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Long burn effects


blasterman

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I've always been partial to long burn effects, and while I can build simple shells, I've found that simple BP rockets seem more practical for this application.. After several years of screwing around with various fuse combinations I finally got several rockets to work darn well.

 

http://www.blasterman.biz/fireworks/purple.avi

http://www.blasterman.biz/fireworks/crak_silvr.avi

http://www.blasterman.biz/fireworks/strobe.avi

http://www.blasterman.biz/fireworks/whistle.avi

http://www.blasterman.biz/fireworks/multi_.avi

 

{Note that I posted this here rather than the rocket forum because that forum seems focused on engine making. My engines were pressed by a friend while I did everything else.}

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woooooow
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do you mind sharing what comp u used 4 the first one?
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Details:

 

This project was driven by my intent from the start to create a mass of long burning stars or similiar, which is something I've experimented with in the past in smaller scale, but until this year I've put off. I started testing this spring with snow still on the ground with various comps and materials, and came to a lot of dead ends before I figured out how to make this all work.

 

I know how to make a basic small shell, and have the mixed up various effects comps before, but after playing around I concluded it was more practical to use chinese effect fuse such as 'falling leaves' and 'crackling flying fish', etc. Depending on the type, a length of 5-8" in a 1 1/2 bundle would deliver the duration and effect size I desired. However, this meant I'd need a helluva big shell - unless the more experienced people here have a better suggestion.

 

Anyways, because I was dealing with long bundles of pre-made fuse, black powder rockets seemed ideal. Also consider I have a strong background with amatuer rockets, both Estes and higher powered Aerotech composites along with building by own custom rockets. Simple Estes class engines make quick and dirty BP fireworks, but I've had significant reliability problems with both Estes and Aerotech engines and cato failures. So, this put me in a mad rush to quickly learn how to press my own engines which is something I've wanted to do for awhile, but was unable to get comfortable with before my self imposed deadline. Fortunatley a retired friend of mine who used to run a local amatuer rocketry club provided some of his own BP engines he had laying and is helping me learn the techniques of rocket making. His engines appeared to have similiar thrust to an Estes D12, but with a shorter burn time which was good. His were also consistent, so, that problem was solved.

 

Next problem to solve was the payload package. Custom rocket parts are easy to find, but rather expensive as 'one shots'. I also wanted to stick with bio degradeable parts that were also cheap to make and yet sturdy enough to trust. For body tubes I bulk ordered 15" x 2" shipping tubes from a local supplier for roughly $.30 each (thinnest walls I could fine). For nose cones I used paper drinking cups, which is an idea I got from the rocketry forum here. The engines were mounted inside the much larger tubes by using 1/4 balsa shims. I used the same paper cone with the tip cut off and cut down a bit to fit inside the tube and over the end of the rocket motor to serve as a kind of funnel to keep my payload in place and serve as an ignition bulkhead.

 

Because of the size of the rocket, stick mounting didn't work, and my ill fated tests to make that work were rather humorous. My intuition initially was that fin stabilized rockets wouldn't work with a tube 15x2", but after attempt after attempt at stick mounting failed to be stable I tried three 2x2" balsa fins, lug launching aka model rocket style, and the rocket flew fine. Further testing shows as long as my center of gravity was at least 1/3 forward of the rear, the rocket was dynamically very stable. Problem solved. As you can seem from the videos, all the rockets fly super straight, so the design works superbly. I had a self imposed payload limit of 100grams, but could probably go heavier (with testing of course).

 

My last problem to solve was my most irritating. Because of the large diameter of the tube my favored BP burst charge didn't work and the rocket would come flaming to the ground with everything intact. Screw this - when in doubt - use flash mix. Half a gram, still no luck. Went up to a full gram loosly confined in a baggy, and boom, even tighly packed fuse shot out fully ignited. I used a short piece of visco fast burn fuse stuck in the flash mix to insure ignition. Problem solved.

 

I experimented with different chinese fuse and found the best were falling leaves purple (see video), and all the crackling varieties especially silver which seems to have a lot of Mag or Ti in it because it throws off a lot of white sparks (see videos). Falling leaves burns much slower and 5" takes more time to burn than 8" of crackling or flying fish. I found regular flying fish fuse nearly worthless because it's not bright enough. The Crackling version is much better, although it's much thicker. Falling leaves white strobe is also worth using and is one of the videos I posted. In the future I might try different color fuses spliced together to form a transition effect, or start mixing my own comp and use drinking straws or simply roll it in long lengths of paper. I haven't figure out which route is cheaper. I need to get my engine making down pact first though.

 

Just a mental note: Don't use falling leaves fuse in place of good old utility visco unless you know it's properties. I had 100' of falling leaves blue fuse laying around, and was using it to launch my test rockets because I was out of visco, and had failure after failure. Turns out the much hotter, slower burning falling leaves fuse was igniting the balsa and inside of the rocket before igniting the engine resulting in a flaming arrow of death heading skyward. Of course spectators always think you meant to do that while you're grumbling and looking for a small animal to kick.

 

Funny as always, but kids and teenagers always like the flash boomers, so I made one or two to shake their sinuses. I prefered the purple falling leaves myself.

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true, im a fan of long burns :D
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Cool story, I didn't think the long burn would be from fuse. That's pretty cool.

 

Also, you can use VLC Media Player to play the movies. It's free, and small.

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i watched them on windows media player. VERY NICE care to share your formulas? i liked the crackling blue and whistles.
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Wow guys, stop the post whoring. If you don't have anything costructive to say, don't say anything at all. God's Knight, I'm looking at you.
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can you tell me the comp for the black powder propelant you used?
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I have no idea, although I'll try to get some info from Jack (my friend who pressed them) and post in the rocket forum. I'm certain though he insisted they were a straight up BP mix with nothing fancy added such as whistle mix, metal, or flash to spike them (that's what I'll do). He likes to shoot musket balls through watermelons so BP is kind of a given :-)

 

I was amazed at how bright the falling leaves and strobe fuse was for something only the diameter of regular visco - A burning single strand is easily visible a mile away. I assume the green version might have barium nitrate in it, but not sure about the blue or purple. The purple is really nice, but the blue barely has any tint in it all indicating it might need a chlorine donor or something. Might as well change the name to 'cool white' because it sure the hell isn't blue.

 

The crackling stuff is obnoxious in terms noise and sparks thrown. One of my cats also grabbed a long piece of it while I was cutting it and ran off with it. Not sure if dried kitty slobber acts as a chlorine donor, but it went up anways.

 

If you're having trouble viewing the videos, download them first and then open them in media player - seems to work. Something about the codec I used....

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