44 replies to this topic

[bonzoronnie]

Inoxia sell 1/2" ID tubes.

Indeed they do. Many thanks for that

I'll be sure to order some soon.

[spanner]

I happened across a free source of tubing, suitable to make small diameter rockets- hangar tubes!

These 2 ounce rockets are made from trouser hangars that have, you guessed it, tubes that form the bottom "leg" of the hangar. They are parallel-wound cardboard, 0.5"OD X 0.375"ID (13mm X 9.5mm), and ~16" (40cm) long. Wall thickness is 1/16". Thin, but I've had no burn-thru's.

Mine are fueled with either straight BP, straight KNSU, or a mixture of the two.

The KNSU is 60/40, melted, cooled, then powdered. I know this sounds wrong, but compared to just milling the two and mixing, without melting, the output is greatly increased. With a larger diameter case, the recommended method (a' la Nakka) would be to finesse the molten mixture into the case, thus forming the grain. This isn't an option, given the small diameter of these tubes.

The KNSU is used most often 2:1 with traditional ball milled 75-15-10 black powder.

At 95mm (3.75") long, and a ready to launch weight of ~20g, these little buggers really scoot!

Tooling was made by myself, from things like the hard rubber roller from a copier, bored out to accept the tube that forms the body. The grain is hand rammed to a density of ~1.55-1.6g/cc, when using KNSU/ BP fuel at a ratio of 2:1.

I use a core, ~2mm (3/32"), to within ~5mm (0.25") of the end of the grain, more if I'm using a header. The grain occupies all but ~5mm (0.25") of the case, and weighs ~9.5g. Length of the grain is ~85mm (3.35"), the unaccounted for 4mm (0.15") is taken up by the top "plug".

This plug is cut from a yardstick or paint stir stick with a plug cutter, on a drill press. These can be bought ready-made, also, or plaster of paris, epoxy, etc. will also work. Just needs to be secure, though.

Stabilization was first by stick, ~20% of the weight of the rocket, ~20in. long. Then, I started using three fins fashioned from sheet aluminum, .008" thick. The fins are made to the specs on the NASA model rocket site.

The nose cone is formed from soda can Al, epoxied in place.

The nozzle started out as a steel washer, 3/8"OD X 5/32"ID held in the case by a wooden plug with a hole in it of 1/8". This plug was epoxied in place. This actually works surprisingly well. Erosion was non existent. Later, I began using a nozzle fashioned from plaster of paris. It has convergence/ divergence angles formed into it, and is secured with J-B KWIK epoxy.

Nozzle erosion is pretty bad with plaster and with Durhams. Kitty litter doesn't work because of the way I make my nozzles, so until I have the proper tooling, I won't be using Bentonite .

Now, for my questions:

I would like to lift some "effects" with these rockets. I've done aerial salutes, so I have the delay and pass-fire schemes worked out. What I need (or do I?), is a shell with some micro stars, for instance. I already have the micro stars, but not the shell to deliver them. Scaling down traditional shells that go on large rockets, maybe? I'm hoping someone may have some input on this.

When referring to a rocket's size, ie "2 oz", "3lb", etc., what is this referring to?

And, I'm having trouble tracking these rockets. They are fast, and don't put out a lot of smoke. What can I add to the fuel that'll help? Remember, the grain is <10g, so what ever is used needs to be light/small percentage/concentrated. Maybe a smoke comp at the apogee? I could at least see how high it went.

Also, is there a practical way to estimate the altitude these things are attaining? I had thought about trying to time the difference in the flash of the report to the sound, but this is fraught with difficulties.

Lastly, what other sources of tubes have you found (other than pyro suppliers- I'm talking cheap or better yet, free)? I'm aware of hand rolling, and have done that successfully. But nothing's better than finding tubes that are ready made!

I realize that these little rockets might well be viewed as insignificant, especially compared to a 3 pounder or something. But though being laughable, they have been an educational tool that has allowed me to get "airborne", at very little cost or complexity. I hope the lessons learned will hold me in good stead as I scale up my rockets in size and output.

In the mean time, I have enough tubing to make another 200 rockets, in addition to the 50 or so that I've already launched. At a cost of ~ $0.15/each for the fuel, nozzle material, fuze and epoxy (everything else I had or cost nothing), the whole enterprise will have set me back about $37.50.

For the record, a post was entered at The Crucible about this, in case it sounded familiar.

Edited by spanner, 18 December 2006 - 07:01 PM.

[fishy1]

I happened across a free source of tubing, suitable to make small diameter rockets- hangar tubes!

These 2 ounce rockets are made from trouser hangars that have, you guessed it, tubes that form the bottom "leg" of the hangar. They are parallel-wound cardboard, 0.5"OD X 0.375"ID (13mm X 9.5mm), and ~16" (40cm) long. Wall thickness is 1/16". Thin, but I've had no burn-thru's.

Mine are fueled with either straight BP, straight KNSU, or a mixture of the two.

The KNSU is 60/40, melted, cooled, then powdered. I know this sounds wrong, but compared to just milling the two and mixing, without melting, the output is greatly increased. With a larger diameter case, the recommended method (a' la Nakka) would be to finesse the molten mixture into the case, thus forming the grain. This isn't an option, given the small diameter of these tubes.

The KNSU is used most often 2:1 with traditional ball milled 75-15-10 black powder.

At 95mm (3.75") long, and a ready to launch weight of ~20g, these little buggers really scoot!

Tooling was made by myself, from things like the hard rubber roller from a copier, bored out to accept the tube that forms the body. The grain is hand rammed to a density of ~1.55-1.6g/cc, when using KNSU/ BP fuel at a ratio of 2:1.

I use a core, ~2mm (3/32"), to within ~5mm (0.25") of the end of the grain, more if I'm using a header. The grain occupies all but ~5mm (0.25") of the case, and weighs ~9.5g. Length of the grain is ~85mm (3.35"), the unaccounted for 4mm (0.15") is taken up by the top "plug".

This plug is cut from a yardstick or paint stir stick with a plug cutter, on a drill press. These can be bought ready-made, also, or plaster of paris, epoxy, etc. will also work. Just needs to be secure, though.

Stabilization was first by stick, ~20% of the weight of the rocket, ~20in. long. Then, I started using three fins fashioned from sheet aluminum, .008" thick. The fins are made to the specs on the NASA model rocket site.

The nose cone is formed from soda can Al, epoxied in place.

The nozzle started out as a steel washer, 3/8"OD X 5/32"ID held in the case by a wooden plug with a hole in it of 1/8". This plug was epoxied in place. This actually works surprisingly well. Erosion was non existent. Later, I began using a nozzle fashioned from plaster of paris. It has convergence/ divergence angles formed into it, and is secured with J-B KWIK epoxy.

Nozzle erosion is pretty bad with plaster and with Durhams. Kitty litter doesn't work because of the way I make my nozzles, so until I have the proper tooling, I won't be using Bentonite .

Now, for my questions:

I would like to lift some "effects" with these rockets. I've done aerial salutes, so I have the delay and pass-fire schemes worked out. What I need (or do I?), is a shell with some micro stars, for instance. I already have the micro stars, but not the shell to deliver them. Scaling down traditional shells that go on large rockets, maybe? I'm hoping someone may have some input on this.

When referring to a rocket's size, ie "2 oz", "3lb", etc., what is this referring to?

And, I'm having trouble tracking these rockets. They are fast, and don't put out a lot of smoke. What can I add to the fuel that'll help? Remember, the grain is <10g, so what ever is used needs to be light/small percentage/concentrated. Maybe a smoke comp at the apogee? I could at least see how high it went.

Also, is there a practical way to estimate the altitude these things are attaining? I had thought about trying to time the difference in the flash of the report to the sound, but this is fraught with difficulties.

Lastly, what other sources of tubes have you found (other than pyro suppliers- I'm talking cheap or better yet, free)? I'm aware of hand rolling, and have done that successfully. But nothing's better than finding tubes that are ready made!

I realize that these little rockets might well be viewed as insignificant, especially compared to a 3 pounder or something. But though being laughable, they have been an educational tool that has allowed me to get "airborne", at very little cost or complexity. I hope the lessons learned will hold me in good stead as I scale up my rockets in size and output.

In the mean time, I have enough tubing to make another 200 rockets, in addition to the 50 or so that I've already launched. At a cost of ~ $0.15/each for the fuel, nozzle material, fuze and epoxy (everything else I had or cost nothing), the whole enterprise will have set me back about $37.50.

For the record, a post was entered at The Crucible about this, in case it sounded familiar.

1lb or 2oz refers to the mass of a lead sphere that can fit in the tube.

For effects for my small rockets, I just leave the tube longer than usual, ram some delay comp on top, then put small stars or fish in and sprinkle bp on top before taping it off with a bit of wallpaper and masking tape.

I use old tubes from used commercial fireworks for tubes. I also like small rockets as they cost me pennies.

Edited by fishy1, 18 December 2006 - 08:59 PM.

[spanner]

1lb or 2oz refers to the mass of a lead sphere that can fit in the tube.

For effects for my small rockets, I just leave the tube longer than usual, ram some delay comp on top, then put small stars or fish in and sprinkle bp on top before taping it off with a bit of wallpaper and masking tape.

I use old tubes from used commercial fireworks for tubes. I also like small rockets as they cost me pennies.

Thanks fish1 for the info and tip. I hadn't considered flying fish fuse for the effect- a simple but elegant solution. Light weight, too.

Using the idea of extending the case to form a chamber atop the grain gives a lot of latitude in effects that could be used. I'm thinking of round stars (two or three), lit and expelled by a small lift charge of BP.

I've built a star gun to test different comps, and while it works well, it doesn't give the height that a rocket can. This will be a good way to test my stars, at the same time as enjoying the launching of the rocket. Kind of a "two for the price of one" thing.

I've made up three different types of micro-stars that I'll be launching this way, too.

A 2 ounce rocket should have the power to get at least 15g up- maybe more. I'll be doing some testing to see just what they're capable of in the near future.

When I was using straight KNSU for fuel, I found that as the weight went up, acceleration went down to the point that even fully cored grains would still launch slowly. To overcome this, I used a BP grain below the main grain of KNSU. This allowed a strong launch, then transitioned to smooth lift provided by the KNSU.

I think this might also work for ammonium perchlorate- fueled rockets that suffer from slow thrust build up at launch. By the time the BP had burned, the main core would be fully lit from the shared core. A waxed paper disc could be used to separate one from the other.

In addition, the blackmatch that was suggested could still be used to transfer flame to the top of the grain.

[cooperman435]

Im having problems with my bp after ramming?

Im using 50/50 sand cement for the nozzle and 75/10/15 bp made from lumpwod charcoal (bbq stuff as its cheap for rocket propelant) milled for an hour to smooth out the burn and mix well together.

Im dampening the mix slightly till it just starts clumping slightly (very slightly) then ramming 1 ID at a time but am finding that the surface of the bp delay which was flat after ramming becomes dome shaped as though the bp has expanded slightly?

Anyone else had these problems before?

Ive also tried puting the motors on a radiator to aid drying as Im using 24mm ID pipe they take a while to dry out but it doesnt seem to make a diference. and even used 5% dextrin to harden the mix but no luck.

[Dj Killerboss]

I would say you don't need the dextrin. I have rammed my bp rockets dry
I also added a bit Al to the bp for nice tail.
Try to make smaller ID rockets and get them to fly.

greez

[newtoolsmith]

I use BP straight out of the mill and add coarse charcoal (pieces of almost 1mm size) in 75/25 ratio.

The mixture is then pressed dry into 12mm ID PVC tubes (thanks to ALDI!).

The nozzle is 4mm, the core reaches 40mm into the fuel. Is press the nozzle wth a hydraulic press, so it expands slightly and stretches the tube (+0,2..0,3mm in diameter).

The lowest part is prevented from expanding so that this nozzles are somewhat conical and cant move out.

The fuel reaches 10mm higher than the core to give some delay, some clay pressed onto top closes the tube.

Last a 2mm hole (not! centered) drilled just till it reaches the fuel will ignite the payload short after burnout of the thrust section.


Theese motors carry a payload of 35gram about 50meters (or higher?) into the sky and produce a tail as long as they climb high. Very pretty.

What if I would soak the coarse charcoal in KNO3/water solution like CIA method to make the tail stand shorter buit shine brighter? We will see...

I also started working on a bigger version theese days with 24mm ID and 2mm wallthickness cardboard tube...

results will follow.

MfG
newtoolsmith

[Give_me_APCP]

You're lucky. Much as I've tried, I just can't get those visco rockets to work.

Skipping back a bit to these visco rockets...

These things are really cool to me, being easily thrown together.

I found that about any visco fuse will actually work, they all just produce different thrust characteristics. You will need to try using 6 strips of fuse to start at about 1" each, then try 7, 8, 5 etc. I use slightly thicker fuse.

First of all, the tutorial in the link on page 1 states that you should make these nice little twisted nozzles and tie them with string. I've found this idea really to be useless and inconsistent. Paper burns away rapidly and loses strength. So does what I recommend but at a much more consistent rate from rocket to rocket.

So what do I say? Use the hot glue gun you already have out to make the nozzles. You simply make sure the main fuse is centered in the bunch. Squirt hot glue all around it, about 1/3" in length. Hold the fuse perfectly centered as the glue hardens.

The hole from the fuse burning through the glue initially gives a nice small hole for higher pressure. The glue erodes quickly but the motor also burns out quickly.

If you make them consistent with strong rolled paper cases, they have some oomph! Easily enough to lift a few more grams.

One other thing, these have a tendency to spit out the nozzles with a pop once you push their limits. Soak Ca glue into the paper ends, so that the paper becomes a solid plastic-like material bonded to the nozzle and plug. This way the nozzle is not bonded to one layer of inside paper, rather the whole roll.

Edited by Give_me_APCP, 06 June 2007 - 06:11 PM.

[TzaRocket]

This is my first stinger missile:Stinger



What do you think?It was a succesful firework?It was made whit black powder 75/15/10 but using charcoal bought from the gas station.

Edited by TzaRocket, 11 July 2007 - 08:42 PM.

[Frozentech]

This is my first stinger missile:Stinger
What do you think?It was a succesful firework?It was made whit black powder 75/15/10 but using charcoal bought from the gas station.

Looks pretty good. It would have been nice to have it go more straight up, but I know how it is, 1/3 of mine have angled off like that too. Nice sound !

[Potassium chlorate]

I made my first stinger missile (and first functioning rocket) ever today. I used the instructions from Skylighter: stinger missile

The powder was 30 grams of homemade black powder. I used simple bbq charcoal, which I milled separately for 1 hour. The potassium nitrate was chrystalline fertilizer of tehcnical grade, which I also milled separately for 1 hour. Then I milled potassium nitrate and charcoal with sulfur of unknown quality (bought it from a fellow pyrotechnician here in Sweden and use it only for BP) for 3 hours. The ratio was 76:15:9 (the old Swedish ratio for BP).
The powder turned out to be excellent.

Alas I still haven't fixed me a video camera but it went pretty high (about 100 metres I'd guess) though a little bit sidewards.

Edited by Pyroswede, 21 August 2009 - 11:55 AM.

[maxman]

Thats good Pyroswede but next time we'd like to see a video!

I take it that you made a 1lb stinger? You need the hottest BP you can make for these. Best to use willow charcoal and they will fly vertical then! How thick did you make your clay nozzle?

Maxman

[Potassium chlorate]

Thats good Pyroswede but next time we'd like to see a video!

I know. It's embarassing not to have a camera when you do these things, so that you can show it to everyone.

I take it that you made a 1lb stinger? You need the hottest BP you can make for these. Best to use willow charcoal and they will fly vertical then! How thick did you make your clay nozzle?

Maxman

Yup, it was an 1 lb stinger. Swedish bbq charcoal is usually made of alder, birch and linden, I think, but it worked out very well considering it was my very first rocket ever.

By "thick", do you mean diameter or thickness in height? I used a 30 mm long spindle, 4 mm diameter at the top and 6 mm diameter at the base. I used 4.5 grams of bentonite but I didn't check out the actual height of the nozzle in mms. I just put masking tape on my dowel as to know where to drill the hole on the side of the rocket.

Edited by Pyroswede, 21 August 2009 - 01:47 PM.

[selwyndog]

This may of interest, a high impulse fuel has been made from aluminium powder and water. About a 50,50 mix. Material is like a silver toothpaste, can be used to fill rocket tubes in this state then it is frozen solid. The fuel is called Alice (Al ice). Looked at the energetics, AP/AL mix about 2.2kcal per gram, Alice around 1.8kcal per gram, gunpowder less than 1kcal per gram. A poster on this material estimated an SI of up to 310seconds. More can be found on youtube.

[44RedHawk]

Hi - thought this might be of use to the community of rocket builders: Cross posted in UKPyro/tools as applicable.

I have had successful results using standard 75-15-10 black powder mix in 1lb rocket motors with the addition of 3% petroleum jelly. The caveat here comes with my lack of formal chemistry background to offer any potential incompatibility or additional safety concerns with this mix.
This solution was inspired by frugality and the need to utilize an existing batch of 75-15-10 and a lack of KN03 for fresh rocket mix. A little web research revealed that petroleum jelly was used extensively by commercial manufacturers of high energy compounds to reduce friction in pressing operations adding greater production and storage safety.

I decided such would be relatively safe in a black powder mix in percentages similar to a Potassium Perchlorate /Salicilate whistle mix and so on with my experiment. I began with an existing 75-15-10 hand blend + 5% dextrin that was slated for polverone. I selected 2lbs to which was added 3% petroleum jelly diluted in a 2:3 ratio of mineral spirits hand blended in a stainless bowl 5-10 minutes then placed on kraft paper lined tray to evaporate off the mineral spirits. The resulting powder is dust free with the consistency of fine loam that compacts very well in a parallel wound paper tube.

This mix was hand rammed in 3/4"ID X 8" L hand rolled 70lb virgin kraft tubes with Wolter 1lb core burner rocket tooling and standard bentonite clay nozzle and plug (NO grog). This is a HOT mix with incredible thrust minus the expected cato from a 75-15-10 blend.
Any feedback, constructive criticism, observations or ideas would be greatly welcomed. -Enjoy

Edited by 44RedHawk, 20 August 2011 - 01:34 PM.