Lots of things for newbie

[pillyg]

Hi, i am new and just starting out with rocketry. I am having a few problems and i was told to go here for help

 

1. What is more powerful sugar/KNO3 or gunpowder?

 

2. I have tried a few nozzles rockets and 2 of them have blown up really bad. i dont know whats going on because there is no nozzle to build up pressure but they have blown up.

 

3. For nozzles, i have kitty litter, sand, and pariffin wax. what would the for nozzle mix?

 

4. when i make r-candy, it turns out not creamy or smooth. there are like little dimples on it. Also, when i try to make a motor. It stutters when i launch it . its like shoop----shup shup ----sh sh ssssshhhhhhhhuuuuuuu when i test a grain out of the rocket, its just fine.

 

5. When i get good rockets, they make ok thrust to lift the rocket, then it reaches apogee but keeps burning. everything is end burner. there is no core or anything so i dont know what would cause this.

 

6. i read on skylighter that you can use nickels (5 cents) as ball mill media. Is that true?

 

7. I have a lortone ball mill and the 2 rods that spin the barrel are slipping on the barrel. The rods spin the the barrel doesn't I put a rubber band on the barrel but the wear out in about 5 hours.

 

This is just what i could think about and im sure i will think of more.

 

thanks, William

[dagabu]

Hi, i am new and just starting out with rocketry. I am having a few problems and i was told to go here for help

 

1. What is more powerful sugar/KNO3 or gunpowder?

 

2. I have tried a few nozzles rockets and 2 of them have blown up really bad. i dont know whats going on because there is no nozzle to build up pressure but they have blown up.

 

3. For nozzles, i have kitty litter, sand, and pariffin wax. what would the for nozzle mix?

 

4. when i make r-candy, it turns out not creamy or smooth. there are like little dimples on it. Also, when i try to make a motor. It stutters when i launch it . its like shoop----shup shup ----sh sh ssssshhhhhhhhuuuuuuu when i test a grain out of the rocket, its just fine.

 

5. When i get good rockets, they make ok thrust to lift the rocket, then it reaches apogee but keeps burning. everything is end burner. there is no core or anything so i dont know what would cause this.

 

6. i read on skylighter that you can use nickels (5 cents) as ball mill media. Is that true?

 

7. I have a lortone ball mill and the 2 rods that spin the barrel are slipping on the barrel. The rods spin the the barrel doesn't I put a rubber band on the barrel but the wear out in about 5 hours.

 

This is just what i could think about and im sure i will think of more.

 

thanks, William

 

Ooooh, ohhhh, me, me!!

 

Hi William, nice to meet you.

 

1. What is more powerful sugar/KNO3 or gunpowder?

A: Gunpowder is generally nitrocellulose as in single based gunpowders and is combined with nitroglycerin as in double based powders. You are (hopefully) referring to black powder which is still called gunpowder on Wikipedia but the name has now been passed on to modern powders. Double based gunpowders are much more powerful per gram then black powders.

2. I have tried a few nozzles rockets and 2 of them have blown up really bad. i dont know whats going on because there is no nozzle to build up pressure but they have blown up.

A: A lot of failures come from the increments of fuel being either to large causing 'soft' spots in the grain or fissures in the grain due to under pressurizing the fuel while compacting it.

 

3. For nozzles, i have kitty litter, sand, and pariffin wax. what would the for nozzle mix?

A: There are lots of views on this one but I have been using straight kitty litter (screened through a 12 mesh screen) for nozzles for the past six months and have seen a much longer tool life due to the less abrasive media.

 

4. when i make r-candy, it turns out not creamy or smooth. there are like little dimples on it. Also, when i try to make a motor. It stutters when i launch it . its like shoop----shup shup ----sh sh ssssshhhhhhhhuuuuuuu when i test a grain out of the rocket, its just fine.

A: Look up James Yawn, you likely need to add some corn syrup to your mix to thin it out some and use very fine sugar, not table sugar.

 

5. When i get good rockets, they make ok thrust to lift the rocket, then it reaches apogee but keeps burning. everything is end burner. there is no core or anything so i dont know what would cause this.

A: You answered your own question, "everything is end burner". you have to much fuel, cut back on the length of your fuel grain.

 

6. i read on skylighter that you can use nickels (5 cents) as ball mill media. Is that true?

A: Yes, you can but I dont and wont. Nickles do not cascade down allowing them to strike each other several times as they fall down the pile, they slide across themselves and are very inefficient. Hardened lead balls, stainless steel balls (303) and some ceramics work much better and are a hell of a lot cheaper.

 

7. I have a lortone ball mill and the 2 rods that spin the barrel are slipping on the barrel. The rods spin the the barrel doesn't I put a rubber band on the barrel but the wear out in about 5 hours.

A: A lot of under-filled ball mills suffer from slipping, use round/roundish grinding media and fill the jar 1/2 way with it and you should have the weight you need. Also, sometimes the rubber just gets a little slick, belt treatment works well in getting the 'tack' back in rubber.

Edited January 14, 2011 by dagabu

[NightHawkInLight]

4. when i make r-candy, it turns out not creamy or smooth. there are like little dimples on it.

 

As Dagabu said, corn syrup will work nicely. Also, if you start by adding about half a cup of water per 100 grams or so of rcandy before cooking, it will dissolve both the nitrate as well as the sugar and make the resulting product burn much smoother and faster. Doing this takes much longer because you must boil out all the water, but the resulting product is worth it. Also adding about 3% iron oxide to your composition will increase the burn rate significantly.

 

6. i read on skylighter that you can use nickels (5 cents) as ball mill media. Is that true?

 

Yes, I did so for a year or two. My mill barrel was shaped like an octagon which lifted the nickles and dropped them, rather than allowing them to slide as Dagabu mentioned. If you put a lifter bar in your mill (made from something non sparking of course) it should work. Nickles are actually pretty close in price to lead balls. Where I'm at the absolute bare minimum I've ever found lead for is $10 for 100 50 cal balls. The 200 nickles you can get for $10 I would estimate to be about 2/3rds the same volume, a harder material, and non toxic. If you use nickles you also have the benefit that they are currently worth about %40 more than face value in their metal content. Nickles are about the only coin left that is worth holding onto for the metal. Everything else is either worth less than face value, or too bulky to hang onto to be worth the trouble (pennies). That said, I use lead.

Edited January 14, 2011 by NightHawkInLight

[pillyg]

Wow, thanks but i have a few comments

 

1 yeah i ment black powder so what i am asking is if i had 2 rockets with the same amount of fuel in both and one was sugar/KNO3 and one was black powder, which one would go higher?

 

4 ahh yes. i actually talked to jimmy for a few months and i did what he told me but it didnt seem to help. the texture doesnt really matter but what the real problem is is that it stutters and i get 0 thrust out of it.

 

5 yes but what i dont get is why dont i get the same thrust at the end if the same amount of fuel is burning?

 

7 i realized the problem about 10 min after i first made this, i was milling outside and im in illinois and its like 15 degrees. The rubber hardened up and that made it stop gripping the spin rods

 

an off topic thing, i was on youtube watching displayfireworks1 talk about "articles of pyrotechnics" he said that they arent really effected by laws so would they be legal in illinois also, where would i get them from is there a website?

[dagabu]

Wow, thanks but i have a few comments

 

1 yeah i ment black powder so what i am asking is if i had 2 rockets with the same amount of fuel in both and one was sugar/KNO3 and one was black powder, which one would go higher?

A: The impulse (measurement of power or thrust over time) is lower in R-candy then it is in BP. The big deal with R-candy is the even and flat thrust it provides, great for moldel rockets, not so good at lifting ball shells and such plus the tail on R-candy is dismal.

 

4 ahh yes. i actually talked to jimmy for a few months and i did what he told me but it didnt seem to help. the texture doesnt really matter but what the real problem is is that it stutters and i get 0 thrust out of it.

A: Just a guess based on my experience but it sounds like your fuel is wet.

 

5 yes but what i dont get is why dont i get the same thrust at the end if the same amount of fuel is burning?

A: BP burns faster, more thrust but shorter burn.

 

7 i realized the problem about 10 min after i first made this, i was milling outside and im in illinois and its like 15 degrees. The rubber hardened up and that made it stop gripping the spin rods

A: I love it when you solve your own problems

 

an off topic thing, i was on youtube watching displayfireworks1 talk about "articles of pyrotechnics" he said that they arent really effected by laws so would they be legal in illinois also, where would i get them from is there a website?

A: Dave was speaking of Federal Law, I and others have been known to disagree with his oration on the legalities and perhaps you should send him a message and ask him for an update if he has one.

 

[madmandotcom]

for number two, make sure you have an exhaust hole of 5mm or above

[dagabu]

*You said Number two!*

[dagabu]

for number two, make sure you have an exhaust hole of 5mm or above

 

*You said Number two!*

 

Lets read that again:

2. I have tried a few nozzles rockets and 2 of them have blown up really bad. i dont know whats going on because there is no nozzle to build up pressure but they have blown up.

 

The exhaust hole size is immaterial.

Edited January 14, 2011 by dagabu

[madmandotcom]

well if he has no end cap, they would just sit there and smoke

[NightHawkInLight]

well if he has no end cap, they would just sit there and smoke

I think you need to clarify what you're talking about. It's not making a lot of sense.

[dagabu]

well if he has no end cap, they would just sit there and smoke

 

A little confusing: He is speaking about three different rocket motors, a end burner with nozzle, a core burner with a nozzle and a core burner without a nozzle. #2 was a core burner with no nozzle. The fire propogates down the spindle hole and finds soft spots or fissures and CATOs the tube.

[madmandotcom]

then how do you get a rocket to fly if there is no end cap?there is nothing to create a pressure to launch the rocket and kno3/sugar does not burn fast enough to create an afterburneeffect

[dagabu]

then how do you get a rocket to fly if there is no end cap?there is nothing to create a pressure to launch the rocket and kno3/sugar does not burn fast enough to create an afterburneeffect

 

Afterburners are fuel being dumped raw into the exhaust stream on military jets, we really have no way to reproduce this on a solid fuel rocket motor.

 

In my last reply I mentioned three different types of motors, one of them is a core burner with no nozzle, they are called nozzleless rockets. The thrust is developed by the fuel in the core burning and being propelled out the back of the motor.

 

I cast R-candy motors in situ and push a spindle that is 3/4 the length of the grain length into the still plastic goo and let cool. I believe that this is what he is speaking about.

[pillyg]

for the nozzless one, its pretty hot BP

 

i still dont think your are understanding what i am asking for about with number 5 but its ok. i just had 2 good sugar (non r candy) rockets so i think i will switch to sugar.

[dagabu]

for the nozzless one, its pretty hot BP

 

i still dont think your are understanding what i am asking for about with number 5 but its ok. i just had 2 good sugar (non r candy) rockets so i think i will switch to sugar.

 

OK, 2 sugar (non R-candy) rockets, are you saying you are just mixing the raw ingredients? R-candy rockets use sugar, table sugar if you do like NHIL says and use lots of water to dissolve the crystals all the way first.

 

BTW- Can you give me some background on your tooling? Its really hard to visualize what you are doing. You can post pictures here pretty easily.

[pillyg]

yeah, i am mixing them and grinding them in a coffee grinder.

 

 

my tooling isnt the best because i made it, but it works pretty good.

Edited January 15, 2011 by pillyg

[dagabu]

I sure hope you wrote that backwards pilly. You can grind them by themselves in a grinder and then combine them but you should never grind them in a coffee grinder after you have combined the chems.

[pillyg]

yeah thats what i meant

[TYRONEEZEKIEL]

Ok. I understand exactly what that "shoop----shup shup ----sh sh ssssshhhhhhhhuuuuuuu" is from. That is resultant directly from the thrust pressure vs your nozzle geometry in your rocket. This effect, in the model/amateur rocketry community, is called chuffing. It occurs because you have these pressure spikes in your burn from having too fast of a burn rate which causes too much hot gas to be thrown out the tube which chokes the burn, creating a cycle. This is because of a few problems with your nozzle geometry.

1. It can be you dont have a smooth convergence and divergence in your nozzle. Hot gasses dont like flat abrupt surfaces.

2. your nozzle opening is not large enough.

3. you have too powerful propellent in terms of thrust, and also a very well built motor, so since the case wont blow out or fail, the propellant chokes itself.

 

I assume you can hear the thrust steadily get more powerful until it chuffs, then it starts over.

I have had APCP rockets as well as BP/ Rcandy rockets completely extinguish themselves due to this blasted chuffing.

 

As for 1st question. If I remember correctly KNO3/Sugar has more powerful in terms of gas expansion, but black powder has a sharper, more violent burn which is good for direct lifting, but not so much sustained power. SO like said above this is what makes Rcandy great for model rockets, because it isnt lifting a heavy load up in the air, It is burning for a long time. Rcandy is like horsepower in a car, and BP is like torque. I dont know a better way to explain it.

For question 5, You will notice an unbelievable boost in performance in your sugar rockets if you make Rcandy out of it. The reason you are seeing your rockets fall before being completely consumed, is your propellant does not have enough thrust during the entirety of the flight to continue pushing it up. e.g. gravity and air resistance beat out your thrust. By creating Rcandy, you are optimally mixing the sugar and KNO3 as well as controlling the caramelizing of the sugar, which is where you get your power boost from. Completely dissolving both in water then cooking in a pot until you have a peanut butter mixture will give you what you are looking for trust me. I have made this stuff more times than I can count and was my very first pyro experience. If you want the full story on why Rcandy beats mixed powder PM me. Also make sure your ratio is 65:35 KNO3:Sugar. That is the golden ratio as far as power goes. Only ramming mixed powder will not give you the results you are looking for. I can, if you like, make some videos showing you the difference in power from rcandy vs mixed powder.

 

I apologize for hogging this thread, but this topic really excites me. I hope that clears a bit up.

[pillyg]

Thanks TYRONEEZEKIEL!!!!!!!!

For Question 5 i was using BP but i guess its still works.

I am not making r candy now because its 10 degrees F and i dont want to sit out in that.

For the r candy, my nozzles are countersunk so i dont think there are any sharp edges. When it gets warmer, i will make a bigger nozzle

[TYRONEEZEKIEL]

I make all of mine in my house haha. however I do have a very intimate knowledge on how this stuff acts. Learning to get to this point was a long road of having the stuff light up in my face. I tried directly melting the sugar. awful idea. Yes. If you are using BP, the same thing is still happening.

 

Can you give me some stats on your rockets. weight, height. amount of BP rammed. flight height. etc? I will be able to diagnose your problem decently from that. When that was happening to me, it was solely because I did not have good enough milled BP. Im 95% sure thats where your problem lies. Check out my rockets on youtube. Mine are 3.5" long 3/4" ID motors taped and glued to just under 3' long, 1/4" square sticks. I get about 300-500' on each depending on my header, and aerodynamics, using straight 75:15:10 meal powder.

[pillyg]

My rockets are 1/2inch ID about 2.75 inches long and have about 15grams of powder.

 

Number 5 isn't really that important becasuse i solve it by coring the top 1/4 of the rocket.

 

I use 75:15:10 BP but not have switched to 60-30-5 KNO3-sugar-sulfur partially (still testing)

 

Singe i am doing more model than pyro rockets, i use fins. (should also give better height)

[TYRONEEZEKIEL]

only 15 grams of powder seems a bit short. dont switch to KNO3/sugar/sulfur until you dial these in. But then again you have shorter motor. Could you take some kind of video of one your your motors burning? Fins wont necessarily add height as much as they do stability. maybe some because of weight reduction, but again, I would have to see your rocket. I love how you are into the model side. I am a NAR and tripoli member.

[madmandotcom]

Afterburners are fuel being dumped raw into the exhaust stream on military jets, we really have no way to reproduce this on a solid fuel rocket motor.

i made this comparison as the fuel being pumped into the exhaust stream creates combusts creating enough heat that the air expands fast enough to create more thrust, if R candy burnt faster, it would be able to-theoreticaly-replicate this

[madmandotcom]

apoligies for thew quoting foopah, it was dagabus if you were wondering