My kno3/su rocket plans, what's wrong?

[Newbergpyro]

first of all, I made 2 of these and neither of them worked at all. I can'y figure out what's wrong!

 

http://i50.photobucket.com/albums/f340/tay1392/123.jpg

 

Any help would be awesome, thanks

[Frozentech]

first of all, I made 2 of these and neither of them worked at all. I can'y figure out what's wrong!

Neither can we. You don't say what went wrong, did they not light, explode, low thrust, slow burn, fast burn, etc.... It will take a lot more info to work out what's going on.

[FrankRizzo]

Did they ignite at all? These mixes are notorious for being so hygroscopic that one needs to either vacuum bag for storage or use them within days/hrs of manufacture.

[itwasntme]

Most likely, its because you're using visco. Try using black match, it will burn faster in the confined core, and light the whole core at once.

[Newbergpyro]

sorry for not explaining, the visco ignited fine, the propellent was 1 day old and kept in a airtight container. so I lit the fuse, it burned very violently and went about 10 ft. into the air, then spun out. the propellant shot out and burned itself up and I never did find the case. But on another just like that one I found the case and the cat litter I grinded up to use as a nozzle was half-way gone. it didn't burn too slow, nor too fast either. So I am stumped!

[rocket]

Sounds like you didn’t ram/press the nozzle hard enough or the propellant had air bubbles in it.

[Newbergpyro]

yeah, and it was going putf, putf, putf. a lot.

[FrankRizzo]

The chuffing "putf, putf, putf" is caused by the core not fully igniting, and your fuel blowing out was caused by your nozzle failing. The ignition problem is easily solved by putting a length of quickmatch up inside the core and wrapping and tying bit of nosing paper around the base of the rocket. Add a bit of grog or crushed clay pot to your nozzle mix and ram it a bit harder to keep them from blowing out.

[Mumbles]

Out of curiousity, what are you using for a casing? I've had problems with PVC and CPVC not holding the nozzle well. For paper, do as FrankRizzo has suggested and add grog, or crushed clay pot, or crushed tile. It will help to bite into the paper more. Using a recessed nozzle also helps. With PVC, I never had much luck with grog helping to the extent it does in paper. I found that roughing up the place where the nozzle should be with a coarse grit sandpaper helped. This was used in conjuntion with grogged nozzle material, so I am not sure if it was the combonation or the roughing itself.

[Newbergpyro]

It's just paper tubes, just like this

 

http://www.cannonfuse.com/store/pc/catalog/tube9L.JPG

 

I wonder if it is my proppellant, even though it burned great when I did tests.

[Frozentech]

It's just paper tubes, just like this

 

 

 

I wonder if it is my proppellant, even though it burned great when I did tests.

OK, a new possibility. Those are spiral wound tubes. They are much less preferred to convolute wound tubes for rockets, because there's the possibility of a gap along that inner spiral seam. The slightest gap can allow flame to propagate outside the core, along the wall of the tube, with bad results.

[Newbergpyro]

so your saying I should use the tubes I wound myself?

[Mumbles]

It could help. It does take one more variable out of the equation. Ramming could be slightly splitting the interior of the tubes causing a blowby and catoing the rocket, or blowing the nozzle out.

 

I would suggest rolling from manilla folder with a few outer turns of kraft to hold it together. They roll much easier, no wrinkles, and they are extremely hard. 50:50 PVA glue:water as the glue. Sanding the edge of the paper that lies along the length of the interior of the tube will make a smooth interior. Otherwise there is a slight lip that some people don't like.

[Newbergpyro]

okay I'll give that a try mumbles. I rammed my nozzle extra hard this time and when I drilled the hole in it It didn't flake at all so I bet this will help. When I launch the rocket I'll let you all know how it turns out.

[mormanman]

It might be your fuel ratios. What were your ratios?

[PyroMan16]

Sounds like all you need is stronger end plugs and nozzels. Use a mix of 50% Bentonite clay and 50% Kyanite. Both are around $4 @ Skylighter.

[Mario1]

I just figured out that ball milling the kitty litter first yeilds much better results then using it right out of the box. After about an hour it was very strong and didnt crack when I made my nozzle. Many of you now this, but for me it is a new discovery.

[TYRONEEZEKIEL]

I ball mill my kitty litter too, and I beat the fire (no pun intended) out of the nozzle mix.

 

Also. I sand the edge around my rammer at an angle to give the nozzle a bit of a divergence on the inside.

 

Ive had nozzle blowout problems just because of flat nozzles. Expanding hot gasses dont like flat nozzles.

[EEguy]

Here is what I do to get consistent 1,000-2,000ft altitude sugar motors that cost about 5-10 cents each:

 

I order the 0.75" I.D. 3.5" long spiral wound tubes from www.cannonfuse.com. Yes I said spiral,...crazy but they work and are really cheap. I use a nozzle tool kit that you can have built at your local machine shop for $50-$100. See link below:

 

http://www.simonclemens.com/Sugar%20Rocket...r%20Tooling.jpg

 

This particular kit has a 50deg diverging angle, and a 3/16" nozzle. The core rods vary in length depending on how hot the fuel mix is. I was using rammed bentonite, but the quick-dry cement from ACE hardware is much better and stronger. Plaster of Paris works well too. The converging angle is made with a 0.75" wooden dowel that has a parabolic taper on the end, with subset holes drilled axially in the end to fit the core rod and nozzle. To make the nozzles, I usually load positions in the base fixture with only the diverging angle molds (without core rods). I then move to the positions that have the core rods to press in the fuel once the nozzle is dry of course.

 

I use ball-milled KNO3 and powdered sugar 60/30 pressed with an arbor press or even a hammer in incrementing amounts until full. I also use the Karo syrup cast candy fuel, which requires less pressing. When the fuel gets above the core rod, I use a dowel with a flat end to press.

 

I use the same cement to make a top plug as well. To separate the wet plug from the fuel, I use the cardboard 0.75" plugs from cannonfuse.com.

 

If the motor is to power a 4th-of-July rocket, I use the small 1/16" Chinese fuse from cannonfuse.com. I tie a not in the end and press the knot up the nozzle so it is wedged against the sugar.

 

If I am launching a model rocket, I use StarLight and Magic electric fuses (http://starmgc.com/ematch.html) powered with my new NichroPulse Angry Spark III timed launch controller (www.nichropulse.com)

 

I have launched hundreds of these, and have sold and given kits to others who love it. It takes minutes to have a motor in hand ready to fly.

[dagabu]

Here is what I do to get consistent 1,000-2,000ft altitude sugar motors that cost about 5-10 cents each:

 

I order the 0.75" I.D. 3.5" long spiral wound tubes from www.cannonfuse.com. Yes I said spiral,...crazy but they work and are really cheap. I use a nozzle tool kit that you can have built at your local machine shop for $50-$100. See link below:

 

http://www.simonclemens.com/Sugar%20Rocket...r%20Tooling.jpg

 

This particular kit has a 50deg diverging angle, and a 3/16" nozzle. The core rods vary in length depending on how hot the fuel mix is. I was using rammed bentonite, but the quick-dry cement from ACE hardware is much better and stronger. Plaster of Paris works well too. The converging angle is made with a 0.75" wooden dowel that has a parabolic taper on the end, with subset holes drilled axially in the end to fit the core rod and nozzle. To make the nozzles, I usually load positions in the base fixture with only the diverging angle molds (without core rods). I then move to the positions that have the core rods to press in the fuel once the nozzle is dry of course.

 

I use ball-milled KNO3 and powdered sugar 60/30 pressed with an arbor press or even a hammer in incrementing amounts until full. I also use the Karo syrup cast candy fuel, which requires less pressing. When the fuel gets above the core rod, I use a dowel with a flat end to press.

 

I use the same cement to make a top plug as well. To separate the wet plug from the fuel, I use the cardboard 0.75" plugs from cannonfuse.com.

 

If the motor is to power a 4th-of-July rocket, I use the small 1/16" Chinese fuse from cannonfuse.com. I tie a not in the end and press the knot up the nozzle so it is wedged against the sugar.

 

If I am launching a model rocket, I use StarLight and Magic electric fuses (http://starmgc.com/ematch.html) powered with my new NichroPulse Angry Spark III timed launch controller (www.nichropulse.com)

 

I have launched hundreds of these, and have sold and given kits to others who love it. It takes minutes to have a motor in hand ready to fly.

 

That was a great tutorial! I do a few things differently but you definitely have it down. Are you dry mixing, granule or melt pressing and are you using anything other than hand pressure on the grain? How long is your grain and do you cast directly in your tube? Do you line the tube?

 

D

[EEguy]

That was a great tutorial! I do a few things differently but you definitely have it down. Are you dry mixing, granule or melt pressing and are you using anything other than hand pressure on the grain? How long is your grain and do you cast directly in your tube? Do you line the tube?

 

D

 

 

I am now dry mixing milled KNO3 with powdered sugar, and packing it with the two dowels with a hammer or arbor press in portions to fill the tube. This eliminates the need for a heat source and those associated hazards. It only works for these smaller motors.

 

I also use the casting method with regular granular salt and granular KNO3.

I cast directly in the tube when I melt the Karo, sugar and KNO3. The grain length is the same length as the tube (3.5"), minus the nozzle. When I cast, I use a longer core rod, since the burn rate seems to be more stable and slower.