Aerial Shells

[cplmac]

I wonder if pyrodex would work as a BP rocket fuel. Anyone try it yet?

[qwezxc12]

I wonder if pyrodex would work as a BP rocket fuel. Anyone try it yet?

I wonder if you could satisfactorily compact the granuals into a solid fuel grain with no voids without a solvent.

 

I tried Pyrodex to fuel fireballs and was un-impresed. At the level of confinement I could manage, it burned too cool and too slow...IMO, of course.

[cplmac]

I don't see why not, you can do it with BP. I think at 7000PSI you can solidify most compositions.

[TheSidewinder]

From what I understand, it's the burn speed of Pyrodex that disqualifies it as a good rocket fuel. Even compressed as you say, it simply burns too slowly to provide optimum performance, or even close to it.

 

And there's another danger, if what I read is true: Pyrodex is based on smokeless powder. Confine it TOO much, and it can detonate under the right (wrong?) conditions. That may or may not be correct, I'm not 100% certain. But if true, that's another MAJOR consideration.

 

To be fair, in Bill Bahr's 2005 "3-inch Color Shell with Report" seminar/class, we used Pyrodex as the burst charge. It worked, but was noticeably weaker than a good, hot, BP burst charge. Whistle mix would have been my choice, personally, but in a beginner class it makes sense to use BP.

 

M

[Mumbles]

Pyrodex to my knowledge is not NC based. It is a Perchlorate alternative to BP, no sulfur, and I think a fair bit of Red Gum actually. I'll have to look up the patent again soon.

[Explosive]

I wonder if pyrodex would work as a BP rocket fuel. Anyone try it yet?

Hey cplmac!

This might answer your question!

Use Pyrodex "P" Instead Of 4F Blackpowder

The topic has come up from time to time about using Pyrodex instead of 4f black powder for ejection charges. We have found the secret to using Pyrodex as a direct substitute for 4f black powder after conducing a series of ground tests and successfully flying 11 rockets with various sized ejection charges all of them using 100% Pyrodex instead of black powder.

 

The Pyrodex to use is Hodgdon "P" or FFFG Equivalent for ejection charges in PVC pipes sealed on one end or phenolic tubes sealed on one end. The sealed end is usually a PVC fitting with a hole in the middle for the electrical wires to the e-match or flashbulb. If you use a flashbulb, make sure the tip of the flashbulb is in the Pyrodex powder. Flashbulbs do work with the Pyrodex as we had 100% success in ground tests and two flight tests.

 

We used an equivalent volume of the Pyrodex "P" as a substitute for the 4F black powder. After putting the powder in the open end of the tube, we would put a wadding material in the tube. We filled the rest of the open tube with wadding so that the powder stays at the base of the tube.

 

On the open end of the ejection charge tube, we would normally use masking tape to seal the tube when using black powder. For the Pyrodex, we used electrical tape to seal the tube. We put one piece across the open end of the tube with the ends of the tape going down the side of the tube. Then, we put another piece of electrical tape across the open end of the tube 90 degrees to the first piece with the ends going down the side of the tube. Looking at the end of the tube, it makes a cross pattern. Finally, we put a piece of electrical tape circumferentially around the tube at the end where we had put the electrical tape. This piece of tape goes over the ends of the first two pieces of tape. That's it.

 

We are flying just with Pyrodex now as it does not leave the residue or stink you get with black powder. Also, it is generally easier to obtain than blackpowder.

 

This was found on : http://www.space-rockets.com/cpnews.html

Hope it answers your quetion!

Cya

P.S. If it works as a ejection charge for model rockets must be it will work for a shell! What do you guys think?

[cplmac]

I think the pressure dynamics inside a rocket motor with nozzle are dramatically different than those of a mortar firing a shell. Very interesting though, thanks for the information. I might try a pyrodex rocket just for the hell of it, I think I still have a pound or so laying around somewhere.

[FrankRizzo]

From what I understand, it's the burn speed of Pyrodex that disqualifies it as a good rocket fuel. Even compressed as you say, it simply burns too slowly to provide optimum performance, or even close to it.

 

And there's another danger, if what I read is true: Pyrodex is based on smokeless powder. Confine it TOO much, and it can detonate under the right (wrong?) conditions. That may or may not be correct, I'm not 100% certain. But if true, that's another MAJOR consideration.

 

To be fair, in Bill Bahr's 2005 "3-inch Color Shell with Report" seminar/class, we used Pyrodex as the burst charge. It worked, but was noticeably weaker than a good, hot, BP burst charge. Whistle mix would have been my choice, personally, but in a beginner class it makes sense to use BP.

 

M

Did he use that crap again at last year's PGI convention seminar? I took the class in 2005, and was very dissapointed in the burst of my shell. Aditionally, the bottom shot was bunk as well.

[Mumbles]

I watched a bunch of the shells on the open B line this year. I wasn't extremely impressed with the Bahr shells. I definatly think they improved the bottom shot this year. It wasn't full bottom shot quality, but still it was a nice bang. Most people timed it way too early though. I have a feeling he used Pyrodex as the burst. They kind of poofed open, but definatly not the pounding open or slamming I like and strive for.

[TheSidewinder]

My mind might be playing tricks on me again, I dunno.

 

I remember way, WAAAY back, when Pyrodex first came out. It's from that period that I seem to recall getting my info re: smokeless based. I do know that the original formula has been changed, largely to address problems with fouling (which Pyrodex was supposed to SOLVE, not make worse!) and some other problem. I THINK the problem was that on rare occasions a gun barrel, that was *perfectly sound*, would rupture because of overpressures. First experiments seemed to point to actual detonation of the Pyrodex under the wrong conditions.

 

I could be off-base on this, but I've heard anecdotal evidence that that problem still remains.

 

Frank, the reason for bottom-shot failure in 2005 was a combination of things, I think.

 

1) Beginner's sloppy technique.

 

I saw a LOT of people slopping paste over the timefuse and crossmatch. I had a LITTLE experience by that time, so I was careful and neat when I built my shell. Also, people punched holes in the timefuse that were ragged, sloppy, offcenter, etc. I think they got paste INSIDE the timefuse doing this. I know I made sure my awl was clean, straight, and dead center on the timefuse, then pushed through *without* twisting the awl (which Im told can smear the asphalt outer coating, INSIDE, therefore preventing passfire of the crossmatch to the timefuse). Net result? MY shell lifted, burst, and the bottom shot worked, JUST FINE (albeit a slightly weak burst, and a somewhat tame bottom shot).

 

2) We crossmatched both shell and bottom shot with genuine Thermalite which, as I have said in another post here, MUST have the outer plastic coating taken completely OFF, or it may fail to take fire from the burst of the color portion of the shell.

 

Since I started doing this with my Thermalite, I have had a ZERO failure rate of my shells. I told Bill of this problem when I first saw him at the '06 PGI, along with the "fix" that I've used. I'm not sure if he took that suggestion to heart.

 

Bill may well have used Pyrodex for burst again in '06. In '05 he used it because he had it, wasn't using it, and wanted to get rid of it. (I know he tries to keep the class as economical as possible, and I'm glad he does.) Whether he had enough left to cover the class in '06, I don't know, but I suspect so. I think he had quite a bit left after the class in '05.

 

And if you took his class in '05, I was in it with you and didn't know it.

 

Like Mumbles, I noticed the result of the '06 class, too. The success rate of the bottom shot *WAS* a lot higher. But a mediocre burst, as he said.

 

Can't wait until Fargo, now!

 

M

[Explosive]

Hey!

Well I'll try out the Pyrodex P (FFFG) to see if I can get ''Good Enough'' results hopefully I will... I should get it within the next week or 2 along with the 2 1/2'' Shells and fuse... I'll let you guys know how they turn out... Last night I made a 1 1/2'' Shell, Hopefully I still got the trick!

Cya

P.S. If I use the Pyrodex in the burst would it be usefull to add some Whistle? Thanks!

[fredjr]

I took Bill Bahr's '06 class (just to kill some time) and we used BP for the burst. His construction methods work but there are easier ways. The bottom shots he brought premade so can't say what the mix or type of Al was. IIRC he said they had 50 grams flash. The timing issues on the bottom shot were due to where the crossmatch was placed. There was around 1.5 to 2 inches of time fuse sticking out of the bottom shot (waste). He told us to crossmatch too close to the can. But I put mine farther up.

[FrankRizzo]

Frank, the reason for bottom-shot failure in 2005 was a combination of things, I think.

 

1) Beginner's sloppy technique.

 

I saw a LOT of people slopping paste over the timefuse and crossmatch. I had a LITTLE experience by that time, so I was careful and neat when I built my shell. Also, people punched holes in the timefuse that were ragged, sloppy, offcenter, etc. I think they got paste INSIDE the timefuse doing this. I know I made sure my awl was clean, straight, and dead center on the timefuse, then pushed through *without* twisting the awl (which Im told can smear the asphalt outer coating, INSIDE, therefore preventing passfire of the crossmatch to the timefuse). Net result? MY shell lifted, burst, and the bottom shot worked, JUST FINE (albeit a slightly weak burst, and a somewhat tame bottom shot).

 

2) We crossmatched both shell and bottom shot with genuine Thermalite which, as I have said in another post here, MUST have the outer plastic coating taken completely OFF, or it may fail to take fire from the burst of the color portion of the shell.

 

Since I started doing this with my Thermalite, I have had a ZERO failure rate of my shells. I told Bill of this problem when I first saw him at the '06 PGI, along with the "fix" that I've used. I'm not sure if he took that suggestion to heart.

 

Bill may well have used Pyrodex for burst again in '06. In '05 he used it because he had it, wasn't using it, and wanted to get rid of it. (I know he tries to keep the class as economical as possible, and I'm glad he does.) Whether he had enough left to cover the class in '06, I don't know, but I suspect so. I think he had quite a bit left after the class in '05.

 

And if you took his class in '05, I was in it with you and didn't know it.

 

Like Mumbles, I noticed the result of the '06 class, too. The success rate of the bottom shot *WAS* a lot higher. But a mediocre burst, as he said.

 

Can't wait until Fargo, now!

 

M

Like you, I'd had just a *bit* of previous experience with Italian construction methods prior to attending Bill's class. I'd seen Louis Semenza's AFN video a few times and read Hardt's excerpts from Pyrotechnica, so I at least understood what each portion of the assembly process was working toward. Funny thing is we were probably each one of the 4-5 people that were going around helping people tie clove hitches and spike their shells

 

I think you may be right about the thermalite being the cause of my bottom shot trouble. I don't remember purposely stripping back the yellow plastic wrap when crossmatching it. Others on the B-line were thinking that maybe the timefuse was to blame because so many of them didn't work...who knows. In any case, the bottom shot didn't go off and ended-up in the cornfield as landmine.

 

I remember wanting to wait until it was dark to shoot my shell, so a group of us trudged down to the magazine (remember that mud...damn), picked up our shells and Dixie-cup flying-fish mines, and then had to hurry to get them fired before curfew. I was so disappointed with the weak burst and that my bottom shot didn't go off, but I did get to fire some of those screwed-up "Mickey Mice" pattern shells that night, so all was good

 

I can't wait for Fargo either! We'll definitely have to get together one night and have an APC forum party.

[TheSidewinder]

Frank,

 

"Funny thing is we were probably each one of the 4-5 people that were going around helping people tie clove hitches and spike their shells"

 

LOL.... I think we were!

I know I was running around doing just that. Most people in that class had ZERO experience building, and having someone show them "how-to" the first time was a real help, I think.

 

 

Mumbles,

 

You're welcome to pitch your tent on my site if you want. I'll have my folding trailer as usual, but it's not so big that there'll be no more room. And if you have no tent, you can borrow my old (but good) one.

 

I had forgotten about that 1st-timer category. Looks like I better read up on that one, too. I think I'll do Beginner Level I this year in addition to whatever else I can manage to build.

 

Looks like Ma Nature is gonna dump on us today. Whee.

 

M

[ThaYankee]

I fired a new shell last week

It's a 3" shell - Chrysanthemum to D1 Glitter.... only the D1 Glitter wasn't really the way it should be.. I probably didn't use the right aluminum (not fine enough).

 

http://s107.photobucket.com/albums/m318/Th...l-D1Glitter.flv

[pudidotdk]

Nice shell, nice break..

[Explosive]

Hey!

Nice Shell and a damn good break!

 

As for all the question about the Pyrodex... I received my FFFG grade(Pyrodex P) today and was doing tests in my mortars(1 3/4") And launched a 50 gram golf ball at the right height with 8or 9 grams of Pyrodex! It may be alot but at leat it worked... It let off a nice bang when it came out of the Mortar... So hope this may answer a few questions!

Cya!

P.S. I would like to thanks everybody that helped me! And Mumbles for helping me get the right grade(FFFG)

[Wyvern]

I fired a new shell last week

It's a 3" shell - Chrysanthemum to D1 Glitter.... only the D1 Glitter wasn't really the way it should be.. I probably didn't use the right aluminum (not fine enough).

 

http://s107.photobucket.com/albums/m318/Th...l-D1Glitter.flv

If you dont mind sharing, what did you use as the break charge and were they paper or plastic hemis?

[ThaYankee]

I fired a new shell last week

It's a 3" shell  - Chrysanthemum to D1 Glitter.... only the D1 Glitter wasn't really the way it should be.. I probably didn't use the right aluminum (not fine enough).

 

http://s107.photobucket.com/albums/m318/Th...l-D1Glitter.flv

If you dont mind sharing, what did you use as the break charge and were they paper or plastic hemis?

It where paper hemi's and I used flash for break... this time I used about 7-8 grams flash, but normally I use about 4 -5 grams flash for a 3" shell. I used a lot of flash this time to check the strength of my stars and if they ignite well... and they pass the test;)

[hashashan]

Hey guys any one ever tried to lift with H3?

im curious because i have a really crappy BP no ballmill

is there any way i can boost up my lift?

[ewest]

Not really, if you don't have a ball mill. Maybe someone else might come up with an idea.

 

You should really think about buying or making a mill, they're pretty simple to make and they're just about the one tool you can't do without. Even a small rock tumbler is better than nothing.

 

If you don't have a way to make good BP you won't be able to do much in the way of pyro.

[Tse-Tse]

Hey guys any one ever tried to lift with H3?

im curious because i have a really crappy BP  no ballmill

is there any way i can boost up my lift?

 

I think it´s possible. I know a few colleagues who make pretty good lift BP at home and they don`t have ball mill. I have also tried it and it`s functioning.

It`s about good charcoal, fine chemicals, homoginity and density of final product.

But the whole procedure is quiet time spending, so in my openion it`s better to buy lift charge and to spend the time with making bigger shells

If you are intersted in, I can write some short turorial how to do it.

 

I also know guy who uses slower flash powder as lift, it`s not very recommendalbe way and it brings a lot of problems but it works, somehow.

 

Bye

[ActionTekJackson]

me once added some whistle mix, but too much blows your mortar.

i also tryed flash, but that didn`t work. flash was just too strong.

What the? No... just... no... flash should never be used as lift, even benzolift is a little shaky... Flash problem watch that then tell me its safe... Yes that piece did hit someone.... pretty hard too... There are ways to make good lift without a ball mill.

[hashashan]

I am actually building a ballmill

for some reason my previous BP (pine charcoal) was much stronger then the willow one ... no reason why ... i make it the CIA method

but now with the willow im really dissapointed. i lift 1/2 ... and that really sucks

[Karlos]

Hallo. I was tested 90mm(3,5 inch) shell, but stars had different trajectory, because burning was very quick.

I used 50/50 KP and Al for stars.

Bye.

photo:

http://img03.picoodle.com/img/img03/8/4/13...37m_a430693.jpg

video:

http://n-joy.cz/?uiqurl=bxOSnPiyk29rQ1jo

 

Sorry, for my english.