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wwattles

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Has any of the commercial AP motor manufacturers ever tried making an AP motor that has the core lined with BP? It would make them easier to ignite and make sure that the entire surface of the grain would be engulfed in flame almost simultaneously. So instead of having to have a long igniter go all the way up the grain to the top, the igniter would only have to go in the nozzle like a standard BP ignitor, and no pyrogen would be needed.

I'm not looking to make anything like this, just wondering if it had ever been tried, and what the results were.

WW
 

jrogers

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Cesaroni uses a BP pellet in the end of the top grain that is lit by an Ematch

Light instantly
 

r1dermon

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i think the reason it hasnt been majorly implemented is because of liability. testing costs...etc...BP ignites really quickly when not pressed. depending on size of the grain. and you'd need a really fine BP to get the desired results. they're probably afraid of the casing exploding. failure rates would probably go up.
i fill the entire core of my homemade rockets with FFF rifle grade BP, and they work fine. but they're heavy PVC and the nozzles arent usually extremely small. it makes a good bang, but the motors impulse is substantially greater.
 

daveyfire

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Originally posted by jrogers
Cesaroni uses a BP pellet in the end of the top grain that is lit by an Ematch
Cesaroni uses Pyrodex. The problem with BP in the motors is that it just burns too fast to provide effective heat transfer to the core and light the propellant. Pyrodex burns somewhat slower, and as such makes a *very* reliable igniter.

When the Gates Brothers were having trouble with their head-end igniters (see http://www.gbrocketry.com/blackrock_xiii_october_2001.htm), it was due to the manufacturer adding black powder to the composition. The igniter flashed, then a few seconds later the motor came up to pressure.

Copper Thermite works well only because it also has huge globs of molten copper flying all over the inside of the core of the motor -- these light it really fast. The BP residue doesn't contain much of anything to transfer the heat.

HTH!
 

r1dermon

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exactly...flash powder would theoretically be a better alternative, due to the aluminum or magnesium, but, flashpowder, when confined, can detonate its container, which means very very very dangerous. i've tried to make a flashpowder rocket motor, even slower burning flash powder will explode the container like an m-80. i've never seen thermite hardened, or pressed....but it burnes extremely hot.
 

daveyfire

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Originally posted by r1dermon
flash powder would theoretically be a better alternative, due to the aluminum or magnesium, but, flashpowder, when confined, can detonate its container
Minor detail :eek:

Flashpowder burns much faster than BP does. The metals within it are too light to do much during its incredibly short burn. It's like trying to light a motor with an unaugmented Daveyfire 28B -- just doesn't work. Though the igniter is hot, it doesn't throw molten slag all over the core. *That* is what lights the motor. Flash powder just goes POOF in a really, really big way... though it would sure as heck pressurize fast!
 

r1dermon

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well, some magnesium and sulfur comps (plus oxidiser) can produce 4000 degree burn temps. and if you could slow it down by adding more reducer than oxidiser, man, that would be a SURE fire igniter. but yes, flash powder deflagrates so fast that it can detonate its container(cause an explosion or outward expansion/release of gas in excess of the sonic barrier creating a shockwave) which would not be a good thing, however impressive the blast may be.
 

BlueNinja

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The thing I would worry about is shock ignition. BP is pretty sensitive to shock, so say you drop your motor and the BP receives enough of an impact to ignite. Poof, you have an unguided motor flying around on the field. May be a somewhat farfetched theory, but I say it wouldn't work.
 

r1dermon

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yeah, BP is sensitive to shock up to a POINT. and thats a HUGE point. estes presses their motors under 1000psi of pressure. if you took a sledge hammer and poured 1 gram of BP on an anvil and then whacked that anvil as hard as you could, it still wouldnt be likely to ignite(unless the hammer and anvile create a spark) my point is, BP is not as sensitive to shock as people are led to believe. its a huge misconception. now, with flashpowder, its a different story. if you stepped on some powerful flashpowder with a low reducer:eek:xidiser ratio then its going to ignite.
 

Anthony Cesaroni

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We do not use Pyrodex. I don't know where that information came from but I can assure you we manufacture the receiver/booster pellets from BP. It is considered as part of the propellant and not an ignition source by DOT and ERD as well.

Anthony J. Cesaroni
President/CEO
Cesaroni Technology/Cesaroni Aerospace
http://www.cesaronitech.com/
(905) 887-2370 x222 Toronto
(410) 571-8292 Annapolis



Originally posted by daveyfire
Cesaroni uses Pyrodex. The problem with BP in the motors is that it just burns too fast to provide effective heat transfer to the core and light the propellant. Pyrodex burns somewhat slower, and as such makes a *very* reliable igniter.

When the Gates Brothers were having trouble with their head-end igniters (see http://www.gbrocketry.com/blackrock_xiii_october_2001.htm), it was due to the manufacturer adding black powder to the composition. The igniter flashed, then a few seconds later the motor came up to pressure.

Copper Thermite works well only because it also has huge globs of molten copper flying all over the inside of the core of the motor -- these light it really fast. The BP residue doesn't contain much of anything to transfer the heat.

HTH!
 

Anthony Cesaroni

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BP pressures at Estes as well as here are well over 1000 psi. One of our senior propeller heads worked there at one time. We routinely press energetics to an order of magnitude higher, including things much hotter than BP.

Anthony J. Cesaroni
President/CEO
Cesaroni Technology/Cesaroni Aerospace
http://www.cesaronitech.com/
(905) 887-2370 x222 Toronto
(410) 571-8292 Annapolis


Originally posted by r1dermon
yeah, BP is sensitive to shock up to a POINT. and thats a HUGE point. estes presses their motors under 1000psi of pressure. if you took a sledge hammer and poured 1 gram of BP on an anvil and then whacked that anvil as hard as you could, it still wouldnt be likely to ignite(unless the hammer and anvile create a spark) my point is, BP is not as sensitive to shock as people are led to believe. its a huge misconception. now, with flashpowder, its a different story. if you stepped on some powerful flashpowder with a low reducer:eek:xidiser ratio then its going to ignite.
 

n3tjm

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Originally posted by r1dermon
yeah, BP is sensitive to shock up to a POINT. and thats a HUGE point. estes presses their motors under 1000psi of pressure. if you took a sledge hammer and poured 1 gram of BP on an anvil and then whacked that anvil as hard as you could, it still wouldnt be likely to ignite(unless the hammer and anvile create a spark) my point is, BP is not as sensitive to shock as people are led to believe. its a huge misconception. now, with flashpowder, its a different story. if you stepped on some powerful flashpowder with a low reducer:eek:xidiser ratio then its going to ignite.
Black powder is preasure sensitive when it ages. Over time, the chemicals will interact with each other, forming a more unstable explosive mixture. I read a newspaper article about a guy who learned first hand how unstable black powder can be. I don't know where I saw the article, but it was many years ago anyway, but the story went somewhat like this:

The guys father passed away, so they were going through his stuff in his fathers basement... and he was throwing away all the old paints and stuff. Anyway, he grabbed a old can orf black poweder, not realizing what it was, and tossed it in a nearby trashcan. the resulting explosion blew him across the basement (luckly he survived), and blew out the stone wall that the trashcan was next to.
 

daveyfire

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Originally posted by Anthony Cesaroni
We do not use Pyrodex. I don't know where that information came from but I can assure you we manufacture the receiver/booster pellets from BP. It is considered as part of the propellant and not an ignition source by DOT and ERD as well.
That's interesting, Anthony, I didn't know that! Do you guys modify the o/f ratio to get it to burn slow enough? The motors sure do light right up :)
 

r1dermon

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BP would pressurize the entire core extremely fast, not only that, but the bi-product of the reaction has no chance to cool down. its like pressure steaming it. only without water. not only that, but BP when compressed burns relatively slowly, compared to how it burnes in powder form.
 

aksarben10

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I have heard that some people use Estes engines to light Aerotech motors.

I am talking about large Aerotech motors where the Estes engine can fit in the core. The Estes BP motor lights easy and quickly brings the whole motor up to pressure.

Scott
 

n3tjm

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Copressed BP burns very slow... for an example of this, static fire a C6-0 or D12-0... but ignite the blunt end.
 

powderburner

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I saw (a couple of posts back in this thread) that someone was thinking about possible uses for flash powder.

Do NOT do this.

Flash powder will not only burn so vigorously that it can easily overpressurize its container, it burns so violently that it will initiate a detonation IN AN UNCONTAINED PILE OF POWDER ON THE GROUND.

Don't ask how I know this.

I cannot say this strongly enough: there are NO applications in any part of rocketry (model, hobby, experimental, etc) for flash powder. You do not want to mess with stuff that has the nasty combination of sensitive, violent, extremely high temps, and blindingly bright light. This is really bad stuff.
 

utahrc

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Originally posted by aksarben10
I have heard that some people use Estes engines to light Aerotech motors.

I am talking about large Aerotech motors where the Estes engine can fit in the core. The Estes BP motor lights easy and quickly brings the whole motor up to pressure.

Scott
I have seen this. They cut the casing off of the BP motor and then cut a chunck of BP just large enough to be press-fit into the top of the upper grain on an AP 'M' motor.
 

jerryb

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ummm... this has the definite ring of an urban legend to it...

as an AVID reenactor, i have stored and worked with bulk black powder for almost 20 years now, i was even involved in the bulk grinding of BP gains down to 7F equivalent safetly and repeatedly without incident.

I can say with certainty that the result of throwing an old can of black powers MIGHT result in a fire/explosion..due to a previous mentioned spark... it wouldnt blow up due to any instability from chemical breakdown of the components..... STATIC discharges cause more premature ignitions with black powder than anything

time and black powder usually end up with MOISTURE ending up in the mix... of which the net result is black powder that fizzles or does not ignite at all.

not saying your story didnt happen... just that in my experience with blackpowder and improper storage it seems very unlikely

Jerryb



Originally posted by n3tjm
Black powder is preasure sensitive when it ages. Over time, the chemicals will interact with each other, forming a more unstable explosive mixture. I read a newspaper article about a guy who learned first hand how unstable black powder can be. I don't know where I saw the article, but it was many years ago anyway, but the story went somewhat like this:

The guys father passed away, so they were going through his stuff in his fathers basement... and he was throwing away all the old paints and stuff. Anyway, he grabbed a old can orf black poweder, not realizing what it was, and tossed it in a nearby trashcan. the resulting explosion blew him across the basement (luckly he survived), and blew out the stone wall that the trashcan was next to.
 

r1dermon

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the moisture thing depends. if its moist at ignition then it will just fizzle, however, if you dampen BP, it creates a much better(closer) bond between the KNO3 and the charcoal, increasing the ignition sensitivity, overall energy, and ignition temp of the BP.

also, that post about flashpowder is all relative. a high grade flashpowder would self detonate(which i hate using the word detonate because its not a high explosive, it doesnt create a mushroom cloud, and it doesnt create a shockwave due to its ignition alone, it needs a container to create a supersonic energy wave) but there are useful low grade ultra fine slow burning flashpowders that will burn about as fast as FFF BP. only they're insanely bright. something that incorporates both magnesium AND aluminum powders in small quantities per the ratio, THAT would really cause a bang. also, it is true, that most FP is quite shock, friction, static, anything sensitive, and in that regard it should not be used. as there are better alternatives. in my experimentation however, i have found that flashpowder CAN reliably ignite BP, however every attempt of mine resulted in a CATO, so you'd have to use so litle flashpowder that it would NOT ignite the BP and in this regard an igniter(magnelite...etc..) is much more preferrable.
 

MarkABrown

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r1dermon, I think you missed the point of powderburner's post. While what you say MAY be true (I doubt it), the idea of trying to use materials that are clearly dangerous is a very stupid one. The style of your postings to this thread lead one to believe that you feel the use of BP, flash powder, magnesium, and fine particle aluminum is not inherently dangerous and no big deal. Any of these components, when not used properly, can kill or seriously injure the user. You need to remember that we also have kids reading these forums and may decide to try one of your ideas since you make it sound so harmless. This is the reason that TRF has such a strict policy on formula discussion. I've had to edit at least 3 of your posts in this forum to remove formula components or ratios. Please consider what you post and how it may come across to a minor aged individual before you hit the submit button.

PS. It may help your cause if you would let everyone know something about your background and credentials and how you know so much about chemicals, their properties and their reactions in situations.
 

Anthony Cesaroni

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Many homebrew ignition compositions tend to be excessively gassy and that's really not an ideal situation. Solids are a very important element of heat transfer in an igniter scheme. Flash powder is a detonation source and the velocities it can attain have no place in a rocket motor. Having said that, a variation of flash powder developed as an igniter by China Lake is known as ALCLO. It lacks the traditional sensitizer (sulfur) use to reduce ignition temperature and the O/F ratio is shifted slightly. It's typically pressed into pellets at up to 10,000 psi. On ignition, it produces about 30% gas. The remainder is very hot liquid and solid Al2O3. The problem with it as with flash composition, is static and impact sensitivity. Most real ignition systems incorporate BKNO3 and generally in pellet form. This is a much safer material to produce and handle and has a number of military specifications. Decomposition proportions are similar to ALCLO. Equipment such as a Mullen is used to prepare BKNO3 as uniform dispersion is important for optimum performance. We use this material in our 6" and 8.5" booster motors and ignition latency to nominal Pc is in the range of 70 milliseconds. There is a video at http://www.cesaroni.net/newspage.html#01feb1304 at the top of the page under the Titan story illustrating this.

A good reference regarding this topic NASA SP-8051 titled Solid Rocket Motor Igniters. It covers a lot of the practical aspects of motor ignition such as heat flux and ignition.

Ignition compositions should not be taken lightly. They are very energetic compounds and can be dangerous. If you don't have experience in this area, stick to what's available and approved for your application. Do your homework and avoid hearsay.

Anthony J. Cesaroni
President/CEO
Cesaroni Technology/Cesaroni Aerospace
http://www.cesaronitech.com/
(905) 887-2370 x222 Toronto
(410) 571-8292 Annapolis


Originally posted by powderburner
I saw (a couple of posts back in this thread) that someone was thinking about possible uses for flash powder.

Do NOT do this.

Flash powder will not only burn so vigorously that it can easily overpressurize its container, it burns so violently that it will initiate a detonation IN AN UNCONTAINED PILE OF POWDER ON THE GROUND.

Don't ask how I know this.

I cannot say this strongly enough: there are NO applications in any part of rocketry (model, hobby, experimental, etc) for flash powder. You do not want to mess with stuff that has the nasty combination of sensitive, violent, extremely high temps, and blindingly bright light. This is really bad stuff.
 

r1dermon

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sorry mark, if i come across as telling people that flashpowder is a safe thing to use, however i thought i pointed that out
it is true, that most FP is quite shock, friction, static, anything sensitive, and in that regard it should not be used
however, it theoretically could be used to ignite a motor, however, the fact that it deflagrates its entire mass in milliseconds is an inherently dangerous proposition. im sorry about the formulas, its just, to display a safer form(though there is no safe explosive) of the said explosive(flash powder), i had to incorporate SOME of the materials. however, i have noticed that in previous posts the formulas have been cut out, so i decided to exclude the oxidiser in all of my FP examples.
my background is, i've been into model rocketry and experimental rocketry since i was like... 5 years old. i used to have a paper route, but that was not sufficient to fund all those estes motors. so i decided to do some research, and i found a lot about chemical reactions. at first is was solely explosives that i was into, however, it really funnels you in, once you get hooked to explosives and breaking down the various compositions, you start to realise that gun powder (while very powerful) is nowhere NEAR as powerful as some other compositions, its quite exciting. also, oxidiser and reducer functions are self tought, its really quite interesting. so after that, i started producing my own sugar motors with that brown tape(for the casing) and pourstone for the nozzle. while it was quite dangerous(i had to boil the sugar and oxidiser together so i could cast a grain) it was really educational and exciting. now im looking into other various things, such as acid etching, with hydroflouric acid(its molecular size lets it penetrate the skin in milliseconds) its so powerful on glass and skin, that 99.9999%conc hydroflouric acid would eat through your finger in less than a second. however, its used extensively in acid etching windows and such. my interest is the flouride which is an anesthetic, so when the acid is actually poured on you, you'll see it eating your flesh, but you wont feel it. quite dangerous. im also exploring plastics. did you know that adding anything acidic to milk will make plastic? take a cup of milk and add vinegar to it, let it sit for a while and you'll have a low grade plastic in a cup. good stuff. thats just a little bit about me, just in-case anyone who was sketched out by me was wondering.:cool:

oh yeah, a detonation means that the actual compositions molecules deflagrate so fast, that they came up with a word detonate for it. with flashpowder, the reaction is subsonic, so it does not detonate. its container CAN, but the FP itself wont. hence the deep BOOM in an m-80, a detonation is a really loud crack. supersonic, it sends a shockwave. trinitrotoluene(dynomite) detonates. and 1 stick of dynomite is about a couple thousand times more powerful than a single m-80, simply because of the shockwave that is released. and dynomite would detonate without a container, while FP would not.
 

wwattles

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Originally posted by Anthony Cesaroni
Most real ignition systems incorporate BKNO3 and generally in pellet form. This is a much safer material to produce and handle and has a number of military specifications.
Okay, so that gets me thinking... The military HAS to have 100% reliability in their missile ignitors, so what do THEY use? I'm assuming it's something exotic, but is there a commercially available product that is reasonably similar?

I'm not looking for a discussion of chemical compositions - just general terms/names would suffice...

WW
 

r1dermon

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depends on the missle. some missles use H2O2(hydrogen peroxide) and something like kerosene or some other gas as the fuel, H2O2 is the second mose energetic oxidiser on earth, and as such, it doesnt take much to ignite. if you have 99.999%conc H2O2 and you opened the bottle and a SPEC a MICRON of dust touched it, it would instantly deflagrate. like a giant wad of BP. anything organic coming into touch the H2O2 would set it off.
on the other hand, the military can afford expensive ignition systems, possibly something like a torch nozzle in the core of a solid rocket motor. a 4 sided torch nozzle that is inserted to the top of the grain. something of that sort. and you'd be surprised at the failure rate of ignition on those tomohawks. my cousin said that out of 100 tomohawks that were supposed to be shot off(my cousin is stationed on the USS john mccain) only 70 ACTUALLY lit the first try.

oh yeah...what is BKNO3? KNO3 is potassium nitrate and is the oxidiser. if you tried to light KNO3 on fire, it wouldnt go. B is boron, boron CAN be a reducer when combined with hydrogen(though i have no idea how to react the two) Boron trihydride is a good reducer and COULD THEORETICALLY be used, but there are WAY lower cost alternatives. :cool:
 

edwardw

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BKNO3 is Boron and KNO3. If you read the Nasa Tech article Anthony mentions it has all sorts of goodies in it about engine igniton. It also has a lot of math formulas, which I'm naturally drawn to...mmmm rockets and math.


Edward
 

r1dermon

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really....is that combined? i wonder how they react boron with potassium salt....now THATS a chem lab...muhahahaha, maybe they dissolve it together, and then some sort of electrolisis, but i dont know how you'd keep the KNO3 from splitting. thats crazy.
 

MarkABrown

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Originally posted by r1dermon
depends on the missle. some missles use H2O2(hydrogen peroxide) and something like kerosene or some other gas as the fuel, H2O2 is the second mose energetic oxidiser on earth, and as such, it doesnt take much to ignite. if you have 99.999%conc H2O2 and you opened the bottle and a SPEC a MICRON of dust touched it, it would instantly deflagrate. like a giant wad of BP. anything organic coming into touch the H2O2 would set it off.
on the other hand, the military can afford expensive ignition systems, possibly something like a torch nozzle in the core of a solid rocket motor. a 4 sided torch nozzle that is inserted to the top of the grain. something of that sort. and you'd be surprised at the failure rate of ignition on those tomohawks. my cousin said that out of 100 tomohawks that were supposed to be shot off(my cousin is stationed on the USS john mccain) only 70 ACTUALLY lit the first try.

oh yeah...what is BKNO3? KNO3 is potassium nitrate and is the oxidiser. if you tried to light KNO3 on fire, it wouldnt go. B is boron, boron CAN be a reducer when combined with hydrogen(though i have no idea how to react the two) Boron trihydride is a good reducer and COULD THEORETICALLY be used, but there are WAY lower cost alternatives. :cool:
Could you cite your sources? I know that we have some rocket scientist TRF members who do this for a living. I've heard of no such example deployed in the U.S. arsenal.
 

r1dermon

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site my sources for what? you quoted my entire post. the quad torch thing is speculation, boron is B on the periodic table, thus BKNO3 would be boron potassium nitrate, maybe you mean the H2O2 missles? i saw a write up about them online somewhere..i'll check my history.;)
oh, if you want to talk to a bunch of scientists, www.scienceforums.net is a good site, and H2O2 is often talked about in the chemistry section. you can find out a lot there.
 
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