Aerial Shells

[Mumbles]

I think you'd be fine with bottom fusing. I bottom fuse all my ball shells. Even that 8" double petal that took me over a year to make. If you're confident in your methods you should have no problems. I use hot glue on the inside and the outside, and it's held up to everything. If you're really worried, you can use 2 time fuses. Some say it creates a weak point, but I feel better with a redundant ignition system.

 

I wish I took a picture of how I did this with the 8" double petal to show you how I got both passfires to the center. Frankly I can't remember how I did it

[qwezxc12]

Trying some precision timing with visco as I've had good results so far making home-made "time-fuse" with it. I'm in the process of putting together some 4" and 5" can shells and I'm making two timed report shells...I've heard them called Timed Hammers, Draw-out Shells, and Rondelles...not sure what the proper nomenclature might be (I'm sure someone will chime in)

 

So the plan is to build:

 

A 4" 7-timed report shell, firing in order at .2 sec intervals, from 1 sec to 2.2 sec and

A 5" 8-timed report shell with bottom-shot, firing in order at .4 sec intervals, from 1.4 sec. to 4.2 sec, followed by the bottom-shot at 4.6 sec.

 

I'm punching the fuse instead of splitting to cross-match. I'm also using 3mm Chinese Visco instead 3/32" American. Timing results seem consistent so far....we'll see, I guess. Here's a pic of the 5" shell insert fusing:

[tentacles]

The thing I found with visco as time fuse is that you've gotta put *good* tape on the fuse, or it will quickmatch between the tape and the fuse. Aluminum tape worked fairly well, and duct tape (cheap stuff) worked best, because of it's thick gooey adhesive and flexibility.

[psyco_1322]

I don't think visco would "quick match" as its not easily lit by sparks on the outside. I have used masking tape for years, no problems. I used to make QM from chinese visco, the stuff that looks like its fill with flash, from skylighter. I would just lay down a piece on some 1" masking tape, run a razor blade down the center of the fuse, cutting it open like you would a baked potato, then fold the tape shut over it. Made good QM, but it wasn't quite economical.

[Brakkie]

I've been having some problems with my shells lately. I've been experimenting with fiberglass reinforced tape for use on my paper hemis. I know it's not normally used on paper hemi's but because of the time savings I decided to give it a shot. I've had failure after failure now. Sometimes the break would (oddly) not be strong enough. Other times with less pasting the shells would break too hard and throw the stars blind.

 

Anyone has any experience with pasting paper hemi's with fiberglass reinforced tape?

 

I've tried, pulverone, pulverone and slowflash & pulverone with various ammounts of KClO4/GD as a booster. None of them gave impressive results except for a shell with pulverone and 10 grams of slowflash (with coarse KNO3).

[Mumbles]

A hammer shell has alternating colors and reports. It's supposed to replicate a hammer and anvil. Tap-bam, tap-bam, tap-bam...(as many sets as you want)......BOOOM

 

Rondelle is when the salutes are thrown out in a circle and go off sequentially in said circle.

 

There are other timing patterns, but I'm not familiar enough with them, and they don't get as defined names. Fusillade, cannonade, etc. They're in the PGI competition book if you're interested on the PGI website.

 

I don't have my copy of Fulcanelli around to definitely know what a draw out shell is. I think it is a break of color followed by 4 sequentially timed salutes. To me it sounds like your timings are a bit short. Then again I like to live dangerously. The shortest timing I use is 1/4" on a spolette, which gives around .75 second delay. I suppose it's better to be safe than sorry on the first try. These are for color inserts generally too, so you need a bit more time to be able to comprehend them and not pile them up.

[tentacles]

I don't think visco would "quick match" as its not easily lit by sparks on the outside. I have used masking tape for years, no problems. I used to make QM from chinese visco, the stuff that looks like its fill with flash, from skylighter. I would just lay down a piece on some 1" masking tape, run a razor blade down the center of the fuse, cutting it open like you would a baked potato, then fold the tape shut over it. Made good QM, but it wasn't quite economical.

 

It's doesn't quick match, per se, in the sense that the fuse burns... but the fire can slip up past the fuse and flowerpot or explode prematurely. Usually you get an almost-flowerpot, the pressure of the lift gases just pushes right up the tape. It helped to use good, very sticky masking tape or better yet, duct tape.

 

edit: REALLY nice weather today so I put up a couple shells. One was the Win12 stars a cut recently.. they burn too fast! I need to get my hands on some regular hardwood lump charcoal.. I used alder in these and they are streamer stars instead of glitter. Here's the video (5mb) - It's my first try with the new camera so it's a bit overexposed. I'll try it with the EV set to -2 next time.

 

 

another edit: It would have helped if I hadn't shot the shell to the moon, I suppose... It was pretty high up there for a 3. 12g of lift was way too much!

Edited December 27, 2008 by tentacles

[qwezxc12]

...To me it sounds like your timings are a bit short. Then again I like to live dangerously. The shortest timing I use is 1/4" on a spolette, which gives around .75 second delay. I suppose it's better to be safe than sorry on the first try. These are for color inserts generally too, so you need a bit more time to be able to comprehend them and not pile them up.

 

Ahhh...thanks for the definitions.

 

I wrestled with the intervals, and finally decided I didn't want to go any longer; the 5" is finishing out at 4.6 sec as it is. I was afraid that the bottom-shot would be on the ground if I went longer that 5 sec. total. I was able to pierce the fuse on 1/10th increments pretty well, measuring with a Starret engineering rule.

 

Like I said, we'll see. It will only be a failure if I don't learn something

Edited December 27, 2008 by qwezxc12

[swervedriver]

12g of lift was way too much!

 

Nice shell, bet it was bright though? "12g is waaay to much" man I need to make a ball mill like yours. I used 20g on my last 3" shells

 

ps- damn, look at the snow! I live in s fl, havn't seen snow in years, it's beautiful.

 

edit: I mean the snow is beautiful.... well, it's nice here in fl too, but I would like to see snow this time of year.

Edited December 27, 2008 by swervedriver

[tentacles]

Thanks, swerve, it was quite bright. I took another look at the formula and realized that I shouldn't have used -400 mesh atomized aluminum, but rather the cheap +325 stuff. I'm sure the alder charcoal increased the burn rate as well. The stars don't look bad, but they're not what I hoped for. They still burn, and nicely, so I can't really complain. I just hope the ~1/2" stars are big enough for the 5's!

[psyco_1322]

I got kicks from the snow too.

 

He's like it was nice out! and I view the video and the ground is covered in like 4" of snow. lmao

[Zmuro]

I fired 3in shell yesterday just to test Willow Diadem Stars. here is the video: Willow Diadem

[jerronimo]

Very nice shell Zmuro, realy like the effect it's a bit like slow gold.

Never had any succes with WIN12 it just won't glitter and I used hardwood charcoal.

[qwezxc12]

Nice Zmuro...the break does look just like Slow Gold.

 

I went a little insert crazy last week...love vacation days for pyro!

I made Ti Farfalle for a 5" can, Golden Serpents to report for a 4" can, Perc/Resin & Ti Hummers for a 4" can, and a 3" Mad Lion...mentioned with no details on pg. 233 in F.A.S.T., so I'm winging it: 3" heavy wall salute core charged with 200g of fairly hot BP & steel with a 1/4" tangential vent, fireproofed with thick Sodium Silicate solution. I plan on lifting it HARD to get it way up there. Gotta make more hummers today...maybe make anther Mad Lion with a 3/8" vent to compare.

Edited December 28, 2008 by qwezxc12

[tentacles]

Anyone have the math to calculate shell height based on round trip, for a given shell size? I tried to test this shell today but it was too dark and I couldn't see it in the air, so I just have the video with the lift charge going, and a "plop" when it hit the snow. About 10 seconds round trip - I can be more definite later when I dissect the video. It's a 5" shell, I could measure it later to be more precise but the OD is very close to 4.75"

 

I lifted it with 1:20 ratio, so 1.5oz of lift for 1lb 14oz of shell.

[Chris]

I lifted it with 1:20 ratio, so 1.5oz of lift for 1lb 14oz of shell.

 

T = 10 secs => T/2 = 5 s.

 

Distance; X = (1/2)g(t^2)

 

(g = 9,81, earths gravitational constant which depends on location (unit: m/(s^2))

 

X= (1/2) x 9,81 x (5^2 )

 

This gives; X= 122,65 metre.

Edited December 29, 2008 by Chris

[tentacles]

Yeah but the thing is, it doesn't fall for half of the airtime - it's more like 2/3 of the time is spent falling. And then there's the whole drag thing. I managed to calculate the terminal velocity, should be somewhere around 165fps (50m/s). I'm guessing it was something like 600 feet.. Way too high! I hate 'wasting' my quick match with this testing, but maybe tommorow I'll try it with 1oz of lift and see how high it looks. Too bad my dummy shell broke on impact.. I guess the ice melting salt deadweight I used was too fluid. Split it clean in half!

[PyroMan LTU]

hello,

 

This weekend I shot my 4" shell:

 

It looked beatiful, but camera didn't catch brightness so it was blur, and I used too way too much lift - 24g of bp, what amount do you use?

And last thing that I was shoocked when next day I went for a walk near the place and I found shell shreads laying around about more than 150m away from explosion, I mean how did thay flew so far away? Thanks for replys

[tentacles]

Pyroman: How much did the shell weigh? I use 1/23 for 3" shells, and probably will use 1/26 for 4". IE for a 3" shell that is 160 grams I use 7-8g of lift. I lifted a 5" earlier tonight with 1/20 and it went somewhere around 700', based on calculation of the timing. WAY too high.

 

Those were some nice C8 stars - what charcoal was in those?

Edited December 29, 2008 by tentacles

[PyroMan LTU]

your bp is more powerful than mine, what charcoal do you use for it? I usaly follow the rule of 1/10... shell's weight was around 300g +-

yes, I get best charcoal streamer stars with birch, with is not coocked like charcoal for bp, but taken out of burned fire and smothered imediately.

[Chris]

For a rough calculation you can neglect air resistance. The rising and falling times are roughly the same. If you need a more precise solution, it would be optimal to have a figure for initial velocity V. To take drag into account, you have to calculate (Sigma)F = ma => mg + F(drag) = ma.

 

solving a = (mg + F(drag))/m , you can look up drag at http://en.wikipedia.org/wiki/Drag_(physics)

 

Use the solved acceleration in t=V/a, which gives time to apogee. Height is; X = Vt - (1/2)a(t^2)

 

I think that should be right.

[Pretty green flame]

Something for NYE

 

 

14 3" shells. You can see two of these in action here

 

The third one was a small 1.75" canister, put a bottom shot in there but it "nuked" when the break went off, was loud though

[Mumbles]

I've heard figures from Ned gorski of around 1/3 time rising, 2/3 falling. Conceptually it sort of makes sense that is taking off a lot faster than it's striking the ground. It seems to fit the data he presented, and fits with generally accepted fusing times. Eh, whatever works.

 

Nice stash ther PGF. Should be quite a show.

 

qwe, be sure to get that mad lion on video. I bet it's quite impressive.

 

I also got a chance to look up a draw out shell for you. It's actually a three break. It opens with a break of color with 4 sequentially timed reports. After the reports have extinguished, the second break of color goes off, then a bottom shot. Fulcanelli has it happen in an even cadence. The second color break happens as if it were a 5th report. The time between the opening of the shell and the start of the reports is the same as the time delay between each report. IE:

 

First break / Report #1 (1/4") / Report #2 (1/2") / Report #3 (3/4") / Report #4 (1") / Second break(1 1/4")

 

Each increment is the same. Fulcanelli uses 1/4" on the spolettes. I put the nominal lengths in the above timing diagram, but any timings could be used.

[psyco_1322]

Tentacles,

 

Check out Neds article on page 24 of Bulletin # 158, March/April 08.

 

It talks about what your interested in. Whether or not it answer your question, I dont know.

 

I hope this red alder works equally as well for me in terms of lifting things. I still am not sure what to do about the giant gaps I have on 3" shells, plastic or papers, they just dont fit good.

 

 

PGF, looks to be like there will be fun at your place on the last hour

[tentacles]

psyco: It seems to me like the chinese sell us all the undersized hemis.. The ones I have that came with the wasp for 5" shells.. are in face 4.4" in diameter! They're small enough, I can paste over on the wasp, use that layer for a hemisphere and STILL have a 1/4" gap after pasting again. And they're bigger than the 5" hemis Bonny has that commercial salutes came packed in, which are like 4.3".

 

And why do they make plastic hemis so small? Even if you paste in over the 3" hemis (pyroplastics), they are still sloppy as all hell in the gun - enough so that I use some as formers for making 3" hemis on my WASP, and again, sloppy fit.

 

Thanks for the heads up on the article - Unfortunately I don't think I got that one, I paid my dues that month. Aren't they supposed to send me the 'back' issues for the year?

Edited December 29, 2008 by tentacles