Help Needed On Rockets

[JS92]

Hey all, um, bonfire night (5th Nov.) is coming soon, and I need to get my ball mill and mill some BP etc. But I need to make some rockets fast time! So if I dont have any bentonite clay ( I could get some, but...£) what could I use? also, what do I need to do to make a header that will report a loud bang! needs to be something to make people go "wow, you made that?" kind of reaction please

[mike_au]

If you can find two of those £'s, go grab some cheap cat litter. It's almost pure bentonite although it is somewhat coarse (and my attempt at milling it made a horrible mess) it will do the trick.

 

If you have a screen (or a kitchen sieve) run the clay through it, use the finer stuff for the nozzle end and the course stuff for the other end (I'm assuming you don't have tooling and will have to drill the nozzle, the finer clay makes it less likely to crumble).

[parkerthepyro]

Your going to want to spend the extra money to get your hands on bentonite clay. To get VERY cheap clay just buy a cheap coffee/spice grinder as well as a 10 lb bag of kitty litter. (I spent 2$USD) Run a handful of litter in the mill for 30 seconds. Once that is done you've just made yourself some nozzle mix

[Mumbles]

You're also no where near ready to be making salutes.

 

If you try to go too fast you're going to without a doubt hurt yourself or worse some others.

 

Seeing as how you have about 2 weeks, and haven't made a single batch of black powder, I think you are biting off more than you can chew.

[optimus]

You're also no where near ready to be making salutes.

 

If you try to go too fast you're going to without a doubt hurt yourself or worse some others.

 

Seeing as how you have about 2 weeks, and haven't made a single batch of black powder, I think you are biting off more than you can chew.

 

My sentiments exactly. Don't want to be a party-pooper here, but given the timescale and your lack of experience, I would suggest that doing a display of homemade rockets with an audience would be a pretty bad idea. The last thing amateur pyro in the UK needs right now is bad press, which setting off insufficiently-tested stuff infront of an audience could well lead to.

[Richtee]

My sentiments exactly. Don't want to be a party-pooper here, but given the timescale and your lack of experience, I would suggest that doing a display of homemade rockets with an audience would be a pretty bad idea. The last thing amateur pyro in the UK needs right now is bad press, which setting off insufficiently-tested stuff infront of an audience could well lead to.

 

Plan on NEXT year's! I'm working on my July Fourth stuff as well as a bit for New Year's now :{) Be safe, and build from the ground up. A good foundation is imperative to a sucessful endeavour! <Added "U" for the Brit spelling LOL!>

[JS92]

^ lol thanks for spelling correctly our way

 

And yeh I suppose guys...but :/ I will have a ball mill by the end of the week, so Ill be able to then have about 2 weeks of testing etc. so ill just get the rockets sorted, then might just do some firecrackers etc....and see from then on....but someone mentioned about the fact that milling kitty litter is not good, as it makes a real mess...is it needed, milling it? cus ive seen youtube vids of people just plugging ends up with kitty litter straight out of bag.

 

Anyway thanks.

[Mumbles]

Have fun with that. A lot of people can't get rockets to really work with even a few months of testing, much less two weeks. We of course wish you the best, and will help you out to the best of our abilities, but I wouldn't be making promises of functional devices before you've actually seen them work.

 

Be sure you have a wide open test area too, as you'll probably blow up more than one in getting them dialed in.

[oskarchem]

I would tell you to make some shells, they're "easier" to make that rockets.

 

It took me probably like 2 months of frustration to get a rocket off the ground, (maybe it's because I don't have tooling...) and I'm still having some problems to get small payloads on rockets into the sky.

[JS92]

I would tell you to make some shells, they're "easier" to make that rockets.

 

It took me probably like 2 months of frustration to get a rocket off the ground, (maybe it's because I don't have tooling...) and I'm still having some problems to get small payloads on rockets into the sky.

 

Hmm could do, but I havent got a mortar tube, and they are expensive, also I will need to get some pretty decent lift for it too....and with this being my first batch soon, im not so sure that the quality and productivity of lift will be achieved, but what the heck, ill give it ago

 

Thanks for the good luck people

[Miech]

When using a non critical design end burner not much can go wrong when you are using 3/4" electronics tubing (PVC stuff) and a proper ramming technique. Just take a 4" piece of it, and ram 5/8" to 3/4" of fine kitty litter in it with a metal rammer and a mallet. Ram it so hard the tube just expands a bit, it takes a bit of practice to find the sweet spot between breaking the tube and not ramming it hard enough. Then put a 1" to 1,5" layer of meal powder in the tube and ram it really hard to compact it. Repeat previous step until your propellant is about 1/2" to 1" from the upper end of the tube. Then ram an end plug of about 1/4" to 1/2" thick, using kitty litter. Now drill a hole into the nozzle, starting with a 6 mm drill, and drill about 5 mm into the propellant. Do a static test with it, if it doesn't cato, make a smaller nozzle the next time. If it does cato however, you should ram the propellant harder. If you finally find the minimum nozzle size that doesn't give a cato, make several (like 5 or so) with the same specifications, and test them until you are absolutely sure they are reliable.

 

For a report I would recommend you to use a small amount of pulverone or 7FA black powder. Using flash would be a very stupid idea when you have so little experience. An optimized rocket of above mentioned way of production should be able to easily carry 10 grams of black powder in a sufficient strong casing to make a nice report. DO NOT put reports on unstabilized or unreliable rockets, this would be plain stupidity.

 

These are several propellant compositions I use on a frequent base, mentioned in order from [edit:] high to low tolerance for non constant manufacture:

 

#1

60 KNO3

30 Charcoal

10 Sulfur

Note: This one is better suited for core burning design, it might not even get your rocket off the ground in an end burner.

 

#2

72 KNO3

24 Charcoal

04 Sulfur

 

#3

70 KNO3

30 Charcoal

 

#4

75 KNO3

17 Charcoal

08 Sulfur

 

For your own safety, do a hell load of testing at a safe remote area before even attempting to shoot a rocket in front of an audience. I think composition #2 is the best to start with, because it is quite forgiving yet sufficiently powerful. Wetting the composition with 10% of water by mass, and granulating it through a 30 mesh screen and letting it dry helps to keep down dust when ramming.

Edited October 20, 2008 by Miech

[JS92]

When using a non critical design end burner not much can go wrong when you are using 3/4" electronics tubing (PVC stuff) and a proper ramming technique. Just take a 4" piece of it, and ram 5/8" to 3/4" of fine kitty litter in it with a metal rammer and a mallet. Ram it so hard the tube just expands a bit, it takes a bit of practice to find the sweet spot between breaking the tube and not ramming it hard enough. Then put a 1" to 1,5" layer of meal powder in the tube and ram it really hard to compact it. Repeat previous step until your propellant is about 1/2" to 1" from the upper end of the tube. Then ram an end plug of about 1/4" to 1/2" thick, using kitty litter. Now drill a hole into the nozzle, starting with a 6 mm drill, and drill about 5 mm into the propellant. Do a static test with it, if it doesn't cato, make a smaller nozzle the next time. If it does cato however, you should ram the propellant harder. If you finally find the minimum nozzle size that doesn't give a cato, make several (like 5 or so) with the same specifications, and test them until you are absolutely sure they are reliable.

 

For a report I would recommend you to use a small amount of pulverone or 7FA black powder. Using flash would be a very stupid idea when you have so little experience. An optimized rocket of above mentioned way of production should be able to easily carry 10 grams of black powder in a sufficient strong casing to make a nice report. DO NOT put reports on unstabilized or unreliable rockets, this would be plain stupidity.

 

These are several propellant compositions I use on a frequent base, mentioned in order from [edit:] high to low tolerance for non constant manufacture:

 

#1

60 KNO3

30 Charcoal

10 Sulfur

Note: This one is better suited for core burning design, it might not even get your rocket off the ground in an end burner.

 

#2

72 KNO3

24 Charcoal

04 Sulfur

 

#3

70 KNO3

30 Charcoal

 

#4

75 KNO3

17 Charcoal

08 Sulfur

 

For your own safety, do a hell load of testing at a safe remote area before even attempting to shoot a rocket in front of an audience. I think composition #2 is the best to start with, because it is quite forgiving yet sufficiently powerful. Wetting the composition with 10% of water by mass, and granulating it through a 30 mesh screen and letting it dry helps to keep down dust when ramming.

 

Thank you very much dude for that help!!!

 

Er, what would be the best composition for an end burner?

 

Thanks again!

[Miech]

You don't have to quote the whole post you are replying to, people don't like scrolling too much .

 

I would recommend to start with #2 or #4, but plain 75/15/10 meal works good too. Composition #3 is very dusty when sufficiently ball milled, and is therefore hard to ram consistently. My first attempt to make a rocket was with #2, and apart from a weak thrust it did work sort of. It flew 20 meters high, which isn't bad for a 6 mm nozzle and no core at all. #2 is very tolerant to nozzle and core size, so it could prevent you getting too much cato's.

 

Before I forget, balance your rockets out before sending them into the air. They should stay upright when you put the nozzle on your finger tip. The center of gravity should always be below the nozzle for safety reasons. This prevents your rocket from going anywhere from up.

[Mumbles]

On this topic, I'd really suggest using cardboard or paper tubes if you can. There is a whole list of things that people don't like about PVC, namely that in event of a cato it will shatter and potentially produce shrapnel.

[FrankRizzo]

Totally off-topic here, but "plox"...are you serious? I can understand "plz" or even "pls", but "plox" is a mockery of language.

 

Sorry, but this new-speak crap really gets on my nerves.

[Miech]

On this topic, I'd really suggest using cardboard or paper tubes if you can. There is a whole list of things that people don't like about PVC, namely that in event of a cato it will shatter and potentially produce shrapnel.

Cardboard tubes are way more likely to give a cato than PVC ones. In a PVC tube the composition can slide a bit during ramming, giving a more consistent and higher average grain density using less increcements. I agree that PVC has a load of disadvantages, that's why rockets are the one and only thing I use them for in pyrotechnics. Just be sure to use the yellow kind of tubing, the grey sort is more brittle and shatters. The yellow stuff is softer and usually stays one piece when the rocket is cato-ing.

[Mumbles]

I haven't either, and personally find it rather intriguing. Even if it is true, it doesn't mean it should be attempted by someone who has never made a rocket before. If you have the proceedure down, and understanding of rockets, fine experiment away. When one has never made a rocket before, I really cannot with a sound mind recomend the use of PVC. Material factors aside, you are far more likely to CATO a rocket when you are getting started.

 

I tried to look up some data to try to give some idea one way or another, but came up more or less fruitless. I found one site that gave minimum burst pressures for PVC pipes. It gave a value of around 1500 PSI for 3/4" schedule 40 PVC, and 2200 PSI for schedule 80. This seems awfully low to me. It's not confirmed, but I've heard of some of the good paper tubes having burst strengths of over 10,000 PSI. Then again when I calculated some stuff, I came back with internal pressures between 300 and 600 PSI to generate normal whistle rocket type of thrusts, which will be on the high side of things. One crack in the grain is all that it takes, which is much more likely with hand ramming.

[XanatoisJulius]

Hello everyone!

 

I don't mean to be a ''forum-whore'' here, but I have a somewhat related question (dealing with rockets, propulsion, and lift, etc.).

 

Simply put, I was wondering if anyone had a general idea on the average (typical-constant) thrust of a small, standard rocket, something like a bottle rocket? I am constructing a small-scale replica of a Hwacha, but I need to know if something like a bottle rocket will do the job. My intended ''arrows'' for this scale model are going to be replaced by standard broadhead blowgun darts, weighing approximately 1.6 grams per dart. They will need to travel (hopefully somewhat accurately) a peak distance of about 50 feet (and therein lies the problem).

 

Any suggestions/ideas/comments?

Edited October 23, 2008 by XanatoisJulius

[oskarchem]

If you can, get a digital scale and a camera.

 

Tape your rocket to the scale, switch it on, get the camera going and light the rocket, let it finish burning, look at the film and you'll be able to see how much thrust you're going to get.

[Richtee]

If you can, get a digital scale and a camera.

 

Tape your rocket to the scale, switch it on, get the camera going and light the rocket, let it finish burning, look at the film and you'll be able to see how much thrust you're going to get.

 

 

And pray <or not...might be a jinx> that it don't CATO spectacularly ;{)

[oskarchem]

Yeah, but he was talking about a commercial bottle rocket, and in the very rare cases where it does CATO, it will do no damage to the scale.

[Richtee]

Yeah, but he was talking about a commercial bottle rocket, and in the very rare cases where it does CATO, it will do no damage to the scale.

 

Ahhh... my bad. I could just see a 8 Oz whistler going south on that puppy... "And all the king's horses and all the King's men..."

[CrazyAngel]

Am... sorry for flood, but I need first post

[Mumbles]

I hope your subsequent posts are more useful.

[thebobman]

I'm sorry, but all I heard was "bottle rocket" and "broadhead blowgun darts". What would happen if the bottle rocket CATO'ed and the broadhead was blown off? Could'nt that injure someone, a spectator?

If I'm totally off the mark, please, say so. Sounds interesting.

 

BTW, hello everyone.