[CrashTestDummy]

As some may know, my wife and I are part of a crew that puts on a commercial fireworks display at a local country club. We have been doing it for about 15 years, or so, and are both Pyrotechnical Technician license holders. (IMG:http://www.frrax.com/rrforum/style_emoticons/default/2thumbs.gif) We started back in the late 1990's when one of the members of an Impala SS club we belonged to revealed that he did that kind of work, and if anyone wanted to help, it's about the most fun you can have with your pants on. Back then, the show was 'manual'. We'd start the afternoon with augering holes in the ground to set some steel pipes of several different diameters (usually 3" to 6"). Once that was done, and it got dark, we'd load the shells into the tubes, and light them off with a road flare. TONs of fun when you're standing beside a 6" steel pipe sitting in the ground, and the shell launches into the air, then exploding about (hopefully) 600 feet directly over your head! Crazy, fun stuff, although we have come home with holes burned in our clothes, but still fun.

At that site, a county park, we'd make a club event of it. There'd be 20-30 Impala SSs, we'd bring grills and have a club picnic while we set up the event. Then, since the cars were too close, would 'caravan' the cars out to a safe distance and get to the show (probably 500' away). We ended up with just about the entire crew from the local fire station join us for food, and support. Great fun!

Anyway, the shows are now 'electronic'. That is, we have a trailer that has ABS tubes mounted in a bed of sand. We load ALL of the tubes, wire them to a circuit bar, then run cables from each circuit bar to the controller panel. When it gets dark, we roll the trailer out into a field, cable it up, cable any extra 'cakes' they have purchased, and set them off with the touch of a little battery power to the right contact on the control board. You're still nearly under the shells when they go off, but we're probably 100' away from the tubes. It's safer, and the work is different, and while fun, the big adrenaline rush is not quite there..... unless one goes off short, or flies overhead, which we've had before.

Anyway, pictures are worth 1000 words, so here's some pictures of the setup and the event:

(IMG:http://media.fotki.com/1_p,rtwfttbtrsfsgfkxgddbwddrbddf,vi/bsbfrdbrrxbrqggwgwsxbsgbrssfg/5/1331095/14009024/Trailerloaded-vi.jpg)

The trailer, loaded, wired and rolling out to the site. Since we do this at a country club, we usually load and wire the trailer under the cover where the greenskeepers are and roll the trailer out to one of the fairways, or green. Yes, all the quotes from the movie 'Caddyshack' are said as we get ready.

BTW: 10,000#+ trailer, V10 turbodiesel Tuareg FTW!!

(IMG:http://media.fotki.com/1_p,rtwfttbtrkrqfdgxgddbwddrbddf,vi/brqggwgwsxbsgrftrgkxbrqsqrkst/5/1331095/14009024/akesreadytotaketothelaunchsite-vi.jpg)

Our truck loaded up with the 'cakes', which are pre-packaged shells that will go off serially at one time. This year they used mostly 3" and 4" cakes. the 3" cakes had 25 shells in each pack, and the 4" shells held 9. They don't seem to be as strong as the individual shells, but, again, we're probably 100' away, so the whole thing seems tame now.

(IMG:http://media.fotki.com/1_p,rtwftdsrwgdqkktxgddbwddrbddf,vi/rsrfbgrqqxbsfsskdbqxbrqggwgws/5/1331095/14009024/IMG_6348-vi.jpg)

The cakes set up on the fairway, wired and ready to go.

(IMG:http://media.fotki.com/1_p,rtwftddfgrgrkgfxgddbwddrbddf,vi/bsgbrssfgxbsfsskdbqxbsgrftrgk/5/1331095/14009024/IMG_6354-vi.jpg)

The control console in the foreground, trailer and cakes connected and ready to go. The console only has about 20 ports on it, and we typically have 35-40 cables, so we're shuttling cables back and forth during the show.

(IMG:http://media.fotki.com/1_p,rtwftddktbgktfwxgddbwddrbddf,vi/brqggwgwsxbsgrftrgkxbsfgbftkk/5/1331095/14009024/IMG_6349-vi.jpg)

Looking down one side of the trailer, all wired up. The big tube is for the 6" diameter shells. The shells go up about 100' per inch in diameter.

(IMG:http://media.fotki.com/1_p,rtwftdfwgbwfqkkxgddbwddrbddf,vi/bsbfrdbrrxswtffststxkkrqfkbdt/5/1331095/14009024/IMG_6351-vi.jpg)

Another shot of the trailer. Wired and ready to rumble. (IMG:http://www.frrax.com/rrforum/style_emoticons/default/rolleyes.gif)

More to follow.

This post has been edited by CrashTestDummy: Jul 6 2016, 09:04 PM

[CrashTestDummy]

Yes, the shell is shaped kind of like a hot-air balloon. I found a picture:

(IMG:http://media.fotki.com/1_p,rrdqfgwdwgfwdkdxgddbwddrbddf,vi/sbqwbwgbdxsdfwwkrbsxsqddgfwkw/5/1331095/13756766/6inchgoldenpalmshell-vi.jpg)

The 'basket' portion is the launching charge, which is pretty much gun powder that launches a more-or-less spherical shell, and lights the fuse to explode the shell. You light them off with a fuse, which is, I think, chordite. You can light that fuse with electricity, via a 'squib' (exactly the same as what they use to light model rocket motors), or fire. Once lit, that fuse burns at about 400 ft/sec. When it lights, you can actually hear the >FOOM< as it burns into the tube, then there's the boom when the launching charge goes off. For the manual shows, we'd bury steel tubes of different diameters about half way into the ground. During the show, the 5" and 6" shells will actually plant themselves deeper (probably a quarter of the length of the tube) into the ground. Heck, the trailer jack pad sinks into the ground during the show. Those have to be dug out when the show is done.

Heh, when we were doing the manual show, we'd let different people take turns with different tasks during the show. One would 'rake', or pull the spent and usually still burning bits of old shell out of the tube (with a stick that has nails driven through one end, it looks a bit like a bottle brush), then another would load (with the proper orientation) the shell, and set the fuse out, and pull the cover. Then one would come by and light the fuse, step to the next tube and wait for that charge to go off, then light the next shell. This process is continued until we run out of shells.

As Kevin says, they can kill you. I guess that's part of the 'fun'. You just have to be very careful. We wear hearing and eye protection, as well as long pants and long sleeved shirts and hats that you won't mind getting burned. During the show, you put no part of the body over the tubes, in case a charge goes off due to all the burning embers still in the tube. The launching charge launches the shell about 100'/inch of diameter of the tube. That is, a 3" shell will go up about 300 feet, and a 6" shell will go up about 600'. So it's a lot of power. If you drop a shell into the tube upside down, when it lights, you immediately know that happened. The tube becomes a big blow torch for a half second, then the >BOOM!<. 5" and 6" shells have the power to blow the tubes up, or bell-bottom them and lift them out of the ground. The guy who puts the show on had that happen once, a 6" got dropped in upside down, the fuse was lit, and the thing went off. He said the tube bell-bottomed, and launched out of the hole about 10', and then laid itself down on the ground. No one was hurt, so they continued with the show. The bottom plate of the tube was still in the hole. They never found it.

We actually got to do the show where we're doing it now, because of such an accident. I think they hurt someone, because the tube blew up, blowing a crater in the ground. It can be a mess.

The electronic shows are mostly shot from a trailer, like what you see above. They have ABS tubes of different diameters which are set in sand up to about half of their length. The unloaded trailer weighs about 10,000' because of all the ABS and sand. The Grand Finale is shot from boxes holding about 40 3" ABS tubes, and most of the cakes are just thick cardboard tubes that are glued and strapped together.

Yes, the color of the display is created by using different powdered minerals and metals. They get the different patterns by packaging the shells differently, usually with thick paper dividers or bundles wrapped up in the spherical shell. The colors and patterns are all part of the magic of the fireworks, part chemistry, part art. The charge to set the shell off is the same stuff they use to launch the shell, probably pretty much gun powder.

The guy who runs our show said he heard of a recent show where they had made a custom-sized 22" shell. It was for a cancer benefit. It's supposedly the largest shell ever made. They used pipeline pipe to launch it from, and yes, they had to get permission from TxDPS and the FAA. So that shell went about 2000' in the air before going off. (IMG:http://www.frrax.com/rrforum/style_emoticons/default/ph34r.gif)

This post has been edited by CrashTestDummy: Jul 8 2016, 01:55 PM