6 inch shell of shells

[fredhappy]

This is a shell I've build and shot recently.

 

Much to my dismay the first insert blew blind. I ran short of 6 mm stars during building, and filled 2 inserts with 5 mm stars which were inadequately primed.Stars were too smooth. Also my rising kamuro 2"comet was too long again....tough titty..

 

Apart from these two imperfections, the shell itself was quite spectacular. Timing of inserts was ok I guess, I like the inserts to go off in about 2 seconds instead from all at once . These large multibreak round shells are a lot of

fun to build!

[BJV]

This is a shell I've build and shot recently.

 

Much to my dismay the first insert blew blind. I ran short of 6 mm stars during building, and filled 2 inserts with 5 mm stars which were inadequately primed.Stars were too smooth. Also my rising kamuro 2"comet was too long again....tough titty..

 

Apart from these two imperfections, the shell itself was quite spectacular. Timing of inserts was ok I guess, I like the inserts to go off in about 2 seconds instead from all at once . These large multibreak round shells are a lot of

fun to build!

 

WOW!! Very nice fredhappy.

I sure will try one of these. One question how many hours did you

put in this shell?

Thanks for sharing,

BJV

[FREAKYDUTCHMEN]

Hi Fred, I think a 6" round shell can hold 12 2" shells. But you'll need another technique to build it

[fredhappy]

@bjv: Thanks for your comment. It takes about 2 evenings to build. Basically I've got all the ingredients such as mcrh 3/1( I use a tempered breakcharge) and stars ready to use. I make myself a nice cup of coffee , put on some old Miles Davis recordings and start building....

I photographed the whole construction in tutorial style. If you have any questions, or would like the pictures, just drop me an email....

 

@FREAKYDUTCHMAN: I'd be interested to know how..hehe. ..I ve tried cramming in 9 2" inserts, but I just could'nt close the shell. I like to attach little comets to the insert shells, this makes it a bit of a hassle to fit them in snugly, since they have this bump on them.

Edited March 30, 2011 by fredhappy

[burningRNX]

Cool shell fred, I am planning one too.

Hi Fred, I think a 6" round shell can hold 12 2" shells. But you'll need another technique to build it

Like this?

And rotating the other hemi an inch so it will fit? (inserts passing equator) this was my goal to fit 12 pieces

Or another bulding technique? (japanese style?)

[FREAKYDUTCHMEN]

Yes like Japanese, first 3 2" inserts in a 6" hemi, then another 6 above them, then place the other hemi with a ± 8cm disc cutted of the top and put in the last 3 inserts. Fill with meal coated ricehulls and tap on the sides so the hulls will fall down.

[fredhappy]

Yes like Japanese, first 3 2" inserts in a 6" hemi, then another 6 above them, then place the other hemi with a ± 8cm disc cutted of the top and put in the last 3 inserts. Fill with meal coated ricehulls and tap on the sides so the hulls will fall down.

 

Hehe....smart indeed. Makes me think about the way Karlos constructed that petal shell, with a loading hole on top. I tend to just fill the hemis and snap them together. I will give this a try on short notice...thx!

[davis050594]

Beautiful. The inserts looked like big shells themselves!!

[ExplosiveCoek]

Yes like Japanese, first 3 2" inserts in a 6" hemi, then another 6 above them, then place the other hemi with a ± 8cm disc cutted of the top and put in the last 3 inserts. Fill with meal coated ricehulls and tap on the sides so the hulls will fall down.

 

Only MCRH, no booster?

How many layers of pasting would a shell like that require to still get a decent spread of the inserts (without destroying some of them of course )?

 

Looked like a fun project to me fred ! Keep 'm coming!

[fredhappy]

Only MCRH, no booster?

How many layers of pasting would a shell like that require to still get a decent spread of the inserts (without destroying some of them of course )?

 

Looked like a fun project to me fred ! Keep 'm coming!

 

With these type off shells absolutely no booster!!

 

I've tried boosting a 6"thousand salute shell with a little bit of hotflash for more spread, resulting in a very comic and loud explosion during break, destroying every salute insert in one giant dry thump with an expanding titanium cloud.

 

Also, 3 layers of 3 strip is more then sufficient for these shells. I even use a "tempered" break for these large multi break insert shells consisting of MCRH with a ratio of 3/1 meal/ricehulls. For normal shells I use a ratio of 5/1.

 

Spread can be achieved with the timing of the inserts.

 

@davis: thanks. My shells started improving big time once I started rolling my stars instead of pumping them. Even with these tiny 2 inch shells an excellent symmetry can be achieved with round rolled stars.

Of course for added timing precision you need a good set of multiple screens, preferably going up from 4 mm to 24mm in 1 mm steps.

[ExplosiveCoek]

On passfire there's an article to where they put some inserts in the shell to (2'' spherical IIRC). Nevertheless they do at a 'slowflash' burst enhancer and 24layers of pasting on that 12'' shell. Maybe it depends to on how strong the inserts are made?

 

With salutes you've got to be really certain that there are no gasleaks, if one insert go's off they'll all go. A friend of mine had the same problems to in a beraq shell.

 

By spread I actually meant symmetry more then distance off the inserts.

 

 

You're right about rolling stars, it really gives good results !

[Mumbles]

It probably depends a lot on the relative size of the inserts. In a 12" shell, the inserts are in the realm of conventionally sized stars, so they might be able to be broken as normal. In a 6" shell however, the inserts are FAR larger than any conventional star you may put in.

 

I doubt it is a real effect, but in my mind when you have large inserts in a shell, and the burst is all around them, I envision kind of a crushing force as all the lift burns around the inserts and rapidly increases the pressure. In a typical star shell all the pressure is coming from the center and pushing everything outward, instead of all around it.

 

I've personally never seen a reason to be boosting such large shells. Multi-petal and other situations where the burst quantity is limited is of course different.

[fredhappy]

On passfire there's an article to where they put some inserts in the shell to (2'' spherical IIRC). Nevertheless they do at a 'slowflash' burst enhancer and 24layers of pasting on that 12'' shell. Maybe it depends to on how strong the inserts are made?

 

With salutes you've got to be really certain that there are no gasleaks, if one insert go's off they'll all go. A friend of mine had the same problems to in a beraq shell.

 

By spread I actually meant symmetry more then distance off the inserts.

 

 

You're right about rolling stars, it really gives good results !

 

Gasleaks are unknown to me. Ive never experienced one. You just have to use a good quality hotglue to glue in the timefuse, and also paste very thorougly round the timefuse when pasting inserts. I only make binary salutes. This means that about 1/3 of the salute shell is left unfilled. This influences the structural integrity of the hemisphere . In plain language: the hemisphere is more weak when filled with a binary salute, since there is air in it as opposed to a kamuro insert, which is really tightly filled. For normal shells this is not a big problem, but when using these binary salutes as inserts you have to do a good job on pasting to strengthen the hemispere.

[ExplosiveCoek]

Mumbles, you're right about the inserts being significant smaller for a 12'' shell but IMO that would only result in more total pressure on the inserts?

About using flash in large shell's, it's kind of a trade-off. If you want to paste more, you'll need less flash (when using just blackpowder for the break)

 

Fred, I do not agree with that. How can you say for sure there wasn't a gas leak who set of some of the inserts prematurely?

I've seen the beraq shell in person, it was only a 3'' can shell however. Even though one of the inserts went of when the shell broke, still two of the inserts survived the break (they went off at the right delay, delay was made with timefuse). There is a high possibility to that the other timefuse's just weren't able to catch fire and that the iserts weren't destroyed at the break.

Personally I think it's not really smart to use binary mixed inserts, you've already given the reasons for yourself.. They contain quite some empty space.

 

Probably you were using more flash in the insert then my friend was (1 g), so that would explain why all the inserts went of/where blown blind IMO.

Edited April 1, 2011 by ExplosiveCoek

[fredhappy]

Mumbles, you're right about the inserts being significant smaller for a 12'' shell but IMO that would only result in more total pressure on the inserts?

About using flash in large shell's, it's kind of a trade-off. If you want to paste more, you'll need less flash (when using just blackpowder for the break)

 

Fred, I do not agree with that. How can you say for sure there wasn't a gas leak who set of some of the inserts prematurely?

I've seen the beraq shell in person, it was only a 3'' can shell however. Even though one of the inserts went of when the shell broke, still two of the inserts survived the break (they went off at the right delay, delay was made with timefuse). There is a high possibility to that the other timefuse's just weren't able to catch fire and that the iserts weren't destroyed at the break.

Personally I think it's not really smart to use binary mixed inserts, you've already given the reasons for yourself.. They contain quite some empty space.

 

Probably you were using more flash in the insert then my friend was (1 g), so that would explain why all the inserts went of/where blown blind IMO.

 

Yeah, I can understand your opinion. It is all a matter of preference I think. I like the binary method due to its simplicity, and the fact that I don't have to mix any flash in the open, which I really dislike. I don't do little

gram inserts, mine are 40 to 60 grams, so I don't like mixing that amount in the open. The downside is that these salutes are a bit weak for use as inserts.

They are however perfectly usable as inserts as long as you paste well. 90lb kraft and wheatpaste gives excellent rockhard results. I probably did a lousy job at pasting, so the salutes were crushed. I've succesfully made 5 inch shells with 2x2.5" binary mixed Ti salutes.

I call these two Ti salute shells, and they've always worked fine.

[allrocketspsl]

This is a shell I've build and shot recently.

 

Much to my dismay the first insert blew blind. I ran short of 6 mm stars during building, and filled 2 inserts with 5 mm stars which were inadequately primed.Stars were too smooth. Also my rising kamuro 2"comet was too long again....tough titty..

 

Apart from these two imperfections, the shell itself was quite spectacular. Timing of inserts was ok I guess, I like the inserts to go off in about 2 seconds instead from all at once . These large multibreak round shells are a lot of

fun to build!

 

awefully great shell for running out of stuff,lol timing all good 10 stars