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Electric Smoke Systems and how to ..

Old 09-05-2017, 11:24 AM
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solentlife
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Default Electric Smoke Systems and how to ..

I have been experimenting with various smoke ignition and had little success.

This came about because supplier didn't provide 'end-caps' for the smoke bombs or the required 'fuse'. All I was supplied was bombs, detonator leads and twin trigger that runs of Rx.

Repeated attempts failed to get a bomb to ignite ... the cap would detonate but it was too short to cause solid fuel to burn.

I researched as much as possible and found out that the bombs should have an end cap to hold the detonator cap to the fuel and its best to have a small piece of conventional fuse in contact with the cap to increase the ignition time ...

Tests today confirmed this works excellently.

I am trying to 3D print the caps ... but so far - my 3D print skills are failing !! But I cut an old credit card to create a pad and with tape secured both cap and short bent fuse wire to the bombs open end ... touched caps leads to a small battery and BINGO ! Near instant smoke.

Once I have a better setup - I will try to video ...



Nigel
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Old 09-05-2017, 06:45 PM
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Wildflyer
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A long time ago I had a friend that fired rockets. He told me that he fixed his ignition problems by scraping the head of matches down into the rocket motor. When the igniter fired, it would light the small amount of match head powder and that lit the rocket motor instantly.
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Old 09-05-2017, 07:07 PM
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I can see that working ...

The problem here is that we have a smoke bomb basically horizontal fixed to UC leg ... we need a solid ignitor ... match powder would be hard to keep in place.

The green fuse you see in photo is a continuous length I bought ... I cut about 1/3" and bend double. This sits against the solid fuel and the detonator cap on top ... with piece of card and tape keeping them in place.

Once I have a flight and test ... I will upload the video ... fingers crossed all goes well.

Nigel
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Old 09-05-2017, 11:05 PM
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The old Jetex motors used a fuse with a thin copper wire through it. I doubt you would be able to get that any more.
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Old 09-06-2017, 07:27 AM
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solentlife
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The fuse I have is similar to the Jetex fuse ...

I contacted a company who provide for pyrotechnics .... they sell in metre lengths ....

Nigel
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Old 09-06-2017, 12:02 PM
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Would it be possible to drill a small hole, the diameter of your green fuse (or a tiny bit smaller) into the center of the smoke bomb? You could then insert a short piece of fuse into the smoke chemical, and use the ignitor to light the fuse. The fuse would have enough contact area to start the smoke, I would think.
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Old 09-06-2017, 12:20 PM
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solentlife
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The solid fuel is extremely brittle and crumbles easily. I tried burying the detonator cap before and it was impossible to get a clean hole without it falling apart.

The fuse wire is cut ... bent in a U ... then the detonator cap placed in the U with tape keeping all in place.

Today I hope to give it an 'flight test' .... video to follow !!

Nigel
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Old 09-06-2017, 07:11 PM
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Flight test .... apologies for out of frame parts - still waiting on my Soloshot 3 !!



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Last edited by solentlife; 09-06-2017 at 07:43 PM.
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