RC Fireracker Lighter and Dispenser

It has been by goal for a few years to design and build a machine that will hold multiple firecrackers, dispense them one by one, and then light them. Not only would this be really cool to just set on the ground and let it run, but my end goal with this idea will be to have it on an RC plane and drop them from the air. Maybe do some ‘bombing runs’ in the field behind my house from like a scale B-25 or something. I recently had an idea of one way to go about it and I have built a very rough prototype.

Before I go any further, I have a note on safety – First, I know this has the potential to be very dangerous. I would never use this device at an AMA sanctioned field, or any other field other than mine for that matter. Like I said, I will only ever use this in my field in a controlled environment. I also know that the plane could catch on fire mid-air, the firecrackers go off in the plane, and more importantly, if not done correctly, a firecracker could land on somebody. I do believe though, that with all the safety measures in place that this can be done safely and responsibly.

Now on to my idea/design . . .

First, this is not the final machine. It has many bugs that need to be worked out, it needs to be built lighter, and most importantly I need to figure out a way I can light the firecrackers in the air. For now I am going to forget the lighting of the firecrackers and I am just going to find a way that I can dispense the firecrackers with no errors.

My design is to build a machine that will dispense the firecrackers in the same way that toothpick holders dispense the toothpick. There will be a rod (most likely wooden) with a groove in it the same depth and width as a firecracker. For now, I am going to say that the firecracker’s diameter is 1/4″ (it is slightly bigger than that though) . So this wooden dowel will have a groove running parallel to the length of the dowel with dimensions of 1/4″ x 1/4″ . This dowel will be placed on the bottom a hopper of sorts in which the firecrackers are stored. As the dowel rotates, one firecracker will fall into the groove. As the dowel continues to rotate, the firecracker, which is in the groove, will fall out of the groove. The dowel will rotate by means of a servo modded to rotate 360 degrees.

So the other night I built my first prototype. Although this will be eventually made of wood, I made a version out of InstaMorph plastic. I did this because it was late at night, it is easy to work with, it gave me a good idea if this design is feasible, and most importantly, it is reusable. If I don’t like the design or something I can melt down the InstaMorph plastic and build something else with it.

Pictures . . .

Problem: Jamming. So far I am having trouble with the firecrackers jamming while trying to dispense. They get lopsided in the hopper and/or get jammed in between the hopper wall and the rotating ‘dowel’. I think my problem is I didn’t build this prototype precise enough – there is too much of a gap in between the ‘dowel’ and the hopper wall. I will build a wooden version with tighter tolerances and hopefully that will help.

Any engineering advice would be greatly appreciated!

And now I leave you with a video . . .