Hey /diy/, I'm building a potato cannon tomorrow and I was

File: image.jpg (80KB, 750x1334px) Image search: [Google]

80KB, 750x1334px

Or would wiring the sparkers in a series be better/even possible? Would multiple gaps cause the circuit to not work?

>>1048287
A piezo igniter generates a spark that can jump [some distance], and the total distance it has to jump (over as many gaps as you want) has to be equal or less than that amount.

If you wired them in series and the total distance was small enough, it would jump all of them.
If you wired several spark gaps in parallel, then it would just jump at the smallest one and the others wouldn't do anything.

Most piezos I've seen only jumped like 1/16 of an inch. And really there is probably no benefit in using multiple spark gaps.
The fuel vapor tends to be heavier than air, so just put a single spark gap near the "bottom" of the chamber (when the cannon is held normally).
If you try dumping in a HUGE amount of fluid, it may not ignite at all as the mix is too rich.

>there is probably no benefit in using multiple spark gaps
Yep. It's a potato cannon, OP, don't overthink it. And things that make sense when you're high don't always translate back to reality.

>>1048286
What the other guys said is correct, but for shits and giggles you could consider using two piëzos. That would then start the combustion at multiple points, which is probably what you are after. By the way, make sure that the end that you are holding is the strongest part, so that if it blows up, you will be fine. I made a potato cannon a while ago, and we really overestimated the amount of fuel that it needs. Really small amounts worked best for us, but it is a trial and error thing to figure out how much it needs. Waiting for a bit (30-60 s) can also help making the gas mixture more homogeneous. And last thing, if it doen't blow, it could still be burning inside. Be careful opening after a misfire, because opening it might cause it to blow since you add more oxygen.

Good luck and have fun!

>>1048328
OP here, it's actually common for multiple sparks to be used in potato cannons. However, these setups use stun guns to provide the power. Sadly, stun guns are illegal where I live and I'm stuck with a bbq lighter for now. Also, upon further research on forums, I found out that you can get 2 sparks with the piezoelectric unit.

I've built many cannons before, but they've all been pneumatic. My best one had two sprinkler valves modified to open by a manual dumping of the air through a single blow gun. Could launch a golf ball in a styrofoam sabot about 1/3 of a mile.

Get in there sunshine

>>1048462
>golf ball in Styrofoam sabot
It is your duty to fire a finned tungsten dart in a sabot now and see how much RHA it can penetrate.

>>1048286
In this config, only one of the gaps will spark

>>1048287
Like that, it will only spark if all the gap's length is less than the maximum distance a single gap will reliably spark.

If you really want a smooth even burn, run turbulent jet ignition. Tough to build, but the results are worth it.

File: ShowImage.jpg (44KB, 758x530px) Image search: [Google]

44KB, 758x530px

Well OP I can't help with the design but here's some ammo