together into a big lump. Don't get it too wet. Screen the lump through a fine spaghetti strainer and you get 200 grams of grained propellant good for dozens of smaller rocket motors.I like the 4" long tube for 3/8 and 1/2" ID motors. My tooling sets the lower edge of the nozzle 1/8" up into the tube and the kitty litter nozzle is like 3/8" long. That takes up 1/2" of your tube already. If your spindle is 1 1/2" long then your core in the propellant will be 1" long. That leaves 2 1/2" above the spindle to ram more comp and the end plug which is another 3/8". I find this gives the rocket a fast take off with long burn time to achieve maximum height before the break. Try the longer tube with your tooling and see what happens. Hope this helps.

[Swede]

Question for BP rocket gurus...

 

I've made quite a few 4 ounce BP rockets, all core burners. My tubes are NOT parallel, they are spiral, but incredibly strong, as far as I can tell. I know they should be parallel tubes, and that may be what my problem is, which I will now describe.

 

For fuel, I use milled BP straight from the jar, with 3% red gum milled in. I then dampen with acetone, just enough to barely moisten the grains, maybe 5% by weight. The rockets are pressed with either a hydraulic press, or mallet.

 

Over 50% of the time, I end up with a CATO due to the overly-hot 75:15:10 BP I am using. When I add additional charcoal, up to 15%, the mix cools, and the flights are successful, but nowhere near as high or as strong as those using the hot mix, that do not CATO.

 

With the idea being maximum power and ultimately max payload, it seems these are my options.

 

1) Cool the BP down and live with reduced performance

2) Find some parallel tubes of greater strength

3) Use the hot BP and make an end burner

 

Thoughts? What direction would you guys go? I want to be able to produce a rocket motor that I can completely rely upon.

[oskarchem]

I would say 3. But you could allways cool down your hot BP by adding let's say 10% C instead of 15%

[psyco_1322]

Thing is, if your bp core burners are too hot, they will blow no matter the tube. There is a major difference between pressing(hydrolic) the motors and ramming them(hammer). Pressing makes a lot more stable motor with added fuel consumtion due to high densities. Im guessing the motors that didnt cato are the pressed ones, that or its your fusing. Ive noticed with some of my bigger nozzle less rockets that if the fuse it pointed up towards the core they tend to cato, but lighting the very edge made them fly.

 

But usually straight 75:15:10 milled is too hot for even small core burners. Then you go and granulate is after wetting, making it even hotter. That would be great for lifting shells. I wuold suggest you try not milling it. Just use straight green powder, mixed by hand. This will still be hot just not as much. Then if its still to hot, rather than slowing it with more charcoal, try the addition of some mineral oil. A few percent will slow it down. If you get up to the 5-6% range the motors will start to chuff and you'll get a strobing bp rocket, but at the lose of quite a bit of power. It also helps with lowering dust and the compacting of fuel. You could use vaseline or wax but that involves steps beyond weighing and screening.

 

Another idea for the bp you have made and are having problems with. Ram the motor will no nozzle, cored tooling will make nozzle less rockets just fine. It may not be as powerful but they do put out some power, surprissingly.

 

The end burner is not going to reach the max payload for the size of motor. It will carry a small payload a lot farther though. They will reach incredible hieghts compared to the cored ones.

[moonshot]

Hello Swede. I have found that the most critical dimension on these smaller motors is the core length when using hot BP. Reducing the core length by 3 to 5mm can be the difference between a CATO and a consistent motor. Also nozzle ID comes into play. Its easier to ream your nozzle with a drill bit to open it up than it is to hack some material off your spindle and hope that works. Instead I try different Mixtures of propellant to get the performance I want and will be happy with one that gets the rocket to a decent height. I don't use any binders or wet my propellant just ram it dry. I haven't tried mineral oil but read on United Nuclear site that they add a few drops of 10-40 motor oil to the comp before ramming. It's all a lot of trial and error so let us know what works for you.

[Swede]

Thanks guys, I need to let go of the "extreme performance desired" type of attitude and be happy if it safely flies with a payload. Sleeter's book has good info, but it is aimed at model rockets, where peak performance is everything. The attitude is infectious, and you start to think of a stick rocket as a NASA moon shot or something. It's just a simple firework!

 

After some thought, I think a good way to do something like this is to adulterate a standard, hot BP with more charcoal. Keep everything else the same... tooling, core length, nozzle, tube, etc, and by diluting the hot BP, ultimately you'll determine what sort of mix will work consistently. With notes taken, you'll then be able to have a standard "recipe" for future builds. Ex. "With THIS set of tooling, THOSE tubes, and XXX PSI on the press, use 68:22:10... works every time." Something like that!

[Aquarius]

Sweede, thats a good way to do it.

 

I have made quite a few drivers, using much from Sleeters book as well as other sources. I tried to maximize thrust and performance, getting some very nice results, but also some unintended CATO's.

So I fell back to a golden standard, maybe not the fastest rocket in the world, but it gets the job done reliably. And if I want to lift heavier/larger objects, I use a bigger and stronger driver.

 

I tried both 70:20:10 and 60:30:10 with and without 3 % Red Gum as binder.

Both works on smaller drivers, but blows the bigger ones, more because I roll my own tubes than anything else.

 

My next challenge will be ramming or pressing, as I am about to build a hydralic press from an old garbage comprimator.

[psyco_1322]

You can still go for the maximum output. Sometimes the max isnt always what you can get away with. There will be times when you make a rocket, light it and it takes off like a bat out of hell. Then you think wow I really hit the head of the nail with that one. Then you make up a few more and they all cato. Sometimes you get away with things being on the other side of the working line. I wouldnt sugesting dicing up your pro tooling if its not homemade. That may bite you in the end. But if its a homemade spindle you can always cut it down to a nub for someting like whistles if you dont like it.

 

Bigger motors require a way slower bp fuel than you can get away with in the little ones.

[moonshot]

Yeah swede I was hung up on the idea of optimum performance for a long time, until i got tired of seeing my rockets explode on the ground. Then I started milling slower propellant comps and seeing my rockets fly great. I have about 12 motors that I rammed with hot powder on a long spindle that I reamed the nozzles almost to the ID of the tube and they still CATO. Great for reports on a stick! My idea was always to figure out ways to build reliable display skyrockets using cheap, readily available materials like brown paper grocery bags for tubes and cardboard paper towel rollers and paper cone cups to build headers. Like you say these are not NASA rockets but it does take time and testing to build a reliable skyrocket. Hope to see some videos of your successful rockets in the future.

[ActionTekJackson]

I dunno... I'm still stuck on high performance... lol, even though only one of my rockets for the 4th was successfull. (and after so many successfull launches before then! Thats what I get for rushing...) I think if you take the extra time to make sure of the following you can get reliable high performance rockets.

 

1. tube strength (most of my catos prior had been due to tube strength, high performance BP rockets in my experience do not like spiral wound tubes very much. If thats all you have, use a strong tight fitting sleeve.)

 

2. Grain quality, A ROCK SOLID grain is a must. I've started examining my rockets (except for the ones for the 4th) grains by shining a red laser pointer down the core and checking for flaws in the way the light reflects off the core wall. Glassy shine is great, you may have some blemishes where the tip of the spindle rubs the core wall as you remove the motor from the tooling, this is generally ok.

 

3. Nozzle and endcap. my nozzle's are almost always the same as the ID 3/4" large and expensive I know... but they get the job done, even when I do get a cato it splits the middle of the tube 1/4" wall thickness parallel paper, and the plugs are still in place. Thats just bentonite.

 

4. For those like me who RAM, SMALL INCREMENTS! I RAM no more than a single standard plastic spoonfull. and I don't mean mounded, I mean the top of the powder is flush with the edges of the spoon bowl and flat all the way. Also consistensy in fuel increments.

[FREAKYDUTCHMEN]

Does someone know how much I can lift with a 2lb BP rocket?

[DIYMark]

How much thrust does it make?

[Mumbles]

I'd say you'd be safe with a 4" ball shell on a core burner, probably 3" ball shell on an end burner. This of course assumes a decent preforming rocket.

 

Mark, you will probably come to realize some people in this hobby are not fans of science, and thus wont give a shit about thrust. Trial and error is far more common method of determination than calculation or measurement.

[nickle]

I need some help! I have yet to get any of my end burners off the ground, they just sit there and would make wondeful fountains. My BP is the 75/15/10 standard mix, tubes are hand rolled 95mm long 9.5mm id with 2.7mm nozzle.

 

My BP is about as hot as it is going to get with the materials at hand. The only thing I can think to do would be to make a smaller nozzle but I am trying to avoid as many loud noises as possible to avoid attracting attention to myself. The neighbors are ok but I would still like to avoid attention.

 

Any help,other then moving, would be appreciated!